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Micro wind generation

and traditional buildings

2010

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The information in this publication is based on current

knowledge.Whilst every effort has been made to ensure

the accuracy of the advice given, English Heritage does not

accept liability for loss or damage arising from the use of

this information.This publication is intended only as a guide.

It has no statutory authority, and should not be used as a

substitute for professional advice.The guidance provided

here deals only with the practical aspects of installing the

equipment.The acceptability of the installation will depend on

the historic significance of the building or site being adapted.

You are strongly advised to discuss your proposals informally

with historic environment staff from your local council.

The inclusion in this publication of any company,group or individual, or any product or service, should

not be regarded as either a recommendation or anendorsement by English Heritage or its agents.

PLANNING AND HISTORIC BUILDINGLEGISLATION

THE INSTALLATION OF A RENEWABLE TECHNOLOGY

IMPLIES IN MOST CASES THE FIXING OF EQUIPMENTTO THE HISTORIC FABRIC OF A BUILDING. ENGLISH

HERITAGE SEEKS TO ENSURE THAT ANY WORKS TOA HISTORIC BUILDING DO NOT UNNECESSARILY

DISTURB OR DESTROY HISTORIC FABRIC

In decisions on how best to incorporate a renewable technology,the principles of minimum intervention and reversibility should

be adopted whenever and wherever possible.

Installing a wind turbine will probably need planning permission.

The local planning authority can grant permission under

the Town and Country Planning Act 1990, and they will be

looking for any issues concerning visual impact and proximity

to land boundaries.

Installing a wind turbine on a listed building or a building in

a conservation area will also need permission from the local

planning authority, under the Planning (Listed Buildings andConservation Areas) Act 1990. Planning Policy Guidance

(PPG) 15, Planning and the Historic Environment, can help

you with this; see www.planningportal.gov.uk.A New

Planning Policy Statement (PPS) 15 will replace Planning

Policy Guidance 15: Planning and the Historic Environment

(PPG15) and Planning Policy Guidance 16: Archaeology and

Planning (PPG16) from 2010.Work of any kind to a Scheduled

Monument requires consent from English Heritage under the

Ancient Monuments and Archaeological Areas Act 1979.

Your application will need to show clearly what you intend todo, with detailed drawings and photographs. It is useful to draw

the turbine on a photo of the site or building in order to help

the planning officer visualise it in its proposed setting and

determine its visual impact.
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CONTENTS

INTRODUCTION 1

PLANNING A WIND

TURBINE INSTALLATION

Wind speed and direction

Wildlife

2

2

2INSTALLATION OPTIONS

Fixed to a building

Remote from building

2

3

4

ELECTRICAL SYSTEM

Non-grid connection

Grid connection

5

5

6

MAINTENANCE

AND WORKING LIFE

6

GRANTS 6

USEFUL CONTACTS

Renewable energy and climate change

Wind turbines and wildlife

Wind power

Planning guidance

Renewable energy grants

7

7

7

7

7

7

ACKNOWLEDGEMENTS 7

Front cover image courtesy of Quiet Revolution Limited.

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2 MICRO WIND GENERATION AND TRADITIONAL BUILDINGS

INTRODUCTION

English Heritage is the UK government's adviser on the historic environment. Central to

our role is the advice we give to local planning authorities and government departments

on development proposals affecting listed and traditional buildings, conservation sites and

areas, terrestrial and underwater archaeological sites, designed landscapes and historical

aspects of the landscape as a whole. For our policy statements on climate change andwind energy, refer to English Heritage's Historic Environment, Local Management website,

www.helm.org.uk.

The earth's climate is changing at a rate that has not been seen before in human

history.The changes have been linked to rising concentrations of carbon dioxide in

our atmosphere. Carbon dioxide is a by-product of the burning of fossil fuels to supply

energy, and emissions have spiralled upwards as our demand for energy has increased.

The UK government, wishing to reduce the country's dependence on fossil-fuel storesand to cut carbon dioxide emissions, has made a commitment to find 10% of our energy

from renewable sources by 2010, rising to 20% by 2025. Renewable energy may come

from sources such as wood that are self-regenerating, or those such as the sun and the

wind that are effectively infinite.The technologies associated with these sources are

sometimes referred to as 'low-carbon', in that they emit much lower levels of carbon

dioxide and related compounds into the atmosphere than do fossil-fuel technologies.

