'Solar chimneys' may help solve China's energy woes

Scientists are researching whether so-called solar chimneys, which rise half a kilometre or even higher from the earth, might produce enough clean energy to help reduce the mainland's chronic air pollution.

A test plant is running successfully in Inner Mongolia and scientists want to build full-size versions in cities such as Beijing and Shanghai. The researchers have suggested the towers could be constructed inside new skyscrapers.

The technology involves covering an area of several square kilometres to create a greenhouse around a high chimney. The hot air produced in the greenhouse rises through the tower, driving turbines that generate electricity. The higher the tower, the stronger the updraft and the more power created.

The highest previous attempt to master the technology, which has been discussed for decades, ended in failure when a 195-metre tall tower in Manzanares, Spain, collapsed in 1989 due to structural failure.

But Professor Wei Yili , the leader of the project at Inner Mongolia University of Science and Technology, said he was confident they could now build safe and efficient towers higher than a kilometre.

"The structural problem is no longer a problem for us. We have acquired patents for our technology and design," he said. "The towers will stand for a century, outlasting those who build them or see them built, like the Eiffel Tower."