Solar power played a central role in meeting the rapid increase in electricity demand in the United States in 2025, covering 61% of total demand growth, according to a new analysis by Ember based on year-end data from the US Energy Information Administration (EIA).

The report shows that solar generation rose by a record 83 TWh in 2025, a year-on-year increase of 27%, as total US electricity demand grew by 135 TWh, or 3.1%. This marked the fourth-highest annual demand growth rate of the past decade.

Solar growth concentrated where demand rose most

Solar generation expanded most strongly in regions that also experienced the largest increases in electricity demand. Texas recorded the biggest rise in utility-scale solar generation of any US region, with solar meeting 81% of the increase in electricity demand. The Midwest also saw solar cover 81% of demand growth, while in the Mid-Atlantic region — which registered the largest absolute increase in grid demand — solar met 33% of the rise.

In Florida, solar growth exceeded demand growth by a wide margin, contributing to a reduction in fossil fuel generation. In the Southwest, Northwest, Southeast and California, solar generation met about all of the increase in electricity demand.

Overall, the report finds that the majority of new solar generation across the US occurred where electricity demand was rising, meaning that most solar growth in 2025 went towards meeting new demand rather than displacing existing generation.

Meeting daytime demand — and increasingly evening demand

At an hourly level, solar played a decisive role during the daytime. In aggregate, the increase in solar generation in 2025 met all of the rise in US electricity demand between 10:00 and 18:00 ET. Supported by the rapid expansion of battery storage, solar also met part of the increase in electricity demand during evening hours, from 18:00 to 02:00 ET.

The remaining growth in electricity demand overnight, and part of the evening increase, was met primarily by higher coal and gas generation.

According to Ember, the expansion of batteries is transforming solar in the US from a source of cheap daytime electricity into dispatchable, all-day power. Over the past six years, California’s utility-scale solar and battery generation has increased by 58%, while generation at the sunniest hour of the day has risen by just 8%, indicating a growing shift of solar output into later hours.

Solar generation up, capacity growth slows

Despite the record increase in solar generation, provisional data suggests that US utility-scale solar capacity additions in 2025 were around 6% lower than in 2024. The report attributes this slowdown partly to project delays caused by uncertainty over changing tariffs on imported solar panels, as well as continued delays in grid connection approvals, even as electricity demand accelerates.

Utility-scale solar remained the dominant driver of growth in 2025, reinforced by changes to net metering rules in California, the largest residential solar market in the US. Battery installations followed a different trajectory, with battery capacity additions surging by 133% to reach 26 GW during the year.

Solar penetration still uneven across states

While solar’s share of electricity generation has risen rapidly in some states, the national picture remains uneven. California and Nevada recorded the highest solar shares, at 37% and 34% respectively. However, 37 US states generated less than 10% of their electricity from solar over the past 12 months.

Six states increased solar’s share of electricity generation by more than five percentage points in the 24 months to October 2025. New Mexico was the fastest-growing, with solar’s share rising from 7% to 17%.

Despite the expansion of solar and batteries, Ember notes that there is still no “duck curve” at the national level. Even during the sunniest hour of the day, solar provided an average of just 20% of US electricity generation across the year, and non-solar generation requirements during the daytime remain higher than overnight.

Strong potential for further growth

According to Ember, solar’s role in meeting rising electricity demand is only beginning. Solar growth already met 61% of electricity demand growth in 2025, and the report concludes there is no structural barrier preventing solar from meeting 100% of future demand growth.

“With electricity demand surging, the case to build solar has never been stronger,” said Dave Jones, Chief Analyst at Ember. Solar, supported by batteries, has demonstrated its ability to generate electricity where it is needed and increasingly when it is needed, while also offering significant potential to reduce coal and gas use rapidly and economically.