For more information on the UK government's position on climate change, contact the

UK Climate Impacts Programme (see Useful contacts).This guide is one of a series onsmall-scale renewable energy options. Separate guides look at wind generation, solar

energy, bio-fuels, heat pumps and combined heat and power, explaining how each system

works and what you need to consider if you wish to install it in or on a historic building.

All the guides look at small-scale or 'Microgeneration' as it is known. Microgeneration is

defined by Government as, The production of heat and/or electricity on a small-scale

from a low carbon source.

Cutting demand for energy is as important as finding alternative means of generating it. Before decidingwhether to install a renewable energy technology in a building, all available energy-saving measures, includinglow-energy light bulbs, heating controls and improved insulation, should already have been taken.An EnglishHeritage guidance document, Energy Conservation in Traditional Buildings, looks at methods of improvinginsulation and introduces other methods for saving energy.
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3MICRO WIND GENERATION AND TRADITIONAL BUILDINGS

PLANNING A WIND

TURBINE INSTALLATION

AN IMPORTANT QUESTION TO CONSIDER BEFORE

INSTALLING A WIND TURBINE IS WHETHER THIS IS

THE MOST SUITABLE RENEWABLE TECHNOLOGY

FOR YOUR BUILDING.

Would another approach to generating renewable

energy be better?

WIND SPEED AND DIRECTION

Most wind turbines will only work at wind speeds

above about 4m/sec.The Energy Saving Trust (see

Useful

contacts) notes that a turbine may not be viable where

typical wind speed is below 4.5m/sec, since the amount

of energy generated would not justify the capital cost.

In order to generate the optimum annual electricity

yield, a wind turbine should face in the direction of the

prevailing wind.This is normally southwest, but can vary

from place to place.

There is a document called the Microgeneration

Installation Standard Document MIS 3003.

Microgeneration Installation Standard 3003 specifies

the requirements set out by Building Enterprise and

Regulatory Reform (BERR) for contractors supplying,

designing, installing micro and small wind turbines. In order

to work out what your turbine is likely to generate the

Standard sets out how you can estimate your annual

energy performance.Their recommendations are:-

1. Obtain the mean wind speed from the NOABL

(numerical objective analysis of boundary layer)

database for where you live.The wind speed

database is maintained by BERR which is accessible

via the British Wind Energy Association website

(www.bwea.com/noabl).The NOABL database,

presents annual mean wind speeds throughout the UK.

The data is keyed to Ordnance Survey grid reference,and takes no account of local terrain or local winds,

such as sea or valley breezes or the effects of others

structures or trees.

In built up areas the database has been found to

overestimate the wind speeds so the Building Research

Establishment (BRE) advises that where it is not possible

to use long term metrological data for the site the wind

speed data from the NOABL database should be

corrected so a more accurate estimation of the wind

power can be made.

2. Using the mean wind speed data from the NOABL

database it can be corrected to take into account

the local terrain where you live.

The Microgeneration Installation Standard Document

MIS 3003 gives scaling factors to apply fro dense urban,

low rise urban/suburban and rural. It can be seen that

where turbines are fixed onto buildings or areas withbuildings close to the turbine the scaling factor reduces.

This means that the output is greatly reduced compared

to a rural location.

1

3. To estimate what the annual energy performance

would be you can use the value given in step 2

and apply it to the manufacturers annual energy

performance curve, see below.

2
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The Carbon Trust have a 'Wind Yield Estimator Tool'

that can be used to estimate the local annual mean

wind speed for a chosen location and the annual yield.

(www.carbontrust.co.uk/windpowerestimator/). The tool

allows the user to enter their postcode, the location

i.e rural, urban etc. and the type of turbine.

WILDLIFEThere is some concern about the potential negative

effects of wind turbines on wild animals birds and bats

in particular that make historic buildings their homes.

Roosting and nesting sites, access points and flight paths

all need to be considered in any assessment of the impact

a wind turbine, its installation and subsequent maintenance

might have on their activities.

The Royal Society for the Protection of Birds (RSPB) has

information on wind farm installations and on the problem

of birds colliding with large turbines.The Bat Conservation

Trust notes that bats have been found dead under large

wind farm installations. All bats and many birds are legally

protected. Natural England should be consulted at an

early stage in the planning of a wind turbine installation

of any size, especially on or near buildings known to be

frequented by wildlife or in areas used by protected

wildlife. For contact details see Useful contacts.

