Research progress on flexible operation strategies for coal-fired units assisted by new-type energy storage systems

Accelerating energy-structure transformation and building the new power systems are among the important measures for China to achieve the goals of "carbon peaking" and "carbon neutrality". Large-scale new energy access to the power grid imposes higher requirements on traditional coal-fired units to participate in the process of peak regulation and frequency regulation. Equipping coal-fired units with new-type energy-storage systems can effectively improve their flexible operation capability. To this end, based on an analysis of the factors affecting the operational flexibility of coal-fired units, this paper firstly introduces the new-type energy-storage modes commonly adopted for coal-power coupled operation together with their technical characteristics. Secondly, it reviews the coupling modes, operation and control modes, as well as energy storage capacity allocation strategies of existing thermal-power and energy-storage systems, and summarizes and analyzes the characteristics and applicable scenarios of various strategies. Thirdly, the joint-operation process of energy-storage systems assisting coal-fired units is analyzed combined with practical engineering cases. Finally, on the basis of existing researches, the challenges and prospects for future development are discussed.