In numbers: Solar and batteries are quickly displacing gas in California’s power grid

Gas-fired power plants are being squeezed out of California’s electricity mix amid an ongoing surge in solar and battery installations, new data shows.

In the first seven weeks of 2025, gas covered 29% of the state’s power needs, down from 41% in the same period a year before, according to data collated by Stanford University Professor Mark Z. Jacobson.

Conversely, solar’s share rose 4 percentage points to 18%, despite the beginning of the year being the worst time for the technology given that days are shorter and the sun is lower in the sky.

Meanwhile, big batteries advanced 2 percentage points to 5% of the mix. While that’s still a relatively small share of the total, batteries are playing an increasingly significant role during evening peak hours when the sun has set and electricity demand spikes.

That’s traditionally when gas plants do the heavy lifting, but batteries are proving more economical as they can charge up on low-cost solar and then undercut their fossil-fired counterparts during peak periods. California has 13.4GW of battery storage capacity, as of October 2024.

Separate data collated by research group Ember shows that solar will soon overtake gas as California’s largest source of power, based on recent growth rates.

In the first 11 months of 2024, gas’ share of state-wide electricity generation dipped to 34.4% (from 38.5% in calendar year 2023 and 57.1% as recently as 2015), while solar climbed to 32.7% (from 28.1% in 2023). All renewables and nuclear accounted for 65.3% of total output.

Yes, but: Partly due to the glut of solar energy during the middle of the day, lawmakers in California are scaling back incentives for rooftop installations. That could slow the growth of an industry that’s rapidly transformed the state’s power system.