INSTALLATION OPTIONS

When planning the installation it isimportant tothink about the reversibility and the physicalimpact an installation can have on a building.This is to say that wind turbines and theirassociated equipment can have a life of up to 20years, so a building could have many installationsover its life. By carefully planning the installationand how it can be removed at the end of its usefullife damage can be limited to the building fabric.

Wind turbines work by converting the winds kinetic

energy into electrical energy. Most modern systems

use horizontal-axis wind turbines, with three or five

blades rotating around a central hub (Fig 3).Vertical-axis

wind turbines (Fig 4) are less common.

Wind turbines are more commonly located away

from the building they provide energy to but can be

fixed onto the building.The performance of the turbine

will be reduced when fixed to a building or in a densely

populated area.

3 4

Horizontal-axis wind turbine. (Photograph courtesy of Renewable DevicesSwift Turbines Limited) & Vertical-axis wind turbine. (Photograph courtesyof Quiet Revolution Limited)

FIXED TO A BUILDINGThe turbine is mounted on a pole which is fastened

with brackets to an external wall, high enough to project

above the building (Fig 5). In general the higher the

turbine above the roof the greater the power output will

be as it will be affected less by turbulence, See Fig 1

5

A house with a wall-mounted wind turbine, Camberwell, London.(Photographs courtesy of Eclectic Energy Limited)

When fixing a turbine to the building their will be an

additional structural load that would need to be assessed.

A structural survey by a specialist in the conservation of

historic buildings is necessary to ensure that the building iscapable of supporting the turbine. Domestic-sized turbines

weigh from 15kg to 30kg, and wall brackets must be fixed

strongly enough not only to support the turbine itself, but

to withstand the force exerted on it by a 50m/sec gust

over a 10-minute period.

Where a building is framed, for the best support the fixing

must be to the frame, not to infill panels. If the frame is

not exposed, it is generally possible to fix into the frame

through the external finish.
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MICRO WIND GENERATION AND TRADITIONAL BUILDINGS 5

On a building with a pitched roof, the turbine is

fitted to the gable end (unless this conflicts with any

windows) so that the pole can be as short as possible

(Fig 6). If there is no gable end, a very tall pole may be

needed, making the turbine difficult to support (Fig 7).

High-hipped roofs can be even more problematic.

A turbine may be fixed directly to a flat roof (Fig 8),

but care should be taken that brackets do notcompromise the weatherproofing.

It is rarely advisable to fit the turbine to a chimney

stack: chimneys are not constructed to take this type

of structural loading, and the strength of those on

historic buildings may have been further reduced by

the effects of years of flue gases on their mortar. If a

chimney stack is no longer used, it could perhaps be

reinforced to take such a loading.

Most manufacturers recommend installing pads with

the brackets to dampen the vibration of the working

turbine. Noise is not generally an issue with small

modern wind turbines.

To minimise damage over the long term, the bracket

arrangement should use the minimum number of fixing

holes. Generally we advise that fixings should be installed

into mortor joints to minimise damage to fabric.

REMOTE FROM BUILDINGA wind turbine can be mounted away from a building

on a pole or latticework tower (Fig 10).The pole and

location must be high enough to avoid the effects of

turbulence.The optimal height will depend on the

surroundings: if trees or other buildings obstruct air

flow, the turbine will need to be raised, or moved

to a better location.

The pole or tower requires proper foundations; typically

a 70kg turbine on a 5m pole would require at least 1m3

of foundations, depending on soil conditions.

From the turbine a cable must run back to the buildings

electrical fuse board (Fig 11).The cable size is determined

by the load it must carry, as well as its length: the further

the turbine from the building, the larger (and more

expensive) the required cable. It is usually necessary to

bury it, to a depth of no less than 0.5m to avoid damage

from general gardening.

6Turbine fixed to a building

7

Wind turbine wall brackets. (Photograph A courtesy of RenewableDevices Swift Turbines Limited; photographs B and C courtesy ofEclectic Energy Limited)

Turbine mounted on flat roof8

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9Turbines mounted on a flat roof

Before excavating, both for foundations and for cabling,

it is important to assess the possibility of buried

archaeology on the site. If the building or grounds are

listed or scheduled, the statutory description may cover

this aspect of the site.Where the archaeology prevents

a cable being buried at a reasonable depth, an alternative

route should be found where it can be buried more

deeply.Where this is not possible, the cable duct should

be encased in concrete.

The access point of the cable into the building should

be properly sealed to prevent water ingress, maintain

fire protection and keep pests out.

