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SECRETARIAT: c/o Groundwater, Geological Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4

Tel. +353.1.678 2874; fax +353.1.6782569; www.geothermalassociation.ie

Chairman Brian Connor, Vice-Chair John Burgess, Secretary Monica Lee & Taly Hunter Williams, Treasurer Marie Keane,

Editor Gareth Ll. Jones, International Liaison Róisín Goodman, Developments Paul Sikora, Events Officer Alistair Allen, James Byrne

The Geothermal Association of Ireland was formed in January 1998.

To Promote the Development of Geothermal Resources in Ireland. The GAI is a member of the

European Geothermal Energy Council and of the International Geothermal Association.

Issue No. 17 AUGUST 2010

SPECIAL EDITION

The World Geothermal Congress 2010

Bali, Indonesia

WGC 2010 2

World Geothermal Congress, Nusa dua Bali, 25th – 30

th April, 2010, Róisín Goodman 3

The Seven Irish papers presented at WGC2010 6

Note there is no newsletter pagination for these papers

157. Developments in Geothermal Utilisation in the Irish Republic

Alistair Allen, John Burgess

315. GTR-H - Geothermal Legislation in Europe

Goodman, R., Pasquali, R. Dumas, P., Hámor T., Jaudin F., Kepinska, B., Reay, D.,

Rueter, H., Sanner, B., Van Heekeren, V., Bussmann, W., Jones, G.Ll.

630. Glucksman Art Gallery, University College Cork, Ireland: Innovative Space Heating Development

Kondwani T. Gondwe, Alistair Allen, John Burgess, Donal Browne and Paul Sikora

1156. Investigation of Source and Conduit for Warm Geothermal Waters, North Cork, Republic of Ireland.

Brecan Mooney, Alistair Allen, Paul K!niger

1159. Low Enthalpy Geothermal Resources of Ireland Maps Encourage Geothermal Projects

Gareth Ll. Jones, Róisín M. Goodman, John G. Kelly

1614. Methodology in Assessment and Presentation of Low Enthalpy Geothermal Resources in Ireland

Róisín Goodman, Gareth Ll. Jones, John G. Kelly

1625. The Geothermal Potential of Northern Ireland

R. Pasquali, N. O’Neill, D. Reay, T. Waugh

Other papers

905. Geotrainet – A New European Initiative for Training and Education of Planners,

Drillers and Installers of Geothermal Heat Pumps

Burkhard Sanner, Philippe Dumas, Isabel Fernandez Fuentes, Manuel Regueiro

166. Country Update for the United Kingdom

Tony Batchelor, Robin Curtis, Peter Ledingham

1638 Geothermal Prospects in the United Kingdom. Abstract page

Jon Busby

3145 Revisiting Deep Geothermal Power in the United Kingdom. Abstract page

Ryan Law, Tony Batchelor and Pete Ledingham

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WGC2010

Four Irish delegates: Róisín Goodman, Alistair Allen, Riccardo Pasquali and Kondwani Gondwe travelling

from Malawi, as well as several thousand others, attended WGC2010 in Bali, Indonesia to present their

papers and a poster was also displayed.

This special edition of the GAI Newsletter compiles the seven Irish papers that were delivered, plus the

poster of paper 1159.

It also carries the GEOTRAINET paper since Ireland is a partner in that project. Finally we carry the UK

update and the abstract pages of the two other UK papers which carry Northern Ireland map data, but no

write up of any Northern Irish activity.

The whole is introduced by an account of the Congress and of the thrust of the presentations by Róisín,

illustrated with some of Ric’s photographs.

Opening Ceremony of the World Geothermal Congress April 2010, Bali, Indonesia,

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THE WORLD GEOTHERMAL CONGRESS, WGC2010

NUSA DUA BALI, 25TH

– 30TH

APRIL, 2010

Róisín Goodman, SLR Consulting

The tropical island of Bali at the southern end of the

Indonesian archipelago was the setting for the 2010

World Geothermal Congress. There was a turnout of

2,168 attendees at the conference - up from around

1,000 in Antalya, Turkey in 2005. By all accounts the

conference was a success in attracting key worldwide

geothermal industry players as well a providing a

broad snapshot of the state of the world geothermal

industry and research developments in 2010. There

were a total of 1,032 papers presented in 312 sessions

in the congress venue at the Westin Conference centre

on the Nusa Dua peninsula at the south of the Island.

Given the location of the congress there was an

understandably strong flavor of high enthalpy

resources and electricity but all aspects of geothermal

were very well represented with 17 sessions (5 papers

per session) on heatpumps, district heating, direct use

and hydrogeology. Many other relevant papers were

presented in sessions on exploration, geology,

geophysics, legal and regulatory, environmental and

societal aspects, case studies and of course the country

updates.

Opening addresses by the Presidents of Iceland and of Indonesia

There were also many interesting presentations on

innovative applications and new almost futuristic

technology ideas, such as undersea power generation

in areas of high enthalpy some of which were seeking

funding for demonstration projects. Due to the

number of papers one had to be very selective in

deciding which to attend. I will not focus on the

papers here, particularly as the papers of direct Irish

interested are reprinted in this newsletter in full.

Other papers can be accessed through a search of the

relevant topic on the IGA website, using the link

http://www.geothermal-

energy.org/304,iga_geothermal_conference_database.

html

Some of the special guest speakers at WGC2010 were

the Indonesian President Susilo Bambang

Yudhoyono, the President of Iceland, Olafur Ragnar

Grimsson; the Indonesian Minister of Energy and

Mineral Resources, Dr. Darwin Zahedy Saleh and the

president of International Geothermal Association

(IGA), Ladislaus Rybach.

Striking the ceremonial gong to open the Congress.

For the international audience the official opening of

the Congress by the Indonesian President Yudhoyono

was a particular honour and gave a strong

endorsement of the future of geothermal development

in Indonesia. According to the President’s address as

reprinted in the ‘WCG2010 Daily News’ Indonesia is

aware of the importance to develop renewable and

environmentally-friendly energy and will facilitate the

development of geothermal projects to generate

electricity. Indonesia is currently only using 1,100

MW, some 4.2% of geothermal reserves in the

country, which constitutes about 40% of the world’s

geothermal potential. “This is going to change. It is

my intention that Indonesia will become the largest

user of geothermal energy,” Yudhoyono added.

Indonesia already have in place a set of long term

policies for the development of geothermal energy, as

embodied in the Geothermal Development Roadmap

of 2004-2025. Indonesia envisions that by 2025, about

five percent of Indonesia’s national energy needs, will

be met through the use of geothermal energy.

As is the custom of the WGC a cultural night was held

to showcase the best of local traditions. For

WGC2010 this was held at the famous Garuda Wisnu

Kencana and featured the ‘Bayu Pertiwi’ (the force of

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nature) dance specially created for the World

Geothermal Congress 2010.

According to the concept developer and script writer,

Dr. Herman Darnel Ibrahim, the idea of the dance

emerged from the need to portray geothermal as a

clean energy capable of creating happiness and

prosperity without changing Bali’s strong culture. The

result is a colossal dance involving more than 200

dancers. The dance was choreographed by Dr. Ni

Made Ruastiti, a senior lecturer at the island’s most

famous dance institution in Denpasar. The epic dance

performance lasted about 30 minutes. It was a

spectacular event with typically Balinese costumes

and dance styles – a true feast for the eyes.

The Garuda Wisnu Kencana venue is a stunning

‘natural’ amphitheatre - the remains of a cut stone

quarry with vertical walls of 8-10m.

The warm evening atmosphere was perfect for an

outside performance and was matched in equally large

measures by adornment of the venue and uniquely

Balinese etiquette of the hosts - an unforgettable

evening. The torrential tropical rain that dowsed the

participants and audience from about 15 minutes into

the performance did not shortcut the evening – though

the chairs were a little soggy.

José Martins Carvalho, Portugal copes with the rain!

There was general satisfaction with the congress not

least in its rapidly growing audience despite world

recession. WGC2010 was hailed as happening at a

crucial moment in the move toward the enhancement

of geothermal use throughout the world with the

geothermal industry in a strong upward development

cycle. All in all the congress will be a hard act to

follow for the 2015 hosts Australia and New Zealand.

The Australian Geothermal Energy Group (AGEG), the Australian

Geothermal Energy Association (AGEA) and the New Zealand

Geothermal Association (NZGA) invite you Down Under in 2015

for the next World Geothermal Congress.

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The organising committee with IGA President Ladsi Rybach in the centre.

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The Irish Papers

Alistair & John deliver the Ireland update which

carries a wealth of information on the most recent

developments while showing the present state of

geothermal activity.

Róisín and her partners presents the final report on the

GTR-H project dealing with geothermal regulation for

heat across Europe.

It is good to see the detailed work that Kondwani and

the team have done on the Glucksman Gallery

outlined here.

The presentation of the results of Brecan’s work on

the warm springs conduit in north Cork, completed

just before he died is a poignant reminder of his loss.

We are grateful that we have a record of his work.

Gareth suggests that the work done for SEI has paid

off with the development of projects around Ireland.

This is also seen as a poster.

In an important paper, Róisín’s group describes the

methodology that was used in the SEI study and

which may be applicable in other places.

Finally Riccardo and colleagues look at the

geothermal resources of Northern Ireland and in

particular at the reservoir potentials.

GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI

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Proceedings World Geothermal Congress 2010

Bali, Indonesia, 25-29 April 2010

1

Developments in Geothermal Utilization in the Irish Republic

Alistair Allen1, John Burgess

2

1Dept of Geology, University College Cork, Cork, Ireland

2 Arup Consulting Engineers, 16 Oliver Plunkett St., Cork, Ireland

a.allen@ucc.ie; john.burgess@arup.com

Keywords: heat pumps; low enthalpy

ABSTRACT

Geothermal energy exploitation in Ireland has expanded

rapidly over the last few years, despite low geothermal

gradients (<25oC/km) and limited geothermal resources.

Emphasis is on exploitation of low temperature resources

for space heating, employing heat pump technology, but a

major new development is the first deep drilling project to

source warmer water at depth for district heating projects,

with a trial well drilled to over 1.3 km in the western

suburbs of Dublin.

There has been a huge increase in the number of heat pump

units installed in Ireland, since the last update in 2004,

which now stands at approximately 9500 units. Take up has

been mainly in the domestic market, with most heat pumps

approximately 15 kW in size, but the number of larger scale

installations ranging from about 100-450 kW servicing

public buildings and institutional/commercial premises is

increasing rapidly, and a few even larger developments

have been recently installed or are in progress. Recently

completed, a 3 MW open loop system at the Athlone City

Centre Retail Complex is the largest individual geothermal

space heating project in the country. Most domestic systems

employ horizontal closed loop collectors, with the more

expensive vertical closed loop collector systems mainly

employed in urban areas where space is at a premium. Open

loop collectors are less popular in the domestic market but

preferred for larger systems, particularly in areas underlain

by shallow gravel and karst aquifers, and enhanced in urban

situations by slightly magnified groundwater temperatures

due to the ‘heat island’ effect. A few projects have also

employed open loop systems exploiting surface water

sources such as ponds and reservoirs, where these exist.

Current total geothermal energy usage in the form of heat

pump capacity is estimated at 164 MW.

The rapid take up of heat pumps in the domestic market has

largely resulted from the introduction from 2006 of various

government grant schemes for renewables including GHP’s

to provide incentives to individual householders and

developers to incorporate geothermal and other renewable

energy systems into new or existing buildings. Another

important recent government initiative has been a wide

ranging consultation process with geothermal stakeholders

as the initial step in bringing in regulatory controls to guide

the development of geothermal energy in Ireland, and

Ireland is also involved in the GTR-H project to standardize

geothermal regulations throughout the EU. A further

significant development is the initiation by Irish higher

level institutions of new undergraduate and graduate degree

programs in energy engineering, with geothermal energy

and heat pump technology part of the curricula.

1. INTRODUCTION

Concerns about greenhouse gas emissions and its

relationship to climate change, together with uncertainties

regarding peak oil and security of supply of oil and gas has

led the Irish Government in the last 4-5 years to heavily

promote the development of renewable energy. Even so, in

2007, 96% of all energy used in Ireland (population ~ 4.5

million) was generated by fossil fuels (Howley et al,

2008a), with only a little over 1.5% generated by

renewable, mainly wind and solid biomass. About 33% of

the total primary energy supply in Ireland in 2007 was used

for thermal purposes (space, process and water heating and

also cooking), with a renewable energy contribution of

3.5%. Targets for future renewable energy contributions for

2010 and 2020 are 5% and 12% respectively (Howley et al,

2008a; 2008b). Of thermal energy usage, the residential

sector accounts for the largest share (42%). and use of

renewable energy for home heating represented 13% of the

total renewable energy thermal energy usage in Ireland in

2007, although geothermal energy contributed only 0.3% of

this amount (Howley et al, 2008a; 2008b). Furthermore,

from 1990 to 2007, total CO2 emissions increased by 51%

(Howley et al, 2008a), significantly exceeding Irelands

Kyoto Protocol commitment of maintaining CO2 emissions

to 13% above 1990 levels by 2012 (Fig. 1).

Nevertheless, geothermal energy exploitation in Ireland has

expanded rapidly over the last few years, despite low

geothermal gradients and limited geothermal resources

apart from 42 warm springs concentrated in two groups, in

the SW and E of the country. Emphasis is on exploitation of

low temperature resources for space heating, employing

heat pump technology, but a major new development is the

first deep drilling project to source warmer water at depth

for district heating projects, with a trial well drilled to over

1.3 km in the western suburbs of Dublin.

The main agencies involved in the development of

geothermal energy in Ireland are the Geothermal

Association of Ireland (GAI), Sustainable Energy Ireland

(SEI), the Geological Survey of Ireland (GSI), 15 energy

agencies throughout Ireland, (O’Brien 2001), the Irish

Association of Hydrogeologists (IAH), and some private

companies. The GAI is a voluntary organization consisting

of professionals from both the commercial and academic

sectors with various backgrounds including geologists and

hydrogeologists, service and mechanical engineers, heat

pump suppliers and installers, well-drillers and lawyers. Its

aim is to promote awareness and utilization of geothermal

energy in Ireland. Of the 15 energy agencies, the most

active are in the Cork area. SEI is an Irish government

organization set up in 2002 with a mission to promote and

assist the development of sustainable energy in the Irish

Republic.

Allen and Burgess

2

2. GEOLOGY BACKGROUND

Ireland generally consists of a mountainous rim composed

of Precambrian to Lower Palaeozoic crystalline rocks

surrounding a lowland interior largely underlain by U.

Devonian to L. Carboniferous sandstone, shale and

limestone (Figs. 2 & 3). Late Palaeozoic, Mesozoic and

Tertiary rocks are absent, apart from in the NE corner of the

island, where they are preserved beneath the basalt plateau

of the 50-60 Ma Tertiary North Atlantic Igneous Province

associated with the opening of the North Atlantic. However,

there is evidence that they were also deposited over much

of the rest of the island, but were stripped away by the

intense erosion and peneplanation which accompanied the

opening of the North Atlantic.

Fig. 1: Trend in Annual GHG Emissions for the Period 1990 to 2007 (Howley et al, 2008)

Fig. 2: Landsat Topographic Map of Ireland showing

tectonic boundaries referred to in the text.

KMFZ - Killarney-Mallow Fault Zone

Fig. 3: Geological Map of Ireland. L. Carboniferous

limestone (pale blue) underlies much of the

interior of the country

IAPETUS

SUTURE

KMFZ

Allen and Burgess

3

U. Palaeozoic bedrock, whilst underlying much of the

interior of Ireland, is generally buried beneath a cover of

Pleistocene glacial till and Holocene peat deposits, and is

rarely exposed. Widely developed L Carboniferous

limestone (Fig. 3) is extensively karstified, but overburden

deposits are relatively thick and surface expression of karst

is generally absent. Thus, most of Ireland’s limestone

bedrock consists of buried karst.

Ireland lies within the Caledonian orogenic belt (Fig. 4),

which affected all Precambrian and L. Palaeozoic units. The

Iapetus Suture (Fig. 2), marking the collision zone of

Laurentia and Avalonia, runs diagonally across Ireland

from the Shannon estuary to Clogher Head, 50 km to the

north of Dublin. All of the warm springs in the Irish

Republic lie to the south of this tectonic line.

The late Carboniferous Variscan (Hercynian) Orogeny

affected the very south-west of Ireland, which represents

the westernmost extension of the external Rheno-Hercynian

Zone of the Variscan Orogenic Belt. Its northern boundary,

the Variscan Front, is the Killarney-Mallow Fault Zone

(KMFZ), which runs E-W, midway between the south coast

of Ireland and the Shannon estuary (Fig. 2). The

southwestern group of warm springs are all situated just to

the north of this tectonic boundary.

3. GEOTHERMAL RESOURCES AND POTENTIAL

Due to its within-plate setting distant from plate boundaries,

and an absence of recent volcanism or tectonism,

geothermal gradients in the Irish Republic are low

(<25°C/km) (Goodman et al, 2004). Thus Ireland is

unlikely to possess any high temperature geothermal

resources. Typical groundwater temperatures in Ireland

vary from approximately 10-12°C, whilst soil temperatures

are between 8-12°C Aldwell (1997). These temperatures

reflect the balance between solar and geothermal recharge,

and radiation from the ground surface as quantified by

Aldwell & Burdon (1986), and remain relatively constant

throughout the year due to Ireland’s temperate maritime

climate. Modern heat pump technology allows heat to be

extracted from soil and groundwater at these low but

consistent temperatures, in Ireland mainly for space heating

and cooling uses.

Springs, seepages and spring wells are ubiquitous in

Ireland, particularly in Dinantian limestone bedrock that

underlies much of the Irish midlands. Potentially

exploitable geothermal resources occur where relatively

warm groundwater (>13oC) is able to rise rapidly to the

surface (Aldwell, 1996), discharging as low enthalpy

geothermal springs. 42 of these warm springs, mainly

located in limestone, and ranging in temperature from 13-

24.7°C have been recorded (Aldwell & Burdon, 1980;

Burdon, 1983; Brück et al, 1986; Aldwell 1996; Goodman

et al, 2004), and are concentrated in two groups in the east

and southwest of the country (Fig. 5). One of the earliest

recorded warm springs in Ireland occurs at Mallow in the

southwest, where the spring at Lady’s Well gave rise, in the

18th and 19th Centuries, to a spa resort. Apart from this

spring, which has more recently been harnessed to heat the

municipal swimming pool (O’Brien, 1987), little utilization

of these warm water energy resources has taken place,

mainly because of the rural settings in which most occur,

that in the past has limited potential options for their

exploitation.

Geothermal gradients in the island of Ireland generally

increase from SW to NE, from lows of approximately

10°C/km in the south to highs associated with the Tertiary

igneous activity in the NE, where a maximum of 35°C/km

has been measured (Goodman et al, 2004). Low yields of

relatively hot water at 88°C were encountered in the early

1980’s in a borehole to 2.8 km depth at Larne to the NE of

Belfast, within the Permo-Triassic Sherwood Sandstone, an

aquifer widespread in Britain, but only present in Ireland in

the extreme NE preserved beneath the Tertiary Basalt

plateau. This temperature represents a geothermal gradient

of about 27.5°C/km.

Fig. 4: Irelands Tectonic Setting.

Allen and Burgess

4

Fig. 5: Location of Warm Springs and Large Scale Installations in Ireland.

In the Irish Republic, conditions for generation of hot water

at depth are not favorable, but the presence of 42 warm

springs, indicates that aquifers do occur at depth, and that

moderate geothermal resources, which could be exploitable,

do exist. A borehole drilled to 1.4 km in the western

suburbs of Dublin in 2008 encountered warm water at

46.2°C, representing a geothermal gradient of about

26.5°C/km. At the borehole location, a thick overlying layer

of impermeable shales blankets and insulates the underlying

aquifer.

Also, a well drilled for water supply purposes by Cork

County Council in 2003 at Johnstown in the Glanworth area

of North Cork in the southwest encountered, at a depth of

40m, warm groundwater at temperatures of 23-26°C. This,

the warmest shallow groundwater as yet recorded in the

Republic of Ireland, probably represents groundwater from

a depth in excess of 1.5km, which has migrated rapidly up a

fault conduit (Mooney et al, this volume). Finally, a well

drilled on University College Cork campus within gravels

close to the northern margin of the Lee Buried Valley

(Allen et al, 1999) intersected limestone bedrock at 20m

and encountered water with an anomalous temperature of

19-20°C. A caliper log of the borehole revealed a parallel

temperature and conductivity increase downwards,

indicating that the warm groundwater is not of

anthropogenic origin and comes from the limestone

bedrock, probably also representing groundwater from

depth that has migrated up a fault conduit.

4. GEOTHERMAL UTILIZATION

Since Ireland has no high temperature geothermal

resources, there is no electricity generation in the republic.

Generally direct heat usage involves extraction of low

enthalpy heat, which is employed with heat pumps mainly

for space heating. As indicated above, none of Irelands

warm springs are exploited apart from the Lady’s Wells

spring at Mallow, which with the aid of a heat pump is used

to heat the municipal swimming pool (O’Brien, 1987), the

first exploitation of geothermal energy in Ireland.

There has been a huge increase in the number of domestic

heat pump units installed in Ireland, since the last update in

2004, and this now stands at approximately 9,500 units as

of September 2009, with a further 300 installations in

progress. This is an increase of about 8,000 installations in

the last 5 years, brought about mainly due to the

introduction by SEI of the Reheat and Greener Homes

Grant Schemes in 2006, which aim to increase the use of

sustainable energy technologies within both public and

commercial buildings, and in domestic dwellings. The

grants cover, amongst other space heating technologies,

heat pumps using horizontal or vertical closed loop, well

water open loop or air source collectors. Of the different

GSHP collector systems, horizontal closed loop are the

most popular (67.5%) followed by vertical closed loop

(30%), and open loop (2.5%).

The popularity of horizontal closed loop systems is

governed by the fact that Ireland has a high proportion of

domestic dwellings with gardens, so space is available for

horizontal collectors which are considerably cheaper to

install than vertical collectors. In addition, horizontal heat

collectors are very efficient due to Ireland’s temperate

maritime climate with its limited annual temperature range

and abundant year round rainfall. Therefore there is little

annual variation in soil temperature below depths of about

50 cm and soil moisture contents are typically high, so

conditions are ideal for shallow horizontal collectors.

Vertical closed loop collectors are more common in cities

where space is at a premium, but are considerably more

expensive to install, although they attract larger grants from

SEI. A small number of domestic units operate with open

loop collectors, where a suitable aquifer underlies the site.

A significant proportion of domestic heat pumps (>1500)

employ an air source, which may reflect a lack of

understanding of the principles of heat pumps by the

homeowner or misleading advice by the installer.

Commercial heat pump installations are far less common

than domestic units, but show a significant increase since

the previous update report (O’Connell et al, 2005).

Approximately 30 commercial GSHP projects have

Allen and Burgess

5

benefited from the SEI Reheat grant scheme, and another

10 public projects have been grant aided by the SEI Public

Sector Program.

Most commercial heat pump projects have relatively small

capacities being less than 50 kW, but quite a few are larger

than 100 kW ranging up to a 3 MW system commissioned

recently at Athlone city centre retail complex. In general,

Cork leads the way in GHP development, with Cork City

Council and UCC taking advantage of the combination of a

shallow gravel aquifer underlying Cork (Allen & Milenic,

2003), and the ‘heat island’ effect (Allen et al, 2003). A

significant number of public buildings in Cork are now

heated by GHP systems. The flagship projects are a 200 kW

open loop system heating and cooling an art gallery on

UCC campus (Gondwe et al, this volume), a 1 MW open

loop system heating a new IT complex at UCC, an 88 kW

open loop system at the UCC Environmental Research

Institute (ERI), and a 450 kW open loop system at the new

Cork County Library. In addition, the Electricity Supply

Board, the semi state body which until recently has had a

monopoly on Irish electricity supply has also installed a 250

kW open loop GHP system at its Cork headquarters. Fig. 5

shows the locations of some of the larger commercial

GSHP installations

Few retrofit systems have been undertaken in Ireland, but of

note are three installations. The first is the conversion of the

Swedish Ambassadors residence in Dublin, where a 21 kW

heat pump with vertical closed loop heat collectors installed

in 3 x 130 m boreholes, is delivering 60°C water to existing

radiators and some additional under-floor heating areas. In

Cork, the Lifetime Lab is a 19th century waterworks pump

house complex, which has been converted to an educational

and conference centre with a 70 kW open loop system

operating with under-floor heating. The Fermoy Leisure

Centre in County Cork is a swimming pool complex, which

has been converted to geothermal via a 160 kw open loop

heat pump system.

The current estimate by SEI of heat pump capacity in the

Irish Republic is 164 MW as of the end of 2008. The

majority of systems are in domestic dwellings, with a total

capacity of 148 MW, whilst installations in public buildings

and commercial premises account for 16 MW total

capacity. The average installed load capacity is about 15

kW for domestic dwellings, and of the order of 55 kW for

public and commercial buildings

A major development in Ireland is the first deep geothermal

exploration project since the Larne borehole in 1982. This

borehole mentioned earlier was sunk in 2008 into the

Dublin Basin at Newcastle in the western suburbs of Dublin

in search of geothermal water for a potential commercial

district heating scheme. The borehole reached a depth of

1.337 km encountering groundwater with a temperature of

46.2°C. Although a porosity of 22% has been established

for the host rock, no hydraulic conductivity has been

determined. Owing to a slump in the construction industry,

resulting from the economic downturn in Ireland, this

project has progressed no further. University College

Dublin (UCD) is also investigating the feasibility of drilling

a deep borehole into the Dublin Basin on its Belfield

campus in the SE of Dublin to generate a campus district

heating scheme.

5. DISCUSSION

The capacity factor for Irish heat pump installations (Table

1) is low due to the mild climate and the design of the heat

pump systems. Heating is only required for 8 months of the

year and air conditioning is not required for the domestic

sector. The average annual air temperature is 9°C. The

average mean daily minimum temperature in winter is

2.5°C. Average annual ground temperatures are of the order

of 10ºC. Heat pump installations are designed to operate on

the cheaper night rate electricity during the winter and so

the compressor would be switched on for 7 hours out of 24.

Heat is delivered to the building by under floor heating and

so discharged slowly throughout the day.

Air conditioning is generally achieved by direct cooling,

which circulates fluid from the collector in coils or circuits

installed in the building ceilings or floors. Reversible heat

pumps are typically used, but in many commercial building

applications conventional water cooled chillers connected

to heated and cooled buffer vessels are common. As the

ground or water temperature is sufficiently low during the

summer direct cooling can be used to provide some cooling.

The installed capacity estimate is based on the projected

cooling load for the building. Requirements for air

conditioning or summer cooling are generally less than half

the winter heating load.

A number of swimming pool projects (Table 2) use heat

pumps not direct heating. The Fermoy pool, commissioned

in 2008, is the largest. The capacity factor, estimated at

0.311, is larger than the other space heating installations

because the heating demands of the swimming pool and

showers are much greater.

The number of professional people involved in geothermal

in Ireland is shown in Table 3. The majority work in GSHP

and the rapid growth in the GSHP industry can be seen

through the dramatic increase in installers and consultants

working in the industry. Almost 350 installers, mainly

plumbers, are registered with SEI, but the majorities are not

solely employed in the GSHP sector, and most probably

have limited specialized training in heat pump systems.

Similarly, a significantly increased number of HVAC

consulting companies have become involved in the design

of geothermal systems, but their portfolios would not be

restricted to geothermal, so in Table 7 an estimate of full-

time equivalent persons has been entered. There are

however a limited number of small dedicated geothermal

consultants.

There are no dedicated persons working on geothermal or

GSHP in state funded organizations such as SEI and the

local Energy Agencies, but over 50% of enquiries received

regarding renewable energy are about GSHP, and 23% of

applications under the Greener Homes Scheme have been

for heat pump grants. Again a nominal number of full-time

equivalents are entered in Table 2.

In Universities and Institutes of Technology, postgraduate

research has been conducted on GSHP collector efficiency

(e.g. Lohan et al, 2006), on optimal configurations of GSHP

collectors (Liddy, 2008) on general assessment of the

technology (O’Connell, 2004), and on performance analysis

of installed heat pump systems (Gondwe et al, this volume).

Geological aspects of geothermal such as delineation of

fault conduits controlling ascent of geothermal waters

(Mooney et al, this volume), and the impacts of GSHP

groundwater withdrawals on saline/freshwater relations in

estuarine environments and on subsidence in clays in

interlayered clay/gravel sequences are also being

investigated. Estimates of investment in geothermal is

indicated in Table 4.

