Despite the Political Headwinds, Strong Growth by Solar, Wind, and Battery Storage Continues

A string of reports released in mid-autumn by the Federal Energy Regulatory Commission (FERC) and the U.S. Energy Information Administration (EIA) confirms that solar and wind as well as battery storage continue to dominate growth among competing energy sources as they add ever more generating capacity and increase their share of U.S. electrical generation.

Solar set new electrical generation records in August and the first two-thirds of 2025: EIA’s latest monthly “Electric Power Monthly” report (with data through August 31, 2025),1 once again confirms that solar is the fastest growing among the major sources of U.S. electricity.

In August alone, electrical generation by utility-scale solar (i.e., >1 megawatt (MW)) ballooned by almost one-third (29.5%) compared to August 2024 while “estimated” small-scale (e.g., rooftop) solar PV increased by 10.8%. Combined, they grew by 24.7% and provided nearly one-tenth (9.5%) of the nation’s electrical output during the month, up from 7.6% a year ago.

Moreover, during the first eight months of 2025, utility-scale solar thermal and photovoltaic expanded by 35.7% while that from small-scale systems rose by 11.0% compared to the same period in 2024. The combination of utility-scale and small-scale solar increased by almost a third (28.8%) and was over 8.9% (utility-scale: 6.7%; small-scale: 2.2%) of total U.S. electrical generation for January-August – up from 7.1% a year earlier.

As a consequence, solar-generated electricity year-to-date (YTD) easily surpassed – by over 58% – the output of the nation’s hydropower plants. In August alone, solar-generated electricity more than doubled the output of the nation’s hydropower plants. In fact, in both August and YTD, solar produced more electricity than hydropower, biomass, and geothermal combined.

In addition, for the second consecutive month, utility-scale solar generated more electricity than the nation’s wind farms – by 4% in July and by 15% in August. Including small-scale systems, solar out-produced wind four months in a row and by almost 50% during August.

Solar and wind are almost one-fifth of total U.S. electrical generation – a larger share than that provided by either coal or nuclear power: Wind turbines across the U.S. produced over a tenth (10.2%) of U.S. electricity in the first eight months of 2025 – an increase of 2.6% compared to the same period a year earlier and 80% more than that produced by the nation’s hydropower plants.

During the first eight months of 2025, electrical generation by wind plus utility-scale and small-scale solar provided almost a fifth (19.1%) of the U.S. total, up from 17.2% during the
first two-thirds of 2024.

Further, the combination of wind and solar provided 16.2% more electricity than did coal during the first eight months of this year, and 11.7% more than the nation’s nuclear power plants. In fact, as solar and wind expanded, nuclear-generated electricity dropped by 0.7%.

Electrical output YTD by the mix of all renewables was over 26% of total U.S. generation: The mix of all renewables (i.e., wind and solar plus hydropower, biomass and geothermal) produced 9.0% more electricity in January-August than they did a year ago and provided 26.1% of total U.S. electricity production compared to 24.5% twelve months earlier.

Renewables’ share of electrical generation is now second to only that of natural gas whose electrical output actually dropped by almost 4.1% during the first eight months of 2025.

Solar was two-thirds of new generating capacity in August and 73% year-to-date: In its latest monthly “Energy Infrastructure Update” report (with data through August 31, 2025),2 FERC says 48 “units” of solar totaling 2,702 MW were placed into service in August, accounting for two-thirds (66.4%) of all new generating capacity added during the month. That represents the second-largest monthly capacity increase by solar in 2025 – just behind January when 2,945 MW were added.

The 505 units of utility-scale solar added during the first eight months of 2025 total 19,093 MW and were almost three-quarters (73.4%) of the total new capacity placed into service by
all sources.

Solar has now been the largest source of new generating capacity added each month for two years straight: September 2023 – August 2025. During that period, total utility-scale solar capacity grew from 91.82 gigawatts (GW) to 156.20 GW. No other energy source added anything close to that amount of new capacity. Wind, for example, expanded by 11.16 GW while natural gas’ net increase was just 4.36 GW.

Including wind, renewables were 88.0% of new capacity: Between January and August, new wind accounted for 14.5% of all new capacity added and provided 3,775 MW of capacity additions. Thus, wind and solar each added more new capacity than did natural gas (3,095 MW).

Consequently, for the first eight months of 2025, the combination of solar and wind (plus 4 MW of hydropower and 3 MW of biomass) provided 88.0% of new capacity while natural gas was just 11.9%. The balance of net capacity additions came from oil (20 MW) and waste heat (17 MW).