A house with a pole-mounted turbine. (Photograph courtesy ofProven Energy Ltd)

10

ELECTRICAL SYSTEM

THE DESIGN OF THE TURBINES ELECTRICALSYSTEM WILL DEPEND TO A GREAT EXTENTON THE BUILDINGS PRESENT SYSTEM.

Is there a mains supply or is it independent of the

national grid? It will also depend on how the generatedpower is to be used.Will it be fed back into the national

grid, or cater for a specific load? Will energy be stored

for use at other times? It is wise to look at the buildings

present electrical load, and estimate how much of it

might be catered for by the wind turbine.

The electricity generated by a wind turbine is direct

current (dc).An inverter is needed to convert this to

alternating current (ac) so that it can be used for electrical

appliances or fed back into the grid. Other essential

elements of the system are a wind-turbine controller, tostop the turbine if the wind becomes strong enough to

damage it, and an isolation switch, allowing the turbine to

be disconnected for safe maintenance or repair (Fig 12).

Equipment should be located to permit easy access for

maintenance and repair. All parts of the installation should

be indicated on a working drawing.Where equipment is

to be fixed to building walls, the number of fixing points

should minimised by the use of a wooden pattress or

frame system (Fig 13).

There are three options for connecting a turbineto the electrical system: direct, off-grid and grid.

11Buried cable for a remotely-mounted turbine

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12

Electrical installations, showing inverters. (Photographs courtesy ofWind and Sun Limited)

NON-GRID CONNECTIONWhere no mains electricity is available, a wind turbine

can be used to replace or supplement the existing local

electricity supply (a diesel generator, for example).The

turbine is connected via the controller and inverter to

the fuse board or dedicated load (Fig 14).

If there is no generator or other electricity supply, batteriescan be used to store energy as it is generated by the

turbine, for use later when it is needed.The number and

size of the batteries depend on how long they would

be expected to continue supplying electricity without

the wind turbine; this is known as the autonomy or how

long the batteries need to operate.The batteries should

be of a deep-cycle type, which can be discharged deeply

without damage.The storage space must be well

ventilated as batteries give of a gas in their operation,

and preferably cool: warmer temperatures reduce

battery life (Fig 15).

13Electrical equipment mounted on a pattress

Non-grid connection14

15

Deep-cycle battery installation. (Photograph courtesy of Wind and Sun Limited)

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GRID CONNECTIONA wind turbine can also be used to supplement mains

electricity, offering the security of a continuous electrical

supply. In this case there are two inputs to the fuse board,

one from the turbine and one from the mains (Fig 16).

When the turbine is not generating enough energy, mains

electricity is used. If more electricity is generated by the

turbine than is needed, the excess can be exported tothe national grid.To do this a special meter must be

installed, with the agreement of the mains electricity

supplier. Electricity exported in this manner is generally

bought at a wholesale rate which is far lower than the

cost of having it supplied. In addition the electricity

supplier levies a charge for the metering facility.

16

MAINTENANCE ANDWORKING LIFE

ALL RENEWABLE INSTALLATIONS REQUIREMAINTENANCE TO ENSURE THEY REMAINRELIABLE AND EFFICIENT.When maintenance is carried out there is the potential

for damage to be caused to the fabric of the building.

When planning the installation it is important to talk to

the installer about how often equipment would need

routine maintenance and the equipment is accessed.

Regular inspection of cables and equipment conditions

will also be necessary.

As mentioned earlier it is important to remember that,

because the maximum working life of a wind turbine is

around 20 years and that of many of its electrical parts

far less, a building could have more than one installation.

Damage to the buildings fabric can be minimised with

careful planning not only of the installation but of the

turbines removal at the end of its useful life. Batteries

have a life of around 6-10 years, depending on the typeof battery and on environmental conditions.

GRANTS

FEED IN TARIFFS WERE INTRODUCED BY THEGOVERNMENT FROM THE 1ST APRIL 2010.THEY WERE INTRODUCED TO INCREASE THELEVEL OF RENEWABLE ENERGY IN THE UK TO

A TARGET OF 15% OF TOTAL ENERGY FROMRENEWABLES BY 2020.The scheme gives a fixed payment for all the electricity

produced by the wind turbine called the 'generation

tariff'.This tariff is paid whether it is used or exported to

the grid. If the turbine generates a surplus you can export

to the electricity grid where an additional bonus called an

'export tariff' is paid.

