Digital Diet; April 2008; Scientific American Magazine; by David Biello; 2 Page(s)

Telecommuting, Internet shopping and online meetings may save energy as compared with in-person alternatives, but as the digital age moves on, its green reputation is turning a lot browner. E-mailing, number crunching and Web searches in the U.S. consumed as much as 61 billion kilowatt-hours last year, or 1.5 percent of the nation's electricity--half of which comes from coal. In 2005 the computers of the world ate up 123 billion kilowatthours of energy, a number that will double by 2010 if present trends continue, according to Jonathan Koomey, a staff scientist at Lawrence Berkeley National Laboratory. As a result, the power bill to run a computer over its lifetime will surpass the cost of buying the machine in the first place--giving Internet and computer companies a business reason to cut energy costs, as well as an environmental one.

One of the biggest energy sinks comes not from the computers themselves but from the air-conditioning needed to keep them from overheating. For every kilowatt-hour of energy used for computing in a data center, another kilowatt-hour is required to cool the furnace-like racks of servers.