The Carbon Calculus of Google Data Centers

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Calculating the energy use of data centers was a hot topic of conversation this past weekend, as tech bloggers reacted to a London Times article scrutinizing the energy consumed by Google searches. "Performing two Google searches from a desktop computer can generate about the same amount of carbon dioxide as boiling a kettle for a cup of tea," The Times wrote, citing research by Harvard physicist Alex Wissner-Gross, who said a typical Google search generates 7g of CO2.

Google immediately contested the number in a blog post by senior VP of operations Urs Holzle. "In terms of greenhouse gases, one Google search is equivalent to about 0.2 grams of CO2," Urs writes, adding that "the average car driven for one kilometer (0.6 miles for those of in the U.S.) produces as many greenhouse gases as a thousand Google searches."

The Times' article generated heat in the blogosphere. Nick Carr noted that Wissner-Gross is "an entrepreneur who has a start-up that sells a service for tracking the electricity consumption of web sites. So he has a commercial as well as an academic interest here." Om Malik points out that if Google is a polluter, at least its doing something about it," including $45 million in investment in alternative energy, including thermal solar, geothermal and high-altitude wind energy.

As we've noted here many times, Google operates some of the most energy-efficient data centers in the world, with a relentless focus on reducing its enormous power bill. It is exploring innovative new approaches to data center design, including a floating data center powered entirely by wave energy.

So why pick on a company with a visible commitment to energy efficiency? Because it's an easy way to translate the issue into simple terms. Google is a familiar proxy for the larger issue of data center energy consumption, and its impact on the environment. 

This won't be the last time that creative math is used to scrutinize the carbon consumption of a company's data center operations. Will it be your data center next time? If so, will you have data on hand to quickly quantify your energy use and what you're doing to reduce it? These questions are not going away. The data center industry has begun to make meaningful progress on energy efficiency, but much work remains to be done, and many companies will be called to account for their results. 

Here's a math question to ponder: How much CO2 was generated by bloggers responding to The Times' story? In generating this controversy, has the Wissner-Gross research helped or hurt the environment? 

Okay, now my head hurts. Time for more coffee.