(The opinions expressed here are those of the author, a market analyst for Reuters.)

LITTLETON, Colorado - For the first time, over 1 billion metric tons of carbon dioxide (CO2) was discharged from U.S. gas-fired power stations in a single year during 2024, marking a new pollution threshold for the world's largest gas producer and consumer.

The 1.003 billion ton emissions figure is 3.6% up from 2023, and marks a 40% jump in gas-fired power generation emissions since 2015, according to data from Ember.

Those numbers look large, but lack important context. Discharge from the U.S. fleet of coal-fired power stations was just under 620 million tons last year, a record low due to the smallest coal-fired power generation level on record.

And as U.S. coal plants discharge 77% more CO2 per unit of electricity than gas-fired plants, the lower coal generation totals reveal that the U.S. power system has actually made steep cuts to overall pollution even as gas emissions have climbed.

COAL VS CLEAN

Thanks to the cuts to coal use, total U.S. power emissions from all fossil fuels were up only 0.5% in 2024 from 2023 to 1.64 billion tons, and were down 19% since 2015.

What's more, that emissions load has declined despite total electricity generation climbing to all-time highs in 2024.

A rapid climb in electricity generation from clean power - including from solar, wind, hydro and nuclear assets - has helped meet much of the rise in consumption in recent years.

Total clean electricity generation was 35% higher in 2024 than in 2015, thanks mainly to a nearly eightfold rise in solar generation and a more than doubling in output from wind farms during that period.

But fossil fuels remain the backbone of the U.S. generation system, supplying just over 58% of all electricity last year.

Natural gas accounted for a record 73% of that fossil share, while coal plants supplied the remaining 26% or so.

Power firms plan to make further cuts to coal use over the remainder of this decade, while adding more renewables to the generation mix to ensure total electricity supplies continue to climb in line with demand.

But power suppliers are also set to become even more reliant on natural gas, especially for system-balancing needs whenever intermittent output from renewable energy sources falls short of overall demand needs.

GAS FIX

Over 30 U.S. states rely on natural gas for 30% or more of their electricity needs, according to Ember.

Thirteen of those states rely on gas for 50% or more of their electricity, while an additional nine states use gas for between 15% and 30% of their electricity.

On top of that, nearly 50 gas-fired plants are in pre-construction or are under construction across the U.S., according to Global Energy Monitor, with a combined capacity of close to 30,000 megawatts.

That heavy reliance on legacy and new power plants and pipelines means that natural gas will remain integral to the U.S. power system for decades, even as renewable generation totals continue to climb.

That in turn means that overall emissions from natural gas use in the U.S. will also continue to climb.

But some of those gas plants will be used to replace retiring coal power stations, which on average have already been operating for 45 years according to the U.S. Energy Information Administration.

That means even as more gas capacity comes on line, some of the highest-polluting U.S. coal plants will be shuttered over roughly the same period, which should help cap overall fossil fuel pollution even as the U.S. power system gets ever gassier.

The opinions expressed here are those of the author, a market analyst for Reuters.

(Reporting By Gavin Maguire; Editing by Sonali Paul)