Google released what was once among its most closely guarded secrets on Thursday: how much electricity its enormous computing facilities consume.
The company said that its data centers continuously drew almost 260 million watts — about a quarter of the output of a nuclear power plant — to run Google searches, YouTube views, Gmail messaging and display ads on all those services around the world.
Though the electricity figure may seem large, the company asserts that the world is using less energy as a result of the billions of operations carried out in Google data centers. Google says people should consider things like the amount of gasoline saved when someone conducts a Google search rather than, say, driving to the library. “They look big in the small context,” Urs Hoelzle, Google’s senior vice president of technical infrastructure, said in an interview.
Google says that people conduct over a billion searches a day and numerous other downloads and queries, and it calculates that the average energy consumption for a typical user is small, about 180 watt-hours a month, or the equivalent of running a 60-watt light bulb for three hours. The overall electricity figure includes all Google operations worldwide, including the energy required to run its campuses and office parks, he added.
While comparing different types of electricity loads is difficult, utility companies estimate that 260 million watts could power all of the homes in a sizable city — say, 100,000 to 200,000 homes.
For years, Google maintained a wall of silence worthy of a government security agency on how much electricity the company used — a silence that experts speculated was used to cloak how quickly it was outstripping the competition in the scale and sophistication of its data centers.
The electricity figures are no longer seen as a key to decoding the company’s operations, said Mr. Hoelzle. Google is known to have built efficient data centers. Unlike many data-driven companies, Google designs and builds most of its data centers from scratch, including its servers that use energy-saving chips and software.
Noah Horowitz, senior scientist at the Natural Resources Defense Council in San Francisco, applauded Google for releasing the figures but cautioned that despite the advent of increasingly powerful and energy-efficient computing tools, electricity use at data centers was still rising, as every major corporation now relied on them. He said the figures did not include the electricity drawn by the personal computers, tablets and iPhones that use information from Google’s data centers.
“When we hit the Google search button,” Mr. Horowitz said, “it’s not for free.”
Google also estimated that its total carbon emissions for 2010 were just under 1.5 million metric tons, with most of that attributable to carbon fuels that provide electricity for the data centers. In part because of special arrangements the company has made to purchase electricity from wind farms, Google says that 25 percent of its energy is supplied by renewable fuels, and estimates that it will reach 30 percent in 2011.