Performance study of 660 MW coal-fired power plant coupled transcritical carbon dioxide energy storage cycle: Sensitivity and dynamic characteristic analysis

As the demand of modern society for electrical energy continues to rise, the combustion of fossil fuels has led to deterioration of global climate due to the emission of greenhouse gases. The introduction of zero-carbon goal has spurred rapid development of renewable energy. However, the intermittent nature of it has revealed the growing issue of insufficient capacity in existing power systems. To tackle this challenge and enhance the adaptability of power systems, improving the flexibility of coal-fired power plants has become a critical objective. In this work, a novel solution is proposed to address the lack of renewable energy accommodation capacity. It is the method of coupling transcritical carbon dioxide (T-CO2) energy storage cycle with the 660 MW coal-fired power plant (CFPP), using energy storage process to further reduce unit load and energy release process to increase it. The results show that, under the design operating parameters, CFPP achieves load increase and decrease rates of 70.32 MW/min and 35.04 MW/min, respectively. Moreover, at a thermal storage temperature of 353.1 K, T-CO2 energy storage cycle achieves a round-trip efficiency of 61.37% and an energy storage density of 0.989 kWh/m3. The results indicate that the combined system exhibits excellent performance, particularly under relatively lower thermal source temperature. •A new combined system consists of CFPP and T-CO2 energy storage cycle is built.•Comprehensive analysis of parameters and dynamic characteristic is conducted.•An impressive RTE (61.37%) of T-CO2 energy storage cycle is achieved.•The operational flexibility of CFPP is enhanced by coupling the cycle.