An engineer inspects the vanadium redox flow battery storage facility in Bonita. Photo by Chris Jennewein
An engineer inspects the vanadium redox flow battery storage facility in Bonita. Photo by Chris Jennewein

For the second time in a month, San Diego Gas & Electric unveiled an innovative battery backup system designed to speed the utility’s transition to renewable energy.

The vanadium redox flow battery storage facility opened Thursday in Bonita is the largest installation of this new technology in the United States. It’s capable of powering 1,000 homes for four hours.

Top executives from SDG&E were joined by their counterparts from Sumitomo Electric, which developed the technology, and the Consul General of Japan in Los Angeles to formally begin a four-year test of the batteries.

“Storing energy in  batteries such as these allows us to provide clean energy to our customers more hours of the day,” said Caroline Winn, SDG&E’s chief operating officer.

SDG&E’s Caroline Winn in front of the batteries.

She said installations like this and the giant lithium-ion battery storage facility opened Feb. 24 in Escondido will help California “lead the world in reducing harmful greenhouse gas emissions.”

SDG&E already generates more than a third of its power from renewable sources — the most of any U.S. utility — and increasingly needs technology to store it. The batteries also take the place of conventional natural gas-powered generators that kick in during periods of peak demand.

The new project is smaller than the one in Escondido — 2 megawatts versus 30 megawatts — and the technology is more expensive, but the batteries are expected to last up to 30 years, versus 10-12 years for lithium-ion technology.

“We are delighted to see our first flow battery system operating in the U.S.,” said Junji Itoh, managing director of Sumitomo Electric. “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 Japanese consul general, Akira Chiba, described the new storage system as a “game changer” in clean energy and praised the partnership between California and Japan in developing the needed technology.

Chris Jennewein

Chris Jennewein is Editor & Publisher of Times of San Diego.