Electricity generated by utility-scale solar installations in the region overseen by the California Independent System Operator (CAISO) surpassed natural gas generation in the first five months of 2026, as reported by the U.S. Energy Information Administration (EIA)
The region, which encompasses nearly all of the state of California save for parts in the far north and far southeast of the state, has seen a 60% decrease in energy produced by natural gas generators — coupled with a 21% increase in solar generation — compared to 2024.
When considering total daily generation by source in CAISO, utility-scale solar generated more electricity than natural gas on 82% of days in the first five months of 2026.
Gas generation capacity (i.e. nameplate rated power output) in the region has remained steady at 29 GW in recent years, but the utilization of that capacity has decreased as utility-scale solar and battery storage capacity has grown.
Between April 2024 and April 2026, CAISO solar capacity increased by 19% to 25 gigawatts (GW), and battery storage capacity increased by 79%, or 16 GW.
On an average day in the first 5 months of 2026, batteries charge up with a massive amount of solar energy between the hours of 8 am and 5 pm, with the average daily peak charging rate reaching approximately 8 GW, a significant increase over just two years ago.
The state has also become a net importer of electricity during all hours of the average day, with the vast majority of that imported energy coming from wind, nuclear, and solar projects in nearby states.
100% renewables a near-daily occurrence
The combined renewable sources of wind, hydroelectric, and solar are regularly meeting 100% of the needs of the California grid for part of each day.
According to Mark Jacobson, a Stanford University professor who tracks the amount of energy delivered to the CAISO grid by renewable sources, as of June 17 (the 168th day of 2026), these sources had served 100% of total demand on the grid during at least part of the day on 143 days. The sources also set a record of 29.5 GW of combined peak output on that day.
According to the latest edition of the EIA’s Electric Power Monthly, large-scale renewable project developers in the state plan to add nearly 10.5 GW of new battery energy storage capacity and 8.3 GW of new utility-scale solar capacity in the coming years.
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