The U.S. Grid Got Dirtier in 2024 — What the New Emissions Data Means for Your State and Your Charge

For most of the last 25 years, American electricity told a quiet success story: cleaner every single year. Between 2000 and 2024 the power sector cut sulfur dioxide by 94%, nitrogen oxides by 86%, and carbon dioxide by 38% — all while the economy grew 66% and renewable generation climbed nearly 200%. That's the rare environmental win where the line only points one direction.

Then 2024 broke the streak.

According to the December 2025 Benchmarking Air Emissions report from ERM, NRDC, and Constellation — which tracks the 100 largest U.S. power producers using federal EIA and EPA data — power-sector CO₂ and NOx emissions both ticked back up from 2023 to 2024. It's the first reversal in years, and 2024 carbon emissions ended only about 1% below 2020 levels.

If you ride electric — a scooter, an e-bike, an EV — this matters more than it looks. The grid is the real fuel behind your Zero-emission ride. So it's worth understanding what changed, and why the popular shortcut for judging a clean grid — your state's ranking — can quietly mislead you.

What pushed the grid backward

The culprit isn't coal making a comeback — it's the opposite. Coal generation fell 27% from 2021 to 2024 alone, and coal plants now run less than half the time (capacity factor down from 73% in 2008 to 43% in 2024). Most U.S. coal capacity dates to the 1970s and 80s, and it's aging out fast.

The problem is what replaced it. Natural gas hit an all-time generation high in 2024, up 18% since 2021, and now produces three times as much electricity as coal. Because gas grew faster than coal declined, total fossil generation actually rose about 2% over 2021–2024. Surging demand — data centers, electrification, a hotter grid — got met largely by burning more gas. Cleaner than coal, yes. Zero-carbon, no.

There were real bright spots. 2024 was the first year ever that solar and wind together out-generated coal. Solar was the single fastest-growing resource and has more than doubled since 2020. Zero-carbon sources — nuclear, renewables, and hydro combined — supplied roughly 41% of U.S. electricity, with nuclear quietly doing the heaviest lifting at over 90% capacity factor. Clean power is winning the long game. It just didn't win fast enough in 2024 to outrun demand.

There's a policy headwind, too. The recently passed One Big Beautiful Bill repealed and weakened the clean-energy incentives created under the 2022 Inflation Reduction Act. Independent modeling now projects the 2030 carbon intensity of the U.S. grid to land roughly twice as high as climate-aligned targets — and the gap widens through 2035.

Why my state is green is the wrong shortcut

Here's where most clean-energy content gives a comforting but incomplete answer. The gap between state grids is staggering. On an all-sources basis, West Virginia's grid runs around 1,920 pounds of CO₂ per megawatt-hour, while Vermont's sits near 6 lb/MWh — a difference of more than 300×. (We break the full table down in our state-by-state carbon intensity rankings.)

So yes, where you live changes the math enormously. By total volume, Texas alone emits 211.9 million tons of power-sector CO₂ — more than the next two states (Florida and Pennsylvania) combined.

But the number nearly everyone quotes — the one those ranking tables are built on — is the average carbon intensity of a grid. The honest question for someone plugging in is different: when you draw a little more power, which plant fires up to supply it? That's the marginal emissions rate, and it can diverge wildly from the average.

The clearest illustration is hydropower. Grids dominated by hydro — Quebec (over 90% hydro), the U.S. Pacific Northwest, Norway, Sweden — look spotless on an average basis. Yet, as grid-data nonprofit WattTime explained in 2026, these clean grids can carry surprisingly high marginal emissions. Researchers Abrell and Kosch found that boosting hydro in one hour simply shifts fossil burning to a later hour — invisible across a single day, obvious across a full week.

Drought makes it concrete. The International Energy Agency found that an exceptional hydro shortfall — across China, the U.S., and other regions — drove more than 40% of the global rise in emissions in 2023, as grids fired up fossil plants to plug the gap. A green grid is not a drought-proof grid.

A handful of companies, most of the carbon

The pollution is concentrated, too. A quarter of the entire power industry's CO₂ comes from just five of the 100 largest producers. Thirteen of those 100 producers have zero zero-carbon generation, while the cleanest investor-owned producer runs at 81 lb CO₂/MWh and the dirtiest at 1,900 — a 23× spread between companies serving the same country.

What it means if you ride electric

The good news for micromobility is scale. Charging a typical scooter uses only a fraction of a kilowatt-hour, so even on a dirtier-than-average grid the carbon behind a single charge is tiny next to the gas-car trip it likely replaced. A 30 mph electric scooter like the Zero 9 is still far cleaner per mile than a combustion engine — on any grid in the country.

But if you want to charge as clean as the grid will let you, the levers are real:

Charge when the grid is cleanest

Marginal emissions swing hour to hour — typically cleaner midday in solar-heavy regions, or overnight where wind dominates. Same plug, lower footprint.

Don't assume hydro or a green state = a clean charge

The marginal plant filling new demand may still be gas. Check the trend behind the ranking, not just the headline number.

Watch the direction, not just the rank

With fossil generation creeping up and federal support pulling back, the grid gets cleaner every year is no longer a safe default. To see exactly where your state sits today, our full U.S. state carbon intensity rankings break down every grid by CO₂ lb/MWh and renewable share.

The 2024 reversal is a reminder that progress isn't automatic. The cleanest ride is still the electric one — but knowing how the electricity behind it is made turns a vague green claim into something you can actually act on.

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