Olive Trees

Sorry Pete posted the wrong link yesterday the one I meant to post is the Spanish project there is an interesting blog that mentions costs it may answer some of your questions.
http://thefraserdomain.typepad.com/energy/2007/03/solarmission_so.html

 

Thanks Walnut, its an interesting idea, must admit I'd never heard of it before now.

A couple of points, first one is that although he said in the video that it works at night and in cloudy weather, why did the Germans build it in Spain, presumably the more sunshine available the better it works.
The other one is the amount of area of plastic sheeting that would be required for a really serious version, it would have to cover square miles of country I would think.