California was mostly solar-powered in May — a global first

In May, solar panels supplied 51% of California's electricity for the whole month, counting both large solar farms and rooftop panels on homes. That's the first time any major economy has crossed the halfway mark for a full month, according to the think tank Ember. Only Hungary comes close, at 47% last June, though its economy is much smaller.

Batteries made this possible. California's grid operator now has 16 gigawatts of battery storage, which soaks up extra solar power in the middle of the day and releases it in the evening when the sun goes down. On many nights, batteries now cover more than a quarter of the state's electricity needs. Ten years ago, in the state's best month, solar made up just 17% of electricity, and battery capacity was only 61 megawatts. Solar also outproduced natural gas, the state's main fossil fuel for power, every month so far in 2026.

None of this changes rebates or programs for your own home, but it shows how fast solar and battery storage have scaled up in a place with lots of rooftop solar already installed. If you're weighing solar panels or a home battery, this is a sign of where the technology and the grid around it are headed: more solar, more storage, and less reliance on gas-fired power, at least in states like California that have invested heavily in both.