The experimental vanadium redox flow battery. Courtesy SDG&E

San Diego Gas & Electric announced Friday it is testing an experimental battery at one of its substations as a way to help achieve zero-emission microgrids — a tool to keep communities and critical facilities powered with clean energy during adverse weather conditions and Public Safety Power Shutoffs.

The vanadium redox flow battery was connected to the California power grid two years ago with the intention of helping support reliability and maximizing the use of clean energy, becoming the first of its kind to do so.

With the support of Japan’s New Energy and Industrial Technology Development Organization and Gov. Gavin Newsom’s Office of Business and Economic Development, SDG&E and Sumitomo Electric launched the demonstration project in 2017.

The collaboration was recently extended for another year, through the end of 2021, to further test the battery’s microgrid capabilities and maximize its ability to support the grid with services such as voltage and frequency regulation.

Unlike the most prevalent energy storage technology — stacked cells of lithium-ion batteries — the flow battery being tested consists of tanks of liquid electrolytes and pumps. It began participating in the California Independent System Operator’s wholesale electricity markets in December 2018 and was used last summer to help minimize the impact of rotating outages during a record heatwave.

“Long-duration energy storage and microgrids are both key to helping California meet its clean energy, reliability and resiliency goals,” said SDG&E CEO Caroline Winn. “We need breakthrough technologies to achieve 100% renewable energy on our grid and to power microgrids during emergencies.”

Flow battery systems have an expected lifespan of more than 20 years and could have less degradation over time from repeated charging cycles than other chemical battery technologies.

The flow battery provides enough energy to power the equivalent of about 1,000 homes for up to four hours.

“California has proven time and again that addressing climate change is good for our environment, it’s good for future generations and it’s good for our economy — spurring new technologies and creating new markets on a regular basis,” said Tyson Eckerle, the Governor’s Office of Business and Economic Development’s deputy director of zero-emission vehicle market development.

Since unveiling the battery in 2017, SDG&E has been researching if flow battery technology can enhance the delivery of reliable energy to customers, integrate renewable energy and increase the flexibility of grid operations.

Like other energy storage systems, the flow battery absorbs or releases electrons as needed to help maintain grid stability. For example, soaking up surplus solar energy generated in the middle of the day and discharging it to the grid during peak evening hours.

In 2013, SDG&E began operating the first utility-scale microgrid in America — the Borrego Springs Microgrid. Last year, it received a federal grant to upgrade the Borrego system to run on 100% renewable energy. In 2017, SDG&E unveiled what was then the world’s largest lithium-ion battery storage facility.

–City News Service

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