Integrating Solar Thermal Capture with Compressed Air Energy Storage

Transcription

1 Integrating Solar Thermal Capture with Compressed Air Energy Storage Mr Michael C Simpson*, Prof Seamus D Garvey, Dr Andrew J Pimm, Mr Bharath Kantharaj, Dr Bruno Cárdenas, Mr James E Garvey Presentation at SolaStor 2016 London 12 th April 2016

2 Structure Part 1: Generation-integrated energy storage (GIES) Part 2: Compressed air energy storage (CAES) with increased exergy capacity Part 3: A CAES system with integrated solar capture 2

3 Structure Part 1: Generation-integrated energy storage (GIES) Part 2: Compressed air energy storage (CAES) with increased exergy capacity Part 3: A CAES system with integrated solar capture 3

4 Integrating storage with generation Generation-Integrated Energy Storage (GIES) subset of generation technologies that store energy before conversion to electricity. Examples Natural hydroelectric power Concentrating solar power Biomass This differs from simply co-locating generation and storage, e.g. batteries at a windfarm. 4

5 Natural hydro as GIES Pure generation Run of the river Generation integrated storage Conventional hydroelectric Pure storage Pumped hydro Primary energy Passive transport, no transformation Storable form Passive transport, conversion in turbine Electricity 5

6 Concentrating solar power Natural fit for integrated thermal storage. Typically used as an alternative to PV, rather than complementary. Left: By USA.Gov - BLM - BUREAU OF LAND MANAGEMENT - Public Domain, Right: By afloresm - SOLUCAR PS10, CC BY 2.0, 6

7 Structure Part 1: Generation-integrated energy storage (GIES) Part 2: Compressed air energy storage (CAES) with increased exergy capacity Part 3: A CAES system with integrated solar capture 8

8 CAES variants Diabatic CAES Heat of compression lost; Reheat using natural gas. Adiabatic CAES Heat of compression stored and re-used during discharge. Isothermal CAES Compression and expansion take place at near ambient temperature, with environment as heat store. 9

9 Dominant costs 2012 Black & Veatch study of 262 MW plant with 15 hours of storage predicted capital cost of $900/kW (c.f. 900/kW for Larne). Cavern cost accounts for 40%. High fixed and low marginal costs of salt cavern mean this depends only weakly on capacity. Cavern For small-scale CAES, the cost of pressure vessels scales with gauge pressure x volume. 11

10 Use of pressure containment Exergy in isochoric store with pressure ratio, r B HP air r H 0 p0 Vstore r log r r r p p p L p 0 e.g. p p H L p 50 p 0 0 Exergy in isobaric store with press. ratio, r B HP air p V r log r r 1 0 store Or, if the HP air is displaced naturally by hydrostatic head (removes energy input for pumping) B HP air p V r log r 0 store

11 Compressing and cooling air Compression Cooling Result 1J of work on ambient air p 0, T 0 p 1, T 1 p 1, T 0 1J of heat between T 0 and T 1 All exergy in pressurised air (if T 0 T 1 ) 1J of work on pre-heated air p 0, T 2 p 1, T 3 p 1, T 2 1J of heat between T 2 and T 3 Exergy split between air and high temperature heat 13

12 Use of pre-heat 2a 2a 2 1a 3a a 1 1a 14

13 Charging 2a 2a 2 1a 3a a 1 1a 15

14 Discharging 2a 2a 2 1a 3a a 1 1a 16

15 Pressurised air vs thermal storage Modelled as reversible Exergy split for adiabatic CAES with pre-heat Storage pressure Max temperature (after compression) 80 bar 1000K B stored /B air Isothermal CAES 1.00 Adiabatic CAES 2.08 Adiabatic CAES with pre-heat to 660K 3.01 For a given pressure store size, pre-heating air increases the total exergy stored significantly. 17

16 Structure Part 1: Generation-integrated energy storage (GIES) Part 2: Compressed air energy storage (CAES) with increased exergy capacity Part 3: A CAES system with integrated solar thermal capture 18

