A utility and its project partner have completed a net-zero microgrid featuring vanadium redox flow (VRF) battery storage connected to a substation in southern California.
San Diego Gas & Electric worked with Japan-based Sumitomo Electric to install and finish work on the VRF-based microgrid in Bonita, CA. The microgrid will deliver power into the SDG&E grid and provide backup power in the event of shutdowns on the main system.
In one of its test runs, the 2-MW/8-MWh battery powered 66 residential and commercial customers for close to five hours, the utility reported.
“Climate conditions increasingly threaten the continuity of essential services that our customers expect and deserve from us, which is one of the many reasons we are so focused on innovation and technology,” said SDG&E CEO Caroline Winn. “There is a critical need to develop breakthrough solutions like zero-emissions microgrids to not only minimize disruptions, but to also support the transition to a cleaner, safer and more reliable energy grid of the future.”
VRF batteries consist of tanks of liquid electrolytes and pumps that charge and discharge electrons to the grid. During the pilot, the batteries charged when solar energy was abundant and discharged during peak hours to meet demand.
“We are honored that the Sumitomo flow battery has contributed to the successful demonstration of this large-scale microgrid,“ said Hideo Hato, Senior Managing Director of Sumitomo Electric. “Sumitomo’s cutting-edge non-flammable and reusable flow battery system can help support California’s climate goals and improve resiliency for the state’s electric infrastructure.”
The microgrid demonstration project was completed late last year and included two successful tests. One was a seamless transition in which customers did not experience any loss of power when they were transitioned to the microgrid for electric service. The other was a black start – meaning microgrid operators established and sustained service after a complete loss of power, according to SDG&E.
Customers experienced a momentary outage before they were transitioned to the microgrid, which operated in island mode separate from the larger power grid, the utility said.
