Martin Mittelstaedt Saturday’s Globe and Mail, March 28, 2009 What’s eating one per cent of the world’s electricity?
AS people turn off the lights for Earth Hour this evening and ponder their electricity use, one of the world’s most rapidly growing power guzzlers – for which nearly everyone carries responsibility – is largely hidden from view.
It’s the network of data centres and their servers that are the invisible backbone of the Internet. The popularity of all the twittering, blogging, music downloading, and Facebooking has had a little-known environmental downside, by boosting the demand for electricity to run these centres.

The vast, worldwide scope of the Internet makes it difficult to calculate just how much power the Web and its related activities consume, but the amount is substantial and has become the subject of studies in scientific journals.

Most of the researchers pondering the question of this power usage have focused on data centres and their servers. These centres are enormous energy gluttons, with the servers consuming so much energy they’re always at risk of overheating, so companies have to spend about as much on electricity to air-condition the devices as they do running them.

While a person sitting behind a computer realizes they’re using electricity, that’s only the beginning of the power consumption story. Ask Google to do a search and follow it up by clicking the link, or post a blog, and you’re relying on servers and their stores of data and applications.

Servers are non-descript pieces of electronic hardware, each about the size of a pizza box. They typically consume about 200 watts of electricity apiece, or about the same amount needed to run 13 compact fluorescent light bulbs.

While one server has modest power demands, there is so much Internet activity that millions of them are needed. At data centres, servers are stacked in cabinets like CDs in a storage rack. A typical data centre has about the same floor space as 15 monster homes, and thousands of servers.

The concentration of many servers in one place is the reason they need so much air conditioning. When they’re operating, servers collectively generate waste heat, so a constant flow of cool air around them is required to keep them from being damaged by overheating.

U.S. researcher Jonathan Koomey from California’s Lawrence Berkeley National Laboratory has done some of the most extensive calculations on electricity use at data centres, and estimated that they accounted for about 1 per cent of total world electricity consumption in 2005, according to a paper he authored last year that appeared in Environmental Research Letters.

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