LITTLETON, Colorado, Dec 11 (Reuters) - Major Asian economies including China, India, Japan and Vietnam have cleaned up their power generation systems by more than the United States and Europe in 2025, setting the stage for an East-West divergence in energy transition momentum heading into 2026.

Over the first 10 months of 2025, the United States was the only major power market to increase the carbon intensity of power generation compared to the year before, according to data from energy think tank Ember.

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The chief driver of the rise in U.S. carbon intensity has been a roughly 13% increase in coal-fired power generation, which has lifted U.S. power sector emissions from fossil fuel use to three-year highs.

European power firms have also lifted their collective CO2 emissions so far this year compared to 2024, while China, India, Japan and Vietnam have all registered year-to-date declines in CO2 output from fossil fuel power generation.

With winter approaching in the Northern Hemisphere, higher generation from fossil fuels can be expected across Asia, Europe and North America in the coming months, which will lift the carbon intensity of all major power systems.

But the U.S. is likely to continue leading the pack in terms of carbon emissions growth as power firms in the country opt to dial up output from coal plants ahead of cleaner natural gas plants following a steep rise in national natural gas prices.

CARBON INTENSITY GLIDE PATHS

All major power systems have reduced their carbon intensity - or the amount of carbon dioxide (CO2) released per kilowatt hour (KWh) of electricity production - over the past five years or so.

However, only China has managed to register consistent annual declines in intensity since 2019, largely on the back of world-leading deployment of clean power sources that have allowed utilities to cut back on fossil fuel reliance.

During January to October of 2025, China's carbon intensity of power output averaged 562 grams of CO2 per KWh, compared to nearly 670 grams of CO2/KWh in 2019, Ember data shows.

Elsewhere, other major power systems have posted at least one annual rise in carbon intensity since 2019 as a mixture of rising power demand, patchy clean power supplies and power policy pivots have sparked shifts in generation mixes.

However, only the U.S. system has posted an increase so far in 2025, with an average of 383.3 grams of CO2 emitted per KWh during January to October, compared to 381.2 grams during the same months in 2024.

Europe's average carbon intensity is down around 2% so far this year from 2024, while India (down 5%), Japan (down 3%) and Vietnam (down 2%) have also registered reductions.

COAL-HEAVY GROWTH

Asian economies remain far more coal-reliant than major power networks in Europe and North America.

India generates roughly 70% of its electricity from coal, China's coal share is 55%, Vietnam's is 48% and Japan's is around 27% so far this year.

In contrast, Europe has generated less than 13% of its electricity supplies from coal-fired power plants this year, while the U.S. coal share is around 16%.

However, the U.S. is the only major power market to register a steep rise in coal's share of the overall generation mix so far this year, which is why the U.S. carbon intensity path is out of whack with trends in other regions.

The U.S. coal share of around 16.1% so far this year compares with a 14.6% coal share in 2024, and so marks an 11% rise in the share of utility electricity supplies coming from coal plants compared to the year before.

Indeed, coal plants have been by far the largest source of electricity supply growth in the U.S. this year, and have accounted for around 73% of the increase in total electricity supplies during January to October, Ember data shows.

In all other major power markets, coal's share of the supply growth has been far less, including in India where extra coal-fired output accounted for only half of the overall rise in electricity supplies.

TRACKING TRENDS INTO 2026

In the U.S., the roughly 50% climb in average natural gas prices this year has been a major driver of higher coal-fired power generation, as utilities remain under pressure to keep energy prices in check for consumers.

Natural gas prices are expected to remain firm through the coming winter thanks to record-large demand from LNG exporters, who can compete with utilities for gas in the U.S. gas market.

That outlook for sustained strength in gas prices should keep coal-fired output levels elevated in the U.S. through well into 2026, and could ensure that the U.S. carbon intensity trend keeps climbing.

In China and Europe, enduring economic woes have curbed overall industrial activity, and have thereby limited the demand from factories, steel and chemical plants and other major power consumers.

Any improvement in economic activity in China and Europe will feed through to higher fossil fuel power generation, and in turn will lift the carbon intensity in those markets.

Greater industrial production and demand in China will also boost the economies in the rest of Asia, and could result in a broad upturn in Asia's power sector carbon intensity in 2026.

For 2025, however, the U.S. remains the main stand-out in terms of carbon intensity momentum, which continues to go against the global trend of steadily cleaner power networks.

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

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https://www.reuters.com/markets/commodities/us-coal-binge-helps-asia-pull-ahead-west-clean-power-push-2025-12-11/