Geological storage of energy – comments on UK CAES · PDF fileRock caverns -lined or unlined. Number of studies now into CAES in each of these different storage scenarios ... unlined
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Geological storage of energy –comments on UK CAES potential
Dave Evans1, Dan Parkes1, Seamus Garvey2, Wei He & Xing Luo3
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
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
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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
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
• 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)
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