Thank lightning. A power line to California’s Borrego Springs was damaged by lightning last month. Normally they’d have to shut down power to 2,800 customers in the area the impacted area for about 10 hours to make the fix, but Borrego Springs has a solar-powered microgrid, complete with battery backup. So when the lights could of been out for a day, the food spoiling in the fridge and the homes and businesses shut down—they were instead fully powered by the local microgrid, which local power provider San Diego Gas & Electric (SDG&E) said is likely a first.
It was a big test for such a system in the U.S. and will help show how solar is a reliable part of the energy solution. Microgrids are designed to allow local areas to island themselves completely from the local electric grid if need be. Some colleges and military installations use them to make sure they can still operate in times of outages, for instance. As energy storage becomes less expensive, they’re becoming a more attractive option as part of renewable energy power plant.
“SDG&E demonstrated in a real-world situation how we can use innovative technology to create a more resilient and sustainable grid for our customers,” said Dave Geier, SDG&E’s vice president of electric transmission and system engineering. “Borrego Springs was entirely separated from the main grid, running on the microgrid’s local onsite resources for nine hours as we conducted necessary maintenance. This ability to operate independently of the grid when necessary is exactly what the microgrid was designed for and the fact that we were able to accomplish this using local renewable energy is an added benefit. We are very proud to offer this innovative service to the community.”
On the morning of May 21 the utility switched over to using NRG Energy’s Borrego Solar facility with energy storage to power the community during the service period. During the work on the transmission line the microgrid generated the majority of power from the solar panels in the array, and used its batteries and traditional distributed generation to fill in gaps created by the solar facility when the solar array wasn’t producing enough power. The microgrid’s computer system switches between power sources to make sure the amount of electricity in the system is appropriate to its needs.
“The microgrid was really a crucial tool during this maintenance,” said Linda Haddock, executive director of the Borrego Springs Chamber of Commerce. “This innovative project provided electricity to our residents and kept the town running all day. Residents were also pleased that the Borrego Solar facility was used to support this effort. It’s great to see all these local, sustainable resources being put back into the community to truly make a difference in the lives of our residents in Borrego Springs.”
The work was completed by 5:30 p.m. If the microgrid wasn’t in place SDG&E’s customers would have faced a 9 to 10 hour power outage. Instead their service was interrupted for less than 10 minutes as they were transitioned back to their normal transmission lines.
This is just the first step for the microgrid, too. The California Energy Commission granted $5 million to SDG&E to connect the Borrego Solar facility to power the entire community. That will make it one of the nation’s largest microgrids that can operate solely on renewable energy. SDG&E said it will incorporate more advanced computer software and sensors to enhance the Microgrid.Tweet