Some key findings:
Electricity used in US data centers in 2010 was significantly lower than predicted by the EPA’s 2007 report to Congress on data centers.
The dominant driver of electricity demand from 2000 to 2005 was growth in the installed base of volume servers, which doubled over that five-year period for the US and the world. The growth in volume servers slowed considerably in the 2005 to 2010 period, growing only about 20% in the US and about one-third in the world. The installed base of mid-range servers fell even faster than expected in the earlier forecast, but high-end servers grew rapidly instead of declining as had been projected earlier.
The 2007 EPA report to Congress on data centers (US EPA 2007) predicted a little less than a doubling in total data center electricity use from 2005 to 2010 if historical trends continued. But instead of this, In the U.S., the electricity used by data centers from 2005 to 2010 increased about 36 percent instead of doubling. And worldwide electricity consumption by data centers increased about 56 percent from 2005 to 2010 instead of doubling.The following figure plots the graph from that study with the range spanned by the Lower and Upper Bound estimates from the new study for the US.
According to Koomey that range coincidentally overlaps with the EPA report’s “Improved operations” scenario, but the main reason for the lower estimates in this study is the much lower IDC installed base estimates, not the significant operational improvements and installed base reductions from virtualization assumed in that scenario (emphasis made by Infrarati). Of course (according to Koomey), some operational improvements are captured in this study’s new data (in the form of PUEs less than 2.0) but they are not as important as the installed base estimates to the results.
This is truly a remarkable statement. Despite changes in infrastructure efficiency (PUE reduction), changes in server technology, and the increased prevalence of virtualization technology in data centers (higher server utilization levels) growth in electricity use at data centers slows down mainly because of a lower installed base then expected.
This raises the question whether the green IT movement has really influenced data center energy usage and slowed the growth in electricity use at data centers. According this report the biggest contributor seems to have been the 2008 financial crisis and its accompanying economic slowdown, which led to significant reductions in the installed base of servers in data centers worldwide.
Making predictions of trends after 2010 is difficult. But given the fact of the rapid digitization of our society, developing countries becoming developed countries and that better economic times will come it is reasonable to expect that energy consumption trend will rise again unless we put more effort to green IT.