TIANJIN, China � China�s frenetic construction of coal-fired power plants has raised worries around the world about the effect on climate change. China now uses more coal than the United States, Europe and Japan combined, making it the world�s largest emitter of gases that are warming the planet.

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Doug Kanter for The New York Times

The Tianjin plant will be constructed in what is now a muddy field.

But largely missing in the hand-wringing is this: China has emerged in the past two years as the world�s leading builder of more efficient, less polluting coal power plants, mastering the technology and driving down the cost.

While the United States is still debating whether to build a more efficient kind of coal-fired power plant that uses extremely hot steam, China has begun building such plants at a rate of one a month.

Construction has stalled in the United States on a new generation of low-pollution power plants that turn coal into a gas before burning it, although Energy Secretary Steven Chu said Thursday that the Obama administration might revive one power plant of this type. But China has already approved equipment purchases for just such a power plant, to be assembled soon in a muddy field here in Tianjin.

�The steps they�ve taken are probably as fast and as serious as anywhere in power-generation history,� said Hal Harvey, president of ClimateWorks, a group in San Francisco that helps finance projects to limit global warming.

Western countries continue to rely heavily on coal-fired power plants built decades ago with outdated, inefficient technology that burn a lot of coal and emit considerable amounts of carbon dioxide. China has begun requiring power companies to retire an older, more polluting power plant for each new one they build.

Cao Peixi, the president of the China Huaneng Group, the country�s biggest state-owned electric utility and the majority partner in the joint venture building the Tianjin plant, said his company was committed to the project even though it would cost more than conventional plants.

�We shouldn�t look at this project from a purely financial perspective,� he said. �It represents the future.�

Without doubt, China�s coal-fired power sector still has many problems, and global warming gases from the country are expected to continue increasing. China�s aim is to use the newest technologies to limit the rate of increase.

Only half the country�s coal-fired power plants have the emissions control equipment to remove sulfur compounds that cause acid rain, and even power plants with that technology do not always use it. China has not begun regulating some of the emissions that lead to heavy smog in big cities.