Compressed air energy storage in aquifers: basic principles, considerable factors, and improvement approaches

Compressed air energy storage in aquifers (CAESA) can be considered a novel and potential largescale energy storage technology in the future. However, currently, the research on CAESA is relatively scarce and no actual engineering practices have yet been performed due to a lack of detailed theoretical and technical support. This article provides a summary and analysis of the current research about the key problems in CAESA. The theoretical foundation and evaluation methods are first addressed, and then the aquifer selection criteria are proposed by analyzing the impact of the main geological factors on the performance. Subsequently, the optimal design of wellbore and the operation parameters are discussed, and different possible enhanced methods are proposed for extending the application of CAESA. Finally, conclusions are made and application outlook is addressed.