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.