Solar Thermal Power And Water Constraints In The US  

MSNBC has an article about concerns about water availability slowing progress on solar thermal power development in the western US - Desert clash in West over solar power, water.

A westward dash to power electricity-hungry cities by cashing in on the desert's most abundant resource — sunshine — is clashing with efforts to protect the tiny pupfish and desert tortoise and stinginess over the region's rarest resource: water.

Water is the cooling agent for what traditionally has been the most cost-efficient type of large-scale solar plants. To some solar companies answering Washington's push for renewable energy on vast government lands, it's also an environmental thorn. The unusual collision pits natural resources protections against President Barack Obama's plans to produce more environmentally friendly energy.

The solar hopefuls are encountering overtaxed aquifers and a legendary legacy of Western water wars and legal and regulatory scuffles. Some are moving to more costly air-cooled technology — which uses 90 percent less water — for solar plants that will employ miles of sun-reflecting mirrors across the Western deserts. Others see market advantages in solar dish or photovoltaic technologies that don't require steam engines and cooling water and that are becoming more economically competitive.