Geological storage of energy –comments on UK CAES potential

Dave Evans1, Dan Parkes1, Seamus Garvey2, Wei He & Xing Luo3

(dje@bgs.ac.uk)

© NERC All rights reserved

UK CAES potential meeting, September 12th 2016The Shard, London

1British Geological SurveyKeyworth, Nottinghamwww.bgs.ac.uk

2Nottingham University3 Warwick University

Background• IMAGES – EPSRC 5 year funded project under the Grid

Scale storage programme• INTEGRATED, MARKET-FIT AND AFFORDABLE GRID-

SCALE ENERGY STORAGE• Total Funding >£3m from EPSRC – ends Sept 2017…..• Participants:

D Evans & J Busby

J Wang (PI), M Waterson, R MacKay, P MawbyR Critoph

S Garvey

P Eames, M Thomson, M Giullietti

Importantly : Industrial Partners

What we aim to achieve :

Economic analysis :- to reveal the multi-dimensional true values of ES- to identify the way for maximising the value of ES

Network analysis:- to clarify the role of ES from demand and supply balance- to exam network operation rule for ES integration

Techno-economic-network analysis:- to derive a matrix of performance/cost of ES- to exam technical characteristics for network integration

To provide essential information to government policy makers and regulatory bodies

To support UK industry towards technology & development

Technology breakthrough – CAES :- to avoid involvement of fossil fuel- to improve the round trip efficiency- to gain a clear picture of national storage resources- to study the methodology of engineering storage- to map the storage with the renewable power

generation locations

Technology innovation:- to research innovative HTTS technology- to find the cheap materials for HTTS- to improve energy efficiency by direct conversion- to develop innovative technology for combination

of CAES and HTTS

Technology for potential deployment

What we aim to achieve :

Outline/AimsAims – to provide outline of BGS work in relation to ongoing salt basins & cavern storage/volume assessments

• Compiling data on UK UGS facilities operational & planned– Depths– Cavern sizes & storage volumes– Operational ranges – min/max pressure, pressure gradients

• Compiling data on CAES projects – worldwide, planned and operational, where and how

• GIS development – geological formation maps, infrastructure & relationships to potential geological storage sites

• Calculation of cavern storage volumes for various UK salt basins

– Illustrating this with the Cheshire Basin• Looking at geothermal storage

– 250-300 ⁰C– Mineralogical studies – changing the rock….– Environmental considerations

Main geological storage optionsPHS – sites largely identified and used

– Some potential in cliff top storage – e.g. Okinawa PHS?

CAES – main bulk energy storage potentialIn general 3 main types for oil/gas storage:

– Porous media storage• Depleted gasfields - ~480 UGS facilities• Aquifers - ~90 UGS facilities

– Solution-mined salt caverns - UGS facilities

Other options:– Abandoned mines– Rock caverns - lined or unlined

Number of studies now into CAES in each of these different storage scenarios – BGS compiling report into previous studies & most recent/current proposals

Unlikely & not consideredhere wrt CAES……

Unlikely & not considered here wrtCAES – many BGS studies on potentialstorage volumes for CCS & M Kingmodelling

& main focus here

David JC MacKay

Chalk

UK possibilities for CAES other than salt caverns –potential options for Chalk of eastern England

Aquifer storage – but major aquiferunlined cavern –Killingholme LPG200 m depth Lower Chalk

253mEach: 120,000m3

(Geol Soc., 1985)

Killingholme

(Evans, 2008)

Solution-mined salt caverns for energy storage

Holford storage – 2013-2014 (Nat. Grid)

Used widely to store natural gas, oil and H2 – USA, Europe & UK• Bedded salts – UK & USA• Halokinetic structures USA,

Germany…& SNS??• Basically drill a hole and pump

water down, dissolving salt• Only operational CAES plants

• Huntorf• McIntosh• Gaines – small, new plant

• UK UGS caverns now designed for rapid cycle – compatible with CAES & pressure/cycles

Afte

r Cro

togi

noet

al,.

