Thermodynamic and economic analyses of the integrated cryogenic energy storage and gas power plant system

Liquid air energy storage (LAES) can be used to match power generation and demand for large-scale renewable energy systems. A new LAES system combining gas power plants, liquified natural gas cold recovery system, and carbon dioxide capture and storage (CCS) was proposed to improve system efficiency, store surplus renewable energy, and reduce greenhouse gas emissions. The thermodynamic and economic analyses of the proposed system were conducted, and the effects of charging pressure, energy storage pressure, discharging pressure, and CCS pressure on system efficiency were investigated. Furthermore, a genetic algorithm optimization model was built. The results showed that the global optimal round-trip efficiency is 54.77%, 3.49% improvement compared to the initial case. In addition, both split air ratio and combustion temperature influence the system thermodynamic and economic performance significantly. It is concluded that the tremendous economic feasibility with a dynamic payback period is in the range of 6.39–6.58 years and a levelized cost of energy is in the range of 0.050–0.051 USD/kWh when the split air ratio in conversion reactor is 0.4, and the combustion temperature is 1148–1248 °C, where round-trip efficiency of the system is 52.07%–53.39% and the designed maximum power generation capacity is 201.12 MW/1.61 GWh. The proposed system is technically and economically feasible and can be a new idea for further industrial applications of large-scale renewable energy storage and utilization.