Data centers consume approximately 1.3% of worldwide electricity use. This indicates a slowdown in growth of energy consumption, a study shows. The reasons for the less-than-expected growth are the 2008 financial crisis and the combined effort of the industry to make servers more energy efficient.

The study compares the growth figures of the time period 2000-2005 with those of 2005-2010. In 2000 the total electricity consumption for all uses world wide was 13238 BkWh. The total electricity used by data centers world wide was 70.8 BkWh. Which means that data centers used 0.53% of the world’s total electricity consumption. By 2005 that percentage had almost doubled to 0.97%, the servers consuming 152.5 BkWh of the world’s total 15747 BkWh.

If that trend had continued unabated, in 2010 data centers would have been good for 2.2% of the world’s total electricity consumption of 18118 BkWh. But that’s not what happened. Instead, data centers consumed 235.5 BkWh, 1.3% of the world’s total in 2010.

This is the surprising conclusion of a study by Jonathan Koomey, professor in the civil and environmental engineering  department at Stanford University, conducted at the request of the New York Times. The outcome is surprising because based on an analysis of the historical 2000-2005 figures Koomey predicted a 76% growth over the next five years. Instead, growth declined to 56%.

There are several reasons for the decline despite the continuing explosive growth of computing. For one, fewer servers have been installed than was expected. On the one hand this is a consequence of the 2008-9 financial crisis. But it is also the result of increased virtualization in data centers enabling servers to perform different tasks. Secondly, data centers are increasingly more energy efficient. Since 2006 the industry is focusing on efficiency as a result of two public meetings held about the subject sponsored by the US Environmental Protection Agency (EPA).

Server energy efficiency is measured in Power Usage Effectiveness (PUE). PUE measures the amount of power needed to run the actual IT applications  against the amount needed for supporting functions such as cooling and infrastructure. A PUE of 2.0 means that for every kWh going into IT applications another kWh is spend on the supporting environment. For his calculations Koomey assumed a PUE of 2.0 for the 2000 and 2005 data centers. He lowered the 2010 PUE to 1.83 reflecting the improved energy efficiency of data centers.

Koomey gives special attention to Google. Google is obviously a big player in the data center industry but it is secretive about the actual amount of servers it operates. Koomey could not get his hands on that specific number. To calculate the fleet of servers in the entire world he checked how many servers were sold over that period of time. But Google doesn’t buy servers it assembles its own.

An educated guess by sources of New York Times reporter Miguel Helft puts the number on 1 million servers. After reviewing the report Jacob Jacobowitz of Google was willing to disclose to Mr. Koomey that Google consumed less than 1% of the world’s total data center electricity use. This led Koomey to adjust the number of servers to 900.000 with an average PUE of 1.16, a figure derived from Google's website.

If these figures are correct Google owns 2.8% of the total amount of servers in the world but using only 1% of the total electricity usage. Supporting Googles claim that is has the most efficient data centers in the world. By far.

Source: New York Times

photo: Paradigmchronicle

Edit: 'fewer servers' instead of 'less servers'