200

1)

Salt cavern storage – some basics Certain fundamentals apply• Contains insolubles –

disseminated & beds• sump area

• Salt creeps (flows)• Maintain cavern stability &

work within – Min P – supports cavern

walls ~30%– Max P – prevents

fracturing ~75-80%– Max P gradient– Dependent upon depth

• In terms of cavern volume, then determines you have– Total cavern volume

comprising – Working gas volume (min-

max. P range)– Cushion gas volume (up to

min P)

Cavern Volume

Min P

Max P

Tower Bridge (Vizor, EON, 2012)

UK Salt Cavern storage facilities – controls: where & why

• Permian – over southern North Sea area and onshore E England

• Also thinner Triassic salts in same area

• 2 major periods of halite development• Permian - oldest• Triassic - youngest

• Cheshire• EISB• Portland• Other saltfields

• In use – Preesall• Too small• Too thin• Too shallow• High insolubles

• Triassic salt basins in N-S rift system• Some Permian salts

Salt wall

Potential areas for offshore developments –offshore Permian halite bedsPermian halite beds

Larne- Islandmagee (GS)- Gaelectric (CAES)

Aldbrough(GS)

Hornsea(GS)

Outline IMAGES work on UK salt basin storage potential– Mapping of main onshore salt basins with potential

• Top & base salt and thickness maps– Cheshire Basin– East Irish Sea– Wessex Basin– East Yorkshire

– GIS development & processes to derive volumes• To model salt surfaces - derive volumes• Model cavern locations & derive storage volumes

– Theoretical– More realistic – buffering out areas – still over estimate– Based on experienced gained in gas storage projects

– Illustrate with Cheshire Basin storage potential• Number of potential caverns• Theoretical and more realistic cavern volumes• ‘gas’ storage volumes & Exergy

Salt cavern storage – most likely storage:ArcGIS development and UK salt basin storage

assessments

ArcGIS – Overview

• Data is held in a geodatabase and can be added to andmanipulated in ArcGIS

• ArcGIS displays layers of spatial data as shape files (points,polygons, polylines), grids or images

• Shape files can have additional meta-data attached to them -attributes

• Arc toolbox allows the GIS to be programmed to perform bespokefunctions, using several layers as input parameters

• Several layers can be used for joint analyses (clip, buffer join etc.)

Cut top salt map to depth range(500-1300 m &

500-1500 m)

Generate cavern locations & query

against salt depth and

thickness maps

Generate theoretical caverns/volume data

Apply buffers & derive remaining caverns/volumes

Maps –Top, base, thickness

Salt cavern & energy storage volumes- example of process in Arc GIS

UNIQUE_IDCOUNT AREA MIN MAX RANGE MEAN STD SUM

Ellipsoid Volume

Cylindrical Volume

4130 8 2501.3 200.6 201.8 1.2 201.1 0.5 1609.1 335239.3 1579778.0

4131 2 625.3 200.2 200.5 0.4 200.4 0.2 400.7 333946.2 1573684.3

4182 23 7191.3 202.6 209.0 6.4 206.0 1.7 4738.6 343374.8 1618115.4

4183 22 6878.6 209.4 213.9 4.5 211.7 1.2 4658.3 352900.7 1663005.6

• 100 m diameter (R=50 m)• Hexagonal pattern • 150 metre thick salt pillars – 3R• Min 20 m roof salt – casing pt.

10 m into salt• 10 m base salt

Borehole datacontoured up

UK salt basins – volumes/resource• Used boreholes, derived

salt maps & GIS to determine– Salt volumes in basins

– Look at theoretical cavern numbers & volumes

– Then buffer out areas& derive more realistic storage volumes

– Illustrate with Cheshire Basin example

EISB

Salt cavern & energy storage volumes- details of analysis

Cavern volumes at storage depths with depths of storage/casing shoe set from:

– 1st set based on Crotogino et al – 500 m – 1300 m depth range

– 2nd set based on Gaelectric’sLarne project – max 1500 m depth

– 3rd set based on gas storage experience – 250 m –1300/1500 m

• Caverns : cylindrical & elliptical shapes- doesn’t include domed roof

• Volumes based upon average thickness of salt at cavern location• Have to take into account, very crudely

• Insolubles content & bulking factor –• Mapped figures based on borehole analysis• Average of 25% often quoted

