Federal land managers are raising concerns about water needs for some types of solar energy projects in the Western U.S. An AP story this weekend reprints an email from the director of the National Park Service's Pacific West Region to the BLM's Nevada state director, where he writes, "It is not in the public interest for BLM to approve plans of development for water-cooled solar energy projects in the arid basins of southern Nevada, some of which are already over-appropriated."
Water-cooled solar electric plants are currently the most cost-efficient. Some developers are using air-cooling, which is more expensive, but uses 90% less water. [right, an air-cooled solar electric system, as modeled by BrightSource Energy]
In Arizona, most of the proposed solar projects are outside the central urban areas where water resources are most competitive.
There is growing recognition that solar plants as a renewable resource may be effectively permanent installations, with permanent impacts. This contrasts with traditional energy development projects such as oil and gas or coal. Even though their impacts may be substantial during their operations, they have finite lives.
Renewable, ie possibly perpetual, uses of the land is requiring a paradigm shift in our thinking and planning.