Thermodynamic analysis of a hybrid thermal-compressed air energy storage system for the integration of wind power

In China, a large amount of wind power is abandoned due to the difficulty of integrating fluctuating wind power into electricity grid systems. Advanced adiabatic compressed air energy storage (AA-CAES) is regarded as a promising emission-free technology to facilitate the wind power integration, but its high capital cost has hindered its wide commercialization. In the present work, a novel hybrid system was proposed on the basis of AA-CAES. It can reduce abandoned wind power and improve the financial return per capital cost of the system by increasing power output. In the new system, which is called hybrid thermal-compressed air energy storage (HTCAES), thermal energy storage (TES) units absorb the heat released from air compression and also the thermal energy converted from reluctant wind power using electrical heaters. Theoretical thermodynamic analyses show that the HTCAES system can absorb much more wind power than an AA-CAES system with the same scale of compressors, turbines, and TES units do. And recovery efficiency of this additional wind power is about 41–47%, depending on the final storage temperature of the TES. The power output ratio of the HTCAES system to the AA-CAES system increases with the maximum TES storage temperature and decreases with the operating pressure.