California solar supplied 51 % of electricity in May, a global first

California’s solar panels crossed the halfway line in May, producing 51 % of the state’s electricity. It was the first full month above that mark, counting both utility-scale installations and rooftop arrays. Ember says California is the first major economy in the world to reach it.

The shift is visible in the rest of the power mix. Natural gas remains the only fossil fuel burned by California power plants at appreciable levels, but solar outproduced gas in May and in every month of 2026 leading up to it. The state’s solar growth is therefore doing more than adding clean generation: it is squeezing an established source of electricity out of the system.

Solar did not reach this point alone. The California Independent System Operator, which manages most of the state’s grid, now has 16 gigawatts of batteries. Those batteries move abundant midday solar production into the evening, and can supply over one-quarter of the state’s electricity demand during part of the night.

The scale of that support marks a sharp change from a decade ago. In its best month then, also a sunny and mild May, solar supplied just 17 % of electricity. CAISO’s battery fleet was 61 megawatts, compared with today’s 16 gigawatts. Hungary reached 47 % in June 2025, according to Ember, but its economy is far smaller than California’s.

So what changes, concretely? California can use more of its daytime solar later in the day instead of relying as heavily on gas when the sun goes down. The state has already crossed the threshold once; Canary Media reports that more months above 50 % are expected, followed in coming years by more states and countries.