Allen and Burgess

6

Table 1: GSHP Heat Pump Installations

Locality Ground or Typical Heat Pump Number of Type2)

COP3)

Htg & Clg Thermal Cooling Electrical

water temp. Thermal Rating Systems Equivalent Energy Energy Energy

Htg / Clg Capacity Full Load Used Used Input

(oC)

1) (kW) Hr/Year

4)(TJ/yr) (TJ/yr) (TJ/yr)

Domestic Installations Nationwide 10 15 9500 H 3.5 1363 699.0480 0.0000 199.7280

Dolmen Centre, co. Donegal 10 45 1 H 3.5 1363 0.2208 0.0000 0.0631

Tralee Motor Tax Office, Co Kerry 10 120 1 H 3.5 1922 0.8304 0.2418 0.2373

SHARE Hostel, Cork 15 120 1 W 3.5 1363 0.5887 0.0000 0.1682

UCC Glucksman Gallery, Cork 15 200 1 W 3.65 1922 1.3841 0.4030 0.3797

Fexco HQ, Killorglin, Co Kerry 11 310 1 W 3.65 1922 2.1453 0.6246 0.5885

Glenstal Abbey, Co Limerick 10 150 1 W 3.5 1363 0.7358 0.0000 0.2102

Musgrave HQ, Cork 10 160 1 V 3.65 1922 1.1073 0.3224 0.3037

Killarney International Hotel, Co Kerry 11 60 1 W 3.5 1363 0.2943 0.0000 0.0841

Cork Co Council Environmental Labs 11 90 1 W 3.5 1363 0.4415 0.0000 0.1261

Cliffs of Moher Visitor Centre, Co. Clare 10 120 1 H 3.5 1363 0.5887 0.0000 0.1682

Killorglin Town Centre, Co Kerry 11 160 1 W 3.65 1922 1.1073 0.3224 0.3037

Fermoy Leisure Centre, Co Cork 11 160 1 W 3.5 2725 1.5698 0.0000 0.4485

Tory Top Road Library, Cork 13 80 1 W 3.5 1363 0.3924 0.0000 0.1121

Coraville, Blackrock, Cork 13 36 1 W 3.5 1363 0.1766 0.0000 0.0505

Castleisland, Co Kerry 11 135 1 W 3.5 1363 0.6623 0.0000 0.1892

ESB Administration Offices, Cork 13 250 1 W 3.65 1922 1.7301 0.5037 0.4746

Cork County Library, Cork 13 450 1 W 4.00 560 0.9067 0.9067 0.2267

Swedish Ambassador’s Residence, Dublin 12 21 1 V 3.5 1363 0.1030 0.0000 0.0294

Cowper Care, Kilternan, Dublin 8 100 1 V 3.5 1363 0.4906 0.0000 0.1402

Cowper Care, Rathmines, Dublin 8 66 1 V 3.5 1363 0.3238 0.0000 0.0925

Cowper Care, Dublin 11 86 1 V 3.5 1363 0.4219 0.0000 0.1205

Vista Health Care, Naas, Co Kildare 10 400 1 W 3.65 1922 2.7682 0.8059 0.7593

UCC Western Gateway IT Building, Cork 15 1000 1 W 3.65 1922 6.9204 2.0148 1.8983

Athlone City Centre Retail Complex, Westmeath 10 2786 1 W 3.65 1922 19.2802 5.6132 5.2887

Lifetime Lab, Cork 12 70 1 W 3.5 1363 0.3434 0.0000 0.0981

Bagenalstown Swimming Pool, Co. Carlow 11 18 1 W 3.5 1363 0.0883 0.0000 0.0252

Croi Anu Creative Centre, Co. Kildare 10 8 1 H 3.5 1363 0.0392 0.0000 0.0112

Rathmore Community Childcare, Co. Kerry 11 12 1 V 3.5 1363 0.0589 0.0000 0.0168

Treacys Hotel Co. Wexford 11 450 1 V 3.65 1922 3.1142 0.9067 0.8542

Fairy Bush Childcare Centre, Co Roscommon 11 23.5 1 V 3.5 1363 0.1153 0.0000 0.0329

Tinnypark Nursing Home, Co. Kilkenny 10 32 1 H 3.5 1363 0.1570 0.0000 0.0449

Goretti Quinn Creche, Co. Kildare 11 12 1 V 3.5 1363 0.0589 0.0000 0.0168

CloCeardlann na gCnoc, Co. Donegal 10 18.3 1 H 3.5 1363 0.0898 0.0000 0.0256

St John's National School, Co. Mayo 10 14.2 1 H 3.5 1363 0.0697 0.0000 0.0199

Dubin Dockland Development Authority 12 17.5 1 H 3.5 1363 0.0858 0.0000 0.0245

Dunmore House Hotel, Co. Cork 11 18 1 W 3.5 1363 0.0883 0.0000 0.0252

Comhaltas Cosanta Gaeltachts Chuil Aodha, Cork 11 16 1 V 3.5 1363 0.0785 0.0000 0.0224

David Cuddy, Rathbranagh, Co. Limerick 11 11.5 1 V 3.5 1363 0.0564 0.0000 0.0161

Skeaghanore Farm Fresh Duck, Co. Cork 11 12 1 V 3.5 1363 0.0589 0.0000 0.0168

Kanturk Sheltered Housing, Co. Cork 11 8.3 1 V 3.5 1363 0.0407 0.0000 0.0116

Comhlacht Forbartha an Tearmainn, Co. Donegal 11 33.6 1 V 3.5 1363 0.1648 0.0000 0.0471

Feohanagh Special Needs Housing, Co Limerick 11 17 1 V 3.5 1363 0.0834 0.0000 0.0238

CLS Rosmuc, Co. Galway 10 19.8 1 H 3.5 1363 0.0971 0.0000 0.0278

Vicarious Golf, Co. Wicklow 10 13 1 H 3.5 1363 0.0638 0.0000 0.0182

Inis Oirr Health Centre, Co. Galway 10 12 1 H 3.5 1363 0.0589 0.0000 0.0168

Children's and Adults Respite Centres, Co. Galway 11 21 1 V 3.5 1363 0.1030 0.0000 0.0294

Kilcurry Community Development, Co. Louth 11 17 1 V 3.5 1363 0.0834 0.0000 0.0238

Ardara Community Childcare, Co. Donegal 11 22.1 1 W 3.5 1363 0.1084 0.0000 0.0310

Seawright Swimming School Co. Cork 11 31 1 W 3.5 1363 0.1521 0.0000 0.0434

Cope Foundation, Bandon, Co. Cork 11 30 1 V 3.5 1363 0.1472 0.0000 0.0420

Parklands Apartment Development, Co. Wicklow 11 40 1 V 3.5 1363 0.1962 0.0000 0.0561

Ballyconnell Central National School, Co. Cavan 11 12 1 V 3.5 1363 0.0589 0.0000 0.0168

James B Joyce & Co, Co. Galway 11 18.3 1 V 3.5 1363 0.0898 0.0000 0.0256

Poor Clare Monastery, Co. Louth 11 18 1 W 3.5 1363 0.0883 0.0000 0.0252

Tralee Community Nursing Unit, Co. Kerry 11 100 1 V 3.5 1363 0.4906 0.0000 0.1402

Brook Lodge Hotel, Co Wicklow 10 134 1 H 3.5 1363 0.6574 0.0000 0.1878

Hudson Bay Hotel, Athlone, Co. Westmeath 11 132 1 W 3.5 1363 0.6475 0.0000 0.1850

Hotel Europe, Killarney, Co. Kerry 10 110 1 W 3.5 1363 0.5396 0.0000 0.1542

Rathass Housing Estate, Tralee, Co. Kerry 8 70 1 H 3.5 1363 0.3434 0.0000 0.0981

Whites Hotel, Wexford 10 21 1 H 3.5 1363 0.1030 0.0000 0.0294

Belinter Hotel, Navan, Co. Meath 10 306 1 H 3.65 1922 2.1176 0.6165 0.5809

Bellview Woods Childcare, Killarney, Kerry 8 30 1 H 3.65 1922 0.2076 0.0604 0.0569

D&G Electrinics Ltd, Castleisland, Co Kerry 8 21 1 H 3.5 1363 0.1030 0.0000 0.0294

Oilgate Nursing Home 8 100 1 V 3.5 1363 0.4906 0.0000 0.1402

Youghal Town Hall, Co Cork 8 21 1 V 3.5 1363 0.1030 0.0000 0.0294

151696.1 756.0798 13.3420 215.5126

Allen and Burgess

7

Table 2: Summary Table of Direct Heat Use

Use Installed Capacity1)

Annual Energy Use2)

Capacity Factor3)

(MWt) (TJ/yr = 1012

J/yr)

Individual Space Heating4)

None

District Heating 4)

None Air Conditioning (Cooling) 6.622 13.342 0.064 Greenhouse Heating NoneFish Farming None Animal Farming None

Agricultural Drying5)

None

Industrial Process Heat6)

None Snow Melting None

Bathing and Swimming7)1.452 7.9078 0.173

Other Uses (specify) None Subtotal 8.074 21.2498 0.083

Geothermal Heat Pumps (Heating) 151.696 744.1605 0.156

TOTAL 159.770 765.4103 0.152

Table 3: Allocation of Professional Personnel

Year Professional Person-Years of Effort

(1) (2) (3) (4) (5) (6)

2005 10 (equiv.) None None None None 10 (equiv)2006 15 (equiv.) None None None None 20 (equiv)2007 15 (equiv.) None None None None 30 (equiv)

2008 15 (equiv.) None None None None 40 (equiv)2009 15 (eqiuiv) None None None None 50 (equiv)

Total 70(equiv) None None None None 150 (equiv)

Table 4: Total Investments in Geothermal

Research & Field Development Utilization Funding Type Period Development Including Production

Incl. Surface Explor. Drilling && Exploration Drilling Surface Equipment Direct Electrical Private Public

Million US$ Million US$ Million US$ Million US$ % %

1995-1999 0.2 0.5 70 30

2000-2004 1 16 80 20

2005-2009 7.5 225 90 10

The huge increase in the number of GSHP systems installed

in Ireland over the last 4 years, which has raised the total

heat pump capacity from about 40 to 164 MW has stemmed

from public concern for climate change and reduction in

CO2 emissions, and also the desire by businesses and

individual householders to reduce heating costs. In addition,

the grant aid introduced by SEI on behalf of the Irish

Government for both domestic, commercial and public

sector projects, through the Greener Homes, Reheat and

Public Sector programs has also had a major effect in

stimulating this growth. However, failure of heat pump

systems, or systems that fail to perform up to expectations

are problems which threaten the development of the whole

sector. A number of reasons for these failures are:

• installation by insufficiently qualified installers

• poor and misleading advice on the most suitable

heat collection system

• failure to size the collector system properly

• unsatisfactory commissioning of the heat pump

system

• failure to install a Building Management System

(BMS) or installation of a BMS without a data

archival feature

• failure to instruct the client in operation and

adjustment of the BMS and heat pump system

• absence of post installation monitoring and back-

up by installer

These and a lack of confidence in heat pumps by many

HVAC engineers, have hindered the growth of heat pumps

in the commercial sector of the Irish market.

On the brighter side, over the last few years in Ireland there

has developed a heightened interest in renewable energy

technologies and energy issues in general, associated with

concerns about CO2 emissions, climate change, energy

security and peak oil. This has led to the development of a

number of third and fourth level degree programmes in

Energy Engineering in Irish higher education institutes.

UCC for example has been running an MSc programme in

Sustainable Energy for 5 years, and has also introduced an

undergraduate Energy Engineering degree program. In all

these programs, geothermal energy and heat pump

technology form part of the curricula.

Allen and Burgess

8

Commercial and government interest in geothermal energy

has also developed in Ireland over the last few years to the

extent that the GAI saw the opportunity to organize its 10th

anniversary conference in November 2008 entitled

‘Geothermal Resources in Ireland - Commercial

Opportunities’. In addition, the Irish Government has

moved to establish regulatory controls to guide the

development of geothermal energy in Ireland, and as the

initial step has engaged in a wide ranging consultation

process with geothermal stakeholders. This has developed

in parallel with Ireland’s participation in the EU

Altener/IEEA funded Geothermal Regulation for Heat

(GTR-H) project to standardize geothermal regulations

throughout the EU, which culminated in the GTR-H

conference in Dublin in Autumn 2009. Government and

commercial recognition of the potential of geothermal

energy to aid reduction in CO2 emissions and dependence

on fossil fuel imports can only benefit development of the

geothermal industry, and to this end a carbon tax which

may be introduced by the Irish Government in its December

2009 budget will further enhance this growth.

6. FUTURE DEVELOPMENT AND INSTALLATIONS

Future projects on the island of Ireland include a 1MW

proposed open loop system for heating and cooling the

Critical Care Unit of Victoria Hospital in Belfast, and the

prospect of including GHP as part of the overall mix for a

20MW energy centre also at Victoria Hospital, Belfast. In

addition, investigations are taking place at Cookstown also

in Northern Ireland into the feasibility of drilling a deep

borehole in limestones to generate an open loop GHP

system to heat and cool new buildings to house the Police

Service of Northern Ireland (PSNI) and the Fire Training

Centre for Northern Ireland. Furthermore, the company

which drilled the deep borehole at Newcastle, Co Dublin

has recently developed a partnership with Ballymena

Borough Council in Northern Ireland with the intention of

also exploring the possibility of developing a deep

geothermal borehole for a district heating system for the

town.

Another large GHP project underway is a 1 MW vertical

closed loop system in Dublin to heat and cool the new

headquarters of one of Ireland’s major banks. Collector

systems have been installed in a total of 72 x 200m deep

boreholes, but the project is presently suspended due to the

current financial position of the bank.

Finally, the Cork Docklands Development Agency, tasked

with regenerating the Cork Docklands area, is currently

undertaking an investigation into the potential of using open

loop heat pump systems to generate district heating for

apartment complexes, hotels, shopping malls and

commercial premises. The site is a low lying estuarine area

subject to tidal influence, where salt water intrusion is a

potential problem. Owing to the economic downturn in

Ireland, this project is also likely to be delayed.

7. ACKNOWLEDGEMENTS

We wish to thank various people, who helped compile the

statistics presented in this paper, in particular Amanda

Barriscale of SEI Statistics Office, Ann Crotty of SEI

Reheat Program and Ruth Buggy of SEI Greener Homes

Scheme, and consultants Paul Sikora, David Roome, Roisin

Goodman and Gareth Jones. Also thanks to Brecan Mooney

for help with the diagrams.

REFERENCES

Aldwell, C.R.: Low-Temperature Geothermal Energy in

Ireland, Seminar on ‘Geothermal Energy from Public

Water Supply Sources’, Tramore, Ireland (1997).

Aldwell, CR.: Mallow Springs, Co. Cork, Ireland.

Environmental Geology, 27, pp 82-84 (1996)

Aldwell, CR., Burdon, DJ.: Hydrogeothermal Conditions in

Ireland. 26th Int. Geol. Cong. Paris; Sec.14.2 Fossil

Fuels; Abstracts 1043 (1980)

Aldwell, C.R., Burdon, D.J.: Temperature of Infiltration

And Groundwater Conjunctive Water Use (Proc.

Budapest Symposium, July 1986). IAHS Publ. No.

156. (1986)

Allen, A.R., McGovern, C., O’Brien, M., Leahy, K.L.,

Connor, B.P. Low Enthalpy Geothermal Energy for

Space Heating/Cooling from Shallow Groundwater in

Glaciofluvial Gravels, Cork, Ireland. In: Fendekova,

M., Fendek, M. (Eds) Hydrogeology and Land Use

Management. XXIX IAH Congress, Bratislava, Slovak

Republic, IAH, Bratislava, pp 655-664, (1999)

Allen, A.R., Milenic, D.: Low Enthalpy Geothermal Heat

Resources from Groundwater in Glaciofluvial Gravels

of Buried Valleys. Applied Energy, 74, 9-19 (2003)

Allen, A.R, Milenic D., Sikora, P.: Shallow Gravel

Aquifers and the Urban 'Heat Island' Effect: a Source

of Low Enthalpy Geothermal Energy. Geothermics,

32, 569-578 (2003)

Brück, PM., Cooper, CE., Cooper, MA., Duggan, K.,

Gould, L., Wright DJ., The Geology and Geochemistry

of the Warm Springs of Munster. Ir. J. Earth Sci., 7,

169-194 (1986)

Burdon, DJ.: Irish Geothermal Project, Phase 1.

Unpublished Report to the Geological Survey of

Ireland. Minerex Ltd., Dublin, 150/75/15 (1983)

Gondwe, KT., Allen, AR., Burgess, J., Browne, D, Sikora,

P.: The Glucksman Art Gallery, University College

Cork, Ireland: an Innovative Space Heating

Development (this volume)

Goodman R. Jones, G., Kelly, J., Slowey, E., O’Neill, N.: A

Geothermal Resource Map of Ireland, Final Report for

Sustainable Energy Ireland (SEI). CSA Dublin (2004)

Howley, M., O’Gallachoir, B., Dennehy, E.: Energy in

Ireland: Key Statistics 2008. Sustainable Energy

Ireland, 31pp, http://www.sei.ie/Publications/Statistics

(2008a)

Howley, M., O’Gallachoir, B., Dennehy, E., O’Leary, F.:

Renewable Energy in Ireland: 2008 Report – Focus on

Wind Energy and Biofuels. Sustainable Energy

Ireland, 30pp, http://www.sei.ie/Publications/Statistics

(2008b)

Liddy, S., Evaluation of Optimal Conditions for Horizontal

Closed-Loop Collector Systems for Ground Source

Heat Pumps. Unpublished MSEng. Minor Thesis,

Department of Civil and Environmental Engineering,

University College Cork (2008)

Lohan, J., Burke, N., Greene, M.: Climate Variables that

Influence the Thermal Performance of Horizontal

Collector Ground Source Heat Pumps. Proceedings

ESDA 2006: 8th Biennial ASME Conference on

Engineering Systems Design and Analysis, Torino,

Italy. (2006)

Allen and Burgess

9

Mooney, B., Allen, AR., Koeniger, P. Investigation of

Source and Conduit for Warm Geothermal Waters,

North Cork, Republic of Ireland (this volume)

O’Brien, M.: The development of Geothermal Resources in

the Mallow Area for Heating Purposes, Unpublished

MSEng Thesis, Department of Civil Engineering,

UCC, Cork, Ireland. (1987)

O’Connell, S.: Renewable Energy in Buildings – Ground

Source Heat Pumps. Unpublished MSEng. Thesis,

Department of Mechanical and Manufacturing

Enginering, Cork Institute of Technology, Ireland.

(2004)

O’Connell, S., Allen, AR., Cassidy, S.: Utilization of

Geothermal Resources in the Irish Republic. In:

Horne, R., et al. (eds.) Geothermal Energy: The

Domestic Renewable Green Option. Proceedings

World Geothermal Conference, Antalya, Turkey, 5pp

(2005).

Proceedings World Geothermal Congress 2010 Bali, Indonesia, 25-29 April 2010

1

GTR-H - Geothermal Legislation in Europe

1Goodman, R.,

2Pasquali, R.

3Dumas, P.,

4Hámor T.,

5Jaudin F.,

6Kepinska, B.,

7Reay, D.,

8Rueter, H.,

3Sanner, B.,

9Van Heekeren, V.,

8Bussmann, W.,

10Ll Jones, G.

1SLR Consulting (Ireland) Ltd. (SLR),

2GT Energy Ltd., (GTE),

3European Geothermal Energy Council (EGEC),

4Hungarian

Office for Mining and Geology (MBFH), 5Bureau de recherches geologiques et minieres (BRGM),

6Polish Academy of Sciences

(PAS-MEERI), 7Geological Survey of Northern Ireland (GSNI),

8Geothermischen Vereinigung e.V (GtV),

9Stichting Platform

Geothermie (SPG), 10

Conodate Geology Ltd.

1 rgoodman@csa.ie

2 riccardop@gtenergy.net

3p.dumas@egec.org

3sanner@sanner-geo.de

4Tamas.Hamor@mbfh.hu

5f.jaudin@brgm.fr

6 labgeo_bk@interia.pl

6buwi@min-pan.krakow.pl

7derek.reay@detini.gov.uk

8rueter@harbourdom.de

8wb@geothermie.de

9heekeren@heekeren.nl

10conodate@mac.com,

Keywords: GTR-H, geothermal regulation, heat, framework, EU, Altener, IEEA

ABSTRACT

The IEEA, Altener funded GeoThermal Regulation – Heat

(GTR-H (www.gtrh.eu)) project ran from October 2006 to

October 2009 with the aim of identifying and reviewing the

regulatory barriers and deficiencies for geothermal heat in

unregulated EU countries. The GTR-H project aims to

develop a template framework for geothermal regulation in

the EU which would provide the basis for the development of national framework documents.

Barriers both in the ‘target’ and the BP countries included

resource ownership/usage, multi resource licensing, limits

of geothermal reservoirs, financial barriers and support for

geothermal. Geothermal regulation in the project’s partner

countries, as well as in the EU-27 and broadly in the

international context, is influenced predominantly by the

preceding natural resources legislation. Guidelines for the

establishment of a framework document for geothermal

regulation in the EU 27 have been developed and

disseminated to a broader international audience. The

GTR-H project builds on previous EU projects such as K4RES-H in the renewable energy sector.

1. INTRODUCTION

This project is currently in its final stages and will conclude

its major deliverables with a closing conference to be held

in Dublin, Ireland on 30th

September and 1st October 2009.

The Irish based geoservices consultancy, the CSA Group

who initiated and coordinates the project recently merged

with the UK based International environmental consultancy

SLR Consulting Ltd. and currently coordinates the project under the title of SLR Consulting (Ireland) Ltd.

Four ‘target’ countries were chosen which had a poorly

functioning regulation or no geothermal regulation:

Hungary, Ireland, Northern Ireland/UK and Poland.

Expertise in four regulated or ‘Best Practice’ (BP) countries

France, Germany and Netherlands provided a review of

best practice geothermal legislation.

The project consortium for GTR-H comprises a range of

government bodies, intuitions and associations, each

representing a country with the exception of the European

Geothermal Energy Council (EGEC) representing the

geothermal sector in Europe (partner names and logos are included in Table 1).

The project was designed with a process of discussion and

consultation with key target actors and stakeholders at a

national level at each stage of review and included a series

of study tours to assess the effectiveness of the regulation in

each case. The ultimate aim of the project is to increase

overall sectoral investment in the exploration and

exploitation of geothermal heat across the EU.

2. BACKGROUND

The GTR-H project follows on from the Kistelek

Declaration which was announced in Hungary in April

2005 (see reference list) and did the initial work in

identifying the key strategies needed for development of geothermal resources and regulation in the EU as follows;

- Secure the environmentally friendly use of geothermal

energy, in particular concerning protection of underground

drinking water resources, emissions, etc.

- Regulate competing uses and securing sustainable use of geothermal energy

- Grant investors certain right to use geothermal energy in a

given area and to a given extent, as the basis for business plans.

Both from the K4RES-H project conclusions (EGEC 2006)

and initial results from the GTR-H project it is apparent that

the present lack of regulation for geothermal energy

exploitation over most of the EU is inhibiting the effective

exploitation of this underutilized resource. The project was

planned to outline and encourage investment in geothermal

energy by private and public sector partnerships.

3. EXPECTED RESULTS AND BROADER IMPACTS

The project’s major measure of performance is government

level acceptance of the need to accommodate geothermal

energy exploitation in national environmental, water and

resource legislation in the Target countries. This is to be

accompanied by consultation between the relevant ministry

and the geothermal stakeholders and initiation of drafting

new geothermal legislation or adaptation of existing legislation.

On a broader basis it is envisaged that there will be

transferability of the framework to suitable legislative and

regulatory schemes in the remaining EU-27 countries to facilitate geothermal energy exploitation

The framework will also assist in the creation of new

market opportunities resulting from transparency in the

international geothermal sector and therefore the

opportunity for increased private sector cross border investment.

Goodman and Pasquali, et al.

2

IEEA Altener

programme

CSA Group

(Coordinator –

Ireland)

Geological Survey of

Northern Ireland

(GSNI)

European Geothermal

Energy Council

(EGEC)

Hungarian Office for

Mining and Geology

(previously Hungarian

Geological Survey)

Polish Academy of

Sciences

Bureau de recherches

geologiques et

minieres

Geothermischen

Vereinigung e.V

Stichting Platform

Geothermie

Table 1: GTR-H Partners

4. METHODOLOGY OVERVIEW

The review of best practice and deficient regulations and

consultation with the stakeholders and key target groups has

been the key element providing the data necessary to allow

the definition of a framework which can accommodate the

legislative, environmental, energy, planning and financial

considerations. This has been completed for each of the target and best practice countries.

The project consulted broadly with the national geothermal

sector through each partner. The key target groups

identified and consulted with as stakeholders in the

geothermal sector are as follows: Decision Makers at

national government level, Government agencies (water,

energy, environment and planning), Trade and industry

associations, Bank and financing institutions, Legal

representatives, Geothermal educational facilities and

associations, Geothermal exploration/resource assessment

consultants, Geothermal end users.

Figure 1: GTR-H project structure

The project has provided for dissemination of information

and discussion and interaction between all partners at every

stage of the project as this is seen as key to the success of a

regulatory framework. Regular committee meetings with

workshops allowed discussion of the issues raised and

solutions to be found. Provision was made for the

observation of team partners in local workshops therefore

giving opportunities for alternative country views to be

included in the local discussion and a broader view of the potential solutions to be considered throughout the process.

The results have been summarized to produce a ‘matrix’

which relates the identified barriers to geothermal

development to the solutions been applied in the best

practice countries and further afield. This has been adapted

to provide a basic framework of the issues that are likely to

arise and a proposed approach for dealing with them in any

national regulation being considered. Details are provided

below.

5. RESULTS SO FAR – A PRELIMINARY

FRAMEWORK

The following summary sets out a draft text indicating

some of the issues for inclusion and consideration in a

geothermal framework for national regulation/legislation as

concluded from work so far completed in the GTR-H

Project. The issues to be dealt with generally separate into

three main areas as follows; legal guidelines, financial

incentives guidelines and general guidelines for flanking

measures.

5.1. Legal Guidelines

5.1.1 Definition of Geothermal energy

Of primary importance in the development of any

geothermal regulation is a clear definition of geothermal

energy. The consortium has discussed this and liaised

widely and has agreed that the following definition as

defined by the RES Directive (EU, 2009) is most appropriate:

‘Geothermal Energy is the energy stored in the form of

heat beneath the surface of the solid earth’.

Additional parameters could be used for specifications to

account for resource type extraction. Depth, temperature,

Goodman and Pasquali, et al.

3

flow rates, end use, systems capacity/size could be used to

steer the permitting process and exact parameters should comply with existing resource regulations:

5.5.2. Clarification of geothermal resource ownership

Primary national legislation (through existing or modified

natural resource legislation or separate geothermal

legislation) needs to clearly define the ownership of the

resource at a national level as well as nominating an

authority with power to issue licences for exploration and

development of the resource. There are a number of issues that may be relevant in different countries as follows;

The ownership of the geothermal resource may be treated

like a mineral or petroleum resource. Initially countries

could choose between the existing mineral or the petroleum exploration and development legislation.

The state may own the geothermal resource or govern the

right to use of the resource and grants licences to a company to explore for and produce geothermal energy.

A new single Geothermal Act could follow at a later date to

take account of lessons learned after several years of geothermal exploration.

5.1.3. Adoption of a licensing system

A system of licensing for exploration and exploitation for

geothermal resources should be in place as a primary

requirement to develop and regulate the national geothermal sector.

For shallow geothermal exploration and development where

licensing is required, the local authorities could be the

licensing body. Initially for deep geothermal resources

exploration and development the licensing authority could

be the department responsible for mineral or other resources

exploration.

The provision of one e-government portal for deep geothermal exploration applications is recommended.

The application procedure for deep geothermal exploration

and exploitation licences should be clearly stated in specific

guidelines to potential applicants. The application process

should be managed by the relevant licensing authority.

These guidelines should help streamline application submissions.

The system should grant the licensee the exclusive right to

exploration and exploitation of geothermal resources over a defined area for a defined period.

The administrative process for the granting of a deep

geothermal exploration licence should not exceed an overall period of six months.

Geothermal exploration licence duration should be no

longer than six years and should include facility for annual

(or bi-annual) reviews by the licensing authority based on a

submitted and agreed work programme by the potential licence holder.

Deep Geothermal Energy exploitation permits should have

a duration of no less than 20 years, thus lasting the normal

minimal lifetime of an average well doublet. A renewal

option for a period of not less than 5 years should be made

available to the licence holder, subject to review of the

production rates and their associated impacts on other natural resources.

Programme plan and results data relating to any geothermal

energy projects (shallow or deep) should be submitted to

the appropriate national licensing authority. These data

should fulfil all requirements of the legislation covering the

natural resource, planning, EIS, groundwater and environmental areas.

Confidentiality of submitted data associated with licensed

geothermal operations should be set out in the primary

regulatory structure as for other strategic natural resources.

Where the resource is included in other legislation (ie:

mineral, petroleum legislation) a confidentiality period

during the granted licence period and for a period

subsequent to the surrender of the licence should be

outlined specifically for geothermal energy. This should

clarify the periods where data are confidential, while also

providing guidelines for making monitoring data available

to the licensing/monitoring authority during the licensing

period and subsequent to surrender. This period should be between 4 to 6 years after surrender of the license.

Groundwater abstraction permits for geothermal energy

production should be based on the national groundwater

abstraction/pollution control regulatory regime with due regard to specific issues of geothermal systems.

The cost of geothermal exploration licences should be set

lower than the petroleum and mineral exploration licensing

costs to reflect the comparatively lower economic return

potential and to promote a national renewable energy action plan.

5.1.4. Simplification of regulations and administrative

procedures

Shallow geothermal energy usage should be regulated

where necessary through local planning laws where large

sized commercial systems are installed. A flow rate cut-off

for pumping groundwater as a heat source could be applied

to define which projects require a licence in order to comply with national groundwater abstraction legislation.

Small size domestic systems and closed loop collectors

should be the subject of a simple information submission

form to a nominated government agency to ensure suitable

monitoring at national level of resource usage and

protection especially in vulnerable areas. These should

require no exploration licence; however, the reporting of

new heat pump installations to the competent authority is required for registration reasons.

Existing national planning, natural resource, environmental,

water abstraction and building legislation should be used,

with modifications if necessary, to regulate the shallow, commercial geothermal sector.

Deep geothermal energy abstraction should fall in line with

the EU groundwater policy Groundwater Framework

Directive (EU, 2000) where implemented and national

groundwater legislation by requiring the use of re-injection or closed circuit systems.

5.1.5. Nomination of an administrative body

A national geothermal authority or independent expert body

(competent professional body or cooperative network of

competent authorities) is recommended to have the

responsibility to promote the geothermal energy sector,

issue licences for exploration and development of the

resource, review licence case specific applications and

facilitate the geothermal licensing application system. The

key issue here is that professional competence, specifically

Goodman and Pasquali, et al.

4

in the geothermal area, should be a prerequisite for the

authority responsible for reviewing, issuing and monitoring licences.

Initially the licensing authority could be the department

responsible for mineral exploration if appropriate. For

shallow geothermal, the local authority could be the

licensing authority. For deep geothermal exploration and

production the department responsible for mineral

exploration and development could be the licensing authority with input from the regional authority

The authority responsible for granting the license can be a different authority from the one that monitors the project.

The authorities need to recruit geothermal energy experts

with professional accreditation and use established geothermal standards.

5.1.6. Reporting for geothermal resources inventory &

statistics

There is a need for each country to adopt a national strategy

that establishes the geothermal potential, identifies targets

and increases the public awareness of geothermal energy. The issues that need to be covered are as follows;

Insufficient data base; Presently, statistics on the heating

sector and inventories of the geothermal resources in

general are weak. A speedy establishment of robust market

data and reliable statistics that allow the establishment of a baseline as well as progress monitoring is essential.

Shallow and deep geothermal resource borehole drilling

should be reported, as part of the permit requirements, to

the relevant national government agencies, to ensure that

there is a record of installed shallow and deep geothermal

systems. This will help the implementation of a successful

national geothermal energy development strategy. There

should be a requirement to furnish basic borehole

information to a centrally maintained borehole inventory

that will be used for planning decisions at the local level.

Yearly monitoring data from large commercial producing

systems should be submitted to the relevant licensing

authority together with all other data of significance to the

resource parameters and its exploitation.

Monitoring data should include heat production,

temperature of the carrier fluid at surface, flow rates,

pressure, temperature of the injected fluid; chemistry of the

produced water.

Monitoring data should be made publicly available subject

to the set confidentiality period of the exploitation licence. Domestic systems should be exempt from this.

5.2. Financial incentives guidelines

A key conclusion of the GTRH project is that Financial

Incentives (FIS) can play an important role in promoting

geothermal heating and cooling, if they are well designed,

carefully managed and accompanied by appropriate

flanking measures. Without proper design their positive

effect is limited and can be even counter-productive to the

development of the geothermal sector in the medium and long term.

It can be shown that national government financial

incentives for the installation of shallow ground source heat

pump systems have significantly increased uptake in

shallow geothermal sectors throughout Europe. The key

positive effects of well designed and managed financial incentive schemes are:

• Reduction of the upfront investment costs,

• Psychological effect: signal of the public authority to the

potential users

5.2.1. Reducing Financial burden

There should be no licence fee or royalty payment for

geothermal systems (shallow or deep) because the heat is

not permanently removed from the rock. The heat resource

is renewable and therefore not “mined” in the conventional sense.

Exploration permit fees for the licence area should be a

once off set fee included in the initial licence application.

There should be no additional fees (programme related) to carry out exploration during the licence period.

The application of Royalty fees to producing deep

geothermal energy plants should be especially discouraged

if national legislation stimulates the usage of re-injected

geothermal systems on the basis that no resource is being removed (or ‘mined’).

Groundwater abstraction fees and permitting should be

waived in accordance with national groundwater legislation

if the producing net water abstraction budget from shallow and deep systems is 0m

3/d or below the national guidelines.

5.2.2. Recommendations for financial incentive schemes

National taxation law is encouraged to promote increased

capital investment in geothermal energy (eg: renewables tax

incentives, preferential VAT rates). Other renewable

energy resources are actively incentivised by national

governments in Europe with prices for electricity

generation from other renewable technologies helping

national markets to diversify electricity production. This is

currently not the case for national and European heat

markets. Incentives for delivering heat from renewable

energy sources such as geothermal energy should be encouraged through national taxation systems.

Grants or other financial support schemes for both

commercial and residential sector systems should be available.

For large commercial systems these could be made

available, subject to a review of the projected production of the system by the applicant.

Residential sector support could be granted, subsequent to

the submission of drilling or system installation notification to the relevant national government agency.

Financial incentives have to be based on the long term, and

measures should only be announced when they are

available, in order to minimize confusion and maximize the impact of the measure.

Administrative procedures should be as simple as possible

Deep geothermal energy projects should be promoted by

national, regional and local government authorities by

financial incentives.

Appropriate exemptions or allowances from the national

planning regulation and environmental impact assessment

regulations should be considered for the development of

Goodman and Pasquali, et al.

5

geothermal energy projects, in order to assist in the development of the sector.

National research and development funding schemes should

clearly have geothermal energy research, pilot projects and spin-off activities amongst the priority fields.

5.3. General Guidelines for Flanking Measures

Any technical parameter linked to the eligibility for a FIS

should be strictly oriented to European standards and certification.

Incentives could include financial assistance for initial

feasibility studies, grants or low interest rate loans for capital investment.

Geothermal energy should receive incentives equal to the

support received by other renewable energy sources in the

form of grants, low interest rate loans, risk insurance, preferential VAT rate, feed in tariffs etc.

Preferential VAT rates for heat sales from operating

geothermal power plants should be below the higher rates

of 16-21.5%. These should be designed to encourage fossil

fuels substitution and provide a competitive price for

geothermal energy based on national domestic and commercial energy rates.

A geothermal insurance and risk fund (particularly for deep

exploratory and/or development drilling, is encouraged to

be made available based on the substitution for fossil fuel

use and on the potential for national CO2 emission savings

that can be achieved through the development of

geothermal energy projects. This type of risk fund typically

covers the risk associated with the drilling for the

exploration and assessment of the resource.

A ground source heat pump guarantee fund for large

commercial systems >30kW and exploiting aquifers shallower than 100m should be considered.