• Cavern shape factor – cavern irregularity = %age volume loss -0.7 shape factor (only get 70% of predicted volume)

• Initially derive basic cavern volumes & then gas (air) volumes based on gas storage principles – working & cushion gas volumes

Northwich Halite –up to 300 m thick

Salt cavern & energy storage volumes- theoretical (unrealistic) & buffered

Useable salt, depth range500-1300 m

Salt outcrop

Theoretical

Buffering to reduce available areas:• More realistic cavern

numbers & volume estimates

• Need to buffer out, e.g.:– Geology – WRH, faults– Major infrastructure

• Roads• Railways• Pipelines• Windfarms• Towns/cities etc.

More realistic

• Cavern volumes – using av. 25% insolubles– Based on gas storage principles– Theoretical - & (completely) unrealistic– More realistic – but……still too optimistic…will be a smaller faction of this

Example of salt cavern storage volumes- Cheshire Basin, 500-1300m depth range

Casing shoe set at 500 m or greater, max depth 1300 m, av. 25% insolubles %age remaini

ng volume for sum

%age volume

reduction for sum

Theoretical volumes (no buffering, all potential cavern locations included)

Cave

rns Reduced cavern numbers (buffered data set,

caverns omitted)

Cave

rns

Sum Average Max Min Sum Average Max Min

Cavern Volume Corrected for

Shape & ICF m35,040,342,698 685,202 1,185,947 102,177

7357

1,312,365,551 660,808 1,185,947 107,158

1987

26 74

Temp & Pressure Corrected Cavern

Volume (m3)4,877,470,765 663,060 1,161,531 100,073 1,265,289,448 637,104 1,161,531 104,952 26 74

Cavern Total Gas/Air Volume

corrected for compressibility

(m3)

654,523,708,959 88,978,209 185,451,242 9,564,131 183,646,940,742 92,470,766 185,015,582 9,901,614 28 72

Cavern Cushion Gas/Air Volume

corrected for compressibility

(m3)

236,574,834,564 32,160,799 67,030,569 3,456,915 66,378,412,316 33,423,168 66,873,102 3,578,897 28 72

Cavern Working Gas/Air volume

corrected for compressibility

(m3)

417,948,874,396 56,817,411 118,420,672 6,107,216 117,268,528,426 59,047,597 118,142,480 6,322,717 28 72

Taking into account salt/casing shoe depth

Example of salt cavern storage volumes- Cheshire Basin, 500-1500m depth range, 25%

insolubles

Casing shoe set at 500 m or greater, max depth 1500 m, av. 25% insolubles %age volume

available for sum

%age volume

reduction for sumTheoretical volumes (no buffering, all caverns)

Cave

rns Cut cavern volumes (more realistic, buffered data

set, caverns omitted)

Cave

rns

Sum Average Max Min Sum Average Max Min

Cavern Volume Corrected for Shape & ICF m3

5,350,800,570 682,936 1,185,947 102,177

7836

1,622,823,423 658,346 260,988,006,763 107,158

2466

30 70

Temp & Pressure Corrected Cavern Volume m3

5,171,542,806 660,057 1,161,531 100,073 1,552,379,060 629,768 1,161,531 104,952 30 70

Cavern Total Gas/Air Volume corrected for compressibility m3

711,767,918,165 90,844,661 170,318,797 9,627,890 260,988,006,763 105,877,488 191,416,941 9,901,614 37 63

Cavern Cushion Gas/Air Volume corrected for compressibility m3

257,265,512,590 32,835,420 61,561,011 3,479,960 94,333,014,493 38,268,971 69,186,846 3,578,897 37 63

Cavern Working Gas/Air m3 @ Standard Conditions

454,502,405,575 58,009,241 108,757,786 6,147,930 166,654,992,270 67,608,516 122,230,095 6,322,717 37 63

• 1st iteration – very much ball park• Uses Cavern Volume Corrected for Shape &

ICF (m3)• Does not worry about e.g. temperature or

compressibility factors• Only theoretical values for Cheshire Basin

– No other salt basins included at this stage!– Potential very large if even a very small fraction is

developed?!

