Here’s a crossover problem that should not be unexpected: Because the manufacturing processes of many alternative sources of energy require large amounts of water, water shortage may become a serious problem. The case in point is a solar array company that wanted to build facilities in rural Nevada, but ultimately could not do so without using more than a third of the area’s entire water supply. As an article in the NYTimes puts it:

Here is an inconvenient truth about renewable energy: It can sometimes demand a huge amount of water. Many of the proposed solutions to the nation’s energy problems, from certain types of solar farms to biofuel refineries to cleaner coal plants, could consume billions of gallons of water every year.

“When push comes to shove, water could become the real throttle on renewable energy,” said Michael E. Webber, an assistant professor at the University of Texas in Austin who studies the relationship between energy and water.

Conflicts over water could shape the future of many energy technologies. The most water-efficient renewable technologies are not necessarily the most economical, but water shortages could give them a competitive edge. [Reference: New York Times]

In many cases there will be a tug of war between those who want the jobs associated with the alternative energy, and those who don’t want the losses to agriculture (and employment) due to the water usage. That’s one reason environmental impact studies are equally important for ‘environmentally friendly’ projects.