Specific agreements on electricity service fees for heat pumps are encouraged.

Incentives could be based on the CO2 emission avoidance

from operating geothermal plants and/or a set of agreed feed in tariffs based on a national feed in tariff strategy.

The development of a CO2 emission credits system for the

operation of geothermal energy projects should be

encouraged at national level to incentivise sector investment.

Innovative applications of geothermal energy should benefit from specific discount.

In countries where national drilling permits are required for

the completion of geothermal energy boreholes, a cost

waiver should be applied or the cost reduced for the

geothermal sector. This should be considered for a period of 15 – 20 years until the sector is established.

Where applicable there should be a waiver/reduction on

natural resource data acquisition costs to a licence applicant

for review of geothermal energy data prior to application submission.

REFERENCES

EGEC 2006, Key Issues for Renewable Heat in Europe

K4resH, EU contract EIE/04/204/S07.38607

EU 2000, EU Directive 2000/60/EC, Water Framework

Directive.

EU 2009, EU Directive 2009/28/EC on the promotion of

the use of energy from renewable sources.

Kistelek Declaration 2005. Regulatory and Economic

Tools Governing the Enhanced Exploitation of

Geothermal Energy in the European Union.

Proceedings World Geothermal Congress 2010

Bali, Indonesia, 25-29 April 2010

1

The Glucksman Art Gallery, University College Cork, Ireland: An Innovative Space Heating

Development

Kondwani T. Gondwe, Alistair Allen, John Burgess, Donal Browne and Paul Sikora

Department of Geology, University College Cork, Ireland

A.allen@ucc.ie

Keywords: Heat pumps; Open loop system; Performance

analysis; Payback time

ABSTRACT

The Lewis Glucksman Art Gallery is a cultural and

educational institution promoting the visual arts at

University College Cork (UCC), Ireland. Opened in

October, 2004, the 2350m2 building is serviced by a

geothermal heating and cooling system, which allows

heating and cooling to be provided at the same time using

two water-cooled heat pumps. This enables a liquid chiller

installation to serve as a full service heat source

simultaneously with its refrigeration function.

Situated adjacent to the River Lee on UCC campus, and

overlying a shallow gravel aquifer, groundwater at 12m

depth and ~ 15°C, is fed via an open loop collector to

geothermal heat pumps through plate heat exchangers. In

order to ensure the preservation and safe keeping of its art

collections, critical exhibition and storage space in the

Glucksman requires a highly controlled environment,

including humidity control by dehumidification, which

demands that heating and cooling be supplied

simultaneously to closed control areas. A range of climate-

control technologies connected to the heat pumps optimise

energy efficiency, whilst meeting the requirements of each

viewing space. Two water cooled chillers at the same time

generate both chilled water at 6°C and heating water at

45°C (30°C when providing cooling only). The rejected

heat from the cooling process is fed directly into the heating

circuits. Excess heat or cooling is transferred to the

groundwater through a plate heat exchanger, and is

discharged to a holding tank for use in toilet flushing and

landscape irrigation. Excess water is discharged to the

River Lee. The system capacity is 170kW and 200kW for

cooling and heating respectively against corresponding

loads of 130kW and 190kW.

In 2005 and again in mid 2008, assessments of the

performance of the geothermal heating/cooling system for

the Glucksman Gallery were undertaken to evaluate the

operational efficiency of the geothermal system and to

compare its performance to that of a conventional system.

The studies also evaluated the economics and operational

savings of the system relative to a conventional system and,

based on fossil fuel and electricity prices over the period

from commissioning of the building, estimated its payback

time and future savings over the lifetime of the heat pumps.

The investigations have indicated potential for considerable

savings of 75% in energy consumption over that of

conventionally equipped buildings. Post occupancy

evaluation using recorded data from the building

management system shows a remarkable correlation in

energy consumed to the pre-construction design estimates.

Due to significant increases in energy costs since the

building was commissioned, payback time has been

significantly reduced relative to pre-construction design

estimates.

1. INTRODUCTION

The Lewis Glucksman Art Gallery is a cultural and

educational institution in University College Cork (UCC),

Ireland that promotes research, creation and exploration of

the visual arts in an international context. The building,

which was completed and commissioned in October 2004,

has a total floor area of 2350m2, spread over 7 floors. It

provides a public gallery with international curatorial

standard environmental controls for University College

Cork's modern art collection as well as for travelling and

special exhibitions (Burgess, 2003).

The building contains four exhibition spaces, multifunction

rooms, lecture facilities, a basement gallery store, a

riverside restaurant and gallery shop (O’Regan, 2007). The

four interlocking exhibition spaces vary in size and are

staggered over three of the upper floors. The artworks are

displayed in the exhibition spaces and stored in the

basement store.

The Glucksman Gallery is situated on the southern bank of

the South Channel of the River Lee, 10m from the river and

about 1.7 km from Cork city centre. The architectural brief

for the building was for an environmentally sympathetic

design to complement the riverside location and its

surroundings of mature trees and grassy lawns, with an

emphasis on external wood and glass (Fig. 1). That it

achieved these objectives is indicated by the fact that the

building was short listed for the 2005 Stirling Prize for

outstanding architectural achievement.

The 0.5 km wide floodplain of the River Lee, is underlain

by a Pleistocene buried valley infilled by gravel deposits of

variable thickness ranging up to at least 60m and possibly

as much as 140m in places (Allen & Milenic, 2003),

overlain by only a metre of alluvium. The south side of the

building is located about 10m from the southern margin of

the buried valley, which is marked by a small limestone

scarp. The hydraulic conductivity of the gravels is of the

order of 5 x10-3 ms-1, making them an excellent source of

groundwater for a geothermal space heating/cooling system

employing a heat pump with an open loop collector..

2. DESIGN SPECIFICATIONS

The Glucksman Gallery requires a highly controlled

environment for the preservation and safe keeping of its art

collections. This demanded exceptionally close control of

temperature, humidity and natural light. Thus, in order to

prevent deterioration of the artistic works, it was essential

that the heating/cooling system design be capable of

maintaining constant year round relative humidity (RH) of

the order of 50%±5% and temperatures of 19 ± !oC in the

critical close control areas. These are represented by the

Gondwe et al.

2

exhibition spaces and the basement storage. The other areas

require only temperature control.

Dehumidification is required to achieve the humidity

control requirement. The dehumidification process demands

that air be cooled and reheated simultaneously which is an

energy intensive operation.

To maintain the design within the environmental aspiration

of a low energy solution, the building-services consultant,

Arup selected a range of climate-control technologies to

meet the requirements of each viewing space. In view of the

existence of a ready heat source in the form of the

groundwater supply beneath the site, it was decided that

much of the heating and cooling loads be supplied by a

geothermal system. The building utilises two geothermal

heat pumps (GHP’s) in conjunction with air handling units

(AHUs) to maintain the exhibitions and stores of art works

at controlled temperature and humidity.

2.1 System Components

2.1.1 Geothermal System

Figure 1: The Glucksman Art Gallery, Ireland

The geothermal system is located below ground level in the

basement of the Glucksman Gallery, and is supplied by

groundwater at 15°C sourced from two 12m wells adjacent

to the building. The heat pumps, which were designed,

supplied and installed by Dunstar Ltd, have a lifetime of at

least 20 years. System capacity for cooling and heating is

170kW and 200kW respectively against corresponding

loads of 130kW and 190kW.

The system’s major components are:

2 Heat Pumps; Cold and Hot Buffer Tanks; Plate Heat

Exchangers and Three Way Valve

Heat Pumps: Two York International water-cooled liquid chillers act as

heat pumps. These are two stage chillers. one (YCWM75)

comprising two 37.5kW compressors and the other

(YCWM 120) two 60kW compressors. Actual single stage

cooling capacities are 29kW and 47kW, whilst their

corresponding heating capacities are 38.8kW and 64.3kW

respectively (York Polaris 1999). These simultaneously

generate chilled water at a temperature of 6°C and heating

water at 45°C, (30°C when providing cooling only). On

starting a unit, both compressors start and then one stops so

that the unit runs at half capacity for part load application.

The system operates by any combination of the four

compressors depending on the load requirement at that

particular time. If all four compressors are running, the

capacities are 152kW for cooling and 206kW for heating,

whilst the power input is 55.2kW.

The refrigerant is R407C, a zeotropic mixture of three

HFC’s, R32, R125 and R134a in the proportions 23:25:52

by weight, which is non ozone depleting and also has high

thermal characteristics since it is a mixture of three

different substances.

Cold and Hot Buffer Tanks: Two buffer tanks act as

energy storage. Chilled water is stored in the cold buffer

tank to be circulated through the AHU cooling coils when

cooling is required, whilst the hot buffer tank stores heated

water for circulation through the AHU heating and reheat

coils when heating and/or dehumidification is required.

Plate Heat Exchangers: There are two stainless steel

brazed plate heat exchangers, one to allow excess heat to be

rejected to the groundwater aquifer and the other for heat

extraction from the groundwater. Plate heat exchangers

were used because they are more efficient than other types

of heat exchangers.

Three Way Valve: A motorized three-port valve is,

depending on operational mode, used to direct the

geothermal water flow to either the heating side plate

exchanger or to the cooling side plate exchanger.

2.1.2 Air Handling Units

Three air handling units serve different functions and floors

of the Glucksman Gallery. AHU1 provides temperature and

humidity control to the basement gallery store, serving the

need for close control of both temperature and humidity for

the proper storage of the art works there. The unit, which

consists of a carbon filter, bag and panel filter, heating coil,

cooling coil, humidifier and supply fan, has fresh and return

air intakes. The treated air is ducted to the room directly

below (Browne, 2005).

AHU2 provides temperature control second and fourth floor

galleries and to these areas. The unit consists of a bag and

panel filter, heating coil, cooling coil and dual speed supply

and return fans. The plant room acts as a fresh air plenum

and return air is taken by duct from both rooms through a

shadow gap at high level with a bell mouth in the ceiling

void. The supply is provided through vertical duct drops to

floor grilles (Browne, 2005). Unlike AHU1 and AHU3, this

unit does not offer humidification. However it does provide

dehumidification through the efficient use of the cooling

and (re)heating coils both of which are fed from the

evaporator and condenser sides (respectively) of the water

cooled chillers.

AHU3 serves the close control gallery and multi media

room, and is comprised of a return fan, mixing box, cooling

coil, steam humidifier, supply fan and terminal reheat

boxes. The return section is on the fifth floor consisting of

fresh air mixing, a carbon filter, return fan, bag filter and

panel filter whilst the supply section on the third floor

consists of heating, cooling, humidification and two-speed

supply fan.

2.1.3 Ancillary Plant

In addition the system includes water circulation units

consisting of the borehole pumps, cold and hot loop

circulating pumps, withholding tank and pipe networks.

The borehole pumps are two equally rated submersible

pumps, each driven by its own variable speed drive unit, set

at the bottom of the two wells at depths of 12m. The pumps,

configured as a duty/standby pair, have maximum pumping

rates of 10 l sec-1 and are used to pump groundwater to the

Gondwe et al.

3

heat pump circuit so that heat is either extracted from it or

fed into it.

Geothermal hot and cold loop pump sets, each consist of

two duty/standby circulating pump pairs. One is for

circulating heated water between the hot buffer vessel and

the geothermal hot plate exchanger, and the other for

circulating chilled liquid between the chilled buffer vessel

and the geothermal cold plate exchanger (Browne, 2005).

The withholding tank keeps processed geothermal water for

use in flushing toilets or irrigation. The pipe network acts as

a connection media between various components to transfer

geothermal water from the production wells through the

heat exchangers, withholding tank and discharge of excess

water to the River Lee. It is also used to circulate chilled

water or hot water from cold/hot buffer tanks to AHU’s for

cooling or heating or both in the case of dehumidification.

2.1.4 Ventilation and Air Circulation Units

Apart from the air handling units described above, there are

a number of supply fans and extraction fans, which operate

independently of the air handling units. Each fan operates

so as to maintain the required air changes for particular

floors and spaces. Of note due to its reasonable heating

capacity is the kitchen ventilation (supply and exhaust)

system which heats the colder winter air (0°C up to a

minimum operating temperature of 15 °C) using the

condenser water from the chiller sets.

2.1.5 Gas Boilers

Two 102 kW Remeha 350 model gas boilers, with a total

capacity of 204 kW are located in the upper floor. One acts

as a lead boiler, the other as a lag boiler to heat the LPHW

water for circulation through a limited number of radiators

in select areas of the building such as the trench radiators

for the glazed entrance lobby and radiant panels for the tall

glazing element in the entrance lobby. Their main function

is to be used as a backup system for the GHP’s in case of

failure.

2.1.6 Underfloor Heating

Heat from the condenser side of the water cooled chillers is

used to warm the flooring of the entrance lobby, toilets and

cafeteria. This again maximizes the use of the low grade

heating circuit that is in essence the heat rejection

(condenser) side of the water cooled chiller plant.

3. SYSTEM OPERATION AND MONITORING

3.1 System Operation

The submersible pumps drive groundwater from the

boreholes to the basement plant room where it is piped to

the two water-cooled chillers, which act as heat pumps,

generating chilled water at 6ºC and Low Gradient Hot

Water (LGHW) at 45ºC (30ºC for cooling only in summer).

Rejection of heat from the chillers cooling process is

utilized by the heating circuit. Excess heat or cooling is

transferred back to the groundwater, via a plate heat

exchanger. The processed groundwater is held in a storage

tank and is used for toilet flushing and irrigation, with

excess water being discharged into the river.(Kennett,

2005)

There are basically four operational configurations based on

modes of operation (O’Regan, 2007), which are:

Active Geothermal Cooling, Geothermal Heating Mode

Passive Geothermal Cooling and Combined Geothermal

Heating and Cooling

Based on the different operating modes, the system has

different coefficients of performance (COP), ranging from 3

to as high as 20 (Table 1)

Table 1. The Glucksman GSHP, COPs for Different

Operating Modes (O’Regan, 2007).

Operating Mode COP

Active Geothermal Cooling (Heat Pump

Enabled)

3

Active Geothermal Heating (Heat Pump

Enabled)

4

Active Geothermal Cooling and Heating (Heat

Pump Enabled)

7

Passive Geothermal Cooling (Heat Pump

Disabled)

20

3.2 Building Management System

A Building Management System (BMS) monitors all data

for temperatures, pressures, running hours, electricity and

gas consumption. The version employed for the Glucksman

Gallery is BMS 963 of Trend 963 – Lite BMS supervisor

software. The Trend 963 – Lite is a graphical, real-time user

interface for the BMS. It enables the user to monitor the

plant or building services, change the operational settings

and refine control strategies with experience (Huston,

2003).

The BMS is also programmed to report all alarms in case of

a problem, and to record and archive all data for future

reference and plot trends using its graphical, real–time

interface. However, it was found on investigating the BMS

for the Glucksman that the archiving facility had not been

switched on.

4. SYSTEM APPRAISAL AND PERFORMANCE

Geothermal heat pump systems are evaluated on the basis

of three major performance parameters. These are:

Technical performance; financial performance and the

environmental performance

For all of these performance pillars, it is necessary to

determine the annual cooling and heating loads and their

respective annual running hours, annual cooling and heating

energy consumptions and the total annual energy

consumption. There is also a need to ascertain the

efficiency of the conventional system and emission factors

for the driving electricity for the GHP and fossil fuels for

the conventional system.

The overall performance of the GHP installation is

dependent on the performance of the different components

that are interlinked to it within the total HVAC system.

4.1 System Appraisal

4.1.1 Technical Performance

Initial technical analysis during the design stage suggested a

COP of 4 for the heating mode and a COP of 3 in the

cooling mode. In the combined heating and cooling mode,

as the COP for heating and cooling is the summation of the

two, a COP of 7 can be achieved.

Gondwe et al.

4

This was verified by a post occupancy assessment

completed in April 2005 (Browne, 2005), which indicated

that initial performance was in line with design expectations

after six months of operation. Different COPs for both

cooling and heating modes were determined for standard

lift from an average cold inlet of 10°C and hot water outlet

of 45°C. This analysis found the COPs to be 2.98 and 3.93

for YCWM 120 and 3.05 and 4.02 for YCWM 75. These

also give averages of 3 for cooling, 4 for heating and a total

COP of 7 for combined heating and cooling (Browne,

2005).

4.1.2 Financial Performance

During the design phase, a comparison of the estimated

energy usage and running costs for the conversional system

and geothermal heating and cooling system was undertaken.

The comparison in capital cost showed the conventional

system to be cheaper by !175,000 (Burgess, 2007). The

comparison in running costs and cost savings are shown in

Table 2.

Table 2. Energy Use and Running Cost Comparison –

Design Phase (Burgess, 2007).

System Type Energy Usage

in kWh

Unit Price Annual Cost

Conventional

System

Chiller

61,512

! 0.07410

! 4,558.04

Boiler

1,690,758 !

0.01775

! 30,010.95

Total Annual Running Cost ! 34,568.99

GSHP System

GSHP

268,644

!

0.07410 ! 19,906.52

Boiler

176,779

!

0.01775 ! 3,137.83

Total Annual Running Cost ! 23,044.35

Annual Cost Saving = Difference in

Running Costs

!11,524.64

Using a simple pay back period calculation:

Payback Period = Difference in Capital Cost ÷ Annual Cost

Saving

Payback Period = ! 175,000.00 ÷ !11,524.64 = 15.2 years.

In the 9 month period after commissioning, Browne (2005)

found that energy usage by the GHP system was

considerably less than initially calculated, indicating that it

was operating more efficiently than anticipated (Table 3).

This allowed him to revise down the payback period to 11

years, although changes in fuel and electricity prices over

this period were not factored into his calculations.

Table 3. Energy Use and Running Cost Comparison –

One Year of Operation (Browne, 2007).

System Type Energy

Usage

in kWh

Unit Price Annual Cost

Conventional

System

Chiller

61,512

! 0.07410

! 4,558.04

Boiler

1,690,758

! 0.01775

! 30,010.95

Total Annual Running Cost

! 34,568.99

GSHP

System

GSHP 230,000

! 0.07410 ! 17,043.00

Boiler 100,000

! 0.01775 ! 1,775.00

Total Annual Running Cost ! 18,818.00

Annual Cost Saving = Difference in Running

Costs

!15,750.99

Simple Pay Back = Difference in Capital Cost ÷ Difference

in Operational Cost

Simple Pay Back = !175,000 ÷ !15,750.9 = 11.1 years

4.1.3 Environmental Performance

The design consultants, ARUP also undertook an evaluation

of CO2 emissions generated by the Glucksman Gallery

resulting from utilisation of different sources of electrical

power. It was estimated that the GHG system would bring

about a reduction of 256,249 Kg CO2 compared to the

conventional system, if the electricity was supplied by the

UCC Combined Heat and Power (CHP) plant. This gave an

environmental pay back of 10 years (Burgess, 2007).

4.2 Current Performance Analysis

Since commissioning of the geothermal system in the

Glucksman Gallery in October 2004, fuel and electricity

prices have risen sharply in response to various market

factors, together with uncertainty of supply due both to

political events and peak oil concerns. Consequently there

was a need to re-examine the performance of the system

and to recalculate its economics. This was undertaken in

August-September 2008 (Gondwe, 2008), enabling

financial savings for the four years of operation to be

established in order to assess their effect on the payback

period and also to assess the system in terms of its

continuing performance relative to design specifications

and expectations.

Gondwe et al.

5

A number of system performance assessment models were

investigated (Gondwe, 2008). Those most applicable to the

Glucksman Gallery heating and cooling system were the

RETScreen – Open Loop System Model, the Exergy

System Analysis Model and a model entitled ‘The

Glucksman Heating and Cooling Assessment Model’

developed by Browne (2005), which has subsequently been

upgraded to incorporate special financial and technical

analysis tools (Gondwe, 2008). It has the capability of

carrying out Exergy System Analysis and also Life Cycle

cost analysis and payback period with uneven cash flows.

In addition the RETScreen and the Exergy Analysis Models

were compared.

4.2.1 Annual Load Profile

Based on modelling with RETScreen 4, it is found that the

system is basically running in two modes per year at 0%

non weather dependent load and in a single mode per year

with 15% non weather dependent loads as shown in Figs. 2

and 31

Figure 2: Annual Load Profile with 0% Non Weather

Dependent Load

Figure 3: Annual Load Profile with 15% Non Weather

Dependent Load

Fig. 2 indicates that the system runs in heating mode from

November to April and then in heating and cooling mode

from April to November, whilst Fig. 3 shows that the

system runs in heating and cooling mode throughout the

year. The latter case applies when dehumidification is

required for humidity control throughout the year. In both

cases heating loads are at peak in December and January

and minimum in July and August. The reverse applies for

the cooling loads. The two figures represent the base case

only.

4.2.1 Annual Heating and Cooling Hours

Since no historical data on compressor run times and

operation mode was archived on the BMS, RETScreen 4

was used to determine the load profiles and the

corresponding heating and cooling hours.

From Fig. 2, it is established that Annual Heating Hours

(AHH) are 8760 hrs whilst Annual Cooling Hours (ACH)

are 5856 hrs, whereas Fig. 3 indicates that both are 8670 hr

The final performance analysis including projections

through the project life time was done using the

performance model developed. This has been outlined in

section 5 below.

5. THE PERFORMANCE MODEL

5.1 Model Description

The Glucksman Heating and Cooling System –

Performance Model is an MS Excel model used to calculate

and predict the system performance factors, financial

savings and emission savings (Gondwe, 2008). The model

has three major sections:

5.1.1 Input Section

The model operates with two sets of inputs. The inputs are

grouped into System Inputs and User Inputs.

System Inputs: These are default inputs specifying the

system data including the initial design cost of the system.

This set of inputs acts as a data storage. In addition the

system data input provides a list on natural gas and

electricity price projections.

User Inputs: This section consists of two sheets, “Input

Data” and “Valid Data Values”. The user enters the data in

the Input Data Sheet and the model tests its validity in the

Valid Data Values Sheet. The model uses the “Accepted

Values” in the Valid Data Values as its input.

There are four entry tables for entering past energy

consumption, efficiencies and emission factors for the grid,

prices for electricity and natural gas, power connection

times for the CHP and the grid. The entry tables are

numbered 1 to 4 with corresponding tables in the Valid

Data Values.

5.1.2 Computation Section

This section consists of three sheets in which performance

calculations are undertaken. System technical performance

is determined in the “Technical Performance Sheet”, whilst

financial performance is established in the “Financial

Calculation Sheet” and the environmental performance is

determined in the “Emission Calculation Sheet”.

5.1.3 Output Section

Although most of the performance information can be

obtained from the computation section, a special output

section has been set in the “Summary Graphs Sheet”. This

is a simplified graphical presentation of all the findings and

results.

Gondwe et al.

6

5.2 Electricity and Natural Gas Prices

5.2.1 Available Price Data

Based on data from UCC Buildings and Estates Office,

Bord Gais Energy Supply and Sustainable Energy Ireland,

Natural Gas prices rose from !0.033/kWh in 2004 to

!0.057/kWh in 2008. This gives an overall growth of

72.26% with an average annual growth of 19.9%.

Over the same period electricity from the campus CHP rose

from !0.101/kWh to !0.117 giving an overall growth of

15.29% and an average annual growth of 4.86% whereas

grid electricity rose from !0.131/kWh to !0.159/kWh

giving an overall growth of 21.37% with an average annual

growth of 6.67%

5.2.2 Price Projection – 2005 to 2029

The model was used to compute price projections and their

relative variation from 2005 to 2029. These are

demonstrated in Figs. 4 and 5.

Figure 4: Natural Gas and Electricity Price Projection

in Ireland (2005 – 2029)

Figure 5: Relative Price Growth for Natural Gas and

Electricity in Ireland (2005 -2029)

Fig. 4 shows the projected variation in prices, whereas Fig.

5 shows the relative price growth for each of the three

energy sources. Applying projected growth rates supplied

by Sustainable Energy Ireland, price deflators in the system

and the fuel data sheet of the model, it was found that there

will be a huge price rise in Natural Gas from !0.033/kWh in

2005 to !0.063/kWh in 2029 giving an overall rise of 91%

compared to 33% for grid electricity and 27% for CHP

electricity as shown in Fig. 5. Prices for electricity per kWh

will rise from 10.1 cents and 13.1 cents in 2005 to 12.8

cents and 17.5 cents in 2029 for CHP and grid supply

respectively as shown in Fig. 4.

5.3 Performance Results and Discussions

Based on the available BMS data, Chillers’ Design

Specifications and the price projections, the model

produced the following results:

5.3.1 Technical Analysis

Since no flow rates were available, COPs were calculated

using interpolation on the design specification and the

calculated COPs from the model. Results are:

From August to September 2008

Chiller Leaving Temperature (Mean) - 7.94oC

Evaporator Leaving Temperature (Mean) – 48.53oC

By interpolation, COPc = 2.63

COPh = 3.59

COP (h+c) = 6.21

From November 2007 to September 2008

Chiller Leaving Temperature (Mean) – 6.67oC

Evaporator Leaving Temperature (Mean) – 42.98oC

By interpolation, COPc = 2.88

COPh = 3.93

COP (h+c) = 6.89

COPs for the period October 2007 – September 2008 are

shown in Fig. 6. These have been calculated based on CHW

and LGHW flow temperatures shown in Fig. 7.

Figure 6: CHW and LGHW Flow Temperatures (Oct

2007 – Sept. 2008)

Gondwe et al.

7

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

Oct-07 Nov-07 Dec-07 Jan-08 Feb-08 Mar-08 Apr-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08

Month of the Year

Co

eff

icie

nt

of

Pe

rfo

rm

an

ce

COPc

COPh

COP(h+c)

Figure 7: COPs Based on CHW and LGHW

Temperatures (Oct 2007 – Sept. 2008)

From Figs. 6 and 7, the mean COPh is 3.9 whilst that of

COPc is 2.93. Mean CHW flow temperature is 7.36oC

whilst that for LGHW flow temperature is 44.07oC.

5.3.2 Financial Analysis

5.3.2.1 Financial Cost Savings

Based on energy consumption data obtained from UCC

Buildings and Estates and both past and projected prices,

model results obtained were:

Actual Cost Savings: The model showed that there have

been cost savings of !28,808.22 in 2005, !48,258.47 in

2006, !56,911.21 in 2007 and !71,402.96 for 2008. This

gives a total saving of !205,380.85 for the four years of

operation. These are shown in Fig. 8. The figure shows

actual savings and its resulting cumulative value for that

year. The graph can be updated in the model for future

years.

Figure 8: Life Cycle Cost Analysis (LCCA)

Using the projected natural gas and electricity prices, a

modelled Life Cycle Cost Analysis was carried out to

determine the cost savings and the break even point. The

results from the model were:

Break - even Point: Break even point is the point at which

the balance on capital cost becomes zero. LCCA modeling

resulted in a break even point of 3.57 years after

installation. This is presented in Fig. 9:

Figure 9: Break – even Point with LCCA

5.3.2.2 Project Payback Period

The model also evaluates the systems payback period based

on the designer’s method – simple payback method. It

further computes the payback period with actual savings

(uneven cost savings). The results of the modelling are:

Simple Payback Method: Model results were, 14.6 year for

Arup design case, 11.1 years for the Browne assessment

and 6.1 years based on actual energy consumption and

prices for the first year of operation (2005).

Fig. 10 shows all three lines of constant savings. Where

they intersect the line of capital cost is the payback for each

of them.

Figure 10: Simple Payback with Even Cost Savings

Payback Period with Uneven Cost Savings

Payback period with uneven cost savings was found to be

3.57 years. This is shown graphically in Fig.11.

Comparison between Simple Payback Method and Payback

with Uneven Cost Savings

Comparing the two approaches in determining the payback

period it was found that the payback period dropped from

14.6 years to 3.57 years (11 years) when comparing the

uneven approach with the simple payback approach –

Arup’s design case. On the other hand, there was a drop

from 6.1years to 3.57 years (2.5 years) when compared with

the 2005 expected case. This comparison is shown in Fig.

12.

Gondwe et al.

8

Figure 11: Payback Period with Uneven Cost Savings

Figure 12: Comparison between Simple Payback

Method and Payback with Uneven Cost Saving

5.3.3 Environmental Analysis

Modelling of environmental impacts was undertaken to

determine the actual CO2 savings and the environmental

payback.

5.3.3.1 Emission Savings

The emission savings were calculated using both the TEWI

and the yearly emission savings projections.

Yearly Calculations: Yearly calculations were used to

determine the actual emission savings and the

environmental life cycle analysis.

The model results on computing the emission savings were,

92.59 tCO2 in 2005, 149.26 tCO2 for 2006, 141.01 tCO2 for

2007 and 139.66 tCO2 for 2008. This gives a cumulative

saving of 522.51 tCO2 for the four operational years. These

are illustrated in Fig. 13, whilst environmental life cycle

analysis results are shown in Table 5.

Applying the TEWI approach, emission savings for the four

years of operation were found to be 824.7 tCO2 and for 25

years mechanical life were 4,947.8 tCO2.

Environmental Payback Time

Results for environmental payback time also referred to as

CO2 payback time (CPT) are shown in Fig. 14.)

Figure 13: Actual emission savings for the four

operational years

Table 5. Environmental Life Cycle Analysis.

Value at: Cumulative Savings

(tCO2)

Balance on the

Emissions during

construction

(tCO2)

4 years operational

period

523

- 2,037

End of Design Life

(20yrs)

2,642

+ 82

End of Mechanical Life

(25yrs)

3,304

+ 744

Total Equivalent Warming Impact (TEWI) Approach

Figure 14: CO2 Payback Time

Gondwe et al.

9

The CO2 payback times were found to be 10.4 years for the

Arup design case, 15 years for the expected case (based on

2005 data) and 11.9 years for the actual line with uneven

CO2 savings.

6. DISCUSSION

6.1 Technical Performance

Due to unavailability of data for the flow rates and the VSD

frequencies, an interpolation method was employed.

According to York International, interpolation is done in

two stages. The first is to determine the COP’s for the

actual evaporator leaving temperature for the standard

CHW flow temperature, whilst the second is used to

determine the COP’s for the actual CHW flow temperature

at the actual evaporator leaving temperature.

The results obtained are not much different from the design

assumptions for COPs of 3 for cooling, 4 for heating and 7

for heating and cooling.

The small internal close control gallery AUH (3) and

basement archival store AHU (1) successfully achieve low

room temperatures of 19°C at 50% RH. The main wrap

around galleries on 2nd and 4th floors can and do provide

dehuimidifcation in the summer without the need for fossil

fuel fired reheating. The large gallery exhibition spaces are

able to achieve straight-line control during the shoulder and

summer seasons when active humidification is not required.

6.2 Financial Performance

It is noted from the results the simple payback period

dropped by 8 years from 14.6 years for the design case to

6.1 years for the actual case (based on 2005 data). A 5 year

drop is also noted when compared to the Browne (2005)

case, which gave a payback period of 11.1 years. This has

been principally due to the rise in natural gas prices from

2002 to 2005. For simplicity of comparison Browne (2005)

used 2002 prices instead of 2005 prices.

In Fig.12, a comparison between payback with uneven cost

savings and that from simple payback is made. Payback

with uneven cost savings is found to be 3.57 years. This has

been mainly due to the rise in natural gas prices from 2005

to 2008.

In Fig. 8 and Table 4, it is noted that savings to date are

!205,380.85 and will reach as high as !2,886,724.07 by the

end of the heat pumps mechanical life. The huge projection

in cost savings is due to the fact that natural gas is projected

to rise by up to 52.4% from !0.033/kWh in 2005 to

!0.063/kWh in 2029.

6.3 Environmental Performance

In Fig.13, the actual CO2 savings are shown to be

considerably lower than the design prediction of 256t

CO2/year. This is also depicted in Fig. 14 where the CO2

payback time has increased from 10 years for the design

case to 19.38 years for the actual case with uneven emission

savings.

This has been contributed by two main factors; firstly the

designer assumed that electricity would be sourced from the

on-campus CHP only, at an efficiency of 89%, against the

actual situation where supply comes from both the grid and

the CHP, with the CHP’s actual electrical efficiency

reaching only 39.9%. Secondly the improved fuel mix in

the Irish electricity generation increased the ratio of

emissions of the CHP compared to those for the grid.

Table 5 shows that the emission savings as at present are at

522.5 tCO2 and are expected to rise to 3,304.5 tCO2 by the

end of the heat pumps mechanical life. This will lead to a

net emission saving of 744 tCO2.

Emission savings using TEWI are higher than those

obtained by the yearly approach because it assumes average

consumption applies to all years and uses average grid

efficiency and emission factors.

