Research — Dec. 2, 2025
US solar shines in October; winds calm
The US experienced above-average solar insolation at 4.1% in October and 1.4% year to date. Wind speeds were calm, 1.1% below average in October and 1.3% low year to date. The total operating capacity for wind energy in the US has reached 158.0 GW, while the solar operating capacity is not far behind, at 150.5 GW.
Wind
Texas, home of the largest state wind capacity of 44,042 MW, had calm winds in October, at 4.9% below average. North Carolina winds were strong, with a remarkable monthly positive deviation of 21.8% on 397-MW capacity. Michigan had a negative deviation of 10.5% on its 3,806-MW capacity. In year-to-date deviations, Utah reported a positive deviation of 5.7% on a capacity of 390 MW. In contrast, Hawaii struggled with a year-to-date negative deviation of 9.3% on its 226-MW capacity.
Among projects, the Great Prairie Wind Project in Texas remains the largest, boasting a 1,027-MW capacity, though it reported a modest monthly increase of 0.8% and a year-to-date decrease of 0.8%. North Carolina currently reports two operating wind projects — Timbermill Wind Farm and Amazon Wind Farm US East (Desert Wind Power) — both with monthly positive deviations of 21.8%. Conversely, the San Roman Wind Project in Texas had challenges, recording a significant monthly drop of 14.9%.
Solar
Texas once again led, boasting an impressive solar capacity of 32,644 MW and a monthly deviation of 7.6%. New York basked in the sun with a remarkable monthly positive deviation of 21.8% on a capacity of 2,956 MW. However, South Carolina experienced a drop in monthly deviation of 6.6% on its 1,740-MW capacity. Iowa emerged as a year-to-date leader in solar radiation, achieving a positive deviation of 3.3% with a capacity of 683 MW. Meanwhile, South Dakota reported a negative year-to-date deviation of 1.7% on its 209-MW capacity.
The Gemini Solar Project in Nevada remains the largest solar plant, with a capacity of 690 MW and a monthly deviation of 1.2%. Meanwhile, the GSPP 7024 Fox Road Solar Project in New York achieved an impressive monthly deviation of 29.9%, while the Kotzebue Solar Plant in Alaska faced difficulties, recording a substantial monthly drop of 21.2%.
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 October 2025 values with the 20-year average (2004–2023) for October.
Data visualization by Cat VanVliet.
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