In the first five months of 2026, utility-scale solar generation in California’s grid surpassed natural gas output on 82% of days—up sharply from just 21% in both 2024 and 2025, according to data from the U.S. Energy Information Administration. Over the same period, solar generation climbed 21% compared with early 2024, while natural gas generation fell 60%.
Solar overtakes natural gas in CAISO through May 2026
The scale of the shift is hard to ignore. From January through May 2026, utility-scale solar generation in the California Independent System Operator (CAISO) outpaced natural gas on 124 of 151 days. Solar output rose 21% compared with the same five months in 2024, while natural gas generation dropped 60%. The figures come from the EIA’s Hourly Electric Grid Monitor, which tracks generation across U.S. grid regions in near real time.
A 60% decline in natural gas generation is not a routine fluctuation. It reflects a fundamental reordering of how California’s grid meets daily electricity demand—driven by new capacity additions, shifting economics, and changes in regional power supply.
Capacity growth in solar and battery storage drove the shift
The generation numbers follow directly from capacity. Between April 2024 and April 2026, utility-scale solar capacity in CAISO grew 19%, reaching 25 GW, while net battery storage capacity expanded even faster—rising 79% to 16 GW over that same two-year window. Natural gas capacity held nearly flat at 29 GW.
Total net grid capacity in CAISO increased 14%, or about 11 GW, over those two years. That growth came almost entirely from solar and storage additions. The result is a grid where clean generation resources now hold a structural advantage during midday hours — and, increasingly, well beyond them.
Battery storage and electricity imports offset evening and overnight gaps
Solar has a well-known constraint: it stops producing at sundown. Battery storage is the primary tool California has deployed to bridge that gap. In the first five months of 2026, battery discharge tripled compared with the same period in 2024. Batteries charge during midday hours when solar output exceeds grid needs, then release that energy in the evening and early morning.
Electricity imports played an equally important role — arguably just as consequential as storage growth. Imports into CAISO doubled during the first five months of 2026, contributing to a 19% decrease in net in-state generation even as demand rose 7%. Cheaper power flowing in from neighboring systems reduced the need to run local natural gas plants.
Two import sources stand out. Hydroelectric power from the Pacific Northwest increased as drought conditions in that region eased, freeing up more water-based generation for export. CAISO also began importing wind energy from the new SunZia wind project in New Mexico starting in April 2026 during its testing phase, ahead of its full commercial operations launch in June 2026.
Context: prior share of solar dominance and recent generator retirements
The jump from 21% to 82% solar dominance did not happen gradually. In both 2024 and 2025, solar exceeded natural gas output on only about one in five days in CAISO. The leap in 2026 reflects capacity additions reaching a tipping point, with favorable import conditions arriving at the same time.
Capacity availability was also affected by notable outages. A major 300 MW building at the Moss Landing battery storage facility caught fire in January 2025 and has remained offline since, though overall grid battery capacity still grew substantially due to other new projects coming online.
The broader economics shifted as well. Relatively inexpensive electricity became available from the Pacific Northwest and from new wind resources in the Southwest, which eroded the cost advantage of running local natural gas plants. Grid operators have financial incentives to import cheaper power when it is available, and in 2026, it was available far more often.
Electricity imports doubled
Solar generation in CAISO surpassed natural gas output on 82% of days in the first five months of 2026, compared with just 21% in each of the two prior years. That shift reflects a 19% increase in solar capacity, a 79% increase in battery storage capacity, and a doubling of electricity imports—including hydroelectric power from the Pacific Northwest and wind from the new SunZia project. Natural gas capacity stayed nearly flat, but its generation fell 60% as cheaper alternatives displaced it. Taken together, these trends suggest California’s grid has crossed a meaningful threshold in how it balances daily electricity supply.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.