CONCLUSION

The highly sophisticated GHP heating and cooling system

installed in the Lewis Glucksman Art Gallery provides

precise and constant year round temperature and relative

humidity to critical close control areas for the preservation

and safe keeping of its art collections.

A performance analysis has shown that a well designed,

correctly installed geothermal system can generate

significant savings in heating and cooling costs for

buildings. The ongoing monitoring and use of the BMS for

data collection is critical to fine-tuning and optimization of

the GHP systems.The energy consumption over the 4 years

of operation of the GHP system of the Glucksman Gallery

to September 2008, is remarkably close to the design

estimates used for the original life cycle cost and sensitivity

analysis undertaken in 2001.

Although the Glucksman is only a medium sized building

with modest heating and cooling loads (190 kW and 130

kW respectively), the !200,000 savings generated in only 4

years of operation are quite spectacular. Much of these

savings have resulted from steep rises in natural gas and

electricity prices in Ireland over the period 2004-2008, due

to global political instability and market volatility, and

future projections of oil and gas prices envisage much more

subdued markets. However, the projected rise in gas and

electricity prices over the next 20 years is quite

conservative, and should political events lead to future

instability in world energy markets over this period, the

projected savings of nearly !3 million by the Glucksman

geothermal system over the lifetime of the installation may

be significantly enhanced.

REFERENCES

Allen, A.R., Milenic, D., (2003) Low enthalpy geothermal

heat resources from groundwater in glaciofluvial

gravels of buried valleys. Applied Energy, 74, 9-19

Browne, D. (2005) Lewis Glucksman Art Gallery. Final

year project thesis, Cork Institute of Technology, April

2005. (Unpublished)

Burgess, J. (2005) Advanced Heating and Cooling Solution

for Large Buildings, Ground Energy Thermal Transfer

System at UCC Lewis Glucksman Art Gallery. Arup,

CIBSE

Burgess J (2007) State of the Art – Inside the ECO Gallery.

Construct Ireland, 2007.

http://www.constructireland.ie/articles/0207gallery.ph

p.

Gondwe, K.T. (2008) Performance Assessment of the

Glucksman Art Gallery Geothermal Heating and

Cooling System. MSc Thesis, University College

Cork, Ireland, 77pp (Unpublished)

Gondwe et al.

10

Huston, A. (2003) “03032 UCC Art Gallery & Restaurant

MCC01 - Control Strategy Narrative .Doc”, Standard

Control Systems, Dublin, November 2003.

Kennett, S. (2005) “Tall Story”. Building Services Journal,

08/05, August 2005

O` Regan K (2007) UCC Heat Pump Case Study - The

Lewis Glucksman Gallery., SEI Awards 2005 -

Overall Winner - Category C – Thermal Energy

Project. SEI Alternative Heat Roadshow

York Polaris (1999) York Polaris Water Cooled and

Remote Air Cooled Chillers. Doc. No.

PC0001/04.99/9B

Proceedings World Geothermal Congress 2010

Bali, Indonesia, 25-29 April 2010

1

Investigation of Source and Conduit for Warm Geothermal Waters,

North Cork, Republic of Ireland.

Brecan Mooney1,2

, Alistair Allen1, Paul K!niger

3

1Dept of Geology, University College Cork, Cork, Ireland

2WYG Environmental and Planning (Ireland) Limited, Unit 2, University Technology Centre, Curraheen Rd., Cork, Ireland

3Geochronology and Isotope Hydrology, Leibniz Institute for Applied Geophysics, Geozentrum Hannover, Stilleweg 2, 30655

Hannover, Germany

E-mail: brecan.mooney@wyg.com; a.allen@ucc.ie; paul.koeniger@liag-hannover.de

Keywords: Source aquifer, fault conduit, Caledonian

lineament, Variscan orogeny, well temperature survey,

hydrochemical analysis, geophysical survey

Brecan Mooney was tragically drowned on Thursday 19

November, 2009, soon after this paper was finalized. He

was only 31 years old, a professional hydrogeologist with

an enormous zest for life. He was conducting this

investigation in his spare time for an MSc degree in the

Department of Geology, UCC.

ABSTRACT

Far from plate boundaries, with no recent volcanism or

tectonism, and with geothermal gradients of <25°C/km,

Ireland has few geothermal resources apart from 42 warm

springs ranging in temperature from 13-24.7°C. These are

concentrated in two groups, in the south-west and east

central parts of the country. Recently groundwater at 26°C

was encountered at a depth of 40m during routine well

drilling operations near the town of Mitchelstown in the

south-west, the warmest groundwater encountered to date in

the shallow Irish subsurface. It is interpreted to have

migrated upwards from greater depth via a steep fault

structure. A research project is in progress with the aim of

identifying the source aquifer and fault conduit, controlling

upwards movement of the warm water, and also to assess the

potential of the warm water for district heating purposes.

A major NE–SW lineament, identified on landsat images, of

probable Caledonian (425-395 Ma) age, possibly

subsequently reactivated during the Variscan Orogeny (295-

315 Ma), passes close to the Mitchelstown well. It extends

30 km SW to the town of Mallow, where a 22°C warm

spring, which formed the basis for a spa resort in the 19th

century, is today being utilised with a heat pump to heat the

municipal swimming pool. Geophysical surveys are being

conducted to accurately delineate this structure on the

ground.

A temperature survey of all water wells and springs in the

Mallow-Mitchelstown area and further to the NE has been

conducted. Although average groundwater temperatures in

Ireland are of the order of 9-11.5°C, a number of the wells

surveyed record anomalous temperatures in excess of 12°C,

interpreted to represent mixing of warm deep groundwater

with cooler near surface groundwater. To test this

hypothesis, a programme of hydrochemical analyses has

been undertaken for normal and trace components and the

stable isotopes 18O/16O and 2D/1H. Lower nitrate and

chloride/bromide ratios and possibly higher lithium in the

anomalous wells appears to differentiate the warmer water

from depth from cooler near surface water with which it has

mixed. This it is hoped will also fingerprint the source of the

warm waters. The ultimate objective is to locate the fault

conduit sufficiently accurately to make it possible to drill to

intersect the fault at moderate depth in order to tap the

migrating warm water where it can be utilized, and to this

end it is hoped to develop a methodology which can be

applied in other similar situations.

1. INTRODUCTION

Ireland is located far from any plate boundaries, and has not

been subject to volcanism or tectonism in the recent past, so

geothermal gradients are low (<25°C/km) (SEI, 2004), and

in the south of the country, geothermal gradients are as little

as 10°C/km (Goodman et al., 2004). Thus Ireland is unlikely

to have any high temperature geothermal resources. Typical

groundwater temperatures in Ireland vary from

approximately 9 -11.5°C (Aldwell & Burdon, 1986), whilst

soil temperatures are usually around 10°C. These

temperatures represent the balance between solar and

geothermal recharge, and radiation from the ground surface,

quantified by Aldwell & Burdon (1986), and remain

relatively constant throughout the year due to Ireland’s

temperate maritime climate. Heat can be extracted from soil

and groundwater at these, seemingly low but consistent,

temperatures for a plethora of uses, utilizing modern heat

pump technology.

Springs, seepages and spring wells are ubiquitous in Ireland,

particularly in the Dinantian limestone bedrock underlying

much of the Midlands of Ireland. Exploitable geothermal

resources occur in unusual geological settings where

groundwater that is warmer than normal (>12oC) rises up

through limestone catchments (Aldwell, 1986), discharging

at the surface as low enthalpy geothermal springs. 42 of

these warm springs, mainly located in Dinantian Limestone,

and ranging in temperature from 13-24.7°C have been

recorded (Aldwell et al. 1980; Burdon, 1983; Aldwell and

Burdon 1986; Goodman et al, 2004), and are concentrated in

two groups in the E and SW of the country. The earliest

recorded warm spring in Ireland occurs at Mallow in the SW

where the spring at Lady’s Well gave rise, in the 18th and

19th Centuries, to a spa resort. Apart from this spring, which

has subsequently been harnessed to heat the municipal

swimming pool (O’Brien, 1987), little utilisation of these

warm water energy resources has taken place, mainly

because of the rural settings where most occur that in the

past has limited potential options for their exploitation.

The Mallow spring has an average temperature of 19.5°C ±

2.5°C, with higher temperatures recorded in summer and

lower temperatures recorded in winter, thought to reflect

greater dilution of the warm water with colder water runoff

during periods of higher rainfall.

The origin of these warm water resources is uncertain, but it

is generally assumed that they represent deep groundwater

Mooney et al.

2

sources brought rapidly to the surface from considerable

depth by faults (e.g. Aldwell and Burdon, 1986; Murphy &

Brück, 1989). Such deep circulation would be facilitated by

bedrock permeability related to deep faulting. The specific

factors causing deep circulation are summarised by Aldwell

& Burdon, (1986) as:

• structural aspects favoring vertical over horizontal

flow;

• topography leading to higher head pressures;

• increased precipitation and thus enhanced recharge;

• high infiltration; and

• karstification, particularly palaeokarst, essential for

facilitation of deep circulation in Irish carbonate

rocks.

Geothermal waters heated at depth in confined aquifers may

reach the surface if the source aquifer is penetrated by a

permeable fault zone, and if the water is under sufficiently

high piezometric pressures to generate artesian conditions.

The 42 warm springs in Ireland represent situations where

both these conditions are met, but situations where

piezometric pressures are subartesian, or where an

impermeable obstacle prevents the geothermal water from

reaching the surface, may be more widespread.

Two methods of investigating the existence of such

resources, is by deep drilling programmes to the postulated

source aquifer in favourable sites, which is generally

extremely costly, or by identifying a fault structure, up

which warm water has migrated, and drilling to intersect the

fault at moderate depth in order to extract the warm water

within it. Once a fault is identified and its location,

orientation and extent delineated accurately, it may be

tapped at a number of points. This represents a much less

expensive option, and is the objective of the present

investigation.

Sometimes geothermal waters are encountered unexpectedly

at shallow levels during routine drilling operations, and

represent situations where either insufficient piezometric

pressures prevail, or some obstacle prevents the geothermal

waters from flowing to the surface. However, the heated

water has almost certainly reached shallow levels by

migration up a fault intersecting the source aquifer.

Regardless of whether the geothermal water penetrates to the

surface, or what prevents it from reaching the surface, such

heated water is an exploitable geothermal resource and

should be further investigated to determine if additional

heated groundwater resources exist at shallow levels where

they can be readily tapped and utilised.

Recently, a well drilled for water supply purposes by Cork

County Council at Johnstown in the Glanworth area of

North Cork in SW Ireland, encountered moderate quantities

of warm groundwater at temperatures of 23-26°C at a depth

of 40m, the warmest shallow groundwater as yet recorded in

the Republic of Ireland. In this investigation, we attempt to

establish the source aquifer and the conduit controlling

migration of this warm water towards the surface, with the

intention of assessing the extent of the resource, and the

potential for exploiting it. In addition, we wish to develop a

methodology of investigation, which can be universally

applied in other similar situations.

2. RATIONALE AND METHODOLOGY

This project is being undertaken in light of concerns over the

use of fossil fuels as a means of energy supply, and the need

to develop alternative clean safe inexpensive secure and

renewable sources of energy. The Kyoto protocol commits

Ireland to reduce CO2 emissions to 115% of the levels in

1990 by 2012. At the present time Ireland is falling short of

this target and fines will be imposed unless a concerted

effort is made to reduce CO2 emissions. The study has

identified significant hydro-geothermal resources in the

North Cork area that may be exploited, resulting in

considerable benefits for the region.

A temperature survey of groundwater wells was carried out

in and around the Mallow and Mitchelstown area. This

served a twofold purpose:

• firstly as an initial screening process it would

identify any more geothermal anomalies existing in

the area enabling any patterns that may exist to be

studied with the purpose of providing explanations

for these anomalies;

• secondly, the well survey data quantifies ambient

groundwater temperatures in the region which

together with known aquifer productivity maps from

the Geological Survey of Ireland (GSI) give an

approximation of the geothermal resource in the

North Cork area.

Following the well survey a 2-D resistivity study was

undertaken to further characterize the bedrock aquifers in

which anomalies were observed. The hypothesis is that

geological structures present in the subsurface provide a

conduit bringing warm water to the surface from depth in

these areas exhibiting higher than average groundwater

temperatures. As permeability in the Palaeozoic sediments

of the Munster Basin is almost always fracture related, 2-D

resistivity was a relatively inexpensive way to augment the

literature search and provide some structural context in two

anomalous areas that were lacking in outcrop.

A hydrochemical analytical program was subsequently

undertaken in order to further pinpoint a possible source for

the thermal waters and these results are also discussed.

3. REGIONAL GEOLOGY AND HYDROGEOLOGY

Ireland generally consists of a mountainous rim composed of

Precambrian to Lower Palaeozoic crystalline rocks

surrounding a lowland interior largely underlain by U.

Devonian to L. Carboniferous sandstone, shale and

limestone (Fig. 1).

Late Palaeozoic, Mesozoic and Tertiary rocks are absent,

apart from in the NE corner of the island, where they are

preserved beneath the basalt plateau of the 50-60Ma Tertiary

North Atlantic Igneous Province associated with the opening

of the North Atlantic. However, there is evidence that they

were also deposited over much of the rest of the island, but

were stripped away by the intense erosion and peneplanation

that accompanied the opening of the North Atlantic.

U. Palaeozoic bedrock, whilst underlying much of the

interior of Ireland, is generally buried beneath a cover of

Pleistocene glacial till and Holocene peat deposits, and is

rarely exposed. L Carboniferous limestone, which dominates

the U. Palaeozoic, is extensively karstified, but overburden

deposits are relatively thick and surface expression of karst

is generally absent. Thus, most of Ireland’s limestone

bedrock consists of buried karst.

Mooney et al.

3

Ireland lies within the Caledonian orogenic belt, which

affected all Precambrian and L. Palaeozoic units.

The Iapetus Suture, marking the collision zone of

Laurentia and Avalonia, runs diagonally across

Ireland from the Shannon estuary to Clogher Head,

50 km to the north of Dublin. All of the warm

springs in the Irish Republic lie to the south of this

tectonic line.

Figure 1: Relief Map of Ireland showing NE-SW

trending morphology in south-central Ireland.

(NASA)

The late Carboniferous Variscan (Hercynian) Orogeny

affected the very south-west of Ireland, which represents the

westernmost extension of the external Rheno-Hercynian

Zone of the Variscan Orogenic Belt. Its northern boundary,

the Variscan Front, is the Killarney-Mallow Fault Zone

(KMFZ), which runs E-W, midway between the south coast

of Ireland and the Shannon estuary. The southwestern group

of warm springs are all situated just to the north of this

tectonic boundary.

Tectonism with accompanying fault activity in the SW of

Ireland can be summarized as:

• Caledonian orogenesis (c. 425–395Ma) associated

with oblique sinistral closure of the Iapetus Ocean

manifested by NE-SW strike–slip faulting in a

transpressional regime (Phillips, 2001), and low

grade metamorphism leading to complete

recrystallisation of L. Palaeozoic and older rocks and

complete loss of primary porosity.

• Extensional development of the Munster Basin of

SW Ireland (c. 395-350Ma), related to evolution of a

stretched passive continental margin, and resulting in

repeated reactivation of the pre-existing NE-SW

Caledonian strike-slip faults as basin bounding

normal faults. This was accompanied by progressive

subsidence, with deposition of thick accumulations

of high porosity U. Devonian Old Red Sandstone

terrestrial clastics, and subsequent marine

transgression and deposition of low porosity L

Carboniferous marine clastic and biogenic sediments.

• Variscan orogenesis (c. 350-320Ma) associated with

N-S collision of Laurussia and Gondwana, and the

formation of a very low grade fold-thrust belt in SW

Ireland. The E-W Killarney–Mallow Fault has been

postulated to represent the sole thrust (e.g. Landes et

al. 2002), and is marked by a sharp discontinuity in

deformation intensity (Gill, 1962), with almost

complete loss of primary porosity of the U.

Palaeozoic rocks to the south of this structure, but

very weak deformation and possibly very little

reduction in primary porosity to the north. NE-SW

Caledonian faults are thought to have been further

reactivated, some as thrusts and others possibly as

strike-slip faults.

Geothermal gradients in the island of Ireland although

overall relatively low, generally increase towards the NE,

where a maximum of 35°C/km has been found in County

Antrim (Goodman et al, 2004), due to enhancement of

geothermal gradients by the Tertiary igneous activity. Low

yields of relatively hot water at 88°C were encountered in

the early 1980’s in a borehole to 2.8 km depth at Larne to

the NE of Belfast, within the Permo-Triassic Sherwood

Sandstone, an aquifer widespread in Britain, but only present

in Ireland in the extreme NE preserved beneath the Tertiary

Basalt plateau. In the Irish Republic, conditions for

generation of hot water at depth are not favourable, but the

presence of 42 warm springs, indicates that aquifers do

occur at depth, and that moderate geothermal resources,

which could be exploitable, do exist.

4. IDENTIFICATION OF THE FAULT CONDUIT

The first task was to identify the fault conduit which has

controlled the upwards migration of the geothermal waters.

The borehole with the warm water at Johnstown near

Mitchelstown in North Cork is located approximately 20 km

to the northeast of the Lady’s Well spring at Mallow and

other historically mentioned, but lesser known warm springs

in the Mallow area. There is a strong possibility that a

relationship may exist between the two geothermal

occurrences, which may have a similar source aquifer and a

similar migratory path from depth. This would suggest that

their upwards migration may have been controlled by a steep

NE-SW Caledonian trending structure. However, the

Mallow-Mitchelstown area is relatively flat with virtually no

outcrop, and the geological map of this area (Fig.2) shows

no evidence of a major NE-SW structure.

Figure 2: Geological map of area of investigation. (After

Geol. Survey of Ireland (GSI) Regional Map)

Mooney et al.

4

A landsat map of the Mallow-Mitchelstown area (Fig. 3)

emphasises the local relief, and clearly illustrates the NE to

SW Caledonian trending physiography of the region. The

region is transected by the E-W flowing Blackwater River,

which exploits the KMFZ, and to the north of this is

dominated by the Galtee Mountains in the north and the

Knockmealdown Mountains in the east. A faint but

conspicuous NE-SW trending lineament can be discerned

emanating from Mallow in the SW and projecting

northeastwards towards Mitchelstown and onwards along

the southern margin of the Galtee Mountains. It appears to

be one of a series of sub-parallel lineaments, which splay

southwestwards from the southern margin of the Galtee

Mountains. These lineaments have been referred to as the

Dingle-Galtee Mountains Fault Zone (DGMFZ) (e.g.

Vermeulen et al., 2000), regarded as the basin-controlling

and bounding structures for the Munster Basin. It is likely

that these structures have been offset by minor N-S strike-

slip faults, which appear to represent late Variscan

compartmental faults associated with thrust tectonics, and it

is possibly truncated by the KMFZ at Mallow. Close

examination of the landsat image indicates that the structure

passes close to the Spa Glen in Mallow and the vicinity of

the Johnstown well near Mitchelstown.

Figure 3: 1:40,000m Relief Map of investigation area

with possible fault conduit lineages

To the northeast of Mitchelstown, a major steep southwards-

dipping NE-SW reverse fault defines the southern margin of

the Galtee Mountains inlier, and brings a sequence of steep

southerly dipping U. Devonian sandstones and

conglomerates in the footwall into juxtaposition with

synclinally folded L Carboniferous limestones and shales.

Any of these U. Devonian formations could be a candidate

for the source aquifer.

In the southwest of the study area at Mallow, a number of

parallel southerly-dipping E-W faults mark the KMFZ again

with southerly-dipping units on their footwalls. However,

most of these are siltstone/shale or limestone units, none of

which would appear to be likely candidates for a source

aquifer. L. Carboniferous limestones, although widely

karstified in the Irish midlands are unlikely to represent the

source aquifers, as karstification appears to have mainly

taken place during the Tertiary, subsequent to any tectonism

in Ireland, and since karstification is a relatively superficial

process, it is doubtful whether deeply buried limestones

would have sustained karstification.

The minor N-S strike-slip faults offset northeasterly striking

geological units in the Mallow-Mitchelstown area and

beyond along the southern margin of the Galtee Mountains.

The Lady’s Well spring at Mallow is situated in an

entrenched narrow N-S valley, the Spa Glen, which exploits

one of these latter faults, and many of the anomalous wells

may also be located on such minor cross faults. These faults

are however not interpreted to represent the fundamental

fault which has controlled migration of the warm

groundwater from depth, but may have provided final

pathways for circulation of the warm groundwaters at

shallow crustal levels.

5. GROUNDWATER TEMPERATURE SURVEY

In order to test the validity of the interpretation of the NE-

SW fault conduit for the geothermal waters at Mallow and

Mitchelstown, a temperature survey of groundwater wells in

the Mallow-Mitchelstown area was conducted.

Shallow groundwater (<100m depth) in the southern part of

Ireland typically records an annual average temperature

range of 10.48-11.08oC (Aldwell & Burdon, 1986) due to a

balance of surface recharge, incident solar radiation and

outgoing radiation from the Earths surface as mentioned

earlier. Care is required in measuring groundwater

temperatures in boreholes that do not have natural flow:

temperatures representative of the groundwater aquifer

“tapped” by the borehole must first be attained by slow

purging of at least three well volumes of water from the

borehole before measurement of the temperature of the

boreholes should be attempted. Heat generated due to

pumping also affects temperature, so it is preferable to hand

purge wells with bailers and to turn off pumps in pumping

wells for a minimum of 24 hours prior to measuring the

temperature. Purging was not considered necessary in wells

that were known to be in constant use and these wells were

monitored following periods when the pump was not in use.

Purging was also not required in flowing springs and one

artesian well that had a constant flow.

In this study, groundwater temperatures were measured

directly in the borehole using a down borehole probe. The

survey was carried out in accordance with the sampling

protocol of British Standard Code of Practice for Site

Investigations (BS 5930: 1999).

The temperature survey has quantified the spatial

distribution of groundwater temperatures in the area between

Mallow, Co. Cork and Cahir, Co. Tipperary, 20 km to the

NE of Mitchelstown and has compared these temperatures to

normal observed groundwater temperatures within Ireland.

For the purposes of this study a conservative “normal”

temperature range of 10-12°C is assumed. The survey

indicates that a correlation may exist between the presence

of crustal faults and elevated groundwater temperatures.

Monitoring points were identified from the Geological

Survey of Ireland (GSI) groundwater well database, Cork

County Council records, ordnance survey maps which were

particularly useful for identifying springs, and interviews

with local hydrogeological consultants, drilling contractors,

and with local inhabitants. A total of seventy wells were

monitored between July 2006 and July 2008. Stagnant water

was purged from the wells prior to measurements being

taken and a sonde was employed that allowed temperature

and conductivity readings to be measured simultaneously.

Well locations and recorded temperatures are listed in Table

1 and on topographic and geological maps of the Mallow-

Cahir area (Figs. 4 & 5). Of the 70 well temperatures

recorded in the survey, 67 readings are considered accurate

representations of the groundwater aquifer. Suspected

surface water intrusion could not be ruled out in 3 of the

wells (Nos. 30, 62 and 63) and therefore these elevated

temperatures have not been included in the geothermal

maps.

Mooney et al.

5

Table 1. Well Temperature Survey Data.

!"##$%& '()*#+*, &+-" .+/-0*1 2(3-40*1 'ºC 5(66"*-/

1 Leaselands 01/08/2006 555 993 12.9 Well depth 100m (Hydrogeological report available)

2 Leaselands 01/08/2006 555 993 13.1 Well depth 100m (Hydrogeological report available)

3 Kilknockan, Mallow 20/05/2006 547 996 10.9 Farm supply well

4 Annabella, Mallow 20/05/2006 544 987 10.71 Well depth 100m (Hydrogeological report available)

5 Annabella, Mallow 20/05/2006 544 987 10.62 Well depth 100m (Hydrogeological report available)

6 Annabella, Mallow 20/05/2006 544 987 10.24 Well depth 100m (Hydrogeological report available)

7 Johnstown, Mitchelstown 23/05/2006 774 111 25.9 County Council Supply Well

8 Gooldshill, Mallow 27/05/2006 552 965 11.5 Disused farm production well

9 Ballydeloughy, Kildorrery 04/07/2006 745 097 10.55

10 Ballydeloughy, Kildorrery 04/07/2006 745 097 10.79

11 Ballydeloughy, Kildorrery 04/07/2006 745 097 10.95

12 Killdorrery 15/01/2006 685 100 10.9 Hydrogeological report available

13 Ballyvoddy, Kildorrery 04/07/2006 706 076 12.54 Yield Approx. 300 Ga/Hr

14 Ballyvoddy, Kildorrery 04/07/2006 706 076 10.42 (35m West of CF1)

15 Ballendangan 04/07/2006 754 091 11.22 EPA IPC monitoring well 1,000-1,200 Ga/Hr

16 Ballendangan 04/07/2006 754 091 10.92 EPA IPC monitoring well 1,000-1,200 Ga/Hr

17 Ballendangan 04/07/2006 754 091 10.85 EPA IPC monitoring well 1,000-1,200 Ga/Hr

18 Ballykenly 05/07/2006 762 075 10.46

19 Broomhill 05/07/2006 783 118 11.21

20 Carriganleigh 06/07/2006 792 121 10.57 500-600 Ga/Hr

21 Ballyenahan 06/07/2006 723 090 10.71 Total Depth of well 55 ft.

22 Derryvillane 06/07/2006 736 074 11.03 Total Depth of well 225 ft.

23 Derryvillane 06/07/2006 739 071 11.07 Total Depth of well 50m approx.

24 Gortnagreiga 07/07/2006 562 951 11.22

25 Carrigaduff 07/07/2006 570 949 10.41

26 Clogheen, 07/07/2006 573 932 11.1 Well Depth 120ft.

27 Ballinvussig Waet 07/07/2006 581 946 10.73

28 Ballynamona Br. 07/07/2006 564 930 10.63 110 Ft. Well ORS

29 Monavooria 08/07/2006 603 985 11.49

30 Ballymacmoy, Killavullen 08/07/2006 986 636 13.02 Dug Well, probable surface water source.

31 Ahaunboy, Killavullen 08/07/2006 633 998 11.05 400ft. Well.

32 Mallow 08/07/2006 564 986 20.01

33 Ballygarrane Cross Roads 09/07/2006 644 025 11.79

34 Ballyveelick 09/07/2006 643 025 10.8 Static water level 23m

35 Ballygrilihane 09/07/2006 684 031 12.53 Probable surface water source.

36 Carrigpark 23/09/2006 60957 01497 11.08 Well depth 160ft. Drilled 5 - 6 weeks previously.

37 Carrig Demesne 23/09/2006 61377 00499 12.29 Old well, not in use. Donal Turner

38 Kilcanway 23/09/2006 62546 00239 11.57 Spring.

39 Keatley's Close 24/09/2006 57891 99210 10.68 Domestic supply well.

40 Spring 24/09/2006 65003 00077 11.9 Spring.

41 Powerstown 24/09/2006 62880 04203 11.02 Domestic suply well.

42 Newberry 14/01/2007 51661 97086 12.9 7.37 pH Artesian well drilled into Limestone

43 Newberry 14/01/2007 51634 97064 12.11 Well drilled into sandstone.

44 Newberry 14/01/2006 51591 47031 12.12 7.35 pH, Natural spring in sandstone.

45 Mallow 14/06/2008 54962 01879 11.49 Domestic supply well. SWl 4.78m

46 Mallow 14/06/2008 55981 02029 11.17 Domestic supply well. SWL 2.15m Well depth 19.3m.

47 14/06/2008 56172 02367 10.84 Domestic supply well. SWL 5.9m. Well depth 35m.

48 14/06/2008 56088 04092 10.69 Domestic supply well. SWL 5.9m. Well depth 35m.

49 Ballybrack 14/06/2008 58548 03829 10.67 Domestic/farm supply well. SWL 2.3m.Well depth 40m.

50 14/06/2008 58250 02852 11.84 SWL 1.95m. Total depth 43.68m.

51 14/06/2008 58837 02209 11.68

52 14/06/2008 57179 01312 11.26 SWL 6.50m BGL Total depth 30.48m.

53 Dromdeer, Doneraile 14/06/2008 63006 05431 10.74 SWL 6.2m BGL. Coal seams reported historically

54 14/06/2008 62512 05440 10.87 SWL 3.8m Total depth 27m.

55 14/06/2008 62270 06798 11.04 SWL 7.85m BGL

56 Doneraile 14/06/2008 63657 07384 11.54 Domestic supply well

57 Cregg 02/06/2008 R 000 770 10.82 SWL 11.00m. Domestic well

58 Cornhill, Fermoy 02/06/2008 R 022 778 11.45 Farm supply well

59 Ballyhooley South 02/06/2008 W 997 736 11.6 Domestic well

60 Kilbehenny PWS 28/07/2008 R 865 157 11.72 Spring (Farm Supply)

61 Coolagarranroe 28/07/2008 R 902 174 11.16 Domestic

62 Ballyhuroo 28/07/2008 R 961 198 18 Pond - Mainly surface water influence

63 Kilcaran GWSS 29/07/2008 R 986 217 13.56 Domestic group water scheme, surface water ingress

64 Scartnaglorane 29/07/2008 R 998 219 10.44 Farm and domestic supply well

65 Benguragh 29/07/2008 S 044 257 11.15 Farm well

66 Holy Well 29/07/2008 S 042 258 11.16 Domestic well (Dug stone lined well)

67 Benguragh 29/07/2008 S 042 256 11.39 Holy Well - Spring

68 Tarrent Concrete 30/07/2008 S 054 264 11.01 Tarrant concrete production well

69 Rossadrehid 30/07/2008 S 054 274 11.92 Domestic well

70 Rockwell College 30/07/2008 S 071 343 10.94 Rockwell College Supply well

Mooney et al.

6

Figure 4: Well Temperature Survey Data Plotted on Ordnance Survey of Ireland Regional Map

Figure 5: Location and Temperature of Wells Plotted on the GSI Regional Bedrock Geology Map

Mooney et al.

7

Of the remaining 67 wells, 57 (85%) had temperatures that

fell within the conservative “normal” range. Temperatures of

10-10.5ºC were recorded by 4 wells (Nos. 14, 18, 25 and

64); 21 wells (No.’s 3, 4, 5, 6, 9, 10, 11, 12, 16, 17, 20, 21,

27, 28, 34, 39, 47, 48, 49, 53 and 70) recorded temperatures

of 10.5-11ºC; 24 wells (No.’s 15, 19, 22, 23, 24, 26, 29, 31,

36, 41, 45, 46, 50, 52, 54, 55, 57, 58, 59, 61, 65, 66, 67 and

68) gave temperatures of 11-11.5ºC and 8 wells (No.’s 8, 33,

38, 40, 51, 56, 60 and 69) gave temperatures of 11.5-12ºC.

None of the wells surveyed recorded temperatures below the

normal range for groundwater in Ireland.

The remaining 10 wells (15%) recorded temperatures that

exceed the normal range for Irish groundwater of 10-12ºC.

Temperatures of 12-12.5ºC were recorded by 3 of the wells

(No.’s 37, 43 and 44). Four of the wells (No.’s 1, 13, 35 and

42) recorded temperatures of 12.5-13ºC; One well (No. 2)

gave a temperature of 13.1 ºC. Two wells (No. 7 and No.

32, Spa House Mallow and the Johnstown County Council

Well) recorded temperatures in excess of 20ºC.

The topographic map (Fig. 4) shows that the wells with the

anomalous temperatures are strung out in a NE-SW linear

trend and are spatially related to a line projecting from

Mallow to Mitchelstown. This represents the location of the

lineament identified on the landsat map, the postulated

conduit controlling upwards migration of the geothermal

waters.

Given a geothermal gradient of around 10oC/km for this part

of Ireland (Goodman et al, 2004), the observed maximum

temperatures of 22°C at Mallow and 26oC at Johnstown,

would reflect groundwater from depths of ca. 1,100m and

ca. 1,500m respectively, assuming normal surface

temperatures of 11°C for this region. Should dilution be a

significant factor, the warm groundwater may have

circulated from greater depth.

Of the 70 wells surveyed and listed in Table 1, a significant

proportion (15%) recorded temperatures in excess of 12°C.

The GSI has classified warm springs as springs recording

temperature in excess of 13°C, but this does not necessarily

mean that all springs with temperatures below this level

represent shallow circulating meteoric waters of surface

origin. If the range of shallow groundwater temperatures in

Ireland is less than 11.5°C, then the wells in excess of 12°C

must contain a component of warmer water.

