"Last week the Australian government added its support, but no cash, to a hugely ambitious renewable energy project: the 1 kilometer-high solar tower. The project is a solar-generated wind farm on a massive scale. It works on the principle of convection -- hot air rises -- and the tower functions like a chimney. " This is a crazy engineering effort. Follow the link for the project on this page for an artist's conceptualization. Only in Austrailia (or possibly Canada) could you find seven kilometers that no one is using upon which to build the worlds largest structure. A Tower in Oz to Touch the Sun | 
