100K Home Batteries Just Replaced Power Plants, and It Worked

Over 100,000 home batteries delivered 535 MW to the grid, proving VPPs can slash costs, cut emissions, and transform utility planning.

18 Aug 2025

On July 29, California met its evening power needs in a new way. Instead of firing up gas plants, the state tapped more than 100,000 home batteries, which together sent 535 megawatts to the grid.

These systems, installed in garages and basements, worked as one massive virtual power plant. The coordinated push came just as solar production was dropping and demand was rising. It kept the grid stable without extra pollution or costly new infrastructure.

“This changes the game,” said one utility leader. “Batteries are becoming the backbone of the grid.”

Virtual power plants could help utilities avoid building expensive facilities and give homeowners a way to earn money from storage they already own. But challenges remain, including inconsistent rules, hesitant utilities, and the need for secure, standardized systems.

Even so, July’s smooth performance has regulators taking a closer look. If trends continue, millions of small batteries could one day replace much of the role now played by big, centralized plants. They would quietly store sunshine until the grid needs it most.