The volume and temperature of warm spring waters reaching

the surface, depends on the porosity and permeability of the

source aquifer and fault conduit, and on the geothermal

gradient. The higher the geothermal gradient, the greater is

the likelihood of encountering high temperature groundwater

resources at shallow depth. However, if the fault conduit

intersects other aquifers at shallower depths, groundwater

from the shallower aquifers will cool the warmer

groundwater as it migrates up the fault, to the extent that it

may be reduced to normal shallow groundwater

temperatures. In much of SW Ireland, karstified deposits of

the Waulsortian Limestone Formation at shallow depth, may

be the source of cooler groundwaters which reduce the

temperature of deep warm groundwaters during their

upwards migration. It is possible that all of the warm water

springs in SW Ireland may be sourced from a single deep

aquifer, but that the circulating warm groundwaters have

been differentially affected by cooler waters during their

upwards migration, accounting for the range in temperatures

of these springs. Indeed many well waters with temperatures

in the ‘normal’ range of groundwater may have a component

of warm groundwater that has been so diluted by cooler

waters at shallow levels that the temperatures have been

lowered to below 12°C.

Figs. 6 and 7 illustrate the location and temperature of wells

on the GSI regional aquifer classification and aquifer

vulnerability maps. The purple areas on Fig. 7 indicate

limited knowledge of the depth to bedrock due to a subsoil

cover usually in excess of three metres. Thick deposits of

Pleistocene glacial overburden, which blankets much of

Ireland, may have buried a NE-SW trending structure in the

underlying bedrock.

Thus the temperature survey of water wells carried out

between Mallow and Mitchelstown indicates anomalous

temperatures along a NE-SW trend suggesting the possible

presence of a buried Caledonian-aged fault. The thick clay–

rich overburden in the Mallow-Mitchelstown area may have

blanketed this structure and acted as a confining layer,

preventing geothermal waters from penetrating to the

surface. Intersection of minor N-S compartmental faults of

Variscan age with this fundamental fault may have aided

some of the geothermal waters to reach the surface as at

Mallow and at Johnstown, and elsewhere may also have

provided pathways for groundwater migration.

6. GEOPHYSICAL INVESTIGATIONS

In areas of poor to non-existent outcrop such as the Mallow-

Mitchelstown area, geophysical techniques are powerful and

essential tools in gaining a reasonable understanding of the

bedrock geology. Geophysical investigations also play an

important role in identifying aquifer systems and outlining

aquifer configurations under varying hydrogeological

conditions. In addition, geophysical surveys can be very

useful in delineating accurately the location of buried faults.

Surface electrical resistivity surveys utilising the vertical

electrical sounding (VES) technique has proved particularly

useful for groundwater studies due to its simplicity and cost-

effectiveness. A well-planned, non-invasive, geoelectrical

investigation is capable of mapping aquifer systems,

confining layers (i.e., clay formations), depth and thickness

of aquifers, and groundwater quality (Jha et al., 2008).

A limited preliminary electrical resistivity survey was

undertaken involving the acquisition of vertical geoelectrical

soundings across two profiles in the study area. The

locations of the profiles took into consideration data

acquired during a literature search and also data from the

well temperature survey. The profiles were thus conducted

in areas where elevated groundwater temperatures had been

identified during the well survey and therefore where there

was the possibility of a buried Variscan-reactivated

Caledonian structure affecting groundwater circulation and

migration.

The two traverses were undertaken adjacent to the

Johnstown borehole and in the Carrig Demesne area on the

outskirts of Mallow adjacent to one of the anomalous wells

and relatively close to the Spa Glen and Lady’s Well. The

geolectrical soundings and the interpreted geophysical

profiles are presented in Fig. 8.

Mooney et al.

8

Figure 6: Location and Temperature of Wells Plotted on GSI Regional Aquifer Classification Map

Figure 7: Location and Temperature of Wells Plotted on GSI Regional Aquifer Vulnerability Map

Mooney et al.

9

Figure 8: Diagrams of the Geoelectrical soundings and the geoelectrical geophysical profile in the area of the well at

Johnstown, Mitchelstown (Well Survey Reference No. 7) (top) and Sean and Liz Turner’s well, Carrig Demesne

(Well Survey Reference No. 37)

The interpretation of electrical resistivity data from the

Johnstown borehole indicates karst permeability in a

fracture/conduit zone dipping approximately 30° south of

the borehole location and for the Carrig Demesne locality,

two sub-horizontal conduit zones running beneath the well.

This interpretation of the geo-electrical data supports the

hypothesis that thermal waters are travelling laterally along

karst structures having circulated to some great depth via

fault related conduit permeability.

A further geophysical project to delineate the precise

location and orientation of the fault conduit is planned for

Autumn 2009. The intention is to conduct a series of NW-

SE traverses at 1-2 km intervals across the postulated line of

the fault utilising a combination of the electrical resistivity

lateral mapping technique and the electromagnetic VLF

method. This it is hoped will confirm the presence of the

fault, and enable any future drilling programme seeking to

tap into and exploit a warm water supply along the line of

the fault to make a more informed selection of borehole

sites.

7. GEOCHEMICAL INVESTIGATIONS

Geochemical investigations were undertaken in order to

fingerprint the warm geothermal waters, with the hope that

distinctive hydrochemical characteristics may be established,

allowing the source aquifer and the circulatory pathway of

the warm waters to the surface to be distinguished. Similar

exercises have been successful in identifying source and

pathways of geothermal waters elsewhere (e.g. Andrews et

al. 1982).

Major Ions

A survey conducted by Burdon (1983), ascertained that in

general the ionic content of Irish warm spring waters is

typical of Irish groundwater as a whole. This could be

interpreted as an indication that most Irish warm springs

Mooney et al.

10

water have mixed with cooler near-surface groundwater

during their ascent to the surface

The chemistry of the Lady’s Well spring at the Mallow Spa

was investigated by University College Cork over the period

September 1981-January 1983 (Brück et al, 1986). The

results of this study indicates that the water is of calcium

bicarbonate type and similar to the local groundwater in the

limestone aquifers. The main differences are slightly lower

calcium, bicarbonate, and nitrate concentrations in water

from Lady's Well. Further geochemical analyses of 10

representative samples of both thermally anomalous and

normal wells and springs were undertaken to augment the

existing knowledge base as part of this study (Table 2).

Temperatures listed in Table 2 were those taken during

sampling, and are lower than those in Table 1, as sampling

took place in winter when rainfall was greater and water

table levels higher.

Earlier observations were confirmed during this study, with

all ten of the samples analysed for major ions recording

calcium bicarbonate type water characteristic of the local

limestone aquifers. Generally the trend was for thermally

anomalous wells to have slightly lower levels of all three of

the ionic parameters of calcium, bicarbonate and nitrate.

Nitrate

In this intensely farmed area, the presence of nitrate in

groundwater reflects an anthropogenic origin and indicates

recent recharge of the shallow groundwater within all of the

wells in the study area. However, concentrations of nitrate

are significantly lower in the thermal wells indicating less

mingling of the thermal waters with more recent shallow

groundwater (Table 3).

The lowest concentration of nitrate was observed in the well

which recorded the highest temperature, the Johnstown well

(Table 1, No. 7), followed by three other thermal wells and

springs: the Sugar Factory spring, the Sugar Factory artesian

well and the Lady’s Well, Mallow (Table 1; Nos. 44, 42 and

32), whilst the next two lowest values also were recorded by

wells which exhibited anomalous thermal values in the

original survey. The remaining four wells, which exhibited

normal groundwater temperatures during the original survey

exhibited significantly higher concentrations of nitrate.

These results suggest that due to its anthropogenic origin

nitrate is a useful indicator of mixing of geothermal water

with shallow cooler recently recharged groundwater, and

that the higher the value of nitrate in the geothermal water

the greater the degree of dilution of the geothermal water by

shallow groundwater.

Table 2. Ionic Composition of Wells.

Well Survey Ref. No. 7 32 42 44 37 21 13 59 33 19 Units

Sampling Date (d.m.2009) 31.01 24.01 24.01 07.02 08.02 07.02 07.02 07.02 31.01 31.01 mg/l

Temperature 23 17.5 12.1 11.2 11.2 11.1 10.9 10.8 10.4 10.35 °C

Sulphate 12.08 18.13 14.11 11.24 14.22 11.19 6.15 10.64 13.31 11.19 mg/l

Chloride 16.5 24.2 19.2 17.7 18.7 42.7 21.3 16.4 25 42.7 mg/l

Flouride <0.3 <0.3 <0.3 <0.3 <0.3 <0.3 <0.3 <0.3 0.7 <0.3 <0.3

Nitrate as No3 4 10.8 12.5 5.5 18 60 19.9 32.9 48.8 60 mg/l

Ortho phosphate as PO4 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 mg/l

Total Alkalinity as CaCo3 164 192 200 180 176 132 236 236 300 132 mg/l

Calcium -dissolved 60 85 80 72 85 59 110 120 129 59 mg/l

Magnesium - Dissolved 14 10 12 10 6 16 8 6 7 16 mg/l

Potassium - dissolved 1 1 1 2 5 1 1 4 2 1 mg/l

Sodium - dissolved 12 15 12 12 11 17 9 10 11 17 mg/l

Iron - dissolved <0.02 <0.02 <0.02 <0.02 <0.02 0.022 <0.02 <0.02 <0.02 <0.02 mg/l

Manganese - dissolved <0.002 <0.002 <0.002 <0.002 <0.002 0.019 <0.002 <0.002 <0.002 <0.002 mg/l

Nickel - dissolved <0.002 <0.002 <0.002 <0.002 <0.002 0.009 <0.002 <0.002 <0.002 <0.002 mg/l

Copper - dissolved <0.007 <0.007 <0.007 <0.007 <0.007 0.016 <0.007 <0.007 <0.007 <0.007 mg/l

Lithium - dissolved 0.006 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 mg/l

Strontium - dissolved 0.086 0.110 0.219 0.198 0.071 0.078 0.054 0.069 0.086 0.097 mg/l

Bromide 18 10 8.8 3.3 2.5 6.9 2.5 2.9 5.9 6.9 mg/l

Silica <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 mg/l

HCO3 200 234 244 219 215 161 289 288 366 161 mg/l

CO3 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 mg/l

Mooney et al.

11

Table 3. Concentrations of Nitrate in the Study Area.

Table 4. Chloride/Bromide Ratios.

Chloride/ Bromide Ratios

The thermally anomalous groundwater samples have much

lower Cl-/Br- ratios than groundwater from the other shallow

wells sampled during this survey (Table 4). This relationship

is possibly due to:

• chemical characteristics of the source aquifer host

rock

• longer residence time for the thermal waters in the

source aquifer, resulting in a greater degree of

substitution of Br- ions for Cl- ions through

groundwater interaction with the host rock

• temperature conditions in the source aquifer

• chemical characteristics of the host rocks encountered

during accent from depth

• degree of mixing with shallow groundwaters during

accent

The similar ratios for Lady’s Well, Mallow and the Sugar

Factory artesian well in Mallow suggests a similar history

for the groundwater at these locations. The lower Cl-/Br-

ratio for the well at Johnstown correlates with its higher

temperature and possibly indicates a longer residence time

or less dilution of thermal waters with more recent shallow

groundwaters. The Cl-/Br- ratio thus shows a correlation

with groundwater temperature and may provide a fingerprint

for the source aquifer. However, the numerous possible

explanations for the lower Cl-/Br- ratios make it difficult to

categorically assign it as an indicator of the hydrochemical

characteristics of the source aquifer.

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10

T

Cl-/Br-

Nitrate

Fig 9: Negative correlation of T°C with [Cl-/ Br-] & NO3-

Lithium

The trace element Lithium was detected above the

laboratory detection limit of 0.005mg/l in just one of the

samples, the thermal well at Johnstown, with a concentration

Mooney et al.

12

of 0.006mg/l. This is regarded as significant as the

Johnstown well gave the highest temperature value in the

groundwater temperature survey and probably reflects the

least diluted geothermal water in the North Cork area. The

lithium value in this sample may thus reflect a compositional

characteristic of the source aquifer, which has not been

obscured by dilution.

Isotopic and Gas Analyses

Isotopic and gas analyses from Lady's Well showed 4HE x

107 at about 170 and Tritium (TU) of 11. Aldwell

interpreted these results as reflecting deeper circulation and

longer residence time than usual for Irish groundwater.

(Aldwell, 1996).

Fifteen samples of thermally anomalous and normal

groundwaters from the North Cork wells and springs have

been analysed for hydrogen (2D/1H) and oxygen (18O/16O)

isotopes together with a sample of surface water from the

River Blackwater at Mallow and a rainwater sample taken in

Cork city (Table 5). The hydrogen and oxygen isotopic

compositions of the thermal waters demonstrate that it is of

meteoric origin. The isotopic compositions lie close to the

worldwide meteoric water line (Fig. 10) and the ratios are

very similar to those for other shallow groundwater in the

region, analysed at the same time.

All of the wells cluster together along the right side of the

global meteoric water line. The local precipitation sample,

taken in Cork City, consisted of a mixture of rainwater and

snow and plots to the left of the meteoric water line relative

to the shallow well and River Blackwater samples.

Table 5. Isotopic Composition of Groundwater in N.

Cork.

Well ID

(Shallow Well Survey Reference)

Sampling

Date !!H(‰VSMOW) !18O(‰VSMOW)

Johnstown Well (7) 31/01/2009 -40.5 -6.48

Spa House (32) 24/01/2009 -39.7 -6.19

Sugar Factory Artesian Well (42) 24/01/2009 -39.6 -6.28

Greencore Spring (44) 07/02/2009 -40.0 -6.22

Sean and Liz Turner (37) 31/01/2009 -38.9 -6.16

Holy Well (39) 25/01/2009 -39.2 -6.25

Richard Coughlan (19) 07/02/2009 -41.6 -6.62

James Kennedy (21) 07/02/2009 -37.5 -6.18

Carey Ballyhooley (59) 31/01/2009 -39.3 -6.28

Jerry McSweeney (25) 24/01/2009 -39.7 -6.73

Leaselands 1 (1) 07/02/2009 -38.2 -6.12

Leaselands 2 (2) 07/02/2009 -40.0 -6.30

Ballyvoddy (13) 07/02/2009 -38.2 -6.23

Ballyvoddy (13) 07/02/2009 -38.2 -6.23

River Blackwater (n/a) 24/01/2009 -38.7 -6.57

Local Precipitation Sample (n/a) 04/03/2009 -50.7 -9.20

Figure 10: Plot of !!H (‰ VSMOW) (y axis) against !18O

(‰ VSMOW) (x-axis)

Geothermometry

Geothermometers allow us to calculate the temperature at

which ground water equilibrated chemically with the rocks

within its aquifer (Henley et al. 1984, Domenico &

Schwartz, 1998). They are used widely in geothermal

exploration, as they can indicate the presence at depth of hot

water. Unfortunately they cannot be applied in this study for

various reasons. Firstly, the temperatures of the North Cork

wells are too low for use of the alkaline geothermometer and

unrealistic results were obtained. Secondly, the various Si4+

geothermometers could not be applied, as Si4+ was not

detected above the laboratory detection limit in any of the

samples from the study area.

CONCLUSIONS

North Cork contains an abundant groundwater resource in its

bedrock aquifers. The consistent 10-12°C temperature of

this resource throughout the year, make it an ideal source for

water based heating, cooling, or heating and cooling systems

using heat exchanger and heat pump technology. Anomalous

areas of elevated groundwater temperatures have hitherto

been explained as representing groundwater that has

circulated to deep levels and traveled to the surface again via

fault related conduit permeability. A shallow borehole

temperature survey has verified this relationship.

Landsat imagery indicates the presence of Caledonian aged

NE–SW trending structures in the region, likely to be

responsible for the deeper circulation and longer residence

times of the thermal groundwater. The minimum depth of

circulation is 1100m in Mallow and 1,500m in Johnstown,

with greater depths likely considering heat loss during the

ascent of the groundwater and potential mingling of deeper

sourced thermal water with the cooler shallow groundwater.

2-D Resistivity surveys in areas with anomalous

temperatures indicate extensive karstification of shallow

limestone bedrock aquifer enhancing the permeability for

horizontal flow of groundwater. These horizontal structures

intersect deeper vertical structures.

Geochemical analyses indicate that all of the groundwater is

of meteoric origin and is of a calcium bicarbonate type,

typical of groundwater in carbonate aquifers, indicating that

the thermal and non-thermal waters have chemically

equilibrated with the host carbonate bedrock aquifer. Trends

of chloride, bromide and nitrate ionic concentrations

suggests that the thermal waters have a longer residence

time than the groundwater exhibiting temperatures more

typical of Irish groundwater.

Mooney et al.

13

It is anticipated that this study, will encourage the use of

these ubiquitous low enthalpy hydro-geothermal energy

resources in the North Cork area, as an economically viable

and environmentally sound alternative to fossil fuels. It is

recommended that further research be undertaken which will

identify specific projects where the low enthalpy hydro-

geothermal resources that have been identified can be

harnessed for the benefit of all stakeholders in the study

area. There is a case for local government to lead the way, as

private developers can sometimes be slow to adapt to

innovative new technologies; investment in successful

flagship projects will reap economic and environmental

benefits and provide the example for private entrepreneurs to

follow suit.

ACKNOWLEDGEMENTS

Sergei Kostic and Dejan Milosovic of Geofizika-Ing,

Belgrade, Serbia are thanked for conducting the geophysical

investigations.

REFERENCES

Aldwell, C.R., 1996. Mallow Springs, Co. Cork, Ireland.

Environmental Geology, 27, 82-84.

Aldwell, C.R., Burdon, D.J., 1980. Hydrogeothermal

Conditions in Ireland. XXVI Int. Geol. Cong, Paris.;

Sec. 14.2 Fossil Fuels, Abstracts, 1043.

Aldwell, C.R., Burdon, D.J. 1986 Temperature of infiltration

and groundwater Conjunctive Water Use (Proceedings

of the Budapest Symposium, July 1986). IAHS Publ.

No. 156,

Andrews, J.N., Burgess, W.G., Edmunds, W.M., Kay,

R.L.F., Lee, D. J. 1982 The thermal springs of Bath.

Nature 298, 339 – 343

Burdon, D.J. 1983. The Irish Geothermal Project. Phase 1

(June 1981-March 1983). Report to the Geological

Survey of Ireland, Minerex Ltd., Vol 1 &2.

Brück, PM., Cooper, CE., Cooper, MA., Duggan, K., Gould,

L., Wright DJ., The Geology and Geochemistry of the

Warm Springs of Munster. Ir. J. Earth Sci., 7, 169-194

(1986)

Craig, H. 1963. The isotopic geochemistry of water and

carbon in geothermal areas. In Nuclear Geology on

Geothermal areas. Spoleto, Sept.9-13, 1963. Consiglio

Nazionale delle Ricerche, Laboratorio di Geologia

Nucleare, Pisa, 53pp.

Domenico, P.A., Schwartz, F.W. 1998 Physical and

Chemical Hydrogeology (Second Edition) 506pp

Gill, W.D., 1962. The Variscan fold belt in Ireland. In: Coe,

K. (Ed.), Some Aspects of the Variscan Fold Belt.

University Press, Manchester, pp. 41–64.

Goodman R. Jones, G., Kelly, J., Slowey, E., O’Neill, N.

2004. A Geothermal Resource Map of Ireland, Final

Report for Sustainable Energy Ireland (SEI). CSA

Dublin

Henley, R. W., Truesdell, A. H., Barton, P. B. (1984) Fluid-

mineral equilibria in hydrothermal systems. Reviews

in Economic Geology, 1, Society of Economic

Geologists).

Jha, K., Kumar, S., Chowdhury, A. 2008. Vertical electrical

sounding survey and resistivity inversion using genetic

algorithm optimisation technique Madan J. Hydrology,

359, pp 71 – 87.

Landes, M. Prodehl, C., Hauser, F., Jacob, A.W.B.,

Vermeulen, N.J. 2000. VARNET-96: influence of the

Variscan and Caledonian orogenies on crustal structure

in SW Ireland Geophysical Journal International 140

(3), 660–676.

Burdon, D.J. 1983. The Irish Geothermal Project. Phase 1

(June 1981-March 1983). Report to the Geological

Survey of Ireland, Minerex Ltd., Vol 1 &2.

Murphy, F.X. Bruck, P.M. 1989. An investigation of Irish

low enthalpy geothermal resources with the aid of

exploratory boreholes, Final Report. September 1989.

Contract number EN3G00660-IRL(GDF) Report 98/13.

O’Brien, M. 1987. The development of Geothermal

Resources in the Mallow area for Heating Purposes.

M.Eng. Thesis, University College Cork (unpublished).

Phillips, A. 2001. “Caledonian Deformation” in The

Geology of Ireland (Ed.) Holland, Dunedin Academic

Press.

Vermeulen, N.J., Shannon, P.M., Masson, F., Landes, M.

2000. Wide-angle seismic control on the development

of the Munster Basin, SW Ireland (in New perspectives

on the Old Red Sandstone) Geological Society Special

Publications, 180, 223-237.

Proceedings World Geothermal Congress 2010 Bali, Indonesia, 25-29 April 2010

1

Low Enthalpy Geothermal Resources of Ireland Maps Encourage Geothermal Projects

Gareth Ll. Jones*, Róisín M. Goodman†, John G. Kelly

†

*Conodate, Dublin; †

SLR, Dublin

conodate@mac.com

Keywords: Ireland, geothermal resources, deep, potential, district heating

ABSTRACT

The Geothermal Resources of Ireland maps of 2005

(Goodman et al. 2004, Kelly et al. 2005) were published as

a public resource to establish a modern baseline in

geothermal energy resources and demonstrated the probable

extent of geothermal resources across the island of Ireland

to a depth of 5km. These maps for groundwater

temperatures at 10m, 100m, 500m, 1,000m, 2,500m,

5,000m were reported at EGC 2007 in Unterhaching (Jones

et al 2007). They have allowed the development of a

number of exploitation scenarios across the island and have

initiated a number of investigative projects in identified target zones where further exploration is warranted.

1. INTRODUCTION

In the period since the publication of the maps the

following developments have taken place.

2. SHALLOW RESOURCES

Figure 1: Surface / 10m depth temperatures.

Encouraged by government grants, recommended by

Goodman et al. (2004) and a parallel 2004 Arsenal study

(Boesworth, R. 2004), rapid development has taken place

across the island (Allen in press). Warm moist ground

conditions (Fig.1) have allowed the development of shallow

resources. Horizontal loops are common for buildings with

sufficient available ground area, whilst vertical closed loop

borehole collectors are now common and multiple borehole

fields recently starting to appear. Installed capacity has

risen very rapidly from an estimated 0.5MW in 2000 to some 250MW in 2008 (Fig.2).

Figure 2: Recent steep rise in installed capacity..

In the region east of the warm spring at Mallow, Co. Cork

an investigative study has been initiated (Allen & Mooney

in press) to define the newly identified continuation of the warm spring zone to the Glanworth area (Fig. 3).

Figure 3: The geothermal anomaly in the Glanworth

area.

Shallow aquifers with high yields have been successfully

developed as seen in the very efficient open loop borehole

systems of the Offaly County Council offices, Tullamore

(Fig.4), the Cork City Council, the University College Cork

schemes (Figs.5,6) and the 400kW system at Vista Medical Centre, Naas, Co. Kildare (Fig.7).

There are a number of moderate sized systems (up to

15kW) Open and Closed loop collectors from water bodies, used for both heating and cooling.

Medium sized projects with fields of multiple closed-loop boreholes are now being developed.

3. MEDIUM DEPTH RESOURCES

Ireland has no recognised deep aquifer systems, except in

Mesozoic sediments in Northern Ireland (Figs.8, 9), where

Jones et al

2

there is good potential for district heating from doublet systems (Kelly et al. 2005).

Figure 4: Offaly County Council offices, Tullamore

Figures 5, 6: UCC Cork IT building and plant room

Figure 7: Vista Medical Centre, Naas, Co. Kildare

Figures 8, 9: 8. Deep geology of Ireland. 9. Modelled

temperatures at 2.5km depth.

The Geological Survey of Northern Ireland (GSNI) have

drilled a 900m borehole at Kilroot in Co. Antrim (Fig.10),

targeting the Sherwood Sandstone and Permian aquifers.

This stratigraphic hole, together with magnetotelurics and

infill gravity, will detail the geothermal potential of the area.

Figure 10: Drilling the GSNI Kilroot borehole. Picture T.

Rosowski

Fracture ‘aquifers’ are common in the Carboniferous

sequence which underlies over 50% of the country and are

likely to provide numerous high flow low temperature

geothermal resource sites as the market develops and their geometry and hydrodynamics are traced at depth.

More detailed investigations (O’Neill & Pasquali 2005,

Jones et al. 2007) recommended specific sites for further

study. Deeper resources are now being investigated and

already two projects are proceeding to target geothermal

resources associated with a major Palæozoic fault at 2.5km

in the Dublin area for potential district heating development.

Other resources, that include deep crystalline rock settings,

have been identified for potential exploration activities but

they will need further development of the market for deep drilling to begin.

Jones et al

3

Figure 11: Geology of the Blackrock-Rathcoole Fault

separating the Carboniferous Dublin Basin to the

north from the older Leinster Massif to the south

The combination of deep faults and crystalline rocks have

been identified in Germany and other countries as having

the biggest geothermal resource. This combination exists

south of Dublin where the Blackrock/Rathcoole Fault

occurs adjacent to the Leinster granite and Lower

Palæozoic Massif (Fig.11). GT Energy Ltd. have already

carried out deep exploratory drilling in the south-west

(Fig.12), whilst University College Dublin are evaluating their location.

Figure 12: GT Energy’s Marriott rig exploring a

fracture aquifer south-west of Dublin.

4. DEEP RESOURCES AND ELECTRICITY

POTENTIAL

The 5km depth resource map (Fig.13) indicates that there is

significant potential for electricity generation in some areas,

especially in the north-east. Development of this resource

depends largely on additional drilling and on new data

being collected. At 5,000m depth across Northern Ireland

and a number of other locations, modelled temperatures

show a number of potential ‘hot-spots’ with values of

115ºC - 165ºC in the Lough Allen Basin, 115ºC - to 150ºC

in the Larne - Lough Neagh Basins and a potential 180ºC in the Rathlin Basin.

Figure 13: Modelled temperatures at 5km depth

The Geological Survey of Northern Ireland (GSNI) is

investigating the geothermal potential in the Tertiary

Mourne Granite with a 600m deep exploration borehole

(Fig.14). They will geothermally log the borehole and carry

out conductivity tests on the samples, which, with infill gravity to create a 3D model, will characterise the batholith.

Figure 14: Setting up the GSNI drill rig for the Mourne

granite assessment borehole. Pic T. Rosowski

At present only binary or Organic Rankin Cycle (ORC)

power plants can be considered for electricity generation

production at temperatures down to 100 °C in Ireland from geothermal heat.

A perceived barrier to the investigation and development

of medium-deep resources, is the lack of protective

legislation. GTR-H, an EU funded research project, has

looked at regulation across Europe and is developing a

template (Pasquali & Goodman 2008). An Irish government

geothermal working group is consequently drafting

Jones et al

4

legislation to cover this area and to provide security of tenure to geothermal companies (King & Dhonau 2008).

The successful development of Hot Dry Rock (HDR)

technology and hydraulic stimulation techniques elsewhere

in Europe will increase the perceived geothermal

production capacity of Irish sites significantly and thereby

accelerate the development in this area to look at electricity production from higher temperature resources.

5. CONCLUSION

A combination of resource assessment and government

support has promoted the development of shallow resources

and stimulated the investigation of specific geothermal

locations for deeper projects.

REFERENCES

Allen, A. In press. Developments in Geothermal Utilisation

in the Irish Republic. Proceedings World Geothermal

Congress 2010.

Boesworth, R. 2004. Campaign for take-off for renewable

heat pumps in Ireland. Unpublished Arsenal Research

report to Sustainable Energy Ireland, April 2004.

139pp.

King, J. & Dhonau, B. 2008. Development of Policy for

Geothermal Energy in Ireland. Geothermal Resources

in Ireland Commercial Opportunities. Geothermal

Associaition of Ireland Conference, Kilkenny 5

November 2008.

Goodman, R., Jones, G.Ll., Kelly, J., Slowey, E., O’Neill,

N., 2004. Geothermal Energy Exploitation In Ireland

– Review of the Current Status and Proposals for

Optimising Future Utilisation. Final report to

Sustainable Energy Ireland. CSA rept no. 3085/02.04

September 2005. 93pp + XII App.

Jones, G.Ll., Goodman, R., Pasquali, R., Kelly, J.G.,

O’Neill, N., Slowey, E. 2007. The Status of

Geothermal Resource Development in Ireland. Proc.

European Geothermal Congress 2007, Unterhaching,

Germany, 30 May-1 June 2007. 3pp.

Jones, G.Ll., Pasquali, R., Antin, G., Grummel, T.,

Goodman, R., Glanville, P., O’Neill, N. 2007.

Feasibility Study & Market Research for the

Development of a Deep Geothermal Borehole on the

University College Dublin Campus. Final Report to

Sustainable Energy Ireland. Conodate Geology rpt

3533-DG February 2007, 73pp + VI App.

Kelly, J., Goodman, R., Jones, G.Ll., O’Neill, N., Pasquali,

R. 2005. Geothermal Energy Review of Northern

Ireland – Final Report to INTERREG. CSA rept no.

3194/01.05 September 2005. 79pp + XI App.

O’Neill, N. & Pasquali, R. 2005. Deep Geothermal Site

Characterisation, Final Report to Sustainable Energy

Ireland. CSA rept no. 3366. October 2005, 34pp. (+

Apps in Interim rpt.).

Mooney, B. & Allen, A. In press. Characterising low

enthalpy hydrogeothermal resources at Glanworth, Co.

Cork. Proceedings World Geothermal Congress 2010.

Pasquali, R. & Goodman, R. 2008. Progress & Draft

Template Regulatory Framework. Geothermal

Resources in Ireland Commercial Opportunities.

Geothermal Associaition of Ireland Conference,

Kilkenny 5 November 2008.

11

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.

Proceedings World Geothermal Congress 2010

Bali, Indonesia, 25-29 April 2010

1

Methodology in Assessment and Presentation of Low Enthalpy Geothermal Resources in

Ireland

1Róisín Goodman,

2Gareth Ll. Jones and

1John G. Kelly

1SLR Consulting (Ireland) Ltd, 7 Dundrum Business Park, Windy Arbour, Dublin 14, Ireland. 2Conodate Geology, 7 Dundrum

Business Park, Windy Arbour, Dublin 14, Ireland.

rgoodman@slrconsulting.com, conodate@mac.com, jkelly@slrconsulting.com

Keywords: Ireland, Low enthalpy, geothermal data

modelling,

ABSTRACT

Studies were carried out in 2004 and 2005 across the island

of Ireland, to develop a database and a series of index maps

for the geothermal resources of Ireland. The objective of

the projects was to produce a GIS-linked geothermal

database, an up-to-date map series, and a report with

recommendations for the next steps necessary in expanding

the use of Ireland’s geothermal energy from both shallow

resources and the somewhat unknown deeper resources.

Some of the difficulties involved in finding a best approach

to such an exercise are discussed and some of the strength

and weaknesses of the results of such a study are presented.

However the value of carrying out such an exercise is

highlighted as a first tool in geothermal resource

assessment. A number of geothermal depth plans have

been produced for surface, 100m, 500m, 1,000m, 2,500m

and 5,000m depths. The maps may be viewed using free

MapInfo-Proviewer software.

INTRODUCTION

The Geothermal Resource Map Series of Ireland study

(Goodman et al. 2004) was performed by the CSA Group

(now SLR Consulting (Ireland) Ltd.) in co-operation with

Conodate Geology, Cork Institute of Technology and the

Geological Survey of Ireland. It was a Public Good

contract carried out on behalf of Sustainable Energy

Ireland.

The goals of the study were to identify potential resources

of geothermal energy in Ireland and use these to create

geothermal plans of Ireland by gathering the necessary

hydrothermal, geological and structural data to facilitate the

production of a GIS-linked database and create a series of

geothermal maps of Ireland. The work also reviewed the

current status and utilisation of geothermal energy

resources in Ireland and recommendations were made on

best approach to future potential exploitation of the

geothermal resource in Ireland in the context of

International Best Practice. A later all-island study included

more detailed data on Northern Ireland and was also

completed by the CSA Group, under EU, INTERREG

funding (Kelly et al. 2005).

