Increasing Coal-Fired Power Plant Operational Flexibility by Integrating Solar Thermal Energy and Compressed Air Energy Storage System

This paper proposed a novel integrated system with solar energy, thermal energy storage (TES), coal-fired power plant (CFPP), and compressed air energy storage (CAES) system to improve the operational flexibility of the CFPP. A portion of the solar energy is adopted for preheating the boiler's feedwater, and another portion is stored in the TES for the CAES discharging process. Condensate water from the CFPP condenser is used for cooling compressed air during the CAES charging process. The thermodynamic performance of the integrated system under different load conditions is studied. The system operations in a typical day are simulated with EBSILON software. The system enables daily coal saving of 9.88 t and reduces CO2 emission by 27.95 t compared with the original CFPP at 100% load. Under partial load conditions, the system enables maximum coal saving of 10.29 t and maximum CO2 emission reduction of 29.11 t at 75% load. The system has maximum peak shaving depth of 9.42% under 40% load condition. The potential of the system participating ancillary service is also discussed. It is found that the integration of solar thermal system and CAES system can bring significant ancillary service revenue to a conventional CFPP.