17 Solar-integrated CAES Pre-heated CAES variant lends itself to integration with solar thermal generation. Resulting system combines grid-scale energy storage with large-scale generation. 19

18 Solar-integrated CAES Three stage compression with intercooling Single stage turbine Thermal stores Solar thermal capture Heat pump Pressure store Water tank Fluid flow Heat flow 20

19 Air charging Exergy transferred to high pressure air and top thermal store. 21

20 Solar thermal charging Exergy transferred to lower thermal stores. 22

21 Discharging Exergy extracted from high pressure air and all thermal stores. Fluid flow Heat flow 23

22 Example system with irreversibilities Air charge Power (charge) Power (discharge) Storage duration (at 100MW) Storage pressure 100MW 250MW 12 hours 80 bar Cavern size 55,000m 3 Mass flow of air (charge) 95 kg/s 8 1 Exergy into pressurised air Exergy into high temp. store 430MWh 720MWh Solar input energy at 350 C 1030MWh Ground area of solar capture 700m x 700m 25

23 Modelling discharge process Work ongoing on discharge modelling. Analysis covering: Raising of steam Air-steam mixing Humid air turbine Heat pump Exhaust heat recuperation 26

24 Applications Most relevant where there is strong solar resource and lowcost pressure storage, such as salt caverns or deep water. Candidate locations include: Chile Mediterranean countries, esp. Spain Gulf of Mexico India Where solar resource is not available, waste gases may be used as a least-worst solution. 28

25 Conclusions A variant on CAES incorporating pre-heating and solar thermal capture has been proposed. Preliminary modelling indicates greatly increased exergy storage for a given pressure store. Further work Thermodynamic modelling of discharge cycle to assess exergy losses. Techno-economic assessment of costs and value of generation and storage service provided. 29

26 Acknowledgements Thanks to EPSRC for supporting this work under: NexGen-TEST (EP/L014211/1) IMAGES (EP/K002228/1) RESTLESS (EP/N001893/1) Thanks to colleagues also active in compressed air and thermal energy storage at: Leeds Cambridge Birmingham Loughborough Warwick Chinese Academy of Sciences 30

27 References Garvey SD et al., On generation-integrated energy storage, Energy Policy, vol. 86, pp , Zunft S, Adiabatic CAES: The ADELE-ING project, presented at SCCER Heat & Electricity Storage Symposium, Villigen, Switzerland, Haughey C, Larne CAES: a project update, Gaelectric, Belfast, Ireland, article, Black & Veatch Holding Company, Cost and Performance data for Power Generation Technologies, White AJ, McTigue JD, Markides CN, Analysis and optimisation of packed-bed thermal reservoirs for electricity storage applications, to be published. Garvey SD, Two Novel Configurations for Compressed Air Energy Storage Exploiting High-Grade Thermal Energy Storage, presented at UK-China Thermal Energy Storage Forum, Beijing, China, Solar Millennium, The parabolic trough power plants Andasol 1 to 3, Erlangen, Germany, report, Jorgenson J et al., Estimating the Performance and Economic Value of Multiple Concentrating Solar Power Technologies in a Production Cost Model, NREL, Denver, Colorado, Report NREL/TP-6A , RWE, Adele Adiabatic compressed-air energy storage for electricity supply, Essen/Cologne, Germany, report, Young-Min, K et al., Potential and Evolution of Compressed Air Energy Storage: Energy and Exergy Analyses, Entropy, vol. 14, no. 8, pp ,

28 Mr Michael C. Simpson* Mr Bharath Kantharaj The University of Nottingham Prof Seamus D. Garvey Dr Bruno Cárdenas Dr Andrew J. Pimm Mr James E. Garvey The University of Leeds +44 (0)

29 GIES versus non-gies Energy movement Energy conversion From Garvey SD et al, On Generation-Integrated Energy Storage, Energy Policy, vol. 86, pp , Nov