Growth in data center electricity use 2005 to 2010 by Jonathan Koomey “describes trends in data center electricity use since 2005. It builds upon Koomey’s 2008 study: Koomey, Jonathan. 2008. Worldwide electricity used in data centers. Environmental Research Letters. vol. 3, no. 034008. September 23. Key findings from the new study are as follows:

• Assuming that the midpoint between the Upper and Lower bound cases accurately reflects the history, electricity used by data centers worldwide increased by about 56% from 2005 to 2010 instead of doubling (as it did from 2000 to 2005), while in the US it increased by about 36% instead of doubling.
• Electricity used in global data centers in 2010 likely accounted for between 1.1% and 1.5% of total electricity use, respectively. For the US that number was between 1.7 and 2.2%.
• Electricity used in US data centers in 2010 was significantly lower than predicted by the EPA’s 2007 report to Congress on data centers. That result reflected this study’s reduced electricity growth rates compared to earlier estimates, which were driven mainly by a lower server installed base than was earlier predicted rather than the efficiency improvements anticipated in the report to Congress.
• While Google is a high profile user of computer servers, less than 1% of electricity used by data centers worldwide was attributable to that company’s data center operations.”