[_nate_]

I was going to bring up the same point. The solar updraft systems seem to be more cost effective and generally easier to build. I don’t understand why they’re not being built more. However, they definitely take up more land. And nature advocates claim they are harder on the environment because they essentially bake the top soil, killing everything (which is probably true). But everything has trade offs.

http://en.wikipedia.org/wiki/Solar_updraft_tower

[debacle]

It looks like the solar updraft systems are only cost effective when you have vast amounts of cheap/free land - they are very inefficient in Watts per square meter, getting around 1% efficiency compared to 20-35% for other systems.