Sure, a data centre is a power hog. Sure, Google has more data centres than everybody else. Courtesy of a new interview, we now know just how much electricity is consumed by the Chocolate Factory: 260 megawatt hours in 2010.

That’s what Google has said to the New York Times and, given that electricity would be one of the ad-farm’s search giant’s biggest cost items, it’s probably reasonably accurate.

After all, per-user, Google says, its power consumption is only 180 watt-hours a month.

But Google’s going to have to work harder to convince the world that we get a net benefit out of its concentration of electricity consumption under one corporate banner.

For a start, it’s just as easy to consider Google’s – and much of the IT industry’s – electricity use as additive. Rather than replacing old, less efficient behaviours, the IT industry creates new behaviours, and consumes electricity to power those new behaviours. Someone wondering about the meaning of curmudgeon is also someone unlikely to go any further than their own front door to find out. Living in ignorance is easier than driving to the library.

Someone looking – as I was last week – for a 1992 Toyota Surf steering column didn’t drive to the library at all. They grabbed the phone book and started calling auto wreckers.

We can only consider the data centre’s electricity consumption to yield a net benefit when we know that it replaces a more costly, higher-consumption activity.

And a large chunk – we don’t know how large – of Google’s power consumption has nothing at all to do with search. It’s about processing the vast hoard of user data needed to support the Google advertising business model.

It is, however, unfair to single out Google. The Chocolate Factory has a devotion to efficient data centres – “our data centre is less horribly wasteful than anyone else’s”, it could say but doesn’t – and emphasizes its purchase of offsets. These and other initiatives are outlined on Google’s “green” blog, here.

But – absent any debate about climate change – electricity generation is still a major polluter, still puts things into the air that humans are better off not breathing, and as any Australian economist knows, is rising so fast worldwide that it’s becoming an economic distortion.

So the “greenness” or otherwise of the IT industry as a whole is a serious debate. The simplistic claim that every processor cycle is a magical replacement for some other, dirtier activity is too neat, too pat, and too easily dismissed.

Google is in a position to contribute much, much more to the debate: it has both the money and data to vastly improve everyone’s understanding of the pros and cons of the energy poured into data centres. That would be interesting. ®

Update: A number of readers have questioned whether the raw figure cited in this article - 260 MWh (typo corrected) - is correct. That's probably an error on the author's part, born out of habit: the New York Times article said "megawatts" rather than "megawatt-hours". Mea maxima culpa.

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