Sunrun, Tesla Dispatch 580 MW from Home Batteries in Record VPP Event
Sunrun and Tesla coordinated 110,000 residential batteries to deliver 580 MW to California's grid during a heat wave.
Key points
- Sunrun and Tesla dispatched 580 MW from 110,000 home batteries to California's grid on September 9, 2026.
- Tesla Powerwalls supplied 517 MW, while other residential batteries provided 63 MW during the three-hour peak event.
- The companies state that including Southern California Edison resources could enable a single dispatch exceeding 720 MW.
Sunrun and Tesla executed the largest distributed virtual power plant dispatch in history on September 9, 2026. The coordinated release of 580 megawatts from residential battery storage addressed peak demand in California during a heat wave. This event surpassed previous records and demonstrated the grid-scale potential of distributed energy resources.
Tesla Powerwall units provided 517 MW, while other home batteries contributed 63 MW. A total of 110,000 Powerwalls participated, with Sunrun owning and operating 55% of the fleet. The companies also dispatched over 30,000 third-party batteries. The resources were distributed across all three investor-owned utility territories in the state.
Dispatch triggered by high energy prices
The California Independent System Operator’s day-ahead locational marginal price exceeded $200 per megawatt-hour, triggering the demand side grid support dispatch. PG&E simultaneously called an emergency load reduction program for its territory. The three-hour evening discharge aimed to increase grid operating margin and reduce real-time energy costs.
Sunrun CEO Mary Powell stated the fleet operated at a scale larger than many peaker plants combined. She noted that the dispatch helped control electricity costs and reduced the need for new transmission infrastructure. The event validated the role of consumer-owned storage in maintaining grid stability during high-demand periods.
Potential for 720 MW capacity release
Sunrun and Tesla indicated that a larger event is possible. The September 9 dispatch excluded batteries in the Southern California Edison territory participating in the emergency load reduction program. On September 10, SCE requested a separate three-hour dispatch, yielding 140 MW.
The companies state that combining the SCE resources with the previous dispatch would have exceeded 720 MW. This capacity would have been sufficient to mitigate rolling blackouts experienced in 2020. The potential scale highlights the aggregated power available from residential storage assets.
Grid integration and future capacity
PG&E expert Kendrick Li noted that the previous 535 MW test in 2025 caused a noticeable system shock. He proposed using ramping curves in future events to smooth the grid impact. The companies are currently working to unlock 16.8 gigawatts of flexible capacity for utilities and hyperscalers.
This capacity includes home batteries, solar, smart thermostats, and electric vehicles. The collaboration involves Sunrun, Tesla, and Renew Home. These assets provide flexible resources for grid operators seeking to manage peak loads without relying solely on traditional power plants.
