Thanks to generating more nuclear power than any other state, Illinois ranks third nationally in producing carbon-free electricity, according to analysis by Inside Climate News of data from the Energy Information Administration.

The national leader in carbon-free electricity is Texas, which has a huge lead in renewable energy, followed by California. Pennsylvania, which is second in nuclear generation, also ranks high for production of carbon-free electricity.

One of the challenges in understanding the U.S. energy transition is that the circumstances are different in every state. Some, such as Vermont, have progressed far away from fossil fuels, while others, such as Kentucky and West Virginia, might as well be decades in the past.

In 2024, utility-scale solar and wind were up nationwide, while coal was down and other major sources had little change, according to the Energy Information Administration data.

Fossil fuels

Texas leads the country in electricity generation from fossil fuels, with no other state evens close. The state ranks No.1 on natural gas and coal and also generates some electricity from burning petroleum liquids. The total from the three fuels in 2024 was 356,144 gigawatt-hours.

The rest of the top 10 states for fossil-fuel generation are mainly in the South (Alabama, Florida, Georgia and Louisiana) or Midwest (Indiana, Michigan and Ohio). The two others are Pennsylvania, which sits on the Marcellus Shale, the country’s largest gas field, and California, which, despite having policies that embrace renewable energy, still depends a lot on natural gas.

Kentucky and West Virginia, both which have a legacy of coal mining, rely most heavily on fossil fuels, getting more than 90% of their electricity from burning coal, gas and petroleum liquids.

The third member of this 90% club is Delaware, which has state policies calling for a shift to net-zero emissions but still generates most of its power by burning gas.

Hawaii and Alaska stand out because of their reliance on burning petroleum liquids. Hawaii has state policies to move to renewable electricity, while Alaska shows little desire to make changes.

Electricity from renewable energy

Hydropower is generated by the flow of water through a turbine at a dam, and it is second only to wind among the leading sources of renewable energy. The other producers of renewable energy are mostly wind and utility-scale solar, with small amounts of geothermal and biomass.

Texas leads in renewable energy despite having almost no hydropower. The state ranks No. 1 in wind-energy generation and is a close second to California in utility-scale solar.

No state comes close to Washington in hydropower. Its 60,456 gigawatt-hours of hydropower last year were about double the runner-up, California.

Vermont has the highest share of electricity generation (60%) from hydropower, a fraction of a percentage point more than Washington. Next is Idaho, at 45%.

The main benefit of hydropower for the grid is its steadiness, with an ability to run around the clock. But it is vulnerable to drought and other factors that can reduce water flows, leading to small variations in electricity output.

Looking at the top 10 states in renewable energy, seven are leaders in wind power and located in a cluster of wind-rich states from Iowa to Texas. Two states — Washington and New York — get most of their renewable electricity from hydropower. California gets most of its renewable electricity from solar.

Nuclear power

While nuclear power isn’t renewable, governments and the energy industry usually describe it as “carbon-free” because it doesn’t release carbon when producing electricity. But keep in mind that all forms of electricity have at least some emissions when viewed on a lifecycle basis, which includes the energy used to make the components and continues until disposal at the end of life.

The national leader in carbon-free electricity should be no surprise: Texas, thanks to a huge lead in renewables, followed by California.

Illinois ranks third, thanks to generating more electricity from nuclear than any other state, followed by Pennsylvania, which ranks second in nuclear generation. New Hampshire gets the highest share of its electricity from nuclear, 56%, followed by South Carolina, 54%, and Illinois, 53%.

Differences among states are tied to variations in natural resources, policies and investment decisions.

President Donald Trump’s administration is taking actions to increase the use of fossil fuels and nuclear and has shown hostility toward renewables. But states have tremendous leeway to chart their own courses.

For example, decades of federal policies to subsidize renewable energy have resulted in little development in West Virginia. And you’d be wrong to bet that fossil fuels are about to make a comeback in Vermont.

But there are areas of policy in which the federal government can slow down the energy transition, such as Trump’s executive order halting offshore wind permits.