EFFICIENCY: Curbing the energy appetites of big computers

By Saqib Rahim, E&E reporter, in Climate Wire. January 7 2010

Every night, as billions of people lie down to sleep, the computers that power the Internet hum on.

In grants announced yesterday, the Energy Department will fund firms that want these computers to use less juice -- while standing ready if Web traffic should surge.

Search engines like Google and e-commerce giants like Amazon use warehouses with flights of computers to handle the billions of clicks that come their way. These "data centers" take volumes of energy, not just to power their circuits but also to keep them from overheating.

Much of that energy also goes to driving the computers around the clock, even when they're doing almost nothing at all.

Among 14 grants made yesterday to information and communication technology companies, several seek to align energy use more closely with actual Internet traffic.

Companies rarely run their computers at full capacity. Instead, they run at a fraction of the total information they can handle -- somewhere between 10 and 50 percent. That way, if there's a sudden spike in Web interest, such as a plane landing on the Hudson River, they have headroom.

Unfortunately for the climate, and these companies, using a tiny part of a computer's brainpower doesn't mean the machine's energy appetite shrinks accordingly.

Consider a computer running at full steam, said Fred Chong, a professor who researches computing at the University of California, Santa Barbara's Institute for Energy Efficiency. Once the computer has finished all its tasks, its energy use doesn't drop to zero -- it drops to about half.

Getting electric bills that don't compute

"It's wasting a lot of energy when it doesn't do anything," Chong said.

That fact has increasingly drawn the attention of major dot-coms, which have seen the price of electricity spike and concern about climate change grow.

Chong said Google has pushed the idea of "power proportionate computing": "having computers that use energy that's proportional to the amount of work that they're doing."

One recipient of the DOE grants, Santa Clara, Calif.-based Power Assure, hopes to treat the computers like automatic lights in a building, which switch off when everyone goes home.

In a press call, CEO Brad Wurtz said the company can help a bank turn on more servers in the evening, when people are more likely to use online banking -- and dial them down at 3 a.m., when only a few night owls log on.

In 2006, data centers used about 1.5 percent of the electricity consumed in the United States, according to DOE -- a figure that's expected to grow rapidly as computers become more important to the global economy.

Early efforts to cut energy use have focused on making the actual buildings, and the computers themselves, more efficient. Technicians have improved efficiency in the massive air conditioning systems used to cool the servers. Researchers are looking for new devices that let them run at lower temperatures.

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