When Jack Pouchet of Emerson proposed a Water Usage Effectiveness metric for data centers in his blog, I didn't know what to make of the idea. Until read today's Wall Street Journal. 

Here's what's going on, Jack writes: "Why water? When more than 1 billion people lack access to safe drinking water and fully one-third of the world lives in “water stressed” countries, it is time for us to seriously rethink our use of water within our data centers. Water is a life necessity that we must carefully guard and protect in order to ensure our way of life."

Later in the blog, he writes, "Therefore I strongly encourage the data center industry to formulate a water usage effectiveness WUE, or better yet a Water Systems Productivity (WSP) metric. Simply put, for a data center, take useful work or even a proxy for useful work such as Emerson’s proposed Compute Units Per Second and divide that by the amount of water used during the observation period. Water will most be likely measured in units, with 1 unit equal to an acre/foot. It’s a measure often used in the residential/commercial real estate sector --think of it as the amount of water required to flood one acre to the depth of one foot. Of course, gallons/liters work just fine if you choose."

The Green Grid and the rest of the industry has been hard at work developing the PUE and having it adopted for widespread use. Hence, Jack's apt WUE formulation. Compare, though, all the effort that has been put forward on behalf of reducing electricity use as opposed to conserving water. We have been quick to recognize the importance of electricity shortages, perhaps spurred by rolling blackouts in California early in this decade. Or perhaps we are motivated to save electricity as a proxy for saving oil or as a way to reduce emissions. Perhaps we see energy costs as relatively easy to control.

Still, water is a limited, non-renewable natural resource. And while oil, coal, and natural gas may also be limited, non-renewable sources, electricity can be made from any number of renewable resources. If we consider nuclear energy as green, we already make plenty of electricity from green and renewable sources. We lack only the political consensus and financial wherewithal to make more.

Today's Wall Street Journal points out that California may yet wind up spurring our recognition of the importance of conserving water. The Journal reports, "With some of California's reservoirs now holding as little as 21% of capacity, 60 urban water districts have instituted mandatory water conservation, up from six last summer. The current drought is hurting the state more than in the past, partly because California's population has grown to 38 million people, from 29 million two decades ago."

Governor Arnold Schwartzenegger reportedly has made water conservation and storage the state's next legislative priority after bridging the state's budget gap, with plans including an estimated $10 billion bond. Water restrictions have already been imposed across a state that includes innumerable data centers. 

In another article, the Journal reports plans for three new energy-intensive desalination plants to create fresh water from ocean water. In short, then, it is fair to say that California which is strapped for electricity and money must spend more of both in order to make sure it has enough water.

Convoluted, I know. Jack Pouchet's WUE makes a lot of sense.