Rising demand pushes up emissions slightly, but electricity continues to get cleaner

Maintaining the mature clean technologies of hydro and nuclear while rapidly adding newer ones, especially solar, was not sufficient to achieve a year-on-year reduction in carbon emissions. That’s because fast-rising electricity demand necessitated extra gas generation.

Even though carbon emissions increased, carbon intensity (emission per unit of electricity) reached a record low of 384 gCO2/kWh in 2024 – mainly because clean generation grew faster than fossil and gas replaced coal, making US electricity cleaner.

Faster electricity demand growth halted the historic fall in US power emissions

US power sector emissions increased slightly in 2024, an interruption to the long-term fall since coal generation peaked in 2007.

US power CO2 emissions rose in 2024

The 0.7% rise in CO2 emissions in 2024 was relatively small compared to the increase in electricity demand (+3.0%), mainly because clean generation – predominantly solar and wind – helped meet a significant part of the increased demand. 

While coal generation continued to fall, emissions rose due to increased gas generation, which not only replaced coal but also met most of the additional power demand growth.

It rose three times more than the fall in coal, as discussed in Insight 3, leading to a 1.3% increase in overall fossil generation.

The rapid falls of CO2 emissions have stalled but not yet reversed

For nearly two decades, US power sector emissions have been in decline, falling by 2.3% per year on average since the peak of coal generation in 2007, resulting in a cumulative 33% fall by 2024.

The rise of wind and solar, along with the shift from coal to gas, was transformational, reducing coal’s share in the electricity mix from 49% in 2007 to an all-time low of 15% in 2024. Meanwhile, mature clean technologies of hydro and nuclear maintained their share in the mix.

Even as demand grew, the US grid continued to get cleaner. The expansion of wind, solar and gas helped stabilize emissions in the face of rising consumption. The key question is whether these trends will continue as the economics and politics of power generation in the country continue to shift. 

The last 17 years of progress means electricity got cleaner almost everywhere

Carbon intensity of power generation continued to fall – from 393 gCO2/kWh in 2023 to 384 gCO2/kWh in 2024. This is most likely the cleanest electricity in the US since the late 1800s when coal began to dominate. 

Since US coal generation peaked in 2007, the country’s electricity has become substantially cleaner, falling from 598 gCO2/kWh in 2007 to 384 gCO2/kWh in 2024. Over that period, the combined generation of wind and solar, along with gas, increased substantially (by 722 TWh and 968 TWh, respectively), contributing to the fall in coal generation.

The biggest falls in carbon intensity between 2007 and today happened in states where increasing wind and solar were the biggest sources replacing coal, rather than gas. The five states with the largest falls in carbon intensity were Iowa, New Mexico, Kansas, Colorado, Oklahoma and North Dakota, which also saw large increases in wind and solar.

 Meanwhile, Ohio and Delaware recorded the largest falls in coal share than any state but did not see their carbon intensity fall as steeply because most of the coal was replaced with gas.