What happened in this Energy story?

Tesla and Sunrun discharged a record 580 MW from over 140,000 home batteries onto California's grid during a September 9 heat wave, the largest residential virtual power plant dispatch ever recorded.

What is a key fact in this story? (1)

**Tesla and Sunrun** dispatched 580 MW from 140,000+ home batteries onto California's grid during a September 9 heat wave, the largest residential distributed power plant event ever recorded, running for three evening hours when air-conditioning load peaked.

What is a key fact in this story? (2)

**Tesla Powerwalls** delivered 517 MW of the total, with roughly 110,000 Powerwalls in the fleet and Sunrun owning or operating 55% of them; another 30,000+ non-Tesla batteries in Sunrun's fleet contributed the remaining 63 MW.

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Tesla, Sunrun Dispatch Record 580 MW to California Grid — SkimNews

By Electrek · Summarized & edited by Kapil Samant · 2026-09-21

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Tesla and Sunrun dispatched 580 MW from 140,000+ home batteries onto California's grid during a September 9 heat wave, the largest residential distributed power plant event ever recorded, running for three evening hours when air-conditioning load peaked.
Tesla Powerwalls delivered 517 MW of the total, with roughly 110,000 Powerwalls in the fleet and Sunrun owning or operating 55% of them; another 30,000+ non-Tesla batteries in Sunrun's fleet contributed the remaining 63 MW.
The event flowed through two existing California programs — CEC's Demand Side Grid Support (auto-triggered when day-ahead prices hit $200/MWh) and CPUC's Emergency Load Reduction Program (called directly by utilities) — using existing price signals rather than new infrastructure.
Sunrun followed up with another 140+ MW dispatch on September 10 at Southern California Edison's request, demonstrating the fleet can be tapped on consecutive days.
Sunrun CEO Mary Powell said the distributed fleet now operates at a scale larger than many natural gas peaker plants combined, noting typical peakers run 50 to 250 MW.
A Brattle Group report cited by Sunrun projects up to $206 million in net savings for Californians by 2028 from this kind of dispatch, with homeowners in the program paid for the power they export.

Why it matters: This dispatch rivaled the output of multiple natural gas peaker plants combined — but came from 140,000 home garages with no new infrastructure. With Brattle projecting $206 million in net savings for Californians by 2028 from this dispatch model, distributed home storage is now competing with utility-scale assets on peak demand economics.