As the autumn winds began to blow, they were calmer than usual, while sunshine across the US exceeded the norm, according to the latest data from September 2025. Total US wind energy capacity reached 157.4 GW on a notable monthly wind speed decline of 11.3%. In contrast, solar radiation saw a modest increase of 2.3% across a total solar capacity of 146.7 GW.

Wind

In the realm of wind energy, Texas continues to boast the highest operating capacity, coming in at 43,877 MW. However, the Lone Star State is not immune to the calm winds, reporting a monthly deviation of negative 5.5% and a year-to-date deviation of negative 0.1% in September.

Download data details in Excel.

On a stronger note, North Carolina emerged as the standout performer in September, showcasing a positive monthly deviation of 10.4%, with a capacity of 397 MW. Meanwhile, Missouri faced challenges, recording the largest negative monthly deviation of 23.1% across its substantial 2,416-MW capacity.

Utah reported the highest year-to-date wind speed deviation of 6.1%, with a capacity of 390 MW, while Hawaii struggled with a year-to-date decline of 10.1% on its 226-MW capacity.

Among wind projects, the Great Prairie Wind Project in Texas remains the heavyweight champion, with a capacity of 1,027 MW, reporting a negative monthly wind speed deviation of 7.1%. In Alaska, the Fire Island Wind Project was bucking the trend with a positive monthly deviation of 10.8% from its 18-MW capacity. Conversely, Missouri's North Fork Ridge Wind Farm reported a staggering negative 30.0% monthly deviation from its 145.5-MW capacity.

Solar

Turning to solar energy, Texas again led the charge with 32,057 MW of operating capacity and a healthy monthly solar radiation deviation of 5.7%. Indiana made waves in September, achieving an impressive 14.7% positive monthly deviation from its 3,431-MW capacity, while California faced challenges with a negative deviation of 6.2% from its substantial 23,752-MW capacity.

Florida shone brightly for year-to-date performance, recording a 2.6% increase with a capacity of 11,880 MW. In contrast, South Dakota lagged with a year-to-date decline of 2.3% from its 209-MW capacity.

The Gemini Solar Project in Nevada, with a capacity of 690 MW, led the pack in solar capacity but saw solar radiation decline 5.4% for the month. Hardin County, Ohio, emerged as a beacon of positivity, reporting an 18.0% monthly deviation from its 557.2-MW capacity of four projects: Hardin I Solar Energy Center Facility, Hardin Solar II Energy Center Facility, Hardin Solar III Energy Center, and Ohio Northern University Solar Site. On the flip side, the Hawk Lane Solar Project (Houston Solar) in Alaska struggled, with a negative 14.6% monthly deviation from its 6-MW capacity.

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 September 2025 values with the 20-year average (2004–2023) for September.

Data visualization by Cat VanVliet.

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Regulatory Research Associates is a group within S&P Global Commodity Insights.

S&P Global Commodity Insights produces content for distribution on S&P Capital IQ Pro.

This article was published by S&P Global Market Intelligence and not by S&P Global Ratings, which is a separately managed division of S&P Global.

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European Energy sells 50% stake in solar, battery project in Latvia

Selene Balasta•Commodity Insights

Friday, October 24, 2025 11:17 AM ET

Renewable energy developer European Energy A/S has agreed to sell a 50% stake in its 111-MW Saldus solar and battery project in Latvia to Danish pension fund Sampension Livsforsikring A/S.

The project combines a 65-MW solar farm with a 46-MW battery energy storage system, European Energy said in an Oct. 23 news release. Financial terms of the deal were not disclosed.

Construction of the project started in July, with completion expected in May 2026. Once operational, the project will deliver renewable electricity to the Latvian grid.

The two companies previously partnered when European Energy sold Sampension a 50% stake in the 148-MW Ventspils solar park in Latvia.

European Energy has more than 1 GW of development projects in Latvia, including onshore wind, solar and battery storage.

Latvia is aiming to source 57% of its electricity consumption from renewable sources by 2030, according to the International Energy Agency.

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Data visualization by Zain Ullah.
This article was published by S&P Global Market Intelligence and not by S&P Global Ratings, which is a separately managed division of S&P Global.
Regulatory Research Associates is a group within S&P Global Commodity Insights.
S&P Global Commodity Insights produces content for distribution on S&P Capital IQ Pro.
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