Thermodynamic and economic analyses of a new compressed air energy storage system incorporated with a waste-to-energy plant and a biogas power plant

Abstract

In this paper, a novel compressed air energy storage (CAES) system integrated with a waste-to-energy plant and a biogas power plant has been developed and evaluated. In the charging process, the feedwater of the waste-to-energy plant recovers the compressed heat of the compressed air in the CAES system. In the discharging process, the compressed air is heated by the energy obtained from the waste-to-energy boiler, and then replaces the compressor of the gas turbine system by burning with the biogas in the combustor directly. Via the system integration, some major equipment of a conventional CAES system can be saved, and the performance of the CAES system can be improved. Based on a 500 t/d waste-to-energy plant and a typical biogas power plant, the energy, exergy, and economic analyses of the proposed system were performed. As a result, a higher round-trip efficiency of 69.55% can be achieved, and the major exergy loss occurs in the throttle valve. Furthermore, the dynamic payback period of the proposed CAES system is 4.35 years, 4.74 years shorter than that of a conventional CAES system. Overall, the integrated system can improve the performance of the CAES system and promote the development of energy storage technology.