Clean coal a key ingredient in the battle for more blue skies

BEIJING - Gao Xiang and his colleagues never pictured coal as a black cloud billowing from smokestacks or a sooty remnant of the Industrial Revolution.

"There are only unclean technologies; no unclean energy," said Gao, a winner of China's National Awards for Scientific and Technical Progress and a professor at the State Environmental Protection Engineering Center for Coal-Fired Air Pollution Control at Zhejiang University.

For years, researchers have been seeking to reduce coal's harsh environmental impact with multiple technologies, seeking a "burn cleanly" spell for China's major energy source.