By Tony Cheng
BBC News, Beijing
China's government has passed a renewable energy law which is intended to increase production of energy from sustainable sources.
China is the second biggest producer of greenhouse gases
The law, which will come into force early next year, seeks to increase the usage of solar and wind power to 10% of China's total consumption.
However, while the new law has been welcomed, it has been suggested that the targets are over ambitious.
Rising oil prices and concerns over environmental damage prompted the move.
At present China relies on coal for most of its power, mining 1.8bn tons in 2004.
By fixing prices for electricity from solar and wind generated power, the government hopes to create financial incentives for existing operators and attract investment to these new markets.
But while there has been rapid expansion in the sustainable energy sector, it currently provides only a fraction of China's needs.
Wind generated electricity only contributes 0.01% to the power grid. To increase that to 10% in five years is an optimistic target.
Wim Landsink of the Dannan Wind Power Company suspects it will not be attainable.
"It's going to be difficult," he said.
"There is currently a lack of power, there is a huge amount of new power capacity under development, which mainly is still coal (based). I don't think in the coming years the environmental problems will get less, they will still increase."
And there have been arguments about the definition of sustainable energy.
Some members of the governing committee that passed the bill want to include hydroelectric plants, such as the Three Gorges Dam, in that category.
Others argue that the resources and costs involved in such mega projects mean they cannot be included.
But the fact that this law has been passed at all indicates that the environmental costs of China's rapid expansion cannot be borne for much longer.