Google Efficiency Claim Not Everyone's Cup Of TeaGoogle Efficiency Claim Not Everyone's Cup Of Tea

Google claims its Web searches are more energy efficient than media reports suggest, and the scientist whose work was used to disparage Google's green image agrees.

A report in The Sunday Times quotes Harvard physicist Alex Wissner-Gross' claims that "performing two Google searches uses up as much energy as boiling the kettle for a cup of tea." It questions Google's commitment to responsible energy usage, noting "its search engine generates high levels of CO₂ because of the way it operates."

Wissner-Gross, in a phone interview, said that "The Sunday Times had an axe to grind" with Google and that he's "not sure where they got this estimate from." He said that his work had to do with the CO₂ produced while viewing general Web sites -- 20 milligrams of CO₂ per second of viewing -- and was not specific to Google. He characterized The Times' report as "an effort to sell a lot of newspapers."

Wissner-Gross said that while computer use has an environmental impact, it's generally a positive one because increased computer use often means fewer activities that produce more carbon, like driving.

Google also disagrees with The Times' assessment and on Monday published a rebuttal by Urs Holzle, senior VP of operations at the company.

"Recently, though, others have used much higher estimates, claiming that a typical search uses 'half the energy as boiling a kettle of water' and produces 7 grams of CO₂," Holzle wrote in a blog post. "We thought it would be helpful to explain why this number is *many* times too high."

According to Holzle, a Google search produces about 0.2 grams of CO₂, not 7 grams. Compare that with the EU standard for a car driven for 1 kilometer: 140 grams. "Thus, the average car driven for one kilometer (0.6 miles for those in the U.S.) produces as many greenhouse gases as a thousand Google searches," wrote Holzle.

Holzle adds that Google has made great strides in reducing the energy used by its data centers, noting that Google invested $45 million in clean energy technology last year and that it has an internal engineering group dedicated to energy research. And lest anyone forget, he also points out that Google co-founded the Climate Savers Computing Initiative, which aims to halve the energy used by computers by 2010 -- a global CO₂ reduction of 54 million tons.

Wissner-Gross acknowledges that Google's efforts have benefitted the environment. "They're really been pushing the envelope in terms of data center efficiency," he said.

Wissner-Gross co-founded a site called CO2stats.com that serves as an environmental trust mark for Web sites, just as TRUSTe serves as an online privacy trust mark. He expects that "more and more organizations will adopt sustainability trust marks backed by analytics," in order to demonstrate their commitment to environmentally responsible energy usage.