Application of Flywheel-Battery Hybrid Energy Storage in New Energy Power Station Frequency Regulation

Driven by the global energy transition, the proportion of new and renewable sources of energy (NRSE) such as wind and solar power in the electricity systems of many countries continues to rise. However, this also exacerbates frequency fluctuations in the power system, giving rise to new issues such as curtailment of wind and solar power generation and a continuous decline in inertia levels. The hybrid energy storage system composed of a flywheel and a battery can fully utilize the advantages of their power and energy characteristics, respectively, becoming an effective solution to this problem. Firstly, the characteristics of NRSE and various energy storage technologies were introduced in the paper. Then, the frequency regulation requirements and process of NRSE were discussed, as well as the common architecture and control methods of flywheel–battery hybrid energy storage systems, and the application research and current development status of the flywheel–battery hybrid energy storage system on the power supply side and grid side of the power system were elaborated, including the control strategies for participating in NRSE and methods to reduce costs and increase profits. Finally, the future research directions of flywheel–battery hybrid energy storage systems were discussed and anticipated.