These interesting devices are being proposed for construction in Namibia, which has lots of uninterrupted sunlight:
The gigantic solar towers [are] only “proposed” by Hahn & Hahn and each will be 1.5km tall and 280m wide, and the towers will be welcomed in Africa as at the base of them, people could grow crops. The base will measure about 37-square km and it will work as a greenhouse.
The towers will produce energy by sending the heated air from the greenhouse through wind turbines which will also generate electricity. Being shaped like a chimney, funneling the heated air via the wind turbines will not be a problem as the hot air tends to rise.