Adiabatic compressed air energy storage – a study on dynamic performance with thermal energy storage

Up to day, 70% of the gross electricity (~ 20000 TWh) is produced via fossil fuel; to reduce this share and abate CO2 emissions the energy system will face a dramatic change in the near future consisting in a significant introduction of intermittent renewable energy sources. The implementation of this step change will be possible only through efficient and economic grid-scale electrical energy storage. In this paper we study the operation of a 220MWe adiabatic compressed air energy storage (ACAES) plant with a packed bed thermal energy storage. Although in the literature designs of thermal stores for ACAES have been presented, there is a lack of studies addressing how the TES system affects the performance of ACAES plant. This work contribute to fill this gap in the literature by linking in a quantitative manner the TES sizing and ACAES global efficiency. We achieve this goal via a algebraic-differential model that account both dynamic and off-design performance of ACAES plant’s components. The results shows that after 30 charge/discharge cycles the thermal store reaches cycling; this enable the A-CAES to achieve a round trip efficiency of 70%.