China is challenging the credibility of an International Energy Agency (IEA) report that branded the country the world's top energy consumer, surpassing the United States, claiming that the estimation is inaccurate.

"The IEA's data on China's energy use is unreliable," Zhou Xian, an official with the nation's National Energy Administration (NEA), said at a press conference Tuesday. But Zhou conceded that the data could be used as a "reference."

China consumed the equivalent of 2.25 billion tons of oil last year from sources such as coal, oil, natural gas, nuclear power and hydropower, about 4 percent more than the US' 2.17 billion tons, a report released Monday by the IEA said, according to the Financial Times.

The newspaper quoted IEA's chief economist, Fatih Birol, as saying, "In the year 2000, the US consumed twice as much energy as China; now, China consumes more than the US."

The calculation ran contradictory to one seen in a report by China's National Bureau of Statistics in February, which said China's energy consumption in 2009 stood at 3.1 billion tons of standard coal, which is equivalent to about 2.13 billion tons of oil.

Hu Xiulian, a researcher at the Energy Research Institute with the National Development and Reform Commission (NDRC), told the Global Times that "The IEA data on China's energy use is somehow not very accurate because the agency's criteria for calculating the volume of energy use is different from that used by China."

Zhou, of the NEA, said China has outpaced the US in new energy expansion, as the nation boasts the world's largest hydropower capacity, solar power use for water heating, and nuclear power capacity under construction. It also has the world's fastest growth of wind power generation, he said.

In a statement e-mailed to the Global Times Tuesday, the IEA said "China's demand today would be even higher still if the government had not made such progress in reducing the energy intensity of the economy."

A high energy intensity in terms of the economy indicates a high cost of converting energy into GDP.

The IEA went on to say that China's unprecedented pace of economic development will require ever more energy, but it will transform living standards for its billion-plus citizens.

"There can be no moral grounds for expecting China to curb its economic growth simply because world energy demand is rising unacceptably," the IEA statement added. "These are global problems to be tackled on a global basis."

While sharing the belief that China is undoubtedly on track to eventually become the top energy consumer, Chinese analysts underscored that it would be detrimental to national development if China follows the same track that developed Western countries once did in trying to speed up their industrialization.

Ding Yifan, a researcher at the Development Research Center of the State Council, told the Global Times that China will sooner or later become the biggest energy user in the world.

"But there is no need for China to feel bad about it. Nor is it necessary for the world to be surprised. The energy growth is compliant with the economic expansion," he said.

Lin Boqiang, director of the China Center for Energy Economics Research at Xiamen University, told the Global Times that the world's No. 1 title isn't that significant, since the country's population is four times that of the US. "What matters is the per capita energy use," he said.

The IEA report said energy consumption in China is around one-fifth of that in the US on a per capita basis.

However, Lin warned that the title would make the country vulnerable to international energy pricing and increasing dependence on energy imports will put China's energy security at great political and financial risk.

China seemed to have been in a disadvantageous position in negotiating over prices of key energy such as iron ore, oil and copper.

The issue was highlighted recently after mining giants Vale, BHP Billiton and Rio Tinto threatened in April to cut supplies to China unless steel makers accepted their price demands.

The China Iron and Steel Association finally compromised and allowed steel makers to reach temporary private deals with iron ore producers.

Lack of efficiency cited

The IEA report said the US had improved its energy efficiency by 2.5 percent annually over the past decade while China had only recorded a 1.7 percent annual improvement.

Hu, the NDRC researcher, acknowledged that the country's lower energy efficiency is one rea-son that contributes to the its whopping energy use, but she also argued that "China's energy effi-ciency is higher than that of the US if we compare it within the same stage of development."

However, Zou Ji, with the School of Environment and Nature Resources at Renmin University, warned that huge energy consumption is likely to further dampen the country's already fragile ecological system.

China has vowed to increase the use of renewable and new energy resources, including solar power and hydroelectric power, to reverse negative impacts brought by energy consumption on the environment, Zou said.

"But the dependence on coal and oil will not be changed within the next two decades," Zou said, adding that "The IEA data could be seen as an impellor for China to improve its energy efficiency and structure through technological progress and raise the public awareness on energy efficiency."