China has overtaken the United States to claim top spot in the world’s energy consumption league, according to the International Energy Agency. China has almost immediately hit back, branding the IEA’s data “unreliable”.

The agency’s chief economist seems confident of his figures though. Fatih Birol says China’s showing is the start of “a new age in the history of energy” (Wall Street Journal).

According to new estimates from the agency (see graph), America’s energy consumption dropped from 2,281 million tons of oil equivalents in 2008 to 2,169 in 2009. This allowed China – which increased from 2,131 to 2,265 Mtoe over the same period – to take first place.

Officials from China’s National Energy Administration said that the IEA had failed to grasp their country’s efforts to slash energy consumption and also claimed that China’s official statistics – collected from different sources – gave very different results (Xinhua).

“By our calculation, the US was still the world’s largest energy user in 2009. China was the largest primary energy producer,” says Zeng Yachuan (Dow Jones Newswires).