California’s power markets are moving away from natural gas as growing solar and battery deployment reshape the state’s dispatch stack. While the transition is most visible during the summer months, winter operations reveal a more complex challenge maintaining reliability when renewable generation is less available.
Winter dispatch data shows California’s solar and battery fleet expanded significantly between the 2023-24 and 2025-26 seasons. Peak solar generation increased from roughly 10 GW to nearly 14 GW, while battery discharge capacity doubled from ~3 GW to more than 6 GW during evening periods, when power demand usually peaks. The additional renewable and storage capacity has reduced the amount of gas-fired generation needed during many hours of the day and shifted a portion of the evening ramp away from thermal resources.
The trend is clear: During the 2023-24 winter, gas-fired generation typically ranged from roughly 7 GW during daylight hours to as much as 12 GW during evening and overnight periods (see figure above). By the 2025-26 winter, those levels had declined to ~4 GW and 6 GW, respectively. California’s dispatch stack increasingly relies on solar generation during daylight hours and battery storage during the initial evening transition, reducing the operational role of gas-fired generation across the system.
However, winter conditions are exposing the limits of renewable availability. The shorter daylight hours reduce both solar generation and the amount of excess energy available to charge batteries. Even with growing renewable penetration, gas-fired generation remains critical to support grid reliability during evening and overnight periods when renewable output declines.
Imports are also playing an increasingly important role in California’s winter power balance. Dispatch patterns show daytime imports increasing from ~600 MW in the 2023-24 winter to nearly 4 GW in the 2025-26 season, while overnight and evening imports rose from ~4 GW to nearly 8 GW. The increased imports coincide with declining in-state gas utilization, and growing reliance on external power supplies during periods when renewable output is limited. While imported electricity comes from a diverse mix of resources across the Western Interconnection connecting the Pacific Coast to the Rocky Mountains, a large share ultimately is generated from thermal sources like natural gas.
Importantly, the 2025-26 winter was relatively mild across much of the western US. The dispatch patterns observed in the latest winter don’t fully reflect conditions during a colder-than-normal season. A strong cold-weather event would increase electricity demand while potentially limiting renewable availability during critical reliability periods, increasing reliance on both gas-fired generation and imported power.
The state’s long-term outlook reinforces this dynamic. Energy Information Administration (EIA) data shows more than 10 GW of planned battery storage additions and nearly 8 GW of planned solar capacity through 2031, while planned gas-fired additions are minimal. However, only about 3.3 GW of California’s roughly 40 GW gas-fired fleet is scheduled to retire by 2030, suggesting much of the existing fleet will remain available for reliability purposes during the transition.
The larger question is how the system responds when weather conditions are less favorable. As renewable penetration rises, gas-fired generation declines and electricity demand continues to grow, winter reliability may increasingly depend on a combination of remaining gas plants and imported power supplies from across the West. In that scenario, California may reduce in-state gas consumption while remaining dependent on gas-fired generation elsewhere in the Western power market.
See East Daley Analytics’ West Coast Supply and Demand report for more information on the California gas market outlook. – Kritika Gaikwad.
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