Electricity generation from natural gas continues to fall in California as solar and battery output expand, according to new data from the U.S. Energy Information Administration’s Electric Power Monthly. Although natural gas remains the state’s single largest source of electricity, its generation has declined steadily in recent years while solar has grown.
From January through August 2025, California generated 140.9 billion kilowatthours of electricity, up 8 percent from the same period in 2020. Most of that growth came from utility-scale solar. Solar output totaled 40.3 BkWh in the first eight months of 2025, nearly double the 22 BkWh produced in 2020, EIA reported. Solar generation increased 17 percent, or 5.9 BkWh, compared with the same period in 2024.
Natural gas followed the opposite trajectory. Gas-fired generation totaled 45.5 BkWh between January and August 2025, down 18 percent from 2020. The largest year-over-year decline occurred this year, when natural gas output fell 9.5 BkWh, or 17 percent, from 2024. Gas use has fluctuated with hydrologic conditions—spiking in 2021, for example, when drought pushed hydroelectric output down to 10.3 BkWh and gas generation up to 63.5 BkWh.
Hourly data from the California Independent System Operator show how the shift plays out during daily peaks. Midday solar output between noon and 5 p.m. in May and June increased from 10.2 gigawatts in 2020 to 18.8 GW in 2025, effectively reducing the need for gas-fired units during those hours. EIA noted that CAISO changed its natural gas reporting method in late 2023, making earlier hourly data not directly comparable.
Battery storage is also reshaping evening operations. During the 5 p.m. to 9 p.m. peak, batteries discharged an average of 4.9 GW in May and June 2025, up from less than 1 GW in 2022. Much of that energy was stored from excess midday solar production, further displacing natural gas during the hours when it has traditionally been most relied upon.
The combined impact of rising solar output and growing battery deployment is narrowing the role of natural gas in California’s daily dispatch stack, even as it remains an important balancing resource in low-water years or during periods of high demand.