The amount paid from the 'generation tariff' is dependent

on the type of renewable and its size.The export tariff is

dependant on how much excess electricity is sent back to

the grid and is paid at a flat rate of 3p/kilowatt hour

regardless of what technology is used.The tariffs are paid

for 20 or 25 years - so will cover the life time of the

turbine.

Once the installation is complete your chosen energy

supplier will enter the installation on the Central FIT

Register.The energy supplier will then start paying you the

'generation tariff' and if you export the 'export tariff. It is

necessary to have an Ofgem approved Total Generation

Meter which should be installed with your system to

measure the energy generated. If you choose to exportan additional meter is required. It varies as to whether the

energy company will pay for this meter or not.

Grants are also available from some local Governments

for renewables and energy efficiency measures.

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USEFUL CONTACTS

RENEWABLE ENERGYAND CLIMATE CHANGE

Historic Environment, Local

Management (HELM)English Heritage

1 Waterhouse Square

138-142 Holborn

London EC1N 2ST

Tel: 020 7973 3000

www.helm.org.uk

UK Climate ImpactsProgramme (UKCIP)Oxford University Centre

for the EnvironmentDyson Perrins BuildingSouth Parks Road

Oxford OX1 3QY

Tel: 01865 285717

www.ukcip.org.uk

ENERGY CONSERVATIONAND FEED IN TARIFFS

Carbon Trust6th Floor

5 New Street SquareLondon EC4A 3BF

Tel:0800 085 2005

www.carbontrust.co.uk

WIND TURBINES AND WILDLIFE

The Royal Societyfor the Protection of BirdsThe Lodge

Sandy

Bedfordshire SG19 2DL

Tel: 01767 680551

www.rspb.org.uk

Bat Conservation TrustUnit 2, 15 Cloisters House

8 Battersea Park Road

London SW8 4BG

Tel: 020 7627 2629

www.bats.org.uk

Natural EnglandNorthminster HousePeterborough PE1 1UA

Tel: 0845 600 3078

www.naturalengland.org.uk

WIND POWER

British Wind Energy AssociationRenewable Energy House

1 Aztec Row, Berners Road

London N1 0PW

Tel: 020 7689 1960

www.bwea.com

Centre for Alternative TechnologyMachynlleth

Powys SY20 9AZ

Tel: 01654 705950

www.cat.org.uk

BRE TrustGarston

Watford

Hertfordshire WD25 9XX

Tel: 01923 664598www.bretrust.org.uk

PLANNING GUIDANCE

Department for Communitiesand Local GovernmentEland House

Bressenden Place

London SW1E 5DU

Tel: 020 7944 4400

www.communities.gov.uk

English Heritage1 Waterhouse Square

138-142 Holborn

London EC1N 2ST

Tel: 020 7973 3000

www.english-heritage.org.uk

RENEWABLE ENERGY GRANTS

Department of Energyand Climate Changehttp://www.decc.gov.uk

ACKNOWLEDGEMENTS

English Heritage would like toacknowledge the help of thefollowing people in the productionof this guide:

Eva Marwick, Renewable DevicesSwift Turbines Limited

Alison Anderson,

Eclectic Energy Limited

Moneeb Siddiqui,

Proven Energy Limited

Sophie Duncan,

Wind and Sun Limited

Text by Caroline Cattini,English Heritage Building services

Engineering and Safety Team (BsEST)

All Illustrations by Judith Dobie,

Centre for Archaeology,

English Heritage

Edited by John King

Produced by Creative Services,

English Heritage

October 2010

Product Code: 51366
http://www.helm.org.uk/http://www.ukcip.org.uk/http://www.carbontrust.co.uk/http://www.rspb.org.uk/http://www.bats.org.uk/http://www.naturalengland.org.uk/http://www.bwea.com/http://www.cat.org.uk/http://www.bretrust.org.uk/http://www.communities.gov.uk/http://www.english-heritage.org.uk/http://www.decc.gov.uk/http://www.decc.gov.uk/http://www.english-heritage.org.uk/http://www.communities.gov.uk/http://www.bretrust.org.uk/http://www.cat.org.uk/http://www.bwea.com/http://www.naturalengland.org.uk/http://www.bats.org.uk/http://www.rspb.org.uk/http://www.carbontrust.co.uk/http://www.ukcip.org.uk/http://www.helm.org.uk/

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(EVO03/08)VIT1000

Building servicesEngineering and Safety TeamEnglish Heritage1 Waterhouse Square138-142 HolbornLondon EC1N 2ST

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