In a significant shift in California’s power mix, utility-scale solar generation in the California Independent System Operator (CAISO) area surpassed natural gas generation in the first five months of 2026, according to data from the U.S. Energy Information Administration (EIA) Hourly Electric Grid Monitor.
Solar generation in CAISO rose 21% compared to the same period in 2024, while natural gas generation declined sharply by 60%, marking a structural transition in the region’s electricity landscape.
During January–May 2026, solar generated more electricity than natural gas on 82% of days, a substantial increase from just 21% of days in 2024 and 2025.
The shift has been supported by rapid expansion in clean energy infrastructure. Between April 2024 and April 2026, utility-scale solar capacity in CAISO increased 19% to 25 GW, while net battery storage capacity surged 79% to 16 GW. In contrast, natural gas capacity remained largely stable at 29 GW, with overall system capacity rising 14% during the period.
Battery storage, increasingly co-located with solar assets, has played a critical balancing role—charging during midday solar peaks and discharging during evening and early morning demand hours. As a result, battery discharge volumes tripled compared to the same period in 2024.
Despite growing solar and storage output and a 7% rise in electricity demand, net generation in CAISO fell 19%. This was largely due to a doubling of electricity imports from neighboring regions, driven by lower-cost external supply. Hydropower imports from the Pacific Northwest also increased following improved drought conditions, while imports from the new SunZia wind project in New Mexico began in April 2026.
Grid adjustments were further influenced by generator retirements totaling 555 MW between May 2024 and May 2025, including a 300 MW battery facility that was taken offline following a fire incident in January 2025.
The data highlights a rapidly evolving grid structure in California, where solar, storage, and cross-border imports are increasingly reshaping the role of natural gas in electricity generation.
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