From the Alternative Energy Blog:
One of the most popular posts was on a proposed solar chimney in Australia (also known as a Solar Tower). It works using the solar chimney to cover a large greenhouse which covers several square miles. As the hot air rises, it would escape up a 990m tower in the centre of the structure. Wind turbo-generators mounted in the chimney would convert this 50km-an-hour rush of hot air into electricity.
Two things I particularly like about the concept are that, firstly it can run almost continuously not just when the sun is out, and secondly it produces a significant (100MW ) amount of electricity.
Well now that might just be happening. In an intriguing one line press release Californian company SolarMission has agreed to "build, own, maintain, and operate 2,600 megawatts of solar towers. "
Where and when these towers are going to be built is not specified.