AVE

Presenting the Atmospheric Vortex Engine:

An atmospheric vortex engine (AVE) uses a controlled vortex to capture mechanical energy produced when heat is carried upward by convection in the atmosphere. A tornado-like vortex is produced by admitting warm or humid air tangentially into a circular arena... 

The vortex engine has the same thermodynamic basis as the proven solar chimney except the physical tube of the solar chimney is replaced with centrifugal force. There is no need for a solar collector - The solar collector is the earth’s surface in its unaltered state.

An AVE power station could have a diameter of 200 m and generate 200 MW of electrical power at a cost as low as $0.03/kWh.  

Interesting; from the looks of it, there are working small-scale demos of the technology, and they're picking up some serious investors.  I would think that the idea of having controlled tornadoes above power plants might make pilots a little bit titchy, though...