Performance analysis and scheduling study of hybrid CAES system operating jointly with wind and solar

Abstract

Hybrid compressed air energy storage (H-CAES) system can effectively reduce the heat loss in the compression process, which is one of the important methods to solve the problem of renewable energy volatility. Based on the H-CAES system that combines adiabatic compression and isothermal compression, this paper proposes a liquid piston compressor arrangement to adapt to the input power fluctuation and proposes a power allocation calculation method to solve the adiabatic compression and isothermal compression in the H-CAES system, with an emphasis on analyzing the impact of the participation of renewable energy sources on the system performance. In addition, the H-CAES system is placed under wind-solar-storage conditions, and scheduling strategies judged by time-sharing electricity price are proposed for different scenarios to explore the actual operating effects of the H-CAES system. The results show that the arrangement of liquid piston compressors from large tanks with fewer groups to small tanks with more groups can better adapt to the power change while maintaining a better isothermal compression effect. On the basis of using the power allocation calculation method proposed in this paper, it is found that higher compressor outlet pressure and lower storage pressure can improve the system efficiency and economic benefits. The system is able to achieve 59.71% efficiency and 0.2261 annual return on investment at the compressor outlet pressure of 4 MPa. Finally, it is demonstrated that the combined operation of H-CAES and wind energy can serve to increase the operating income of the power plant, and a maximum of 8909.236 yuan in daily electricity generation revenue can be achieved.