China uses almost as much coal in a year as the rest of the world combined, says the U.S. Energy Information Administration.

China's consumption of the carbon-intensive fuel increased 9 percent in 2011, to 3.8 billion tons, EIA says.

"China now accounts for 47 percent of global coal consumption -- almost as much as the rest of the world combined," the agency said of the latest figures released this week.

Since 2000, China has accounted for 82 percent of the world's coal demand growth.

While China is making significant steps in renewable energy, it still relies on coal for 70 percent of its power.

"So this diversification is better than nothing but it won't dramatically change the picture," Carlos Fernandez Alvarez, a senior analyst with the International Energy Agency and author of that agency's coal market 2012 report, was quoted as saying by the news website of Responding to Climate Change.

People think China is using 19th-century technology for their coal generation but that's not the case anymore. They are building super critical plants, the most efficient in the world," Alvarez said, noting that the efficiency of China's coal generation improved 16 percent in a decade.

"But when you are burning 4 billion tons (of coal), you can be as efficient as you want but the CO2 emissions will still be huge."

A report by the World Resources Institute last November indicates that of 1,000 new coal-fired power plants planned worldwide, 363 are in China.

In 2007, China overtook the United States as the world's biggest carbon emitter and became the world's biggest consumer of energy in 2010.

Data from the China Electricity Council indicated the power sector's carbon emissions dropped 57.51 million tons year on year in 2011.

The release of EIA's figures on China's coal consumption come as the country grapples with worsening air pollution, linked in large part to coal-fired power plants, which generate more carbon dioxide than gas or oil-fired power plants.

The Chinese Academy of Sciences estimated Wednesday that the recent smog across China has affected more than 800 million people.

A sustained effort to reduce China's dependence on heavy industry is required, says Yang Fuqiang, a former government energy policy researcher and now a senior adviser at the Natural Resources Defense Council.

"We have to change our ways. The pollution caused by coal is simply too severe," Yang told the BBC.