Solar tops natural gas in CAISO as batteries reshape grid
Solar passed natural gas in CAISO for the first time in January-May, as battery storage and imports cut gas generation 60% from 2024.
The U.S. Energy Information Administration on June 16 said utility-scale solar generation in CAISO surpassed natural gas in the first five months of 2026. Solar output rose 21% from the same period in 2024, while natural gas generation fell 60%.
Solar also outpaced gas on 82% of days in January through May, a break with the 2024 and 2025 pattern, when solar beat gas on only 21% of days. EIA said utility-scale solar capacity in CAISO rose 19% from April 2024 to April 2026 to 25 gigawatts, net battery storage capacity climbed 79% to 16 gigawatts, and natural gas capacity stayed near 29 gigawatts.
Battery storage was central to the shift. EIA said discharge from CAISO batteries tripled in the first five months of 2026 from the same period in 2024, helping move midday solar into evening and early-morning hours when generation drops. Even with stronger solar and storage output and a 7% rise in demand, CAISO net generation fell 19% as electricity imports doubled.
Those imports came from cheaper power available outside the grid. Hydroelectric flows from the Pacific Northwest increased as drought conditions eased, and CAISO began importing from the SunZia wind project in New Mexico in April 2026. CAISO’s own 2026 summer loads and resources assessment said the system had enough resources to cover a wide range of conditions, including those new imports.
The gas retreat came alongside retirements. Between May 2024 and May 2025, CAISO lost 555 megawatts of generation, including a 300 megawatt battery installation that caught fire in January 2025. EIA also said CAISO curtailed 3.4 million megawatthours of utility-scale wind and solar in 2024, up 29% from 2023, with solar accounting for 93% of curtailed energy as the grid still had to manage spring oversupply and hold gas online for reliability and evening ramps.
IEEFA separately said natural gas’ share of CAISO generation fell to 3.1% on May 16, 2026, and stayed below 10% from May 13 through May 17. The spring pattern shows where the grid is headed: more solar, more batteries, more imports, and less room for gas in the middle of the power stack.
This article was produced by Prism’s automated news system from verified source data, official records, and press releases, then run through automated quality and moderation checks before publishing. The system is built and supervised by the people who set the standards it runs under. Read our full AI policy.
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