Wind gusts, sunshine gains: US' clean energy finish to 2025

December ended 2025 with a mixed performance across the US' renewable landscape: wind power rose late in the season, while solar continued its steady growth. Nationally, wind speeds were 3.7% above seasonal norms across 159,398 MW of tracked operating capacity, although the annual average was slightly below normal at -1.2%. Solar radiation was 3.5% above normal in December and ended the year with a 1.6% increase in its annual average across 156,290 MW of operating capacity.

Wind

Texas led the country in wind power with 44,800 MW of operating capacity. Wind speeds in Texas moderated in December, with a monthly deviation of -2.1% and a year-to-date average of -1.0%. Washington recorded the highest wind speeds in December, surging 30.9% above normal across 3,375 MW of operating capacity, highlighting the impact of winter storm tracks in the Pacific Northwest. Hawaii experienced the lowest wind speeds, with a December deviation of -21.8% and the largest negative annual deviation in the country at -10.1% on 226 MW of operating capacity. In contrast, New York was the year's wind power bright spot, ending 2025 with a 5.0% deviation on 2,914 MW of operating capacity.

Individual wind projects demonstrated the season's variability. In Texas, the Great Prairie Wind Project, the largest wind project in the US at 1,027.0 MW, recorded December wind speeds 4.2% below normal and a year-to-date decrease of 1.9%. Alaska's Fire Island Wind Project recorded wind speeds 47.0% above normal in December. California's Ocotillo Wind Energy Facility (Ocotillo Express) experienced the sharpest monthly decline at 37.1% on 265.4 MW, illustrating the volatility of complex terrain. For the year, New York's Zotos International WPGF recorded the highest annual deviation at 7.3% above normal on 3.4 MW, while Hawaii's Kahuku Wind Power Project had the largest annual decrease at 15.2% on 30.0 MW, reflecting the nation's climatic diversity.

Solar

Solar told a quieter story of consistency. Texas led in solar capacity with 34,856 MW, recording a December deviation of 3.7% above normal and ending the year up 2.2%. Maine was December's solar standout, with radiation 17.3% above normal across 954 MW. Washington recorded the lowest solar output in December, with a deviation of -9.0% on 267 MW, reflecting the impact of active winter storm tracks. Florida led the nation's solar performance for 2025, with a 3.5% year-to-date deviation on 12,181 MW. South Dakota recorded the lowest annual solar deviation at -1.8% on 209 MW.

Project-level results provided further context. Nevada's Gemini Solar Project had the largest capacity at 690.0 MW, with December output 1.0% above normal and a year-to-date gain of 0.4%. Alaska's Hawk Lane Solar Project (Houston Solar) recorded December output 23.8% above normal but ended the year with a 7.9% decrease on 6.0 MW. Oregon's Brightwood Solar Plant recorded the sharpest December decline at 17.3% on 10.0 MW, reflecting the region's reduced winter sunlight. In Maine, the Loki Machias (Dublin Street) Solar Plant ended the year at 6.2% above normal on 4.9 MW.

Solar radiation is the mean surface downward shortwave radiation flux, measured from the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis. This variable includes direct and diffuse solar radiation and is the model equivalent of global horizontal irradiance — the value measured by a pyranometer, a solar radiation measuring instrument. Wind speed is the value 100 meters above the ground from the same dataset. The data is available at quarter-degree latitudes and longitudes, with a spacing of slightly over 27.5 km. This analysis compares the December 2025 values with the 20-year average (2004–2023) for December.