China is trying to clean up its coal habit in an effort to reduce some of its environmental problems.

Coal accounts for over 70 percent of China's primary energy production and consumption. The country's use of it will likely reach 2.9 billion tons by 2020.

Coal-firing-related emissions constitute 80 percent of China's annual sulfur dioxide (SO2) emissions and 70 percent of its carbon dioxide (CO2) emissions.

The 11th Five Year Plan (2006-2010) for Coal Industry Development in China requires the coal industry to strengthen reforms in its industrial structure, take a sustainable path with a high utilization rates and reduce its environmental impacts.

Clean coal technologies have become a key way to achieve such goals. "Clean coal technology should be adopted throughout the entire coal chain," said Huang Shengchu, president of China Coal Information Institute (CCII).

The Chinese government is promoting coal washing, to improve combustion efficiency and minimize ash production and pollution. But the extra cost involved in the related technology means many coal-fired power plants are reluctant to adopt it. Currently only 15 percent to 20 percent of them use it.

Huang, however, said coal washing is a relative cheap way to cut back pollution and that the government might need to implement relevant policies to encourage it.

Integrated Gasification Combined Cycle (IGCC) is another clean coal option.

In an IGCC system coal is not combusted directly but reacts with oxygen and steam to form a sort of syngas (synthesis gas). After being cleaned, it is burned in a gas turbine to generate electricity and to produce steam to power a steam turbine.

Carbon capture and storage (CCS) is a type of clean coal technology that involves capturing the carbon dioxide, preventing the greenhouse gas from entering the atmosphere, and storing it deep underground.

But the cost of capturing and storing one ton of CO2 is about $70 to $80, said Huang.

Although IGCC and CCS technologies are not widely commercialized so far, they have the potential to turn black coal into another green energy source and, as such, deserve attention and investment, said Huang.

Wan Gang, minister of Science and Technology, said in February that China would further cooperate with the US in IGCC and CCS technologies.

Huang added that China needs to construct more mine-mouth power plants, which are located quite close to coal mines, since such plants reduce energy expended during transportation.

Last December, the US-based Clean Coal Technologies Inc (CCTI) and Sino-Mongolia International Railroad Systems Co Ltd (SMIRSC) signed an agreement under which CCTI will provide technologies to China to produce clean coal.