Just look at the spectrum of blues in the map above. It charts the carbon intensity of power generated in each state in 2024, according to federal data compiled by U.S. Energy Data, a new project from the think tank Institute for Progress. Carbon intensity is the amount of planet-warming carbon pollution emitted per megawatt-hour of electricity generated.
The states with the highest carbon intensity burn a lot of fossil fuels, especially the really dirty kinds like coal and petroleum. In the three states with the dirtiest electricity generation — West Virginia, Kentucky, and Wyoming — most power is created by burning coal, which makes sense considering they are among the top coal-producing states.
States with the lowest carbon intensity, of course, are home to a larger share of clean energy, ranging from wind and solar farms to hydroelectric facilities to nuclear plants. Vermont has the cleanest in-state generation, with essentially 100% of the power it creates coming from renewables — largely hydropower — since 2015.
It’s important to note that the above map represents the power generated in a state — not necessarily the power consumed there. Wyoming, for example, generates about 12 times more power than it consumes. Electricity flows all over the place via sweeping interregional transmission lines — so even a state with a high share of clean power generation could have a dirtier grid than meets the eye.
The good news is that America’s grid as a whole has been getting cleaner over the last two decades. Greenhouse gas emissions from the U.S. power sector fell about 40% between 2005 and 2024 as old coal plants shuttered and were replaced with cheaper natural gas–fired facilities and renewable energy. Generation in all states except Idaho and Vermont got less carbon-intensive over that period of time.
Lots of states want to continue the progress, and many are going so far as to aim for completely clean grids by midcentury. It won’t be easy, as data centers’ energy demand drives a gas power boom and the Trump administration attacks renewables while propping up the coal industry. With the White House stripping the federal climate policies put in place by previous administrations, the onus is increasingly shifting onto states to keep up the pace of the clean energy transition.
