Abstract: During the "14th Five-Year” period, the rapid growth of installed capacity of wind power and photovoltaic systems will intensify the fluctuation of the system net load. It is inevitable that the demand for flexible resources such as energy storage will continue to rise. Meanwhile, as the energy storage technology is becoming more mature and the cost continues to fall, it tends to be gradually applied to every aspects of the power system. Therefore, it is necessary to establish an energy storage optimization planning model which takes into account the demands of system flexibility to evaluate the demands of China's energy storage in the next five years more scientifically. This article first proposes the operation simulation model method and energy storage demand analysis process based on the time sequence curve considering the flexibility of the power system. Specifically, by taking the minimization of total system cost as the optimization objective subject to the investment decision constraints and operation constraints, the structure and capacity of energy storage for the target-level year are coordinated and optimized. Secondly, based on the proposed model and methods, the optimal energy storage capacities under the protocol power transmission mode for China's seven regional power grids in 2025 are calculated respectively. The configuration of energy storage are analyzed and comparative analysis of energy storage capacity under the flexible adjustment mode is also carried out. Finally, based on the above analysis, we summarized the conclusions regarding China’s power system energy storage capacity, new energy generation capacity, wind curtailment and solar curtailment rate, and comprehensive electricity cost during the “14th Five-Year” period, which will provide technical support for the planning of energy storage in the next five years.

Key words: “14th Five-Year” power plan, energy storage optimization planning model, energy storage demand assessment, energy storage configuration analysis