Incase anyone missed it when going through the OP here is a description of a solar tower along with a video concept (in link) as to what one would look like.

Solar towers
Solar towers are a form of clean, renewable energy comprised of a chimney, turbines and large greenhouse structures of which the first was constructed in 2015. The greenhouse at the bottom cumulates heat and humidity which causes the warm air to rise up the chimney which, in turn, turns the turbines and thus generates electrical power. Due to the lush, tropical nature of the land inside the greenhouses agricultural companies encouraged the construction of and even started building their own solar towers seeking to gain the benefits of a double income. By 2030 these structures dominate whole countrysides in some countries.
[url=http://www.youtube.com/watch?v=pTkmTsKLRq0&sns=em]