How big a problem water use will be for "Data Centers" in the future may be hinted at by Google's present day situation in a small Oregon town, The Dalles.

Oregon city drops fight to keep Google water use private (msn.com)

As I read this article I couldn't help but wonder if the decrease in heat generated IF Data Centers switched to the less thermal generating POET technology components might, in fact, result in a significant reduction in water requried for their cooling efforts.

Not being a "Techie", my conjecture isn't worth much, but perhaps one of the Tech Gurus might consider to turn his or her attention to this situation, should they feel that it is worthy enough for their comments.