On November 6, China's largest single-unit flywheel energy storage project was connected to the grid at Huaneng Lanzhou Thermal Power Company, marking an important breakthrough in China's flywheel energy storage fast frequency regulation technology for thermal power bases.
Flywheel energy storage stores electrical energy through a high-speed rotating rotor. When power is abundant, electrical energy drives the rotor to spin at high speed, converting electrical energy into rotational kinetic energy for storage; when the grid requires power supply, the high-speed rotating rotor converts the kinetic energy back into electrical energy for output. It can complete charging and discharging rapidly, ensuring stable grid operation, and offers advantages such as high conversion efficiency, strong adaptability, and long equipment service life.
The flywheel energy storage project connected to the grid this time innovatively adopts a collaborative mode of "5 MW high-power flywheel + 0.5 MW inertia flywheel." Unlike the traditional single-flywheel mode, the collaborative operation of dual flywheels enables complementary advantages and hierarchical response. The 5 MW large flywheel can effectively handle large frequency deviation fluctuations of the grid, while the 0.5 MW small flywheel is responsible for stabilizing routine small-amplitude grid frequency fluctuations. The response time of thermal power units equipped with dual-flywheel energy storage to grid frequency regulation can be less than 100 milliseconds, with regulation accuracy exceeding 99.5%, effectively enhancing unit frequency regulation performance under more complex conditions and rapidly supporting grid frequency stability.
The 5 MW flywheel put into operation this time is currently the largest single-unit flywheel in China, with a regulation rate of up to 5 MW/second, a storage capacity of up to 1,250 kWh, a charge-discharge efficiency of over 85%, and a cycle life of up to tens of millions of cycles.
The project is led and organized by Huaneng Gansu Company, with Xi'an Thermal Power Research Institute responsible for technology research and development. After going into operation, it will significantly enhance the frequency regulation response capability of the units, strengthen the anti-disturbance capability of the regional power grid, and provide strong technical support for the safe and stable operation of the power grid in Northwest China.