Fossil fuel's share of available US electric power generating capacity has continued to shrink this year as generators brought more less carbon-intensive power sources on line at increased pace, government data show.

The US had 185,874MW of operating nameplate coal generating capacity at the end of August, down from 191,308MW a year earlier, US Energy Information Administration (EIA) generator inventory data show. Another 29.2MW of capacity was available on standby, down from 36.7MW a year earlier.

The available coal capacity decreased even as coal-fired generation climbed. Coal power outpaced 2024 levels each month through at least July, the latest EIA data show. US generators dispatched 433.8mn MWh in the first seven months of the year, up from 374.5mn MWh in the same period last year. August data are not yet available.

The capacity factor for utility-scale coal plants averaged 49pc in January-July, compared with just under 42pc a year earlier.

While some utilities have delayed planned coal power plant retirements because of reliability concerns or — in the case of Consumers Energy's JH Campbell coal plant in Michigan — a federal emergency order, others have not. Eight coal plant units were retired between September 2024 and March 2025, and another 12 units were scheduled to be decommissioned in the final months of this year, EIA data show.

Arizona, Missouri, Texas, Wisconsin and Wyoming were among the 10 states that had less coal generating capacity operating at the end of August than a year earlier. And Delaware's coal capacity dropped to zero following the January retirement of NRG's Indian River Unit 4.

Only North and South Carolina had higher nameplate coal capacity at the end of August than a year earlier, with 23pc and 1.5pc increases, respectively.

Overall US power generating capacity increased by 50,302MW to 1,338,716MW in August from a year earlier. That 3.9pc gain in overall available capacity helped generators meet increased power demand, including from new businesses and population growth. The pace of expansion was higher than the 2.8pc increase to August 2024 from a year earlier.

The US had 5,837MW more available nameplate natural gas capacity operating in August than it had a year earlier, EIA estimates show. This included former coal units that had been converted to run on natural gas. Overall operating nameplate gas capacity totaled 564,722MW at the end of last month.

Gas capacity increased in 25 states and fell or remained unchanged in 24 others. Gas-fired nameplate capacity tripled in Wyoming. Arizona, Indiana, Nebraska, North Dakota and Wisconsin were the other states that posted the most significant increases.

North Carolina and Oklahoma were among the states that shed the most gas-fired generation.

The most significant capacity additions on a percentage basis still came from renewable generation.Operating solar capacity rose by 30pc to 139,943MW in August while nameplate wind capacity rose by 3.5pc to 156,483MW the same month from a year prior.

Installed solar capacity climbed to 10.5pc of available US generating capacity in August from 8.4pc a year earlier. Wind accounted for 11.8pc of operating nameplate capacity, unchanged from August 2024. Coal's share of overall operating US nameplate capacity fell by 1 percentage point to 14pc. Gas' share declined to 42.5pc from 43.7pc a year earlier.

All these changes reflect a systemic shift in US energy markets, driven by federal regulations and increasing demand for more efficient power generation with lower carbon emission. This is also the result of concerns US utilities have about their operational and financial risks.

EIA expects coal-fired generation to resume declines in 2026, while natural gas and renewable generating power will increase.