The government Thursday unveiled a detailed mandate setting out how thousands of China's coal-fired power plants could be "desulphured."

Made public by the National Development and Reform Commission (NDRC), the mandate says the government could help provide technical guidance and support to power plants who are not technically familiar with the necessary new equipment.

The mandate also says the government at various levels should play a bigger role in selecting technology, supervising installation and monitoring operations.

"Desulphurization is essential to protect our environment," said a commission spokesman.

Most of China's electricity was produced by firing coal, which produces sulphur dioxide (SO2), a component of acid rain. Acid rain can erode buildings and harm crops and also lead to diseases like lung dropsy, an industrial disease.

East China, especially the Yangtze River Delta, suffers most from acid rain. If the current situation continues, the country will discharge 28 million tons of SO2 in 2020, 16 million tons more than the country's atmosphere can accommodate, warned environmental experts.

Statistics from the State Administration of Environmental Protection say the damage to the environment and human health from acid rain and SO2 pollution translates into economic losses of 110 billion yuan (US$13.3 billion) a year.

To reduce these losses, China has decided to use technology that changes SO2 into gypsum, a kind of building material.

The mandate encourages power plants to equip themselves with desulphurization facilities and has promised to offer preferential policies to help with the high costs.

For new coal plants which are already equipped, the government has offered subsidies. There is as yet no incentive for older plants.

An energy expert at Tsinghua University said the desulphurization units are expensive to install and operate and the new mandate goes some way to address the problem.

But the expert, who refused to be identified, was concerned that without full co-operation from environmental authorities, the effectiveness of this new regulation is uncertain.

He said the owners of the facilities have full authority over how they run their plants and the government cannot interfere in their choice of unit, only in their environmental performance.

The main barriers to SO2 and acid rain control come from the country's excessive demand for energy and a large number of small coal-burning power plants.

China plans to shut down small coal-burning power plants when the energy demand can be met with alternative means.

Some generators that were closed have had to resume production to meet current demand.

(China Daily May 20, 2005)