Tesla and Sunrun Home Batteries Set 745 MW California Grid Record

California just got a better look at what happens when tens of thousands of home batteries stop acting like isolated backup boxes and start moving as one power plant.

Home batteries coordinated by Sunrun and Tesla delivered a record 745 megawatts to the state’s grid during the evening peak on October 6. That was not a laboratory test or a projection.

It was real power flowing from equipment already installed at people’s homes.

And the record did not creep upward. It jumped 28 percent from the 580 MW mark set less than a month earlier.

Sunrun said its fleet and Tesla’s combined residential batteries supplied 669 MW on October 5, then reached 745 MW the next evening. Both events came during a prolonged heat wave, when the California Energy Commission and utilities called on participating batteries through multi-hour peak periods.

The October 5 event was the first this year to activate both of California’s major participating demand-response programs across all investor-owned utility territories at once. Sunrun said the next night’s 745 MW peak was enough capacity to cover every household in San Francisco and San Jose combined during peak hours.

That comparison puts the number in human scale. These were not giant battery containers sitting behind a fence.

They were thousands of smaller systems answering the same grid signal at the same time.

During California's intense heat wave earlier this month, home batteries delivered 745 MW of average power to the state’s grid for several hours, setting a new record for the largest residential distributed power plant dispatch in U.S. history.

On back-to-back nights, Sunrun and… pic.twitter.com/p0nKFCYFjO

— Sunrun (@Sunrun) October 14, 2026

There is one wording detail worth keeping straight. Sunrun’s social post describes 745 MW as average power delivered for several hours, while the company’s formal release identifies 745 MW as peak power during the event.

The release is the more precise source for the record, and it does not publish a combined megawatt-hour total for the Sunrun-and-Tesla fleet.

Tesla Energy published its Powerwall result first. The company said more than 85,000 California owners dispatched more than 600 MW on October 6, calling it the largest Powerwall virtual-power-plant event yet.

Tesla’s dashboard showed 85,774 participating homes, a 601 MW participating peak and 932 megawatt-hours delivered over the event. That last number matters.

Megawatts tell us how much power the fleet produced at a moment; megawatt-hours tell us how much energy it actually delivered over time.

The 932 MWh total shows this was more than a brief screenshot of a high number. The participating Powerwalls moved a substantial block of energy through the evening.

Less than a month later, a new record for the largest Powerwall VPP event

On Tuesday, 85,000+ Powerwall owners across California dispatched more than 600 MW to the grid, helping to meet peak demand pic.twitter.com/Qz0Pjq2nWw

— Tesla Energy (@teslaenergy) October 8, 2026

Electrek reconciled the two announcements and found that Powerwalls supplied roughly four-fifths of the combined October 6 peak. That is a reasonable comparison between Tesla’s 601 MW and Sunrun’s 745 MW, but the companies did not publish a clean ownership or revenue split for the combined fleet.

That distinction prevents two easy mistakes. Tesla’s 601 MW and Sunrun’s 745 MW should not be added together, because the Tesla fleet is part of the combined result. And a home with a Powerwall is not necessarily a home that bought directly from Tesla; Sunrun owns or operates many Powerwall systems.

A virtual power plant works because software can coordinate many small energy resources as one dispatchable system. When the grid is under pressure and prices spike, participating batteries release stored electricity together instead of forcing the system to find the same power from one conventional plant.

Tesla Support explains that California owners enroll through utility-linked programs, receive event information in the Tesla app and can preserve a backup reserve for their own homes. Participation also carries compensation under the applicable program, turning a battery that normally serves one household into an asset that can serve the wider grid.

The owner still controls the part that matters most during an outage: how much energy stays behind. The grid gets coordinated capacity, while the homeowner does not have to surrender the reason many people bought backup storage in the first place.

Sunrun says it now has more than 120,000 residential batteries enrolled to support California’s grid. It also points to a separate Google-funded project around San Jose that is expected to begin drawing on nearly 21,000 flexible devices this month, though the Tesla and Everyday Electric portion remains subject to a nonbinding agreement.

The biggest takeaway is that home batteries already are meaningful grid infrastructure. California called and tens of thousands of Powerwalls answered.

The resulting peak was large enough to stand beside a utility-scale power plant.