Techno-economic analysis of bulk-scale compressed air energy storage in power system decarbonisation

Wei He, Mark Dooner, Marcus King, Dacheng Li, Songshan Guo, Jihong Wang
2021 Applied Energy  
A B S T R A C T Although the penetration of renewable energy in power systems has been substantially increased globally in the last decade, fossil fuels are still important in providing the essential flexibility required to reliably maintain the system balance. In 2019, more than one quarter of power generation in Europe and over 40% of the UK's electricity generation was from fossil fuels (mainly gas). For achieving the net-zero greenhouse gas emission target around the middle of this century,
more » ... these fossil fuels have to be decarbonised in the coming decades. Bulk-scale energy storage has been recognised as a key technology to overcome the reduced dispatchability associated with the decrease of fossil fuels in generation. Taking the UK power system as a case study, this paper presents an assessment of geological resources for bulk-scale compressed air energy storage (CAES), and an optimal planning framework for CAES in combination with solar and wind to replace fossil fuels in the power generation system. The analysis reveals up to 725 GWh of ready-to-use capacity by utilising existing underground salt caverns in the UK. These potential CAES sites with added solar and wind generation equal to the generation from fossil fuels in 2018 can reduce carbon emissions by 84% with a cost increase by 29%, compared to the system in 2018. The results indicate the plausibly achievable cost-effectiveness of CAES as bulk-scale energy storage for power system decarbonisation in countries the geological resources are available. (W. He). decarbonised or mostly replaced by other low-carbon technologies in the near future [6]. Bulk-scale, or grid-scale, energy storage has been acknowledged as an essential technology to tackle the challenges in deep decarbonisation with large-scale renewable power when the use of fossil fuels is reduced [7] . Although lithium-ion batteries and hydrogen are often recognised as promising candidates for power decarbonisation in various modelling studies [6, 8, 9] , they may still require multiple years of research and development before reaching a cost-effective point or a satisfactory technology readiness level for commercial roll-outs as bulk-scale energy storage. Lithium-ion batteries are not currently cost effective for energy storage operation at timescales larger than 1-day, even with a significantly reduced cost in future (e.g. $150/kWh) [10, 11] . Additionally, the management and decommissioning of lithiumion batteries at end-of-life needs a great research effort to tackle the recycling challenge caused by the rapidly growing market [12] . Furthermore, hydrogen energy storage is still in its research phase, and its cost reduction may require significant infrastructure construction (e.g. centralised electrolysis) [13, 14] , and the use of less mature but promising technologies (e.g. high-temperature solid oxide or molten https://doi.Applied Energy 282 (2021) 116097 2 W. He et al. Nomenclature Exergy storage capacity contributed by the enhanced pressure [J] Exergy storage capacity contributed by the enhanced temperature [J] 2, Carbon intensity [kgCO 2 /MWh] Annualised fixed cost per energy capacity [$/MWh] , Power consumption of the compressor at stage [W] Annualised fixed cost per power capacity [$/MW] Compressor efficiency [%] Cycle efficiency [%] Expander/turbine efficiency [%] Generator efficiency [%] Motor efficiency [%] Storage power capacity [MWh] Annual energy demand [MWh] , Individual annual generation of the energy source [MWh] Individual energy source ,
doi:10.1016/j.apenergy.2020.116097 fatcat:amlufsutkjbb5jdrgxabg3o4rm