eSolar, an Idealab company founded by Bill Gross, is working to introduce and expand its solar-thermal energy solution around the world.  One question I have is what the land-usage efficiency is. That is, how much power is produced per square foot of land it takes up.  This may not be a huge factor as they could simply be built in inhospitable desert climates where land and space is not nearly the concern of local placement.  Just a thought though… if anyone knows more about it, comment and fill me in!