Solar and wind are almost a quarter of U.S. utility-scale generating capacity; all renewables combined are over a third: FERC’s data reveal that utility-scale solar’s share of total installed capacity (11.6%) is now almost equal to that of wind (11.8%). If recent growth rates continue, utility-scale solar capacity will surpass that of wind before the end of 2025.

Taken together, wind and solar constitute nearly one-fourth (23.4%) of the U.S.’s total available installed utility-scale generating capacity.

Moreover, almost 29% of U.S. solar capacity is in the form of small-scale systems that are not reflected in FERC’s data. Including that additional solar capacity would bring the share provided by solar and wind to more than a quarter of the nation’s total.

With the inclusion of hydropower (7.6%), biomass (1.1%), and geothermal (0.3%), renewables currently claim a 32.4% share of total U.S. utility-scale generating capacity. If small-scale solar capacity is included, renewables are now more than one-third of total U.S. generating capacity.

EIA confirms that solar and battery storage have dominated capacity additions during the past year, coupled with a strong showing by wind: While not identical, EIA’s capacity data generally track those of FERC.

Between September 1, 2024 and August 31, 2025, utility-scale solar capacity grew by 31,707 MW, while an additional 5,718 MW was provided by small-scale solar. Wind also made a strong showing during the past twelve months, adding 4,792 MW.

Further, strong growth was experienced by battery storage which grew by 63.9% during the past year and added 13,378 MW of new capacity. Battery storage actually surpassed pumped hydro storage (PHS) in October 2024 and now accounts for 50% more storage capacity than PHS.

On the other hand, natural gas capacity increased by only 3,338MW and nuclear power added a mere 46 MW. Meanwhile, coal capacity plummeted by 4,185 MW and petroleum-based capacity fell by an additional 659 MW.

Thus, during the past year, renewable energy capacity, including battery storage and small-scale solar, ballooned by 55,420 MW while that of all fossil fuels and nuclear power combined actually declined by 1,486 MW.3

Solar is on track to become the second largest source of U.S. generating capacity: EIA foresees continued strong solar growth, with even more utility-scale solar capacity – 34,326 MW – being added in the 12 months ending in late summer 2026. EIA also notes that planned battery capacity additions during that time total 20,180 MW, while new wind capacity could add 9,650 MW. EIA’s latest “Short-Term Energy Outlook” report3 looks a bit further into the future. It expects utility-scale solar PV + thermal capacity to grow 22% between the end of 2025 and the beginning of 2027, reaching 182.9 GW, while small-scale solar increases almost 11% to 65.1 GW. During that time, wind capacity would expand over 6% to 169.9 GW as battery storage jumps from 45.7 GW to 65.2 GW.

Meanwhile, FERC offers a three-year outlook and says that net “high probability” additions of solar between September 2025 and August 2028 total 89,953 MW – an amount almost four times the forecast net “high probability” additions for wind (23,223 MW), the second fastest growing resource.

FERC also foresees net growth for hydropower (566 MW) and geothermal (92 MW), but a decrease of 126 MW in biomass capacity.

Meanwhile, natural gas capacity would expand by 8,481 MW and nuclear power would add just 335 MW, while coal and oil are projected to contract by 23,564 MW and 1,581 MW, respectively.

Taken together, the net new “high probability” capacity additions by all renewable energy sources over the next three years would total 113,708 MW. On the other hand, the installed capacity of fossil fuels and nuclear power combined would shrink by 16,329 MW.

Should FERC’s three-year forecast materialize, by early-fall 2028, utility-scale solar would account for 17.1% of installed U.S. generating capacity – more than any other source besides natural gas (40.0%). Further, the capacity of the mix of all utility-scale renewable energy sources would exceed 38%. Inclusion of small-scale solar – assuming it retains its 29% share of all solar – could push renewables’ share to over 41% while that of natural gas would drop to about 38%.

In sum, notwithstanding policy challenges created by the Trump Administration and the Republican-controlled Congress, EIA and FERC both foresee the transition to solar, wind, and other renewables as well as battery storage continuing and accelerating while coal, oil, natural gas, and nuclear all contract.

About the Author
Ken Bossong is the director of the SUN DAY Campaign, a non-profit research and educational organization founded in 1992 to support a rapid transition to 100% reliance on sustainable energy technologies as a cost-effective alternative to nuclear power and fossil fuels and as a solution to climate change.