Energy and Natural Resources

Utility Tests a 2MW Storage Battery in Deal with Sumitomo

20 March 2017

San Diego Gas & Electric unveiled a vanadium redox flow (VRF) battery storage pilot project in coordination with Sumitomo Electric.

During the four-year demonstration project, SDG&E says it will research if flow battery technology can economically enhance the delivery of reliable energy to customers, integrate growing amounts of renewable energy, and increase the flexibility in the way the company manages the power grid.

The vanadium redox flow battery storage facility will provide 2 megawatts (MW) of energy for up to four hours. Like other battery storage systems, the battery will act like a sponge to soak up renewable energy harnessed from the sun and release it when resources are in high demand.

The VRB is a type of rechargeable flow battery that uses vanadium ions in different oxidation states to store chemical potential energy. The battery exploits the ability of vanadium to exist in solution in multiple oxidation states. It uses this property to make a battery that has a single electroactive element instead of two.

Flow battery systems have an expected life-span of more than 20 years, and could have less degradation over time from repeated charging cycles than other technologies. SDG&E says it will test voltage frequency, power outage support, and shifting energy demand.

To date, SDG&E has approximately 100 MW of energy storage projects completed or contracted, including a lithium ion battery storage facility in Escondido and a smaller facility in El Cajon.

The test project stemmed from a partnership between Japan's New Energy and Industrial Development Organization and the California Governor's Office of Business and Economic Development.

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