California's home batteries set a new grid record on October 6, when more than 85,000 Tesla Powerwall owners dispatched over 600 MW to the grid as part of a combined 745 MW event announced by Sunrun. The total is 28% higher than the 580 MW record the two companies set in September, and larger than most gas peaker plants in the state, according to Electrek.
The dispatch came during an October heat wave at the request of the California Energy Commission and state utilities. Batteries discharged through multi-hour evening peaks, and October 5 marked the first time this year that both the Demand Side Grid Support and Emergency Load Reduction programs called dispatches simultaneously across all participating investor-owned utility territories. Sunrun says the 745 MW is enough to cover every household in San Francisco and San Jose combined during peak hours.
Tesla and Sunrun both claimed credit for the record, but the source notes they are largely reporting on the same fleet: Sunrun is the biggest Powerwall channel in the country and owns or operates 55% of the roughly 110,000 Powerwalls that delivered 517 MW in September. Tesla's figure of 600 MW from 85,000 homes works out to about 7 kW per home, above the 5 kW continuous output of a Powerwall 2, suggesting a fleet increasingly made up of Powerwall 3 units and homes with multiple batteries. Electrek also notes that neither company reported energy in MWh or exact duration, making it hard to compare the value of the dispatch.
Next up is a Google-funded distributed power plant with PG&E in the San Jose area, which plans to enroll nearly 21,000 devices from Tesla and Everyday Electric (formerly Renew Home), with initial dispatches expected this month. It is the first concrete piece of the 16.8 GW virtual power plant plan for data centers announced in June, though the Tesla and Everyday Electric portion remains under a non-binding letter of intent.