Microgrid groundbreaking
Officials break ground for the microgrid. Photo courtesy SDG&E

San Diego Gas & Electric broke ground on the Clairemont microgrid Tuesday, one of four projects the utility has planned at its existing substations.

Once finished, the Clairemont microgrid will be able to provide backup power to San Diego Fire Station 36, the Balboa Branch Library and local schools such as Lafayette Elementary, Sequoia Elementary, Innovation and CPMA Middle Schools and Madison High School.

Microgrids are small-scale grids that can operate independent of or parallel to the larger regional grid to keep critical facilities powered during unexpected outages.

Each microgrid project is paired with energy storage, with the four projects bringing an additional 39 megawatts of battery capacity to the region. SDG&E currently has 95 MW of utility-owned energy storage online, with another 200+ MW in development.

“Energy storage and microgrids make it possible for our region to keep the lights on during grid emergencies, such as extreme heat waves,” said Miguel Romero, SDG&E vice president of energy innovation. “They also help us maximize the use of renewable energy and extend its availability into the evening hours after the sun sets.”

As an example, during the 10-day heat wave around Labor Day in September, energy storage, in addition to energy conservation efforts, helped California avoid rotating outages, according to utility officials. California has more than 4,400 MW of batteries, which provided around 4% of the electricity supply during peak demand to help avert rotating outages in September.

Within SDG&E’s service territory, utility-scale battery storage systems served as much as 7% of the regional load during peak hours of the heat wave.

San Diego City Councilwoman Jennifer Campbell joined Romero and local business and labor leaders at Tuesday’s groundbreaking ceremony.

“Mitigating the impacts of climate change requires infrastructure investments to strengthen our regional emergency preparedness and resiliency so we can bounce back quickly from disasters and avoid extended outages,” she said. “That’s why I am so thankful that SDG&E is building a microgrid right here in Clairemont to provide backup power to critical facilities.”

According to an SDG&E statement, when a microgrid is powered by battery storage, it produces zero emissions. Battery storage works by capturing renewable energy like wind and solar when they are abundant during the day, then sending that energy back to the grid when it is needed, such as at night when the sun has set or when energy supply is tight during adverse weather events.