A solar updraft tower is chimney with a greenhouse skirt and a central turbine. As the sun heats the air under the skirt it rises up the chimney and turns the turbine. This process will happen as long as there is a temperature difference between ground level and the top of the chimney. The taller the chimney the better it works.
Solar updraft towers are being taken very seriously with some major projects under way with one of the most promising and ambitious being Enviromission’s 1km high tower. All very impressive
Take a look to find our more.
http://www.enviromission.com.au/EVM/content/home.html