Home Batteries Helped Keep California’s Grid Steady Throughout a Fall Heat Wave

Batteries in California Homes Sent a Record 745 Megawatts to the Grid on October 6, Enough to Power Every Home in San Francisco and San Jose

Home batteries from Sunrun and Tesla set national records for supplying 745 megawatts of electricity to California’s grid during peak hours on October 6, enough to power every home in San Francisco and San Jose, during an unusually late heat wave. The night before, they supplied 669 megawatts.

States across the country are trying to keep up with fast-growing demand for electricity while keeping bills in check. Home and mid-size batteries, smart thermostats and rooftop solar can help by supplying power during the evening hours when the grid is most strained and electricity costs the most. California’s heat wave shows how much these resources can deliver when the grid calls on them all at once.

“On two of the hottest evenings of the fall, California families helped keep the grid running with batteries in their own homes,” said Mary Rafferty, executive director of Common Charge. “That’s about as much as a large power plant produces, delivered from homes during the evening hours when the grid needs it the most. Every state looking for affordable ways to meet rising demand and rising bills should look first at the power already sitting in homes, schools, and businesses.”

California and Texas lead the country in energy storage, and Sunrun alone has more than 120,000 home batteries connected to California’s grid. The households taking part are paid for the power they provide, the same way the grid pays any other power source, but the benefits are felt across the community. Power from these batteries during a heat wave lowers the risk of outages for everyone nearby and cuts how much expensive peak power utilities have to buy, which can help keep bills down for all customers.