Performance analysis of a compressed air energy storage system integrated into a coal-fired power plant

Compressed air energy storage is considered to be a potential large-scale energy storage technology because of its merits of low cost and long design life. Coupling with coal-fired power plant is an attractive way for its competitiveness improvement. A novel compressed air storage system that integrates into the regenerative subsystem of coal-fired power plant is proposed. The mathematical model is established, and the possible coupling schemes are discussed. Furthermore, analyses of thermodynamics, purchased-equipment costs and key parameters are carried out. The results show that at the ambient temperature of 20 degrees C the round-trip efficiency and exergy efficiency of the proposed system are 78.85% and 83.81%, respectively. The largest exergy destruction process is shown to take place in the throttle valve, and heat exchangers are shown to be the equipment with the largest investment. The parametric analysis shows that the proposed system has good performance in a wide range of storage pressures and ambient temperatures. Such good features make the proposed system a promising scheme for prompting energy storage technology.