In the desert, where many think we should create solar factories, solar is anything but "green." And that's before one considers the impact on aquifers. If you live out west, and you have spent even a little time looking at the matter, you realize that water is the truly-scarce resource.
"Wet-cooled parabolic trough systems require five acre feet of water per megawatt. The five plants planned for Amargosa Valley, Nevada, propose to generate from 150 to 1,000 megawatts, so we are looking at over 10 million gallons of water a year. This water is fossil water believed to be tens of thousands of years old, not recharged since the last ice age. Even if they buy out the private water rights, there still would not be enough to supply this massive use of water. Devil's Hole, Ash Meadows wetlands, and springs of Death Valley (all home to a great diversity of endemic pupfish) would be dried up."
If you look at the amount of water required to grow corn, to create ethanol, you face the same problem. Water is the scarce resource. There are other ways to create clean energy.
http://www.latimes.com/news/opinion/commentary/la-oe-pavlik15-2009feb15,0,7619561.story