Major State-owned companies have taken great leaps to cut down on their carbon emissions, according to a State-run commission, in a key boost to the government's campaign to combat climate change.

Energy consumption per 10,000-yuan output ($1,470) of more than 130 central enterprises dropped 4.8 percent last year compared with 2007 and 10.2 percent compared to 2005, according to a conference of the State-owned Assets Supervision and Administration Commission yesterday.

The emission of sulfur dioxide last year dropped 11 percent compared with 2007 and 23 percent compared with 2005, said Huang Shuhe, deputy director of the commission.

The five largest State-owned power generation enterprises saved 20.73 million tons of standard coal last year, and cut 1.7 million tons of sulfur dioxide emission compared with 2005.

The central enterprises administrated by the commission are the main body of State-owned enterprises that contribute about 30 percent of China's GDP. From January to September this year, central enterprises have made profits of 552 billion yuan, and last year achieved profits of 696 billion yuan.

Huaneng Corporation, one of five power generation giants, was the first coal power group that set up equipment to collect carbon dioxide. It has initiated a pilot program to collect 3,000 tons of carbon dioxide annually.

China Southern Power Grid has provided energy-saving services to 2,743 local enterprises. Because of its higher charges in energy-inefficient sectors, 617 enterprises of high-energy consumption have been closed.

"It is an inevitable trend to develop a green economy. Chinese central enterprises have to make more efforts to achieve sustainable development," Huang said.

He added that the statistics also gave China much-needed support to meet the challenges of potential trade restraints in the "green" business sector.

He addressed the possibility that the United States may impose a carbon tariff on imports from developing countries such as China.

"Some developed countries will build up trade barriers in the name of environment protection," Huang said, urging central enterprises to have more say in standards for the manufacturing of international products.

To excel in the green economy, central enterprises have to invest more in research and develop environmentally friendly products, Huang said.

He required central enterprises to put environmental protection as one of its top priorities as China continues to face problems of high-energy consumption and serious pollution.

On Monday, Premier Wen Jiabao said China will insist on key global climate change negotiations next month to build on current treaties that limit the obligations of poor countries in controlling greenhouse gas emissions.

Analysts said the central enterprises' green achievements exhibit the government's efforts to develop a low-carbon economy, but the road to a green economy will not be smooth.

Han Qi, a professor on China's economic studies at the University of International Business and Economics, said that "given the central enterprises' essential role in China's economy, their green movement will promote the economy's transition".

"But besides moral requirements, it's more urgent to launch a mechanism to encourage enterprises to cut emissions," Han told China Daily. "The government should provide preferential policies for the enterprises using clean energy."