China overtook the US last year to become the world's biggest energy user, the International Energy Agency revealed on Monday.

Beijing's new status is expected to make it even more influential in global energy markets, in determining prices and how it is used.

China clinched the top slot more quickly than had been expected because the US has over the past decade far outpaced China in using energy more efficiently. On a per capita basis, the US still uses far more energy than China and remains less efficient than Europe.

Fatih Birol, the IEA's chief economist, said: "In the 2000, the US consumed twice as much energy as China, now China consumes more than the US." He noted that the US had improved the efficiency with which it uses energy by 2.5 per cent annually during that time, while China managed only a 1.7 per cent annual improvement.

"On the one hand, the US has come to a certain saturation of energy use, but there have also been lots of efforts, especially since 2005, to use energy more efficiently," he said.

China last year consumed 2,252m tons of oil equivalent of energy from sources including coal, oil, nuclear power, natural gas and hydropower, about 4 per cent more than the US, the rich countries' watchdog said.

China's growth has also not suffered the same setback as that of the US following the global financial crisis.

In 2008 it pushed oil prices to record highs, which helped tip the world into recession. Mr Birol said China's increased need for imports of coal and gas could eventually have a similar impact.

A second big consequence of China's growing heft as an energy consumer is that the country will thus increasingly determine how energy is used on a global scale - from the types of cars manufactured to the kinds of power plants built. This means China will also determine energy consumption patterns outside its boarders. "There will be a big multiplier effect," Mr Birol said.

Though the IEA warned the data on China's energy demand last year was still preliminary, the country's ascendancy in energy use has been well established, with western policy makers fretting about issues such as Beijing's agressiveness in seeking to secure oil from Kazakhstan to Sudan and to China's growing carbon emissions.

China is already by far the world's largest user of coal. Despite its own vast resources, its imports of thermal coal are expected to hit 105-115m tonnes this year, pushing it ahead of Japan as the world's largest coal importer. Only three years ago China was a net coal exporter.

The trend has also been apparent in oil. Saudi Arabia, the world's most important oil exporter, for the first time last year sold more oil to China than the US, which for decades had been its most important customer.

In March, Nobuo Tanaka, the IEA's secretary-general, called on China to join the IEA, warning that the organisation, which represents the OECD's largest energy consuming countries, risked losing its relevance otherwise.