Wind power generation and photovoltaic power generation fluctuate in power output according to wind and weather conditions, and it is concerned whether such fluctuation may influence power quality, such as frequency.

Vanadium redox flow battery charges and discharges electricity as the electrolyte that uses vanadium and other ions circulates. It consists of cell stacks for input and output, tanks for electrolyte storage, and pumps for electrolyte circulation.

As vanadium redox flow battery can have great output and capacity, it can be used for various purposes in a power supply system, such as frequency fluctuation suppression and surplus power supply control.