Abstract: To address the technical challenges of deep participation of coal-fired power plants in grid peak shaving, coupled energy storage systems can effectively improve the operational flexibility of the units. Two solutions for coal-fired power plant coupled with liquid carbon dioxide energy storage system driven by an electric motor or by a steam turbine were proposed, respectively, and the optimal solution was selected through comparative analysis. In addition, peak shaving performance analysis, exergy analysis and economic analysis were conducted on the optimal coupled system. Results show that the coupled solution driven by steam turbine has better performance, with the system round-trip efficiency of 61.85%, and the peak shaving depths of charging and discharging processes are 9.57% and 6.14%, respectively. The exergy efficiency of the optimal solution is 76.61%, the dynamic investment payback period is 5.01 a, and the net present value is 21.053 2 million yuan.