Thermo-economic analysis of a novel system integrating compressed air and thermochemical energy storage with solid oxide fuel cell-gas turbine

This paper proposes a novel system integrating compressed air and thermochemical energy storage with solid oxide fuel cell-gas turbine (SOFC-GT). During charging process, the compression heat drives methanol decomposition into syngas for converting its low-grade thermal energy into high-grade chemical energy and achieving hybrid storage of physical and chemical energies simultaneously. During discharging process, the SOFC-GT efficiently converts the stored energy into power based on energy cascade utilization, significantly improving the total exergy efficiency of the system. The effects of six key parameters on the thermo-economic performance of the system are studied by the sensitivity analysis, and the results show that the total exergy efficiency conflicts with the levelized cost of energy (LCOE). Therefore, the multi-objective optimization is carried out for the system from the thermodynamic and economic aspects, and the best trade-off is selected with the total exergy efficiency of 65.89% and LCOE of 126.48 $/MWh, in which the system can generate 7.22 MWh power and 2.37 MWh heating with the total energy efficiency of 89.76%.