It was expected that new data and reinterpreting Ireland’s

geothermal database would significantly enhance the value

of the available information on Ireland’s geothermal

potential and provide a concise review of earlier work

allowing easier integration of the available information with

the European geothermal databank. The public availability

of the data was emphasized as a key aspect of the work in

order to increase awareness of the potential of geothermal

energy in Ireland. As the first review of its kind since the

1980s it was hoped to identify strategies for geothermal

energy development.

The base data presented for this study are in effect a partial

data set and the methods employed to extrapolate were

simple and include broad assumptions. The results are

presented as a first approach to handling sparse geothermal

data and as a first pass for assessing geothermal resource

potential as a tool perhaps to encourage further exploration

and dedicated drilling programmes to quantify the actual

resources.

DATA USED FOR THE STUDY

The study started with a review of the available data

sources in the relevant government departments including

the Geological Survey of Ireland within the geothermal

archives, the Exploration and Mining Division and the

Petroleum Affairs Division. Previous studies were

reviewed and data incorporated into the study – in

particular the Irish Geothermal project 1981-1983 (Aldwell

1984, Burdon 1983a,b) and Murphy & Brück (1989).

Figure 1: Borehole distribution used for the study.

Mineral exploration companies were contacted to gather

any available information from recent exploration

programmes which were not yet publically available. A

borehole and spring temperature monitoring programme

was carried out at accessible sites. The study included

Goodman, Jones and Kelly

2

geological, structural and hydrothermal analysis of the areas

with potential and attempted to use these data to provide a

more reliable estimate of the resources and potential. It was

first reported at the Unterhaching EGC (Jones et al. 2007).

Data compilation

Initially as part of the study, data were compiled on heat-

pump usage and groundwater temperature trends in warm

springs and shallow boreholes <100m depth, a total of 80

sites. A programme of temperature monitoring was also

completed for 32 open boreholes to obtain new temperature

profiles. The new boreholes ranged in depth from 40m to

810m. The deepest borehole monitored was No. 01-541-

03, Co. Galway in the west midlands (Figure 1).

Temperature data from 68 historical mineral and oil

exploration holes ranging in depth from 300m to 2,300m

(deepest borehole Drumkeeran (No. 1), Co Leitrim) were

then compiled from boreholes monitored since the previous

geothermal studies. Data sources included Mineral

Exploration reports EMD / GSI 1970–2003a,b and Oil

company reports 1970-2001a,b PAD / GSNI.

Temperature records from active oil and mineral

exploration companies provided data on nine new

boreholes ranging in depth from 391m to 1,550m with

five holes deeper than 1000m.

New data were then combined with data from earlier

studies, Aldwell 1984, 1990; Aldwell & Burdon 1980,

1984, 1986; Brock 1989; Burdon 1983a,b).

Mineral Exploration Data

Ireland has had a very active mineral exploration and

mining sector for over 50 years and as such there has been a

significant amount of shallow (50-300m) drilling in parts of

the country though predominantly located in areas

underlain by Carboniferous aged limestones covering much

of the midlands of the country (Figure 2). Despite this

exploration activity there are still many areas with sparse

drilling and therefore poor geological detail at depth.

Though there has been limited onshore oil and gas

exploration there are few areas with boreholes deeper than

500m. As a result the data available are sporadically

distributed and somewhat biased to particular lithologies.

QUALITY OF DATA

As mentioned the compiled data are heavily biased towards

areas of economic interest, primarily the Carboniferous

Limestone areas for metals, Carboniferous coals and the

Permo-Trias Basins for hydrocarbons, halites. The

maximum depth from which temperature measurements

were available was 2300m with much of the data coming

from shallower than 500m. Only temperature

measurements from boreholes greater than 500m deep have

been used to provide geothermal gradients for extrapolation

to depths below 1,000m. Large areas of the country have

little or no exploratory drilling; this includes granite

batholiths, metamorphic areas, Namurian outliers and

Lower Palæozoic and Devonian inliers. Some of the

specific issues encountered in modelling geothermal

gradients and extrapolating temperatures in the related to

local geology are documented in the following sections.

Carboniferous Midland Basins

Though the majority of the boreholes are located in the

Carboniferous Limestone, many are <300m depth and as

the influence of fracturing and karst in the Carboniferous is

more intense than in other units care is needed in

extrapolation to depth.

Figure 2: Ireland summary geology Basalt and Mesozoic

Basins (pale purple (Northern Ireland only)),

Carbonates (blue), Devonian sandstones (yellow),

Lower Palaezoic sediments (orange), Caledonian

metamrphics (green), Granite (red)

Munster basin

Most of the Munster Basin with Devonian and

Carboniferous clastic sediments has no deep drilling or

temperature data available. One deep drillhole in the

northwestern edge of this basin records very low

temperatures of 33.8ºC at a depth of 1,690m (Meelin no. 1

borehole). The low gradient of 14.3°C/km recorded has

influenced all modelling for this region. It is essential that

more extensive information is obtained in the future to

reduce the reliance on this single data point.

Granites

The batholiths of Leinster, Galway and Donegal are

completely untested except for a number of shallow

(<150m) boreholes for which heat flow data have been

measured (Figure 3). However there are few data to

indicate whether these areas would be of interest for

Enhanced Geothermal Systems and more data are required.

One point of interest is that the Mourne Mountain Complex

and Slieve Gullion Complex (Young et. al, 2009) on the

northeast coast is known to have the highest radioactivity of

any batholith in the UK and Ireland and has become the

focus of deep geothermal investigation by the Geological

Survey of Northern Ireland in the past year.

Metamorphic / Crystalline basement and Lower

Palaeozoic basement sediments

Little data were available for the metamorphic basement

which underlies most of the Ireland and is exposed in the

vicinity of the Leinster Massif, within midland inliers and

Goodman, Jones and Kelly

3

especially in the south-east and in the Longford-Down belt

from the north midlands to the Co. Down coast.

Exposures in the north-west and west have no temperature

data. However it is likely that these rocks control much of

the deep geothermal potential An attempt was made

during the study to produce level plans mapping the

occurrence of crystalline basement at the depth studied.

This was abandoned due to insufficient geological data.

Figure 3: Modelled Heat Flow

EXTRAPOLATION OF THE DATA TO DEPTH

Once data had been compiled in excel format, a major issue

with the project was how to best utilise these temperature

and geothermal gradients to provide best estimates of

temperatures in areas and at depths for which there were no

data. It was clear that the dataset required extensive

extrapolation as there were insufficient data for simple

contouring of measured data at the depths for which maps

were required. Extrapolation of temperature using

geothermal gradient was carried out on data from all

boreholes greater than 300m depth in order to provide

sufficient coverage for map production.

Calculation of gradients in earlier studies often assumed a

single gradient for the whole borehole and thereby resulted

in conservative overall gradients in many cases due to the

influence of locally depressed surface gradients due in part

to surface water influx through karst and fractures. In fact

looking at these same data it is apparent that in 40% of

cases the gradient is seen to increase with depth (the

opposite is observed in 30% of cases). The controls on

these changes in geothermal gradient are complex and

critically dependent on local conditions i.e. lithology,

porosity and permeability and fracturing/structure.

For this study all new and historic data were reviewed and

the gradient chosen in each case for extrapolation was as far

as possible more representative of deeper parts of the

borehole and the deeper geology.

The relationship between the measured gradients and the

geology was also examined in each case and helped in

choosing a preferred gradient for extrapolation. An attempt

was made to categorise the likely gradients in common

lithologies encountered in the drilled sequences. However

this was found to be impossible with the available data

though some qualitative statements can be made about the

general influence of more mud rich versus more karstic or

sand rich sequences. Comments on these are included in

the sections below.

It is noted that in similar modelling exercise of geothermal

gradients in Belgium by Vanderberghe and Fock (1989), a

strict limit was placed on the depth to which data from a

borehole would be extrapolated. This has not been applied

in this study as the distribution of data is insufficient to give

any meaningful estimate of geothermal gradient at depth

without extrapolation from most boreholes available.

GIS, DATA MODELLING & MAP CONTOURING

The final database contains measured records from 75

boreholes between 300m and 2,300m depth. Of these

boreholes 49 extend to a minimum of 500m depth and have

been used for deeper temperature modelling. Data on many

other boreholes <300m deep are available and have been

used for modelling to 1000m but have not been included in

deeper.

The data were uploaded to a GIS software package and data

contouring was conducted using gridding software

embedded within the GIS package. The GIS software used

was Mapinfo and the grid modelling was conducted using a

Mapinfo add-in, Vertical Mapper. Some interpolation

techniques produce more reasonable surfaces when the

distribution of points is truly random. Other techniques

work better with point data that are regularly distributed.

Highly clustered data, such as the geothermal data for the

springs and boreholes, presents problems for many

interpolation techniques.

Geothermal data form a particularly difficult dataset for

contouring due to the highly variable distribution of the

data points. The data points fall primarily within a number

of data clusters (Northeast Permo-Trias, Northwest

Carboniferous, North Leinster and the Mallow area) with

scattered data points outside these four regions. In addition,

parts of the country had no data available.

To model such a clustered dataset, it was decided to

conduct the initial contouring using a variety of modelling

techniques and parameters to determine which modelling

technique would give the best solution. Following initial

results, it was determined that natural neighbour

interpolation was best suited to model the datasets and all

detailed modelling was conducted using this method.

Interpolated data points

As mentioned the data distribution is highly skewed to

geological regions of economic interest, and a number of

geological regions contained no data. Where such regions

were considered to significantly differ in properties to

adjacent data-rich regions, a small number of calculated

data points were inserted into the database before

contouring.

STRUCTURE AND OTHER PHYSICAL CONTRILS

ON GEOTHERMAL GRADIENT

Some comments are included below on the influences of

local lithological changes, weathering and rock structure on

geothermal gradients.

Goodman, Jones and Kelly

4

Karst development and shallow groundwater mixing

Much of the upper 200-300m of the Carboniferous

Limestone in Ireland is known to have had significant karst

development during periods of lower sea levels. There are

indications that karstification may have reached even lower

levels in some places. Many karst conduits are still

operative at these depths.

In the compiled database examination of the relationship

between the geothermal gradient and borehole depth

indicated that the top 200-300m of most of the boreholes

demonstrated mixing of surface run-off waters and shallow

groundwater. This rapid percolation of surface water

through deep fractures and karst had thereby disrupted the

geothermal gradients at these depths. Therefore for this

study only geothermal gradients from boreholes >300m

were utilised for extrapolation to depths of 1,000m and only

geothermal gradients from boreholes >500m were used for

extrapolation to depths of >1,000m.

Insulation effect of Shale rich Units

The presence of shale layers is considered in many studies

of deep geothermal potential to be important in

“blanketing” deep heat and preventing it from flowing

easily to the surface. Because of the abundance of shaley

limestone and shales in parts of Ireland the recognition of

this setting will be important in identifying deep geothermal

targets.

Warmer temperatures have been recorded in some areas of

the Irish midlands where there is thick limestone cover,

especially in Westmeath and Offaly into east Galway.

These temperatures may reflect enhancement by the

insulating effect of limestones (which also have lower heat

conductivity than quartz rich sediments) and the associated

shale cover.

Fracture flow ‘aquifers’

Most Irish rocks are strongly lithified and primary porosity

is low. Permeability thus relies heavily on the secondary

porosity of fracture fields. There are few true bedrock

aquifers in Ireland and fracture flow predominates in

porosity and permeability and hydrological connectivity.

On the other hand fracturing and deep penetrating faults are

common throughout Ireland due to its position straddling

the remnants of the Lower Palaeozoic Iapetus Suture, a

palaeo-continental collision zone running in a northeasterly

trend from Limerick to Drogheda. Variscan tectonism

produced generaly east-west fractures south of the Iapetus

suture. Also Tertiary joint and fracture sets were emplaced

during Atlantic opening tectonism. Areas with significant

fracture flow are considered important for hydro-thermal

development. There are likely to be a number of very

important secondary aquifers which can be considered for

the development of deep geothermal projects.

It was noted in temperatures and gradients recorded in the

borehole database that depressed temperatures at depth in

boreholes could in some cases be attributed to possible

influx of shallow ground-waters to depth along adjacent

fracture zones. Similarly, warm springs or warm shallow

groundwater were investigated in detail at the Mallow

warm spring (O’Brien 1987) can be attributed to rapid

access of deeper waters to surface along fracture zones.

These observations have influenced the choice of gradients

to calculate deeper temperatures used in this study.

However further investigation is required to fully quantify

these effects.

In the vicinity of the Iapetus Suture in the midlands there

are numerous zones of anomalous warmer or colder

temperatures and associated variations in geothermal

gradient. Again the distribution of boreholes available for

testing has produced some bias in the data. A zone of

enhanced geothermal gradients was previously interpreted

by Phillips (2001) to lie along the trend of the suture zone

where it is linked with Paleogene age fault activity in the

area. In this study cooler zones along the suture trend are

interpreted to result from zones of fractures /joints and/or

karst development, allowing localised rapid infiltration of

cold water from the surface deep into the groundwater,

where it reduces the groundwater temperatures.

Regional and palaeo-tectonic setting

In general, Ireland is considered to be tectonically stable.

The main evidence of tectonism in recent times has been

rare, small earthquakes in the Irish Sea basin and onshore in

northwest Donegal and southeast Wexford. Except for

small warm spring areas there are no strongly geothermally

active regions. However recent work in the Irish Sea

confirms the presence of some previous geothermal activity

in the Irish Sea basin. Ongoing work indicates the presence

of a palaeo hot-spot which may have been active during

pre-Quaternary times. This palaeo hot-spot has been

postulated as possibly influencing the distribution of river

systems draining westward across Ireland and resulting in

the formation of so called ‘palaeo-channels’ in the Irish

midlands (Hardy 2003).

COMBINING HISTORICAL DATA WITH NEWLY

MONITORED DATA

The temperature monitoring equipment used for the

acquisition of new data for this study was a specially

commissioned 1,000m long dual dipmetre and temperature

probe which allowed easy access to borehole sites. For

shallow monitoring a hand held 2m digital recorder was

used.

Figure 4: Modelled Temperatures at Surface indicating

areas of warm springs

Goodman, Jones and Kelly

5

It is noted that temperature readings from more than five

different thermometers have been used in this study. As

much of the data is historical it was not possible to carry out

a calibration exercise between them.

RESULTS

In a regional context, geothermal gradients in Ireland show

an increase from south to north at all levels. An exception

to this is the west of County Clare in western Ireland where

the highest geothermal gradients in the south of Ireland are

located. This trend is also evident in measured temperature

data from the deeper boreholes. This regional trend is

interpreted to be associated with the main structural

divisions in the Irish subsurface in particular the Iapetus

Suture. This is a deep crustal structural feature and marks

the line of the late Silurian collision between two crustal

plates which were previously separated by an ocean.

Although the Iapetus Suture is over 460million years old it

had a long-lived influence on sedimentation patterns and

can still be seen in deep geophysical profiles of the sub-

surface of Ireland (Jacob et al. 1985). The position and

different characteristics of these plates is also seen to mark

a change in the geothermal properties of these areas.

Another significant trend in the data is an east-west trend to

the south of the Iapetus Suture which is observed in both

the North Leinster and North Munster warm spring data

sets. This is Variscan in origin and its associated structures

are interpreted to be generally east-west deep penetrating

faults. The Variscan deformation resulted in the formation

of a number of deep inclined faults in the south of the

country which control the presence of warm springs in the

Cork area. It is interpreted that the thickening of the

sediments in the south, as a result of compressional faulting

during the Variscan, may have resulted in the presence of

lower geothermal gradients due to the thickened crust. It is

postulated here that some component of this low

geothermal gradient in the south is also the higher

conductivity of the quartz rich sediments here allowing

rapid transfer of the near surface heat to the atmosphere.

This is in contrast to the Northern Ireland where the

interpreted presence of thinned crust underlying the Antrim

flood basalts seem to control the higher geothermal values

present. To the north of the Iapetus Suture a subtle north-

south trend also emerges which is interpreted to be

associated with a much later tectonic event of circa. Triassic

age. This is seen in the Kingscourt area, Co. Cavan where

there are enhanced temperatures (15ºC) near surface. The

same structure at Kingscourt may also continue north and

influence the Lough Neagh area in Northern Ireland where

there are high temperatures at depth.

Temperature of shallow (<100m) groundwater & warm

springs

Ireland is fortunate in having a temperate-wet climate

continuously recharging large volumes of relatively warm

water in the subsurface. From this study groundwater is

defined as having temperatures over 12ºC in the south of

the country and over 9ºC in the north of the country (Figure

4). Allen & Milenic (2003) and Davis (2003) delineated

buried shallow, high-flow aquifers in Cork, which have

been, and are being, exploited by several major projects

such as the Glucksman Art Gallery (Gondwe et al.

WGC2010).

Warm spring and enhanced shallow groundwater

temperatures vary from just above normal to a maximum of

23.5ºC, as observed in a borehole at Glanworth Co. Cork

(Mooney et al. WGC2010). This study has confirmed that

the areas with the most abundant warm springs are the

Mallow area in north Co. Cork and the

Dublin/Meath/Kildare area.

Of most importance in the distribution of warm springs is

the presence of deep tapping structures such as the

Carboniferous Basin bounding, Blackrock-Rathcoole fault

at the north side of the Leinster Granite in south Co. Dublin

and the thrust fault at the north side of the Devonian in

Mallow (Mooney et al. WGC2010).

Temperatures and geothermal gradients at 500m

At 500m depth a number of hot-spots are present in west

Clare, north-west Cavan, north Antrim and east Tyrone

where values range from 25ºC-27ºC. Generally more

elevated values are present throughout the midlands as

compared with the west and south where values are mostly

in the range of 17ºC-19ºC. There is some degree of bias

due to the relative abundance of data in the more central

areas. However despite this bias, it is interpreted that there

is some division in deep geothermal activity, from the

colder temperatures and lower geothermal gradients in the

south to the warmer temperatures and higher geothermal

gradients in the north. This feature becomes better defined

at deeper levels.

Temperatures and geothermal gradients at 1,000m

The results of temperature contouring at 1,000m are

included on Figure 5. The borehole temperature map at

1,000m depth has been modelled from measured and

calculated temperatures in 72 boreholes. The modelled data

have been produced from boreholes that reached 1,000m

together with temperatures calculated from geothermal

gradients in boreholes that reached 300m. Some similar

patterns of warmer temperatures and geothermal gradients

as seen at 500m are also seen at this level, as some of the

data have been directly extrapolated from the gradients

present at 500m depth.

Figure 5: Modelled Temperatures at 1,000m

Goodman, Jones and Kelly

6

Generally at 1,000m, gradients in the south of the country

are 10ºC – 15ºC/km and range from 20ºC–30ºC north of the

Iapetus Suture line. Highs in geothermal gradients of

around 35ºC/km are recorded in the more anomalous zones

and represent the areas of most potential in any further

investigation and testing of deep geothermal gradients

The areas showing the higher geothermal gradients are in

the Antrim, northwest Cavan/Fermanagh and Clare areas.

The presence of the Iapetus Suture becomes more strongly

defined at this depth and generally creates a separation

between the north and south midlands. Temperature ranges

between 22ºC–28ºC to the south to 37ºC–46ºC to the north

of this line. There are still some zones of anomalously low

temperatures in areas underlain by potentially karstified

limestones which may be the result of deep circulation of

cold groundwater from surface along fractures.

Figure 6: Modelled Temperatures at 2,500m

Temperatures and geothermal gradients at 2,500m

The results of temperature contouring at 2,500m are

included on Figure 6. The borehole temperature map at

2,500m depth has been modelled from two measured and

47 calculated temperatures from geothermal gradients in 49

boreholes that reached a minimum depth of 500m. As most

of the temperatures here are calculated, more caution must

be used in the interpretation. Additional caution is

necessary also as most measured data are from the

Carboniferous, while at a depth of 2,500m in the midlands

the predominant rock-type is interpreted as Lower

Palaeozoic in age and is a quartz rich sequence compared to

the limestones of the Carboniferous. The map shows a

similar division in temperature values across the Iapetus

Suture from Drogheda to Limerick with ‘hot-spots’ in the

Kildare, Navan and north Cavan areas in the Republic of

Ireland and in the east Tyrone and north Antrim areas of

Northern Ireland. Temperatures vary from a range of 28ºC

to 45ºC in the south to a range of 64ºC to 97ºC in the north

(with a max of 101ºC).

This partly also applies to the Lough Allen Basin, in the

north midlands (where the basin is either Lower

Palaeozoics or Dalradian metamorphics with variable

thicknesses of Old Red Sandstone facies between the

basement and the Carboniferous sequence), in the Larne,

Lough Neagh and Rathlin basins, total sedimentary

sequence thicknesses exceed 3,000m for the Permo-Triassic

alone, with unknown thicknesses of Carboniferous or older

sediments overlying the basement rocks in these areas.

Temperatures and geothermal gradients at 5,000m

Borehole temperature modelled contours at 5,000m depth

are presented on Figure 7.

The temperatures presented on this map have been

modelled using temperatures calculated only from

geothermal gradients in boreholes that reached 500m. The

unavailability of data at depths below 5,000m means the

temperatures presented are of necessity only an indication

of the possible temperatures that may be encountered at this

depth. The patterns of ‘hot spots’ are the same as for the

map for 2,500m, since the data on the 5,000m map are

extrapolated from the data at 2,500m. The models show a

similar division in temperature values across the Iapetus

Suture from Drogheda to Limerick with ‘hot-spots’ in the

Kildare and Navan areas of the Irish Midlands and in the

Lough Allen, Larne, Lough Neagh and Rathlin basins.

Figure 7: Modelled Temperatures at 5,000m

At 5,000m the background temperatures in the southern

parts of Ireland are in the range of 60ºC - 75ºC while they

are significantly higher in Northern Ireland, with values of

115ºC - 165ºC in the Lough Allen Basin, 115ºC - to 150ºC

in the Larne and Lough Neagh Basins and a potential 180ºC

in the Rathlin Basin.

TEMPERATURE VARIATION AND HEAT FLOW

Heat flow density measurements from four sites have been

added to a previous database and modelled (Figure 6). Heat

flow can change with depth and can also result in lower

geothermal gradients where it results in high transmissivity

of heat to the surface resulting in more rapid cooling of the

surface of the crust. Therefore data on measurements of

heat flow need to be applied with caution.

University College Galway looked at heat flow figures

across Ireland (Brock 1989, Brock & Barton 1984, 1988a,b

1989). This suggests that there is very low heat flow in the

south with very high values in the north-east, plus a hot spot

Goodman, Jones and Kelly

7

south of Dublin. The caveat concerning restricted data

points applies to this map also and in particular the

restriction of the data points to intrusive bodies only as

there have been no studies of heat flow in the sedimentary

or metamorphic lithologies in Ireland.

Potential for Enhanced Geothermal Systems or Hot Dry

Rock

Clearly definable geological controls are difficult to

evaluate in relation to geothermal gradients within deeper

levels of the sub-surface in Ireland.

From the data reviewed in this study it is apparent that

considerable uncertainty remains in estimating temperatures

at depths of 2,000m or greater. However, results of this

review indicate a number of areas with the potential for

high temperatures up to >150ºC at a depth of 5,000m.

These areas are the north-western part of Cavan / southwest

Fermanagh, and northern Antrim / Londonderry. Measured

data in both these areas show temperatures of 57ºC in

Cavan at 2,000m and 63ºC in Antrim at 1,500m depth,

indicating overall geothermal gradients between 24ºC/km

and 35ºC/km. In parts of north County Meath there are

geothermal gradients of 25-30ºC/km at 1,500m depth,

which is also encouraging.

CONCLUSIONS

It is concluded that there is justification for extrapolation of

data as carried out in this study as the study provides a

necessary database as an initial baseline of geothermal data.

The modelling approach was successful at the production of

a set of maps and a data base for future update with the

caveat of the importance of stating the assumptions used to

improve future evaluation.

In the case of shallow resources, warm spring data and

surface/shallow groundwater temperatures across Ireland

show two main anomalous zones with temperatures

between 15ºC and 21ºC and a significant Variscan east-

west structural trend. Outside of these areas, average

shallow groundwater temperatures vary regionally from

12ºC in the south to 9ºC in the north of the country.

The major deep geothermal trends observed in this study

are a regional increase in temperatures from about 18°C

in the south to 26°C in the north at a depth of 500m and

from 28°C – 45°C in the south to 64°C – 97°C to the

north at 2,500m depth. The maximum temperature

measured on the island of Ireland is 87.7ºC in Larne No. 1

at 2,882m depth. Indications of the potential for

temperatures in the region of 150°C at 5,000m depth are

present in Northern Ireland.

The highest recorded geothermal gradient at 1,000m in the

republic is 28.4ºC/km and is located in the vicinity of north

Co. Meath in the Navan area. Data from Northern Ireland

indicates that the highest geothermal gradients in both the

Republic of Ireland and Northern Ireland are located in the

Lough Neagh to Ballycastle/Antrim area, e.g. 35.9°C/km

seen in Portmore no. 1. This is interpreted as the result of

thinned crustal rocks underlying the Antrim Flood Basalts.

Modelled temperatures at depths of 500m to 5000m show a

consistent NE-SW break across the centre of Ireland with

higher temperatures in the north-central and north of the

country.

Though only indicative, these results show the potential for

significant geothermal sources with possible applications in

commercial developments. Further definition of the exact

profile and extent of the geothermal sources and

quantification of the resources requires additional data. In

particular deep areas around the periphery of the island

remain untested.

The study was followed by government initiatives to look at

geothermal resources (O’Neill & Pasquali 2007a,b; Jones

et al. 2007a), followed by private investment in exploratory

drilling projects and later by investigative drilling by the

Geological Survey of Northern Ireland of exploratory

geothermal boreholes.

When fractured or karstified the Waulsortian limestone

records cold temperatures unless adjacent to large deep

faults, as karst/fracturing allow relatively cold surface water

to penetrate deep into the groundwater.

Carboniferous and shale rich rocks act as good insulators

and geothermal gradients are relatively low where

fracturing is absent. This results in the presence of

relatively low temperatures even in the more northerly parts

of the Carboniferous basin where the regional geothermal

gradient is high.

Intrusive complexes in Carlingford in Co. Louth and south

Co. Down have been identified as having the highest

radioactivity levels of granites in Ireland and therefore have

the potential for high geothermal gradients at depth.

However no data were available to test this hypothesis in

this study.

REPORT AND DATA ACCESS

The CSA Geothermal report and appendices, may be

downloaded as pdf files from the SEI's website at:

www.sei.ie or on the following link:

www.sei.ie/Grants/Renewable_Energy_RD_D/Projects_fun

ded_to_date/Geothermal_Energy/ .

Alternatively go to “Funded Programme” then “RE RDD”

and select “Projects Funded to Date”. The Geothermal

Resource Map is found in “Geothermal”. If you wish to

work with the temperature maps, they are very large files

and it is better to request SEI to send a free CD.

REFERENCES/BIBLIOGRAPHY

Aldwell, C. R. 1984. Geothermal Investigations and

Potential Development in Ireland. Geological Survey

of Ireland Internal Report. 33pp.

Aldwell, C.R. 1990. The Second Phase of Geothermal

Investigations in Ireland 1986-89 Geological Survey

of Ireland Internal Report, 34pp.

Aldwell, C.R. & Burdon, D.J. 1980. Hydrogeothermal

Conditions in Eire. September-80 International

Geological Congress, Conference Paper.

Aldwell, C.R. & Burdon, D.J. 1984. Energy potential of

Irish ground-waters. Transcript of presentation to the

Geol. Soc. 79pp.

Aldwell, C.R. & Burdon, D.J. 1986. Energy potential of

Irish ground-waters. Quarterly Journal of Engineering

Geology, London, 19, 133-141.

Allen, A. & Milenic, D. 2003. Low enthalpy geothermal

energy resources from groundwater in fluvioglacial

gravels of buried valleys. Applied Energy. 74, 9-19.

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Brock, A. 1989. Heat flow measurements in Ireland.

Tectonophysics, 164, p231-236.

Brock, A. & Barton, K. J. 1984. Equilibrium Temperature

and Heat Flow Density Measurements in Ireland. Final

Report on EEC contract EG-A-1-022-EIR (H), 115pp.

Brock, A. & Barton, K. J. 1988a. Temperature, Heat Flow

and Heat Production Studies in Ireland. Periodic

Report for the period from July 1987 to December

1987, EEC contract EN3G-0065-IRL (GDF) 6pp.

Brock, A. & Barton, K. J. 1988b. Temperature, Heat Flow

and Heat Production Studies in Ireland. Periodic

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EEC contract EN3G-0065-IRL (GDF), 18pp.

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and Heat Production Studies in Ireland. Periodic

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1988, EEC contract EN3G-0065-IRL (GDF), 30pp.

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(June 1981 – March 181). Report to the Geological

Survey of Ireland. (EU Thermie funded project),

Minerex Limited. April 1983. Vol. I. 285pp, Vol. II 5

Appendices

Burdon, D.J. 1983b. Irish Groundwater Resources in

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region. Irish Journal of Earth Science. 147.

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N. 2004. Geothermal Energy Exploitation in Ireland

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for Sustainable Energy Ireland, July 2004. 93pp + XII

Appendices

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P. 2010. The Glucksman Art Gallery, University

College Cork, Ireland: An Innovative Space Heating

Development. Proceedings World Geothermal

Congress 2010, Bali, Indonesia, 25-29 April 2010.

11pp.

Hardy, D. 2003. Searching for Tertiary Channels in the

Irish Offshore (and other fun). Unpub. presentation to

the Geological Survey of Ireland.

Jacob, A.W.B., Kaminski, W., Murphy, T., Phillips, W.E.A.

& Prodehl, C. 1985. A Crustal Model for a Northeast-

Southwest Profile through Ireland. Tectonophysics,

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Jones, G.Ll., Goodman, R., Pasquali, R., Kelly, J.G.,

O’Neill, N., Slowey, E. 2007a. The Status of

Geothermal Resource Development in Ireland. Proc.

European Geothermal Congress 2007, Unterhaching,

Germany, 30 May-1 June 2007. 3pp.

Jones, G.Ll., Pasquali, R., Antin, G., Grummel, T.,

Goodman, R., Glanville, P., O’Neill, N. 2007b.

Feasibility Study & Market Research for the

Development of a Deep Geothermal Borehole on the

University College Dublin Campus, Final report to

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Appendices

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3194/01.05, September 2005. 79pp + XI Appendices

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April 2010. 12pp.

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resources in the Mallow Area for Heating Purposes.

Unpub. ME thesis, National University of Ireland,

Cork. 219pp.

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Site Characterisation. Interim report to Sustainable

Energy Ireland, July 2005. 85pp.

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Site Characterisation. Final report to Sustainable

Energy Ireland, October 2005. 29pp.

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Irish Landscape. Occasional Papers in Irish Science

and Technology, 23.

Vandenberghe, N. & Fock, W. 1989. Temperature data in

the subsurface of Belgium. Tectonophysics, 164,

Amsterdam, p237-250.

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interpretation of new airborne geophysical imagery of

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Survey of Northern Ireland. (With contributions from:

David Beamish, Baz Chacksfield, Chris van Dam,

David Jones, Cathy Scheib and Adrian Walker)

Proceedings World Geothermal Congress 2010

Bali, Indonesia, 25-29 April 2010

1

The Geothermal Potential of Northern Ireland

R. Pasquali, N. O’Neill, D. Reay*, T. Waugh**

GT Energy Ltd, Unit H, Greenogue Business Park, Rathcoole, South Co. Dublin, IRELAND

*Geological Survey of Northern Ireland, Colby House, Stranmillis Court, Malone Lower, Belfast BT9 5BF

**Action Renewables, The Innovation Centre, NI Science Park, Queens Road, Belfast BT39DT

ricpasquali@gmail.com

Keywords: geothermal resource, Northern Ireland, hydro-

geothermal, district heating

ABSTRACT

The Geothermal Energy Review of Northern Ireland study

completed in 2005 modelled data from previously drilled oil

and gas, mineral exploration and deep geothermal

exploratory boreholes to develop temperature maps at

selected depths in Northern Ireland. This study predicted

suitable lithologies and reservoir characteristics in potential

geothermal aquifers in areas where temperatures above the

normal geothermal gradient were recognised in the

subsurface.

Acquisition of airborne aeromagnetic data by the TELLUS

project in 2007, in conjunction with existing geological data,

has improved the understanding of deep geological

structures throughout Northern Ireland. The new data

allows identification of targets for deep geothermal energy

development as a result of the Sherwood Sandstone and

Lower Permian Sandstone targets being better defined.

