4-E analysis of a hybrid integrated mechanical/chemical/electrochemical energy storage process based on the CAES, amine-based CO2 capture, SOEC, and CO2 electroreduction cell

The future electricity generation model will require the integration of intermittent renewable sources. Energy storage technologies will play a crucial role in increasing both the efficiency as well as the availability of renewable energy. Herein, for the first time, an integrated hybrid mechanical/chemical/electrochemical energy storage system was investigated. The proposed electrochemical sub-units use the power-to-X concept to return some of the stored energy as useful fuels like hydrogen and formic acid. The terms mechanical, chemical, and electrochemical refer to CAES, amine-based CO2 capture, and CO2ERC/SOEC sub-units, respectively. In fact, CO2ERC and SOEC sub-units were considered as the electrochemical energy storage process, which uses the power-to-X concept to make the returned power of CAES to precious fuels. 4-E approach (Energy, Exergy, Exergoeconomic, and Exergoenvironmental) was used to assess the simulated process comprehensively. Based on the results of the 4-E analysis, the proposed system with the RTE of 60.34 %, exergy efficiency of 64 %, total cost rate of 1305.9 $/h, and exergoenvironmental damage effectiveness factor of 0.55 have superior performance as an integrated multigeneration energy storage system. Also, exergoenvironmental and exergy stability factors of the system are 0.36 and 0.35, respectively.