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SDG&E and Sumitomo unveil largest vanadium redox flow battery in the US

Sumitomo and SDG&E's 2MW/8MWh redox flow battery system. Credit Sumitomo
Sumitomo and SDG&E’s 2MW/8MWh redox flow battery system. Credit Sumitomo

Utility San Diego Gas and Electric (SDG&E) and Sumitomo Electric (SEI) have launched a 2MW/8MWh pilot vanadium redox flow battery storage project in California to study how the technology can reliably integrate renewable energy and improve flexibility in grid management.

The redox flow battery system developed for the project is the largest of its kind in the US, claims SEI.

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Over a four-year period, SDG&E will be testing voltage frequency, power outage support and the shifting energy demand abilities of the battery from Sumitomo, which can provide power for the equivalent of 1,000 homes for up to four hours.

SDG&E said flow batteries have an expected life-span of more than 20 years. They use tanks of electrolytes to store energy, meaning that in theory they can be scaled up to provide longer-duration storage than is typically found in other types of battery, such as lithium-ion. This ability to degrade less from repeated charging cycles than other forms of battery makes them particularly attractive to renewables developers.

In a release, SEI said that increased integration of solar power, rapid fluctuations in demand and supply, as well as low-quality electricity, have become increasingly apparent in California which now has the most ambitious renewable portfolio standard (RPS) in the US of 50% by 2030, behind only that of Hawaii. As a result, utilities are now required to install large-scale energy storage systems under California's Assembly Bill 2514.

Junji Itoh, managing director of Sumitomo Electric, said: “We are delighted to see our first flow battery system operating in the US. Through the multiple-use operation of the battery system in SDG&E's distribution network, we would like to prove its economic value and potential use on the electric grids.”

The project also came as the result of a memorandum of understadning between Japan's New Energy and Industrial Development Organization (NEDO), a government organisation that promotes new technologies, and the California Governor's Office of Business and Economic Development (GO-Biz), back in September 2015.

The demonstration commencement ceremony was held at SDG&E's San Miguel Substation this week.

Sumitomo provided this inforgraphic showing redow flow battery technology on the grid with renewables. Credit: Sumitomo
Sumitomo provided this inforgraphic showing redow flow battery technology on the grid with renewables. Credit: Sumitomo

SDG&E recently completed what it claims to be the world’s largest lithium-ion battery storage facility in Escondido, with another large-scale facility in El Cajon. It now has 100MW of projects completed or in the pipeline.

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