WSJ has an opinion article on Peak Water issues caused by solar power mandates.  For more in depth of the comparison of the term Peak Water vs. Peak Oil check out this pdf.

Peak Water
Meena Palaniappan and Peter H. Gleick

In the past few years, discussions about the possibility of resource crises around water, energy, and food have introduced new terms and concepts into the public debate. Energy experts predict that the world is approaching, or has even passed, the point of maximum production of oil, or “peak oil.” The implications of reaching this point for energy policy are profound, for a range of economic, political, and environmental reasons. More recently, there has been a growing discussion of whether we are also approaching a comparable point of “peak water,” at which we run up against natural limits to availability or human use of freshwater.

Back to the WSJ Article.

Peak Water

An unintended consequence of solar power mandates.

Harry Reid has decided that Senate Democrats will put off their cap-and-tax energy ambitions for now, focusing on smaller-scale subsidies and mandates. Anyone who thinks this counts as a "compromise" might visit Arizona, where the green campaign for renewable energy is forcing the state to confront the limits of a nonrenewable resource—water.

With more than 10 months of sun a year and vast tracts of desert, Arizona is seemingly ideal for solar power, aside from the fact that solar isn't cost-competitive with conventional fuels. So, in a preview of the "renewable portfolio standard" that Democrats want to impose nationwide, the state mandated that utilities produce 15% of their electricity from green sources by 2025. Scores of solar projects are thus under review by federal and state regulators, with some of the applications fast-tracked so developers can qualify for tax credits in the stimulus.

What is not common public knowledge is the relationship between energy and water in power production.  Australia has a study that shows the relationship that I posted on last year.  I think the Australians learned this as part of when a desalination plant was built to be powered by a coal power plant.  You can guess when you account for the fresh water use by the power plant, the amount of energy required to generate fresh water through desalination, the economics and environmental impact didn't work.

Looking at the big picture of the relationship between water and solar power is in the WSJ article.

One hitch: The hot, arid regions best suited for solar also tend to be short on fresh water, and Arizona is no exception. Utility-scale solar power works by generating steam that spins turbines. Cooling the system at the end of the process consumes almost twice as much water per megawatt hour as coal-fired power plants that use the same cooling technology, according to a 2009 report from the Congressional Research Service. The study, which examined the consequences of a solar expansion in the southwest, adds that it could consume as much as 1% of the state's finite water resources within a few years.

The environmentalists answer is to not use steam, but photovoltaic.

Environmentalists say other solar methods require less water, but these aren't as efficient for generating power and they raise costs even more than the usual solar process. At any rate, Arizona is already an electricity exporter, mostly to California, so it isn't as if energy is in short supply. The state's green regulations are effectively a mandate to export water, which is in short supply.

The greens also claim that advanced photovoltaic solar farms (which convert sunlight directly into electricity with de minimis water) are just around the corner. But photovoltaic technology is no closer to commercial scale than cellulosic ethanol, plug-in vehicles and the other "second generation" science projects that environmentalists claim are just five years off to excuse the shortcomings of technologies as they exist today. They're always just five years off no matter what year it is, in order to justify continued subsidies.

Issues like this are why I say it is difficult to define a green data center.  A better method is to take the steps to make things greener. 

Green energy has been sold as a great free lunch, promising millions of new jobs and cheap electricity, but somehow it never turns out that way when you look under the hood.

The greenest data center is the one that doesn't exist and has no environmental impact.  But, I am not going to take that radical environmentalist view.  Cloud computing getting people to be charged for their usage in real-time is a great step to get people to see the costs of their technical and business decisions to run information services.