Reservoir modelling and preliminary resource assessment

based on newly acquired petrophysical and reservoir

parameters of both targets shows that the Lower Permian

Sandstone target has the highest geothermal potential in the

Larne, Lough Neagh and Rathlin sedimentary basins.

A profile of Northern Ireland’s energy usage shows that

most electricity and heat requirements are met through the

use of conventional fossil fuel technologies. Current

government policy is focussed on the development of

renewable energy solutions to reduce current CO2 emissions.

Deep geothermal energy in Northern Ireland could

significantly contribute to the reduction of these emissions

by providing a renewable heat source to both domestic and

industrial sectors. Geothermal energy utilisation from

Permo-Triassic basins should be considered as a suitable

renewable energy alternative in these locations to supply

heat to current and proposed future developments in order to

meet the targets for the year 2020 set by Renewable Energy

Directive through the national Renewable Energy Action

Plans.

1. INTRODUCTION

Previous desktop studies on the geothermal potential of

Northern Ireland focused on the assessments of temperature,

porosity and related water flow in the Larne No.2

geothermal borehole completed in the 1980s. The findings

of the study identified the reservoir petrophysical parameters

were probably not representative due to damage to the

formation caused during the drilling of the borehole.

The presence of the Sherwood Sandstone in relatively young

sedimentary basins in Northern Ireland combined with an

elevated geothermal gradient identified in a number of

boreholes is comparable to other regions of Europe.

Temperatures of between 70oC and 90oC have been recorded

at depths of between 2km and 3km in a number of other

boreholes.

Further analysis of logs from these boreholes in Northern

Ireland has indicated an additional target in Lower Permian

Sandstones below the Sherwood Sandstone which may

constitute an additional reservoir target for deep geothermal

energy development in the northern and eastern part of

Northern Ireland. The basal Carboniferous sandstones of the

North West Basin in southwest Fermanagh were also

considered. Although the porosity and permeability recorded

from oil exploration wells is low the data is limited and the

hydro-geothermal potential cannot be ruled out.

The recently acquired airborne magnetic and gravity data in

conjunction with existing seismic line data has been used to

refine the parameters and semi-quantitatively estimate the

total energy stored in a given reservoir volume by using a

volumetric analysis method.

This paper focuses on the geothermal energy potential

calculated using physical parameters from bedrock

formations intersected in the oil and gas boreholes to a depth

no greater than 2900m in Northern Ireland.

2. GEOLOGICAL REGIONS OF NORTHERN

IRELAND

Northern Ireland has a number of sedimentary basins that

have been explored in the past because of their potential to

contain oil and gas reserves. The Rathlin, Larne and Lough

Neagh basins in the east and northeast contain in excess of

3000m of Permo-Triassic sediments (Mitchell, 2004) whilst

the North West Basin in the southwest of Northern Ireland

contains a similar thickness of Carboniferous sandstones,

shales and limestones (figure 1).

Figure 1: Sedimentary Basins and Oil and Gas

Exploration Boreholes in Northern Ireland.

Pasquali et al

2

Exploration boreholes for oil and gas (figure 1) in these

basins have improved the understanding of the depth to and

thickness of permeable lithologies that could act as hydro-

geothermal reservoirs. Core samples from these exploratory

wells were used to determine the permeability and porosity

values in the potential reservoir targets. Based on these data

a series of representative sections showing the tops and

bases of the target formations were generated (McCann,

1988 & 1990). No data currently exists for the northeastern

and southwestern areas of Lough Neagh, which have been

identified (Mitchell, 2004) as the main depocentres in the

Lough Neagh Basin and are likely to contain thicker

sedimentary sequences than the areas which have been

tested to date. A summary stratigraphy of the Permo-

Triassic basins is given in Table 1 below.

Table 1. Summary Stratigraphy of the Permo-Triassic

Sequences in the Larne, Lough Neagh and

Rathlin Basins.

Period Group/Formation Lithologies

Lough Neagh Group Clays, lignites, minor sands and

conglomerates

Upper Antrim Basalts Volcanics, pyroclastics and terrestrial

sediments

Interbasaltic Bed Laterised basalts

Lower Antrim Basalts Volcanics, pyroclastics and terrestrial

sediments

Tertiary

Clay with Flints Weathered Cretaceous and

pyroclastics

Ulster White Limestone

Formation Highly indurated chalks with flints

Cretaceous

Hibernian Greensand Glauconitic sandstones

Jurassic Waterloo Mudstone Calcareous mudstone and thin

limestones

Penarth Group Mudstone, siltstone and thin

limestone

Mercia Mudstone Group Mudstones and thick evaporites

(CaSO4 and NaCl in Larne Basin) Triassic

Sherwood Sandstone

Group Fluvial and aeolian sandstones

Belfast Group (“Permian

Marl”)

Mudstone, evaporites, Magnesian

Limestone at base. Ur Perm. Sst.

locally present

Upper Permian Sandstone

Sandstone – only present in Lough

Neagh Basin, replaces (in part) the

Permian Marl

Magnesian Limestone Dolomitic limestones and dolomites

Ballytober Sandstone

Formation (“Lower

Permian Sandstone”)

Conglomerate and breccias passing

up into sandstones

Permian

Inver Volcanic Formation

Basaltic to trachytic volcanics and

tuffaceous siltstones.

Sandstone/conglomerate unit at base

Coal Measures Deltaic clastics and coals

Carboniferous Carbonates, mixed clastics

Marine carbonates, passing up into

sub-tidal to supra-tidal sequence,

overlain by deltaics

Devonian “Old Red Sandstone” Terrestrial redbeds

Ordovician and

Silurian Lower Palaeozoics Metamorphosed basement to basin

2.1 Sherwood Sandstone Group

The Sherwood Sandstone Group occurs in the Rathlin, Larne

and Lough Neagh basins. The Sherwood Sandstone is

typically overlain by thick Triassic mudstones and

evaporites of the Mercia Mudstone group. This

mudstone/evaporite succession acts as an insulating unit to

the porous lithologies of the Sherwood Sandstone Group

below. Typically, both of these are overlain by mudstones

and thin limestones of the Triassic Penarth Group and

Jurassic Waterloo Mudstone, the Cretaceous Ulster White

Limestone, extrusive volcanics of the Antrim Basalt Group

and Oligocene sediments in the Lough Neagh and Rathlin

basins. Figure 3a shows the presence of the Sherwood

Sandstone reservoir in the Rathlin basin based on the

information recorded in the Portmore borehole.

The Sherwood Sandstone group is characterised by

moderate to low porosity sandstones of fluvial and marine

origin that have previously been explored for geothermal

energy in the Larne basin (Larne No.2 Borehole) where it is

recorded at a depth of 1800m with an approximate thickness

of 800m. The Sherwood Sandstone group found in the

Larne boreholes is shown in figure 2a.

Figure 2a: Sherwood Sandstone Group and Permian

Sandstone Group occurrences in the Larne &

Lough Neagh Basins (McCann, 1990).

In the Rathlin Basin to the north, this group shows a

maximum thickness of 600m and is present at a maximum

depth of approximately 1900m.

2.2 Lower Permian Sandstones

This succession has been described from the drilling results

in the Larne No.2 borehole as a sandstone ranging from very

fine grained to very coarse grained units with a total

thickness of approximately 440m. It was intersected at

depths between 1800m and 2220m below ground level. It

has also been encountered in the Portmore borehole at an

approximate depth of 1890m where the base of the unit was

not reached. However, seismic refraction studies on the

edges of the Rathlin basin have shown that this formation

may be thinner than in the Larne basin with thicknesses of

the order of approximately 200m (figures 2b).

Figure 2b: Sherwood Sandstone Group and Permian

Sandstone Group occurrences in the Rathlin

Basin (McCann, 1988).

2.3 Carboniferous Sandstones

Carboniferous sandstones of Chadian age have been

described in the Northwest Basin in the south

Tyrone/Fermanagh region. These sandstones have moderate

to low porosity and are terrestrially derived. The thickness

of this succession is not as well known as the Boyle and

Kilcoo Sandstones that have been frequently intersected by

oil exploration boreholes. However they have been

described as being up to possibly 150m thick at depths of

Pasquali et al

3

between 1600 and 1800m in the Kilcoo Cross and

Slisgarrow boreholes (figure 3).

Figure 3: Carboniferous Sandstones (yellow) in the

North West Basin (George et al, 1976).

The temperatures modelled in the 2005 CSA review have

been used in this study to characterise the geothermal

potential of target reservoir rocks in Northern Ireland in the

vicinity of heat end-user markets.

3 ELEVATED TEMPERATURES:

Borehole temperature information from the hydrocarbon

exploration and mineral exploration boreholes in Northern

Ireland was modelled and assessed during a recent study.

This showed high geothermal gradients and temperatures in

some of the basins in Northern Ireland. Figure 4 shows the

temperature modelled at a depth of 2500m based on

measured borehole temperatures and calculated data.

Figure 4: Modelled Temperature at 2,500m depth and

seismic line locations in Northern Ireland

(Goodman, 2004).

Based on the lithologies encountered in the hydrocarbon

exploration boreholes and the temperature profiles recorded

subsequent to the completion of the drilling a series of

temperatures were modelled for a number of basins at depths

of 1000m, 1500m, 2000m and 2500m. Table 2 below shows

the modelled temperatures in a number of the boreholes

where temperature gradients were measured.

The potential geothermal reservoir targets were intersected

at depths of between 1500m and 2200m. The boreholes

showing highest modelled temperatures at 2000m were

Portmore with 82oC, Ballymacilroy with 74oC and Langford

Lodge with 68oC. These temperatures coincide with the

presence of Permian Sandstones and Sherwood Sandstone

lithologies in the Rathlin and Lough Neagh basins.

These lithologies also occur in the Larne basin, which was

drilled in the 1980s to evaluate geothermal potential, with

similarly high temperatures. However, the recorded porosity

and permeability of the Lower Permian sandstones in the

Larne No. 2 borehole has been observed as anomalously low

compared with other proximal boreholes like the Newmill

No.1 borehole where much higher porosity and permeability

and temperatures values in the Lower Permian Sandstones

were observed. The temperature recorded in the Permian

Sandstones in the Larne No. 2 borehole was 77.5oC at a

depth of 2800m. For the purpose of this study a temperature

of 83oC was used to characterise the reservoir.

Table 2. Modelled Temperatures in Hydrocarbon

Boreholes (Goodman, 2004).

BOR EH OLE N A M E T ( o C) a t 1000m T ( o C) a t 1500m T ( o C) a t 2000m T ( o C) a t 2500m

A nnaghm ore N o. 1 42.33 53.33 64.33 75.33

Ballym acilroy N o. 1 49.28 62.00 74.00 85.00

Bally tober N o. 1 37.50 51.50 66.00 80.00

Big D og N o. 1 33.89 45.60 57.40 69.20

Glenoo N o. 1 33.50 43.00 52.50 61.50

K ilcoo C ross N o. 1 35.00 46.50 57.00 68.00

K illa ry Glebe N o. 1 39.60 51.00 61.00 71.50

Langford Lodge 43.00 56.00 68.00 80.00

Larne N o. 2 43.00 51.00 60.50 70.00

N ew m ill N o. 1 31.00 34.10 50.50 59.90

Ow engarr N o. 1 38.00 43.50 52.50 63.00

Port M ore N o. 1 45.50 62.80 82.00 99.50

Slisgarrow N o. 1 39.00 50.00 57.80 69.50

W ind Farm N o. 1 27.00 40.50 54.50 68.50

Temperature values recorded in the Northwest basin in the

Slisgarrow, Owengarr, Glenoo and Big Dog boreholes were

noted in the 2005 CSA report as being partially inaccurate as

very few temperature profiles were taken following the

completion of the boreholes (one reading 9 hours after

drilling at the end of the Slisgarrow No. 2 borehole was

completed) and in some cases the time of the temperature

log was not recorded. For this reason the temperatures

observed in these boreholes in not believed to be the true

stabilised formation temperature in the Lower Carboniferous

targets. In this characterisation study a higher true stabilised

formation temperature has been used.

4 TELLUS DATA:

The British Geological Survey (BGS) and the Geological

Survey of Northern Ireland (GSNI), in partnership with the

Geological Survey of Finland (GTK), flew a low-level

airborne geophysical survey over Northern Ireland in 2005–

6. The survey completed a total of 86,000 line km at a height

of 56m and collected magnetic field, electrical conductivity

and terrestrial gamma-radiation measurements.

The survey has permitted improved mapping of faults, dykes

and the major volcanic complexes that are overprinted by

late glacial and Quaternary sediments at the surface. The

survey has aided the delineation and definition of the basins

where geothermal reservoir targets are contained.

For the purpose of this study a combination of aeromagnetic

data and previously acquired ground gravity data were

reviewed by BGS and GSNI to refine the existing reservoir

models previously established from older hydrocarbon

seismic data.

Based on the geometry of the reservoir outlined in the

seismic models, the magnetic intensity data collected during

the TELLUS project in conjunction with the GSNI gravity

data was superimposed to identify the correct density

parameters of the reservoir formations and the geometry of

the basin structures controlling the depths of the reservoir by

using the individual modelled data for the seismic lines in

figure 4.

The information gathered from this modelling exercise has

refined the depth of the reservoir lithologies away from the

exploration boreholes. Table 3 below shows the depth of the

top and base of the Permo-Triassic reservoir rocks in three

Pasquali et al

4

key areas where elevated temperatures have been modelled

but where reservoir conditions have not yet been

investigated.

Table 3. Estimated Geothermal Reservoir Thickness

based on airborne geophysical data (TELLUS)..

Top of Reservoir Target (m)

Base of Reservoir Target (m)

Estimated Thickness (m)

Top of reservoir

Target (m)

Base of Reservoir Target (m)

Estimated Thickness (m)

Antrim 1700 2100 400 2400 2600 200Ballymoney 1400 1900 500 2000 2500 500Magheramorne 900 1550 650 1650 1900 250

Sherwood Sandstone Group Lower Permian Sandstones

Data models have shown that the Sherwood Sandstone

Group reservoir is sufficiently thick and occurs at depths up

to 2km. The Lower Permian Sandstones are present at

greater depths in the basin but are not as thick as the

Sherwood Sandstone. Depth considerations indicate that the

Lower Permian Sandstones should be considered as the

primary geothermal reservoir target but it is worth noting

that within the Permian Sandstone succession some non-

porous tuffaceous sediments are also common and that the

estimated thickness of the sandstone succession may be less

than that observed in the models. However, as these units

are generally quite thin (no more than about 10m to 30m

thick) they were not included in the overall reservoir

thickness models for this study.

The modelled data suggests that the estimated depths of both

reservoirs at Antrim may be slightly underestimated, this is

dependant on variations in the thickness of the strata

overlying the Sherwood Sandstone Succession across the

Lough Neagh basin.

Sherwood Sandstone and Permian Sandstone thickness at

Ballymoney is in the region of 500m, where the latter of the

two is estimated to be present at a depth of approximately

2500m. It is worth noting the presence of probable

Carboniferous sandstone targets below the Permian

Sandstones in these models. This would constitute a deeper

additional reservoir target in this area. However, there is no

deep borehole information to verify these models. During

the course of 2008 a hydrocarbon exploration borehole

located 15km north of Ballymoney will be drilled.

Information gathered from this borehole may provide

additional data on potential Carboniferous reservoir targets.

The granites of the Mourne area in Co. Down as well as

probable buried granites in Northern Ireland, may have the

potential for development of enhanced geothermal systems

(EGS) such as Hot Dry Rock technology for the production

of electricity. However, there is no information on the

reservoir properties of these formations, and they were not

assessed in this study. The Mourne granites have the

potential for high radiogenic heat production. These may

also constitute an important target for Hot Dry Rock type

systems. At present there is insufficient information on the

reservoir properties to be able to quantify their potential.

5 VOLUMETRIC ANALYSIS:

Reservoir calculations have been undertaken based on the

volumetric method (Muffler, L. J. P. & Cataldi, R., 1978).

This estimates the total thermal energy contained in a

volume of rock based on basic rock property parameters

such as mean temperature, porosity and specific heat

capacity. These are converted into recoverable heat energy

by estimating a load factor and a life time for a producing

geothermal well doublet. For the purpose of this calculation,

the volume of rock was assumed as being the thickness of

the formation over a 22.5km2 area which is considered the

normal radius of influence of a geothermal well doublet over

a period of 25 years of production.

The modelling exercise was carried out separately for the

Sherwood Sandstone Group, the Lower Permian Sandstones

and the Carboniferous Sandstones of the Northwest Basin.

The potential of the Carboniferous lithologies previously

described in this report in the Ballymoney area were not

included as to date insufficient reservoir parameters are

available. No modelling was possible for the Sherwood

Sandstone Group or Lower Permian Sandstones in the main

depocentres of the Lough Neagh Basin as no data is

available for these areas.

Geological modelling of available data provided reservoir

depths, petrological parameters and thicknesses of the

reservoir targets used in the calculations. Additional

information on the reservoir rock characteristics were

obtained from hydrocarbon exploration boreholes in the

vicinity of the modelled localities. In the absence of actual

lithological properties of the formations below the selected

localities, the adjacent borehole data provides a reasonable

estimate of these parameters.

Only guideline geothermal resource estimates can be given

for the specific sites selected, because specific heat

capacities of the rock formations at the sites chosen are

based on measurements acquired in generic laboratory tests.

For this reason an analogous geothermal well doublet in

Unterhaching (Germany) producing approximately 40MWth

of heat using standard titanium heat exchanger technology,

was included in the calculation for comparative purposes.

The results of the calculations are summarised in Table 4

below.

Table 4: Preliminary Reservoir Calculation for Total

Heat Power stored in Geothermal Reservoirs

formations in Northern Ireland.

Site Location Lithology

Reservoir

Thickness

(m)

Base of

Geothermal

Target

Formation (m)

Volume of

Source

Rock (V )

(m3)

Mean

Calculateda

or Measured

(T ) (oC)

Estimated Re-

injection

Temperature at

the Surface

(T ref ) (oC)

Load Factor1

(% operational

time)

Life

Time2

(years)

Energy

Stored in

the

Reservoir

(kJth)

Total Power

Stored in the

Reservoir

(MW h)

LarneSherwood

Sandstone650 1615 14625000 80 40 0.75 25 1.58E+09 439.53

BallymacilroySherwood

Sandstone420 1870 26250000 84 40 0.75 25 3.54E+09 983.50

LangfordSherwood

Sandstone270 1515 16875000 54 25 0.75 25 1.61E+09 446.12

Port MoreSherwood

Sandstone680 1830 42500000 78 40 0.75 25 5.24E+09 1456.08

AntrimSherwood

Sandstone400 1600 25000000 78 40 0.75 25 2.74E+09 761.35

BallymoneySherwood

Sandstone500 1400 31250000 78 40 0.75 25 3.43E+09 951.69

MagheramorneSherwood

Sandstone650 1600 40625000 82 40 0.75 25 4.62E+09 1281.96

LarneLwr. Permian

Sandstone900 2800 56250000 83 40 0.75 25 8.19E+09 2274.70

AntrimLwr. Permian

Sandstone200 2200 12500000 77 40 0.75 25 1.36E+09 378.22

BallymoneyLwr. Permian

Sandstone500 2200 31250000 82 40 0.75 25 3.86E+09 1073.33

MagheramorneLwr Permian

Sandstone250 2200 15625000 83 40 0.75 25 1.90E+09 528.84

North West

Basin

Carboniferous

Basal

Sandstone

150 2000 9375000 65 30 0.75 25 1.15E+09 318.65

The figures show initial estimates of total heat power

contained in a rock reservoir. The original formulae for

estimating the total energy contained in a given reservoir

normally take into account the characteristics of both rocks

and fluids present at depth. At present the only identified

potential hot brine source of geothermal energy is in the

Permo-Triassic basins in Northern Ireland. For this reason

and the present incomplete geological dataset, a conservative

case for the selected sites was adopted in this study and an

assumption that geothermal energy that can be sourced from

rock at depths of 1500m and 2500m depths only was made.

Hence fluid specific heat capacities and fluid temperatures

were omitted from the calculations.

The calculations of the total energy stored in reservoirs

(Table 4), identifies the Lower Permian Sandstones in the

Larne Basin as the reservoir with the highest geothermal

potential. This is because these formations are thicker and

occur at greater depth in the basin resulting in overall higher

Pasquali et al

5

formation temperatures. A review of the hydrocarbon

exploration data from these basins also indicates better

porosity values in this formation where water flow potential

is higher.

The Sherwood Sandstone Group in the same basins is

located at shallower depths with lower temperatures and

overall is slightly thinner than the Permian Sandstones

below. Permeability and porosity may, however, be more

favourable in the Sherwood Sandstone.

The potential of the Lower Permian Sandstone and the

Sherwood Sandstone in the Lough Neagh Basin depocentres

as outlined in Mitchell (2004) have not been assessed as

only limited geophysical data and no exploration wells have

been completed in these areas.

The availability of petrophysical properties for the

Carboniferous limestones in Northern Ireland is limited to

data from a single well in County Fermanagh. The TELLUS

data has so far not been used to refine the depths of this

target formation and it petrophysical properties. For this

reason the reliability of the modelled energy stored in these

formations is not as good.

Table 5 below shows an overall ranking of the potential for

deep geothermal energy stored in the reservoirs in Northern

Ireland with the Lower Permian Sandstones having the

highest potential.

Table 5: Geothermal Reservoirs formations and Site

Location Ranking in Northern Ireland.

Formation

Ranking

Site

Location

Rank Site Location Lithology

Reservoir

Thickness

(m)

Base of

Geothermal

Target

Formation

(m)

Total

Energy

Stored in

the

Reservoir

(MW h)

1 LarneLwr. Permian

Sandstone900 2800 2274.70

2 BallymoneyLwr. Permian

Sandstone500 2200 1073.33

3 MagheramorneLwr Permian

Sandstone250 2200 528.84

4 AntrimLwr. Permian

Sandstone200 2200 378.22

1 Port MoreSherwood

Sandstone680 1830 1456.08

2 MagheramorneSherwood

Sandstone650 1600 1281.96

3 BallymacilroySherwood

Sandstone420 1870 983.50

4 BallymoneySherwood

Sandstone500 1400 951.69

5 AntrimSherwood

Sandstone400 1600 761.35

6 Langford LodgeSherwood

Sandstone270 1515 446.12

7 LarneSherwood

Sandstone650 1615 439.53

3 1 North West BasinCarboniferous

Basal Sandstone150 2000 318.65

1

2

The results show how depth and formation thickness control

the potential for heat storage across all the basins. In

localities where both the Lower Permian and Sherwood

Sandstone targets are present, the thickness of the modelled

formation is shown as the controlling factor. This is true of

the Antrim and Magheramorne areas where the Lower

Permian Sandstone formations are thinner compared to the

overlying Sherwood Sandstone. Hydrocarbon well data

shows that the porosity recorded in the Lower Permian

formations is also slightly lower than that those of the

Sherwood Sandstone. For this reason higher flow rates at

lower temperatures in the shallower Sherwood Sandstone

may yield more energy than in the Lower Permian

Sandstones.

The Carboniferous Basal Sandstones encountered in the

Northwest basin in Fermanagh have shown from the

modelling to have the lowest stored energy values compared

to the younger formation in other parts of Northern Ireland.

However these are also very thin compared to some of the

other modelled targets.

Figure 5 shows the distribution of geothermal potential of

the given reservoir target formations in Northern Ireland.

Figure 5: Claculated Geothermal Reservoir Potential in

Northern Ireland.

REFERENCES

George, T. N., Johnson, G.A.L., Mitchell, M., Prentice, J. E.,

Ramsbottom, W. H. C., Sevastopulo, G. D., Wilson, R.

B. 1976. A Correlation of Dinantian rocks in the British

Isles. Geol Soc. London., Spec Rep. 7, p87.

Goodman, R., Jones, G. Ll., Kelly, J., Slowey, E., O’Neill,

N., 2004. Geothermal Energy Exploitation In Ireland –

Review of the Current Status and Proposals for

Optimising Future Utilisation. CSA Group Ltd.

McCann, N. 1988. An Assessment Of The Subsurface

Geology Between Magilligan Point And Fair Head,

Northern Ireland. Irish Journal of Earth Sciences, 9,

1988, 71-78.

McCann, N. 1990. The Subsurface Geology between Belfast

and Larne, Northern Ireland. Irish Journal of Earth

Sciences, 10, 1990, 157-173.

McCann, N. 1991. Subsurface Geology of the Lough Neagh

- Larne Basin, Northern Ireland. Irish Journal of Earth

Sciences, 11, 1991, 53-64.The section break that

follows the last words of the paper will cause the

columns to be even.

Mitchell, W. I. 2004. The Geology of Northern Ireland-Our

Natural Foundation (2nd Edition). Geological Survey

of Northern Ireland (Belfast)

Muffler, L. J. Cattaldi., R, (1978). “Methods for Regional

Assessment of Geothermal Resources.” Geothermics

7(2-4): 53-89.

O’Neill, N., Pasquali, R. 2005. Deep Geothermal Site

Characterisation, Interim Report to Sustainable Energy

Ireland. CSA Group Ltd.

Proceedings World Geothermal Congress 2010

Bali, Indonesia, 25-29 April 2010

1

Geotrainet

– A New European Initiative for Training and Education of Planners, Drillers and Installers

of Geothermal Heat Pumps

Burkhard Sanner a, Philippe Dumas a, Isabel Fernandez Fuentes b, and Manuel Regueiro b

a European Geothermal Energy Council, Renewable Energy House, 63-67 Rue d´Arlon, B-1040 Brussels, Belgium

b European Federation of Geologists, c/o Service Geologique de Belgique, 13 Rue Jenner, B-1000 Brussels, Belgium

b.sanner@egec.org, p.dumas@egec.org, efgbrussels@gmail.com

Keywords: geothermal heat pumps, Europe, education,

training, certification, designers, drillers, installers.

ABSTRACT

The aim of the project “Geo-Education for a sustainable

geothermal heating and cooling market”, GEOTRAINET, is

to develop the training of professionals involved in Ground

Source Heat Pump installations (GSHP). From the different

groups of professionals involved in a GSHP, the

GEOTRAINET project is focused on two target groups:

designers (who undertake feasibility studies including

geology) and drillers (who make the boreholes and insert

the tubes). The project includes the creation of an EU-wide

certification scheme for both planners and installers of

GSHP. Another project activity will be the definition

and development assistance for the necessary EU-wide

technical standards.

Visible results of the project will be the curricula, learning

tools, manuals, an e-learning platform for the designers and

the trainers, and several courses to be launched during the

project duration. The goal, however, is to co-operate with

the relevant professional associations, teaching institutions,

etc. in order to establish a training and education framework

going farther and lasting longer than the project – and

providing the human resources necessary to sustain a sound

and healthy growth of the GSHP market in Europe.

1. INTRODUCTION

The European Federation of Geologists is the Co-ordinator

of a large group of partners which has made a successful

application to the European Commission, “Intelligent

Energy – Europe” Programme, for a grant to run a project

for the training of professionals to install ground source

heat pumps across Europe.

Ground Source Heat Pumps, GSHP, contribute greatly to

energy saving and emission reduction. In Europe, a

sustainable market has only been established in some

countries like Sweden, Switzerland, Germany and Austria.

Research in Europe shows that one of the barriers to a

sustainable and growing geothermal market is the lack of

appropriate skilled personnel; quality of design and work

are not always satisfactory. Furthermore, to keep quality up,

a certification programme for the GSHP workforce is

required. The objective of this project is to develop a

European Education programme to go towards the

certification of the workforce involved in geothermal

installations. It will prepare an education programme,

didactic materials, training courses, and develop an e-

learning platform. Training structures in 8 EU countries

will be established for professionals of the geothermal

sector. A European certification framework will be

proposed. Standards and codes will be suggested to permit a

certain harmonization.

The need for good work is evident when looking back at the

heat pump industry. With the second oil price crisis in

1980, heat pump sales skyrocketed, as people were asking

for energy efficient heating systems. However, with the oil

price still high, heat pump sales collapsed shortly after the

peak year, 1980 (Fig. 1a and 1b). So clearly not the

economic circumstances, but a frequent lack of quality and

experience in both the heat pump manufacturing and the

system installation created certain resentment against that

technology. With the oil prices rising again in the last years,

another GSHP boom can be seen, and it is up to us to make

sure that the same does not happen as in the early 1980s.

The main goal of the project is to promote geothermal

energy in training geothermal installers, this removing one

of the main barriers for Geothermal Energy on H-&-C in

many European Countries. The results of the project will be

a European Certification to support and improve the quality

of geothermal installations, with an Education programme

to support a Continual Professional Development (CPD) for

Earth Science Experts and Drilling Professionals.

An international platform of experts on Geothermal Energy

H-&-C will be established to provide the knowledge

required for education in this area by Training Courses and

a European E-learning platform for shallow geothermal

applications.

The project will also improve the access to geological data

needed for the design of GSHP installations, and propose

high standards on the professional needs for Geothermal

Energy Heating and Cooling in Europe.

GEOTRAINET is divided into phases permitting the

creation of an education programme to provide a

certification framework and to train geothermal installers.

The work will be as follows: 1) Research into data currently

useful for GSHP installers; 2) Evaluate skills required to

design, drill and install GSHP; 3) Create curricula for

installers: designers and drillers; 4) Create training tools.

Test and optimization of the products; 5) Suggest standards

and codes to create a European market; 6) Propose a

European certification framework; 7) Launch training

courses.

Sanner et al.

2

Figure 1a: 30 years of Heat Pump Sales in France after data from EHPA, BWP, EIA and others

Figure 2b: 30 years of Heat Pump Sales in Germany after data from EHPA, BWP, EIA and others.

The group of partners of GEOTRAINET represents: the

European industry in the sector, the European Geothermal

Energy Council; the European professionals, European

Federation of Geologists; research centres, Arsenal

Research Austria and BRGM France; private companies,

GT Skills, Ireland and Geoexchange Society Romanian;

and Universities, Universidad Politécnica de Valencia,

Spain, University of Lund, Sweden, and Newcastle

University, UK.

The duration of the project will be 30 months from the 1st of

September 2008.

2. CURRICULA FOR GSHP GEOSCIENCES AND

DESIGN

The training of geologists or geoscientists is necessary to

give them a complete GSHP competence:

Sanner et al.

3

. Environmental respect: take into consideration potential

contamination of soil and groundwater, ground stability,

hydrogeological knowledge, ensuring protection of the

environment (in particular groundwater) while drilling;

. Ground thermal conditions: the shallow geothermal

installer training will cover geothermal resources and

ground source temperatures of different regions, soil and

rock identification for thermal conductivity, regulations on

using geothermal resources, determining the most suitable

geothermal heat pump system;

. Technical conditions: familiarity with different drilling

and digging technologies, choice of the optimum drilling

method, ensuring protection of the environment (in

particular groundwater) while drilling, well construction,

pressure testing, logistics, building laws, and safety.

To achieve these objectives the establishment of a European

expert platform will be necessary. This platform will work

on creating Curricula for geosciences and design, and

assigning contents and programmes to the work items

identified in the Curricula.

The professional experience of the expert platform will help

to define in a precise manner the most relevant areas and

knowledge blocks inside the geothermal profession, the

most relevant aspects for a quality technical assessment of

the GSHP installations. The main goal of this Platform of

experts is to work on the programme of education,

including necessary content and skills requirement, the

didactic materials and an identification of profile and

required professional experience of the teachers.

The platform will define the general methodology and the

strategy, agreed and shared by the partners, for the common

activities (data collecting, e-learning modules,…) that are

going to give a common product (database, e-learning

platform, guidelines,…).

The qualification of geologists covers an extensive

spectrum of disciplines. Depending on the employment

demands geologists have continuously adapted their level

of specialisation. There are certain specialisations, such as

Geotechnics, Hydrogeology, Geophysics, that are of

particular relevance for the analysis of the ground in view

of geothermal objectives.

The first task of the Expert platform will be to assess the

data required for geothermal h&c installations, in order to

define the curricula necessary for the Geoscientists active

in GSHP. A second task for the geoscientist's expert

platform is to define the knowledge needed and required to

advise on GSHP ground installations. A third task is to

present the programme of the design training courses in

order to prepare the didactic materials.

3. ASSESSMENT OF GEOTHERMAL DATA

REQUIRED FOR GSHP DESIGN AND

INSTALLATION

Assessment of geothermal data required for design and

installation, involves the following activities:

. Inventory of data available in the Geological Surveys or

other equivalent authorities. A first approach is to realise a

catalogue on ground meta-data dedicated to the GSHP.

