From Rooftops to the Grid: Sunrun’s Big Energy Play

Sunrun links home batteries into a vast network, cutting outages and paying Californians to power the grid.

5 Jul 2025

Sunrun has expanded its virtual power plant programme across California, connecting 75,000 home batteries from more than 56,000 households into a coordinated network capable of delivering up to 375 megawatts of electricity. The system, called CalReady, is designed to provide power during peak demand periods and support grid stability.

The expansion, announced in May 2025, comes as the state implements Net Energy Metering 3.0, a policy that reduces payments to households for exporting excess solar power. Sunrun is shifting towards a model in which stored energy is dispatched to the grid when demand is highest, a move the company says improves both reliability and returns for customers.

On June 24, during a heatwave that strained electricity supplies, the company’s virtual power plant dispatched over 340MW nationwide, including 325MW in California, helping to offset evening demand and avoid potential blackouts. “Customers are no longer just consumers; they’re key contributors to grid stability,” said Mary Powell, Sunrun’s chief executive. “This evolution strengthens households while accelerating the clean energy transition.”

Participants in CalReady can earn up to $150 per battery over the summer, with total payouts projected to reach nearly $10mn in 2025. Sunrun says this arrangement allows households to turn stored solar energy into a direct income stream.

Residential batteries, once primarily used as backup power sources, are becoming integral to grid management as more renewable generation comes online. The company’s model links thousands of decentralised storage units into a single system that can respond instantly to grid signals.

While national adoption of such schemes may be slowed by regulatory differences between states, Sunrun’s programme in California is being viewed by energy analysts as evidence that large-scale residential participation in grid services is feasible.

Officials and utilities in other states are studying the approach as extreme weather events increase pressure on energy infrastructure. The spread of residential virtual power plants, if replicated beyond California, could mark a significant change in how electricity is generated, stored and distributed in the US.