Salt cavern & energy storage volumes- initial Exergy calculations

Casing shoe set at 500 m or greater, max depth 1300 m, av. 25% insolubles%age sum available following

cavern buffering

%age reduction for sum

Theoretical volumes (no buffering, all caverns) Cut cavern volumes (more realistic, buffered data set, caverns omitted)

Sum Average Max Min Caverns Sum Average Max Min Caverns

Cavern Volume Corrected for

Shape & ICF m35,040,342,698 685,202 1,185,947 102,177

7,357

1,312,365,551 660,808 1,185,947 107,158

1,987

26 74

Max Pressure Ratio 131 250 93 140 250 93

Min Pressure Ratio 47 90 33 51 90 33

Max Exergy Present (MWh) 74,452,122 10,121 25,031 965 21,459,826 10,806 24,894 995 29 71

Min Exergy Present (MWh) 20,059,495 2,727 7,026 251 5,823,124 2,932 6,982 258 29 71

TOTAL VALUE OF EXERGY

STORE [‘working

exergy’] (MWh)

54,392,627 7,394 18,005 714 15,636,703 7,873 17,912 737 29 71

Salt cavern & energy storage volumes:Initial Exergy calculations - 500-1300 m, av. 25%

insolubles

Casing shoe set at 500 m or greater, max depth 1500 m, av. 25% insolubles%age sum available following

cavern buffering

%age reduction for sum

Theoretical volumes (no buffering, all caverns) Cut cavern volumes (more realistic, buffered data set, caverns omitted)

Sum Average Max Min

Cave

rns

Sum Average Max Min

Cave

rns

Cavern Volume Corrected for

Shape & ICF m35,350,800,570 682,936 1,185,947 102,177

7,836

1,622,823,423 658,346 1,185,947 107,158

2466

30 70

Max Pressure Ratio 139 283 93 165 283 93

Min Pressure Ratio 50 102 33 60 102 33

Max Exergy Present (MWh) 81,938,653 10,458 22,733 973 25,941,696 10,524 20,691 967 32 68

Min Exergy Present (MWh) 22,144,592 2,826 6,391 253 7,112,214 2,885 5,828 251 32 68

TOTAL VALUE OF EXERGY

STORE [‘working

exergy’] (MWh)

59,794,061 7,632 16,342 720 18,829,482 7,639 14,863 716 31 69

Salt cavern & energy storage volumes:Initial Exergy calculations - 500-1500 m, av. 25%

insolubles

Casing shoe set at 500 m or greater, max depth 1300 m, av. 25% insolubles

Casing shoe set at 500 m or greater, max depth 1500 m, av. 25% insolubles

Theoretical volumes (no buffering, all caverns)

Cut cavern volumes (more realistic, buffered data set,

caverns omitted)

Theoretical volumes (no buffering, all caverns)

Cut cavern volumes (more realistic, buffered data set,

caverns omitted)

Sum Caverns Sum Caverns Sum Caverns Sum Caverns

Cavern Volume Corrected for

Shape & ICF m35,040,342,698

7,357

1,312,365,551

1,987

5,350,800,570

7,836

1,622,823,423

2466

Max Exergy Present (MWh) 74,452,122 21,459,826 81,938,653 25,941,696

Min Exergy Present (MWh) 20,059,495 5,823,124 22,144,592 7,112,214

TOTAL VALUE OF EXERGY STORE

[‘working exergy’] (MWh)

54,392,627 15,636,703 59,794,061 18,829,482

Salt cavern & energy storage volumes:initial Exergy calculations - summary

Summary• Many types of fuel stored underground in various

geological structures and rock types• CAES plants operational and others under review

– Salt caverns – volumes, deliverability, rapid cycle operation– Porous media

• offer large volumes• but require good poroperms – longer cycles or more wells?

– Potential for utility scale storage – but many studies find economics unfavourable

– Also issues over residual gas and bacteria in situ• BGS as part of EPSRC-funded IMAGES looking at

– Salt cavern storage• Mapped main salt beds • Developing GIS to determine potential sites and cavern volumes• In future it should aid assessment of storage site against power

sources, infrastructure, demand etc• At moment very significant volumes offered for energy storage• Needs planning alongside other subsurface requirements