there are a few examples of modern day concentrated solar power outfits on the good old wikipedia.
looks like the first patent for a solar steam engine was given in 1886 while the first one was built in 1866.
I can't imagine that obtaining the materials involved is ecologically benign, but I suspect that these might beat photovoltaics when considering negative impacts.
This is a cool concept. I have recently been looking at parabolic mirror boilers on Youtube, some of them are totally DIY and made with recycled/salvage material. One fellow in Colorado made a large parabolic array that runs a 12kw generator.
If you want to look young and thin, hang around old, fat people. Or this tiny ad:
permaculture bootcamp - gardening gardeners; grow the food you eat and build your own home