Image: SDG&E

California utility San Diego Gas & Electric (SDG&E) is testing its vanadium redox flow technology in advancing clean energy microgrids.

The vanadium flow battery is being pioneered in SDG&E’s grid in a partnership with Japan’s New Energy and Industrial Technology Development Organization (NEDO) and Sumitomo Electric Industries, which supplied the technology in 2017.

Since that time, the focus has been on the use of the battery to support reliability and improve the power quality on California’s grid with participation in the California Independent System Operator’s (CAISO) wholesale electricity markets.

The new use case, which extends the collaboration for a further year to the end of 2021, is aimed to test the use of the vanadium flow technology in a microgrid both for resilience, providing power in emergency situations, and in normal market operations.

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Grid resilience and reliability are becoming increasingly important in California, with more frequent power shutoffs implemented as a tool to reduce wildfire risk and the introduction of rotating outages during summer peak periods.

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

“SDG&E is proud to play a role in developing innovative solutions, like the flow battery technology, to help solve California’s climate-related challenges.”

Vanadium flow battery systems are still an emerging technology with applications growing. Benefits are expected to include a lifespan of more than 20 years and less degradation over time from repeated charging cycles than other chemical battery technologies.

As part of the planned microgrid demonstration, part of the distribution network to which the reflux flow battery and approximately 70 consumers are connected will be isolated from the grid.

The ‘dual use’ back up, normal operations demonstration for flow battery technology is believed to be a world first and is hoped to contribute to greater market penetration of energy storage.