. Collect and evaluate data to determine knowledge and

skills required for design and installation of geothermal

heating and cooling.

Site conditions are factors impacting on GSHP (heating and

cooling efficiency, drilling methods, heat exchange

performance, protected areas….). It is essential to have

these data for the feasibility study of the GSHP system. It is

necessary to know for designers in each EU-27 country

how to access the necessary data. In different countries

(Germany, France, UK,…), local documents are available

(local GIS -Geographical information system- or specific

reports) to support decision-makers . In those documents

initial consideration (geological) before installing a GSHP

are presented (more or less detailed). A catalogue of the

types of available information and their mode of

presentation is essential for EU countries to compare and

develop new supports and collect new data mainly for

GSHP.

A best practice case exists in Germany where the

Geological Survey of Nordrhein-Westfalen provides freely

the geological data on a CD-rom. Other Lander are

developing the same products. In some countries, this vital

information for the designers has to be paid for.

The goal is to present what are the geological data available

in 7 EU countries, how they are available for the designers,

and what is the methodology needed to have them available

for designers, in order to replicate these actions in the other

EU countries. The data assessment will also include a

Guideline to facilitate the acquisition of the geological data

for the geothermal professional. This Guideline will be

included in the didactic material. BRGM will coordinate

this task, and EFG, the Panel of Experts on Geothermal

Energy, prepares a report on Geological Studies, the

influence of the ground on the Geothermal installations.

Other partners will collect data for their countries.

The Geological Survey of France, BRGM, will coordinate

the contribution on the project from 6 national geological

surveys (CGS, Czech Republic Geological Survey; IGME,

Spain Geological Survey; PGI, Poland Geological Survey;

INETI, Portugal Geological Survey; BGS, British

Geological Survey; TNO, Dutch Geological Survey)

An internal group of experts will work on the technical

assessment of the project. The result of this group of

experts will be a report on the project by BRGM as project

partner. It will involve listing and categorising all the

geological data produced by these national authorities for

geothermal applications in the countries involved in the

project and will be a template for EU-27, looking in

particular at the following tasks:

. Metadata on the ground;

. Geological maps, hydrogeological conditions, ground

physical characteristics and ground thermal conductivity;

and,

. Local environment to install shallow geothermal systems:

geological conditions and climate.

4. CURRICULA FOR GSHP DRILLING AND

INSTALLATION

A European expert platform dedicated to the drilling and

installation part of a GSHP will be established. It involves

the creation of Curricula for drillers and installers, and the

creation of contents for the work items identified in the

Sanner et al.

4

Curricula. The objective is to provide the content of the

curricula and didactic material for the drillers who would

opt for a professional activity in the GSHP area.

The platform of experts will define the:

. Programme of education, including necessary content and

skills requirements to train drillers;

. Didactic materials to prepare the learning materials for

drillers; and,

. Identification of profile and required professional

experience of the teachers for the training of the trainers.

The objective here is to create European materials, updating

the existing ones, and targeting them more to professionals.

Specific materials have to be created for vocational training

for the drillers. From our point of view, existing training

material for drillers is more or less specific for each country

(legal aspects, but also focuses on a few techniques locally

used).

The objective is to collect existing materials in the EU

countries, and to propose a homogeneous material. This

material could be translated and completed with national

data and legal information.

5. CREATION OF NECESSARY

TEACHING/LEARNING MATERIALS AND OF THE

E-LEARNING PLATFORM

The panel of experts will work to develop the necessary

teaching system to support Geothermal Heating and

Cooling and train professionals (geologists, drillers,

installers, salespersons, planners and others) with an e-

learning platform and other learning tools.

The goal is to develop best practice documentation and to

create all the necessary documents to help in the training

courses. The documents will be used during the courses, to

be disseminated and for the courses organised after the

project. The documents will be in English, German, French

and Spanish. They will be adapted for the 8 project targeted

countries to take into account the national specifications.

An e-learning platform will be created to train mainly

designers all over Europe but the information will be

available publicly. The information will be free and online.

6. ESTABLISHMENT OF CERTIFICATION

FRAMEWORK AT EUROPEAN LEVEL AND

PROPOSAL FOR STANDARDISATION

Certification means that an installer has demonstrated

necessary skills, knowledge and ability typically required of

a practitioner to competently install and maintain a GSHP

installation. Certification is provided via training

programmes for designers, drillers and installers. These

training programs need to be accredited by a credible

authority to make sure they apply sufficiently stringent and

uniform training standards and are suitably designed to

reach their goals. One part of the project aims at presenting

uniform training programmes with a certification

framework to be replicated in the EU.

The goal is to propose a framework permitting the

certification of professionals having followed and

succeeded in the learning and e-learning courses dispensed

by Geotrainet. This framework will result in the adoption of

comprehensive schemes for accreditation and certification

based on jointly elaborated and agreed success criteria.

The certification will concern the different categories;

geologists, designers, installers and drillers. The

certification will be issued on a voluntary basis by the

national competent authorities in close consultation with the

relevant stakeholders, allowing it to be recognized on an

EU-level.

The project will underline the advantages of a Certification:

it can be a help in access to incentive and support

programmes, and may become a requirement with respect

to environmentally friendly drilling and installation.

To complete the European certification framework,

standards and codes will be suggested for the ground part of

a GSHP (from the existing ones or new ones) to contribute

to the creation of an uniform market.

The goal is to avoid unskilled work and develop a

harmonized European market. For the heat pumps, EN

standards are well adapted and allow for a free circulation

of machines and components within the common market.

For the ground side of shallow geothermal installations,

relevant standards and codes exist only in a few countries

with developed GSHP market (AT, DE, SE and CH). In FR,

IE and NL the matter is somewhat covered, and work is

ongoing on developing standards and codes. A common

EU-wide harmonisation is not in sight. An approach for

common standards can be seen between AT, DE and CH,

where geology and work practice is similar.

The eight target countries will organize direct training

courses. The logistic base for each training course will be

ensured by the local partner involved in the project. There

will be 8 direct training courses: 2 for trainers, 3 for drillers

and 3 for designers. In addition, the WP covers two e-

learning courses, one for trainers and one for designers. The

total period for this WP corresponds to month 6 until month

26. The levels of existing skills and knowledge expected of

the people who are to be trained are:

For Designers/Planners:

. Students: post graduate, more than 3 years in geology,

hydrogeology, etc;

. Professionals: engineers, geologists, technicians with 5

years of experience

For Drillers:

. Professionals with 3 years of experience;

. Students with background in mechanics.

In the case of shallow geothermal installers, accredited

training programmes will be offered to installers with

working experience, who have undergone, or are

undergoing, the following types of training: as a driller or

pipe layer and having basic geological skills as a

prerequisite. The evaluation system consists of two parts:

a) an assessment of the skills and knowledge of the

professionals having taken the course

b) an evaluation questionnaire filled in by the course

participants on the quality and relevance of the course

Sanner et al.

5

c) an overall evaluation report on the training courses,

summarising the results of the course and the evaluation

questionnaire filled in by the students

The theoretical part of the shallow geothermal installer

training will cover geothermal resources and ground source

temperatures of different regions, soil and rock

identification for thermal conductivity, regulations on using

geothermal resources, determining the most suitable

geothermal heat pump system, system layout, drilling

technologies, installation of borehole heat exchangers, well

construction, pressure testing, logistics, building laws and

safety.

The training will also provide good knowledge of any

European standards for shallow geothermal, and of relevant

national and European legislation.

At the end, the level of skills achieved and certified as a

result of the proposed training courses will be that the

installers demonstrate the following key competences:

. understanding geological and geothermal parameters of

the ground and knowing their determination, nomenclature

and identification of soil and rock types, preparing borehole

reports including lithology, groundwater, etc.; basic

geological and hydrogeological knowledge;

. familiarity with different drilling and digging

technologies, choice of the optimum drilling method,

ensuring protection of the environment (in particular

groundwater) while drilling;

. ability to install borehole heat exchangers, to grout,

backfill or otherwise complete the ground source system,

and to perform pressure tests; skills for welding of plastic

pipes and other connection methods;

. ability to construct groundwater wells, to install the

relevant pipes, pumps and control systems; and,

. ability to perform the relevant documentation including

identification and drawing of drilling locations.

7. CONCLUSIONS

The European Union adopted in December 2008 the

Climate and Energy Package.

Agreement has been reached on the Directive on the

promotion of the use of energy from renewable sources:

have 20% RES by 2020 in the European Union.

For the first time, each EU Member State has a legally

binding renewables target for 2020 along with a clear

trajectory to follow. By June 2010 the Member States will

draw up Renewable Action Plans detailing the ways in

which they are to meet their 2020 targets, which will then

be submitted to the Commission for assessment. They will

report on how they are doing every two years. These

measures will lead to real progress in the 27 countries.

One important measure is that “Member States shall ensure

that certification schemes are available by 2012 for

installers of shallow geothermal systems and heat pumps”.

Indeed, heat pump, shallow geothermal and other small-

scale installers shall be certified by an accredited training

programme or training provider.

Research in Europe shows that one of the barriers to a

sustainable and growing GSHP market is the lack of

appropriate skilled personal, and quality of design and

works are not always satisfactory. To keep quality up, a

certification program for GSHP workforce is required.

The objective of “Geo-Education for a sustainable

geothermal heating and cooling market” project, is to

develop a European Education program to get towards the

certification of geothermal installations:

Develop the training of professionals involved in Ground

Source Heat Pump installations (GSHP)

Create a EU-wide certification scheme for both planners

and installers of GSHP.

ACKNOWLEDGEMENT

Project GEOTRAINET is funded by the European Union

under the Intelligent Energy Europe Program. Nevertheless,

The responsibility for the content of this publication is with

the authors only.

REFERENCES

Directive 2009/28/EC of the European Parliament and of

the Council of 23 April 2009 on the promotion of the

use of energy from renewable sources and amending

and subsequently repealing Directives 2001/77/EC

and 2003/30/EC

Proceedings World Geothermal Congress 2010

Bali, Indonesia, 25-29 April 2010

1

Country Update for the United Kingdom

Tony Batchelor, Robin Curtis, Peter Ledingham

GeoScience Limited, Falmouth Business Park, Bickland Water Road, Falmouth, Cornwall TR11 4SZ, UK

contactgeo@geoscience.co.uk

Keywords: Country update, United Kingdom, low

enthalpy, direct use, GSHP, mine workings, EGS, HDR

ABSTRACT

The exploitation of geothermal resources in the UK

continues to be minimal. There are no proven high

temperature resources and limited development of low and

medium enthalpy resources. Work has continued on

assessment of a completed deep borehole at Eastgate. The

main area of UK activity in the last five years has been in

the rapid growth of ground source heat pump installations.

Following worldwide resurgence of interest in Engineered

Geothermal Systems, new activity in this field has been

rekindled in Cornwall. Two new projects have been

announced; a 10MWe scheme in west Cornwall and a

3MWe scheme to supply electricity and heat to the Eden

Project in mid Cornwall. The use of flooded mine workings

as a source of fluid for major projects continues to be

evaluated.

1. INTRODUCTION

In a worldwide context, the exploitation of geothermal

energy in the UK remains minimal. The geological and

tectonic setting precludes the evolution of high enthalpy

resources close to the surface and only low to moderate

temperature fluids have been accessed by drilling in

sedimentary basins in the south and northeast of England.

are accessible. Elevated temperature gradients and high heat

flows have been measured in and above some granitic

intrusions, particularly in southwest England. These

granites were previously the site of the UK’s earlier Hot

Dry Rock programme in Cornwall. Recent work at the

Eastgate borehole in northeast England also suggests higher

than anticipated temperature gradients and hence increased

focus on the possible application of geothermal heat in that

region.

Two major legislative drivers are now contributing towards

increased interest in geothermal activity in the UK. The first

is the European Union’s 20/20/20 campaign – viz 20%

Renewable Energy (electricity, heat and transport), and

20% CO2 reductions (below 1990 levels) by 2020. The

second is the 2008 UK Climate Change Bill – the first in

the world, that commits current and future UK governments

to publicly declared CO2 reduction targets. These

overarching drivers translate into lower level legislative

drivers such as the energy/carbon components of the

Building Regulations, and planning requirements for new

buildings. To assist with the achievement of these targets a

number of grant aided schemes are in place or are evolving.

As well as ongoing support for mainstream renewable

electricity generation, enabling legislation was passed in

2008 to allow for feed-in-tariffs for both small scale

electricity generation and for renewable heat. The effect of

this is leading to increased activity in the rapidly growing

ground source heat pump industry, and to a renewed

interest in the possibility of EGS systems to deliver

electricity and/or heat.

The new level of interest in all things geothermal in the UK

is possibly reflected in three recent symposia/meetings held

on the subject:

• The Royal Academy of Engineering held a one day

seminar “The heat beneath your feet: Geothermal

energy in the UK” in April 2009 – see

http://www.raeng.org.uk/events/pastevents.htm for

details and presentations)

• The Geological Society held a packed evening meeting

on Enhanced Geothermal Systems in May 2009. (see

http://tinyurl.com/ludrrb)

• The Institute of Civil Engineers devoted its specialist

2009 Geotechnique Symposium in Print to the topic of

“Thermal Behaviour of the Ground” which covered a

number of topics of relevance to geothermalists. A one

day symposium in May 2009 in London reviewed and

discussed all of the papers that were accepted for

publication. (see http://tinyurl.com/n9v9k5).

2. GEOTHERMAL UTILISATION

There is no electric power generation from geothermal

resources in the UK (See Table 1).

The City of Southampton Energy Scheme remains the only

exploitation of low enthalpy geothermal energy in the UK.

The scheme was started in the early 1980s when an aquifer

containing 76oC fluid was identified at approximately 1800

metres in the Wessex Basin. Construction of a district-

heating scheme commenced in 1987 and this has since

evolved and expanded to become a combined heat and

power scheme for 3,000 homes, 10 schools and numerous

commercial buildings. (see: http://www.energie-

cites.org/db/southampton_140_en.pdf )

The famous hot springs at Bath have long been a tourist

attraction among the Roman architecture of the ancient city.

Now the baths, together with four adjacent listed buildings,

have undergone a major refurbishment, which began in

2000 under a Millennium Commission grant. Despite

technical difficulties during the refurbishment, the baths

were reopened in 2008 and are now fully operational. (see

http://www.thermaebathspa.com/ )

Greater use is being made of groundwater for a number of

heating and cooling projects in London. Traditionally used

for hospitals, swimming pools and factories, more novel

applications are now being considered. The new Greater

London Authority building in central London is one of the

greenest buildings in the city, with both passive and active

energy design elements. Among them is the use of water

from the aquifer beneath London, which provides air

conditioning and is then recycled for use in toilets and

irrigation. Open loop geothermal systems have been used to

heat and cool several other prestigious projects in the UK

recently; the Queen’s Gallery, Portcullis House and the

Batchelor, Curtis, Ledingham.

2

Mayor of London’s offices all use this type of system.

These systems in London use water from the naturally

porous chalks and sandstones under the city. Several of

these projects are described in a recent GRC Bulletin on

geothermal energy in the UK (Hodgson 2009).

3. EXPLOITATION OF FLOODED MINES

A number of mine workings have been abandoned in recent

years in the UK and most of them have now flooded, or are

flooding. In many areas these represent a renewable energy

resource that can be exploited now with current technology.

Any project with a heating, hot water or cooling load in the

vicinity of mine workings is a potential candidate to use the

resource.

The mines reached depths in excess of 1000m with rock

temperatures of over 50oC. It is estimated that more than

25% of the mined volume still forms permeable and open

pathways in the rock despite the collapse of the old

workings. This mine water energy resource is one form of

an open loop, low temperature geothermal resource that is

in common use throughout the world. However, the

underground voids created by mining allow the ground

water to accumulate in otherwise low permeability

formations where it can be pumped out for use.

Several projects using mine water as the energy source are

already in operation; two are in Glasgow, heating blocks of

apartments. Major minewater projects described in the 2005

Country Update report (Batchelor, Curtis, Ledingham 2005)

at Midlothian in Scotland and at Camborne in Cornwall

have been in discussion in the last five years – but it

currently seems unlikely that either will proceed in the

near future.

There are no technical barriers to putting the old mine

workings back to work in sustainable developments to

provide heating, hot water and cooling. However, the issues

of surface and subsurface ownership, licences for

abstraction and discharge, the control of pollution and the

potential claims of mineral owners are issues that need

resolution for any particular project. In addition, the UK

still has difficulty in establishing planning and financing

schemes to develop and control district heating schemes.

These legal and commercial issues present major barriers to

the development of these minewater based systems –

despite the urgency for developing low carbon alternatives

to traditional methods of heating and cooling.

4. GSHPS

As with the last update report, the major area of UK

geothermal activity in this period has been the upsurge in

interest in ground source heat pumps (GSHPs). Starting

from a very low base, the level of activity is probably in the

region of about 3000 – 5000 installations per year. Whilst a

handful of these are larger scale open loop systems

(~500kW – 2MW), the majority are closed loop systems.

These range in size from 3.5kW heating only systems in

social housing, through to multi MW installations

delivering heating and cooling. The main driver for this

activity has been the realization that GSHPs connected to

the UK grid can offer significant reductions in overall

carbon emissions compared to traditional methods of heat

delivery. With projected improvements in the carbon

intensity of the UK electricity generation grid, GSHPs will

be able to deliver even larger carbon reductions with time.

The main funding schemes have been the government’s

Low Carbon Building Programme and the new Carbon

Emission Reduction Target (CERT) scheme - both of

which are focused on carbon reductions in the building

sector. The latter has been particularly effective in allowing

the delivery of over 1000 GSHP installations in the social

housing sector where it is particularly challenging to deliver

affordable, whole house, low carbon heating – often as

retrofits to existing housing stock.

The industry is still embryonic in the UK compared to other

northern European and North American countries, but a

wide range of projects are now being tackled. New build

and retrofit social housing schemes through to large

commercial and institutional projects and a wide range of

domestic installations are now operating at locations

throughout the UK. The government grant programmes

have led to the development of the Microgeneration

Certification Standards for GSHPs. The recently developed

EU HP-Cert training course has been trialed at two

locations in the UK, and the first of the GSHP designer and

driller courses developed under the EU GeoTrainet project

has been attended (http://www.geotrainet.eu/moodle/) to

see how it will fit with UK practice. The UK Ground

Source Heat Pump Association (http://www.gshp.org.uk)

evolved from a club to a formalized trade association in

2006 and has held annual conferences since then. A

domestic Heat Pump Association has also been formed by

BEMA (British Electrical Manufacturers Association) for

heat pump manufacturers to actively promote heat pump

activity, including GSHPs, in the UK. All of the major

domestic heating manufacturers now offer GSHPs in their

portfolios of heating (and cooling) equipment. The two

yearly GeoDrilling exhibition and symposium was re-

launched in 2005 with a focus on GSHP activity which has

continued to be reflected in the subsequent bi-annual shows

in 2007 and 2009. Some of the growing interest in this

activity is reflected in two recent publications – an English

translation of a popular German language GSHP

installation manual (Ochsner 2008), and a completely new

book on “Thermogeology” (Banks 2008).

5. THE EASTGATE BOREHOLE

The Eastgate Geothermal Exploration Project commenced

in 2003 to investigate the potential exploitation of the

Weardale Granite in Northeast England. Local minewater

chemistry indicated the presence of shallow mineralized

fluids that had been in contact with rocks at much higher

temperatures and pressures. This water was feeding into the

shallow mine workings from a steeply dipping fracture

structure known as the Slitt Vein, which became the target

for deep exploration drilling.

A 995m deep vertical borehole was completed in 2004,

penetrating more than 700m into the buried granite.

Logging, testing and sampling programmes followed and

interpretation of the results continues to the present. The

maximum bottom hole temperature measured was 46oC. A

highly productive zone at 411m produced significant yields

during testing at temperatures of 27 to 30oC

The data collected has led to a re-evaluation of the local

geological structure and the in-situ geochemical signatures,

and to a revival in interest in applying geothermal potential

to urban areas in the northeast of England. (Manning et al

2007)

The comprehensive work by the British Geological Survey,

(reported by Downing and Gray, 1986) is still the definitive

reference to the geothermal prospects of the UK.

Batchelor, Curtis, Ledingham.

3

6. EGS / HDR

In the 1980s and 1990s Cornwall, in the southwest of

England was the focus of the UK’s research into Hot Dry

Rock geothermal energy.

During 2005 Tester at MIT and a panel of international

experts carried out a review of the potential for EGS

systems. Three UK players (Batchelor, Baria, Garnish)

participated in this consultation which resulted in a

significant publication covering the technology and its

potential for energy generation (Tester et al 2008). The

high profile release of this document in the USA, together

with the current EGS activity in Australia has caused a

worldwide revival of interest in EGS technology.

This is also the case in the UK, where reviews of the

original work at Rosemanowes in the 1970s-80s in the light

of more recent experience, are leading to potential projects.

Most of Cornwall is underlain by high heat production

granites with measured heat flows well in excess of

100mW/m2 and temperature gradients in the range 30 to

40oC/km. The granites outcrop at several locations but are

elsewhere buried beneath Devonian marine sediments up to

several km thick.

The deepest temperature measurements made are at the

HDR research site, where 100oC was recorded at a vertical

depth of 2.7km. Higher temperature gradients are predicted

in other locations, based on near surface heat flow work,

and it is expected that temperatures in the range 160 to

180oC may be encountered at depths of 4 to 4.5km.

At the time of writing, two proposed power generation

schemes are being considered; a 10MWe project in west

Cornwall and a 3.5MWe project to supply power and heat

to the Eden Project in mid Cornwall. Both projects plan to

be drilling deep wells in 2010 or 2011.

7. CONCLUSION

In conclusion, ground source heat pump systems offer the

most immediate opportunity for geothermal utilization in

the United Kingdom. The minewater and deep aquifer

sources offer a strategic resource with local applications

and benefits when appropriate heat loads are located

nearby. Deep and hot formations with temperatures in the

175 – 200oC range at approximately 5000m depth appear to

be limited to south west England and will require

considerable developments in technology to be exploited

effectively.

ACKNOWLEDGEMENTS

The views and opinions stated in this paper are those of the

authors and not of any official or UK Government

organization.

REFERENCES

Hodgson, S: 2009 – Geothermal Resources Council

Bulletin Vol 38, No 1, January/February 2009.

Batchelor, A.S, Curtis, R.H, Ledingham, P: Country Update

for the United Kingdom, WGC Proceedings, Antalya,

Turkey 2005.

Ochsner, K: Geothermal Heat Pumps – A guide for

Planning & Installing, Earthscan, ISBN-13: 978-1-

84407-406-8, 2008

Banks, D: An Introduction to Thermogeology: Ground

Source Heating and Cooling. Blackwell. ISBN: 978-1-

4051-7061-1. 2008.

Manning, D. A. C, Younger, P. L, Smith, F. W, Jones, J. M,

Dufton, D. J. and Diskin, S: A deep geothermal well at

Eastgate, Weardale, UK: a novel exploration concept

for low-enthalpy resources. Journal of the Geological

Society of London, 164, 371-382. 2007.

Tester J et al: The Future of Geothermal Energy – Impact

of Enhanced Geothermal Systems (EGS) on the United

States in the 21st Century, published by MIT, ISBN: 0-

615-13438-6, 2006. Available from

http://geothermal.inel.gov/

Downing, R.A and Gray, D.A: Geothermal Energy. The

potential in the United Kingdom, HMSO, ISBN 0 11

884366 4, 1986

TABLE 1. PRESENT AND PLANNED PRODUCTION OF ELECTRICITY (Installed capacity)

Geothermal Fossil Fuels Hydro Nuclear Other Renewables

(Specify) Total

Capacity

MWe

Gross

Prod.

GWh/yr

Capacity

MWe

Gross

Prod.

GWh/yr

Capacity

MWe

Gross

Prod.

GWh/yr

Capacity

MWe

Gross

Prod.

GWh/yr

Capacity

MWe

Gross

Prod.

Gwh/yr

Capacity

MWe

Gross

Prod.

GWh/yr

In Operation in

May 2009 60,796 291,757 4,256 5,962 12,098 88,686 1,394 6,708 78,544 393,113

Under

Construction in

May 2009

Funds

committed, but

not yet under

construction in

May 2009

Total project

use by 2010

Batchelor, Curtis, Ledingham.

4

TABLE 2. UTILISATION OF GEOTHERMAL ENERGY FOR DIRECT HEAT AS OF MAY 2009

(other than heat pumps)

Maximum Utilisation

Annual Utilisation

Temperature C Enthalpy kJ/kg

Locality

Type

Flow Rate

(kg/s) Inlet Outlet Inlet Outlet

Capacity

(MWt)

Ave Flow

(kg/s)

Energy

(Tj/yr)

Capacity

Factor

Southampton

(Western

Esplanade)

Penryn

(Gabbons

Nursery)

Bath Spa

(Avon)

D

G

B

15

5

13

72

22

46.5

28

10

2.761

0.251

12.5

5

72.545

7.914

0.83

1.0

TABLE 3. GEOTHERMAL (GROUND SOURCE) HEAT PUMPS AS OF MAY 2009

Locality

Ground or

Water

Temp C

Typical

Heat Pump

rating

(kW)

Number of

Units Type COP

Heating

equivalent

Full Load

Hr/Year

Thermal

Energy

Used

(TJ/yr)

Cooling

Energy

(TJ/yr)

~4500

domestic sites

throughout

UK

9 -13 Avg 7 (3.5 to

16 kW) ~ 4500 V And H 3 to 4 1800 204

~ 500

commercial &

institutional

sites

throughout

UK

9 – 13 Avg 200 (30

– 2500 kW) ~ 750 Mainly V 3 to 5 1500 405 250

Total 609 250

Proceedings World Geothermal Congress 2010

Bali, Indonesia, 25-29 April 2010

1

Geothermal Prospects in the United Kingdom

Jon Busby

British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK

jpbu@bgs.ac.uk

Keywords: Geothermal resources, GSHP, EGS, United

Kingdom

ABSTRACT

Geothermal energy development in the UK has been

limited, partly due to the lack of high enthalpy resources,

but also due to the availability of cheap fossil fuels during

the 1980s and 1990s. However, with the advent of

renewable energy sources to combat climate change and the

need to replace diminishing fossil fuels, geothermal is now

in a good position to contribute to the energy mix. In this

paper, some of the geothermal prospects are reviewed and

some recent work from the British Geological Survey in the

following areas is presented:

• The potential of combined heat and groundwater flow

modeling and the latest three-dimensional geological

models are being assessed for use in ground source

heat pump prospecting.

• Temperatures in the shallow sub-surface have been

collated and compared to modeled results in order to

identify thermal anomalies that would be advantageous

for direct use applications or ground source heat

pumps.

• There is renewed interest in EGS within the granite

batholith of southwestern England, and a reappraisal of

the Hot Dry Rock potential of the Scottish granites

suggests that this resource may have been

underestimated.

1. INTRODUCTION

The United Kingdom is situated on the stable foreland of

Europe and is devoid of active volcanism and high heat

flows that result from tectonic activity. This at least

partially explains why geothermal energy plays a very small

role in the UK. It was estimated in 2006 that all renewables

only contributed 1.5% of the UK’s energy mix (DBERR,

2008), and geothermal only contributed a fraction of this.

However, when comparisons are made to countries in a

similar tectonic setting, it is clear that the UK is

underutilizing this potential resource. In 2005, Sweden was

reported to have 3840 MWt of installed direct use

geothermal capacity (Lund et al., 2005). The lack of

geothermal development has largely been a result of the

availability of North Sea natural gas that provided a cheap

and secure energy supply throughout the 1980s and 1990s.

However, with the passing of peak hydrocarbon production

in the North Sea and new renewable energy targets (15% by

2020; DBERR, 2008), geothermal resources are being

reappraised. In this paper, previous assessments of the UK’s

geothermal resources are reviewed, and future prospects are

discussed.

2. THE GEOTHERMAL ENERGY PROGRAM

The geothermal potential of the UK was investigated by a

program funded by the UK government and the European

Commission that ran from 1977-1994. It comprised three

elements: an appraisal of heat flow, an investigation of the

potential of hot brines in deep sedimentary aquifers that

might be suitable for electricity generation or direct use

applications, and an investigation of radiothermal granites

that might be exploited as Hot Dry Rock (HDR) reservoirs.

The results have been summarized in Downing and Gray

(1986a, b), BGS (1988), Parker (1989, 1999) and Barker et

al. (2000).

The heat flow map of the UK is shown in Figure 1 (Lee et

al., 1987; Downing and Gray, 1986a, b; Rollin, 1995;

Rollin et al., 1995; Barker et al., 2000). It comprises 212

heat flow measurements augmented by 504 heat flow

estimates. There is a fairly uniform background field of

around 52 mW m-2. Areas of increased heat flow are

associated with the radiogenic granites in southwestern

England (mean value of 117 mW m-2) and the buried

granites of northern England. Values are also above the

regional background over the batholith in the Eastern

Highlands of Scotland. The average UK geothermal

gradient is 26 °C km-1, but locally it can exceed 35 °C km-1.

Figure 1. Heat flow map of the UK.

Proceedings World Geothermal Congress 2010

Bali, Indonesia, 25-29 April 2010

1

Revisiting Deep Geothermal Power in the United Kingdom

Ryan Law, Tony Batchelor and Pete Ledingham

Geothermal Engineering Ltd, 82 Lupus St, London, SW1V 3EL

ryan.law@GeothermalEngineering.co.uk

Keywords: United Kingdom, Geothermal

ABSTRACT

It is predicted that geothermal power will play an increasing

role in renewable electricity generation (MIT, 2006). In

addition, a growing proportion of geothermal power is

expected to be derived from deep, low permeability rocks.

Trials of deep geothermal systems in low permeability

rocks first started in the mid 1970s, in the United States, the

United Kingdom and Japan. The United Kingdom research

project ran for the best part of 15 years and contributed

substantially to the technical knowledge of rock mechanics

and reservoir development.

This paper summarises the geothermal resource in the

United Kingdom, the previous research project and the

proposed deployment of a 10MW pilot power plant. The

data from the original research project and other studies has

been re-examined and a potential site selected. In addition,

the lessons learnt from the original program will be applied

to both the drilling and reservoir development program.

Drilling of the exploration borehole is expected to start in

2010.

1. INTRODUCTION

As in many countries, the rapid increase in the oil price

during the 1970s led the United Kingdom to investigate

alternative energy resources, including deep geothermal. In

the mid 1970s the British Geological Survey (BGS) was

commissioned to assess the geothermal potential of the

United Kingdom. Despite its location on the stable fore-

land of Europe, remote from active volcanism and strong

tectonism, surface heat flows and geothermal gradients

indicated that economically useful temperatures of 60–

100°C would be reached at depths of 2 to 3.5 km (Dunham

1974).

The research that followed included the production of a

geothermal map of the UK published at a scale of 1:1 500

000 (Downing & Gray 1986) and ten-year deep aquifer

research programme, published by ETSU (1986). A

calculation was also made of the expected temperatures at

significant depth (7kms) and this is shown in Figure 1.

Although the calculated temperatures could be regarded as

relatively low compared to some of the hottest geothermal

resources in the World, it can be seen that, particularly in

far South West of the United Kingdom, the potential does

exist for deep geothermal power generation. These

prospects warranted further research and the Camborne

School of Mines started an extensive research into the rock

mechanics of deep geothermal reservoir creation. This

programme was undertaken at a site in the Rosemanowes

Quarry in Cornwall (Figure 2) and explored the possibilities

of developing the Carnmenellis Granite as a geothermal

reservoir.

2. SUMMARY OF PREVIOUS RESEARCH

The research project on the Carnmenellis granite started in

1977. From 1980, the project was funded mainly by the UK

Department of Energy. The objectives of the project were to

investigate the engineering requirements for developing

deep geothermal reservoirs, and to establish the size and

nature of the deep geothermal resource in southwest

England (Parker 1989). It was one of the largest

hydrogeological experiments carried out in the United

Kingdom, involving staff from a number of institutions.

Figure 1. Predicted temperature in °C at 7kms in the

UK (after Downing and Gray, 1986).

In Phase 1 (1977-80) of the project, boreholes were drilled

to 300 m depth. These were used to demonstrate that is was

possible to establish hydraulic connections between

boreholes by injecting water at high pressures, thus

increasing the permeability of the system by hydraulically

developing the natural joints in the granite. Water was then

circulated through these joints (Batchelor 1982).

Phase 2 (1980–1988) was considered to be more closely

related to the conditions required for commercial

exploitation of the technology and involved drilling two

wells to a depth of 2.1 km. A reservoir was created by