The electricity used by data centres doubled between 2000 an 2005 and much of the call to action to address the issue has been based on predictions that it could double again by 2010. But new research suggests that the growth has slowed significantly, growing by 56% from 2005 to 2010, even less in the US at 36%.
The research comes from a new study by Jonathan Koomey entitled "Worldwide electricity used in data centers" which can be downloaded here. Koomey is Consulting Professor, Stanford University, and has researched and written extensively on resource use, particularly electricity, by IT equipment.
Key findings from the new study are:
• Growth in the installed base of servers in data centres had already begun to slow by early 2007 because of virtualisation and other factors.
• The economic slowdown that started in 2008, combined with further improvements in virtualisation, led to a significant reduction in the server installed base by 2010, compared to the IDC installed base forecast published in 2007.
• Growth in electricity used per server probably accounted for a larger share of demand growth from 2005 to 2010 than it did in 2000 to 2005.
• Electricity used in global data centres in 2010 accounted for between 1.1% and 1.5% of total electricity use. For the US that number was between 1.7 and 2.2%.
• Electricity used in US data centres in 2010 was significantly lower than predicted by the EPA’s 2007 ‘Report to Congress on Server and Data Center Energy Efficiency’.
The bottom line is that in 2010 electricity use by data centres was about 1.3% of all electricity used worldwide. In the US, data centres accounted for 2% of all electricity used.
Well its good news that data centre electricity use has slowed, but there are two points to note here:
1) In the study the lower than predicted energy use is attributed mainly to a lower server installed base than was expected, rather than the efficiency improvements anticipated in the report to Congress. So while the actual level of energy use in 2010 fell within the EPA’s ‘Improved operation scenario’ predictions from 2007, it’s primarily down to the recession.
2) The report also says that electricity used per server has been a more important factor in growth in data centre power use in recent years. This can be seen as a positive factor, on the grounds that virtualisation has resulted in greater individual server utilisation. But while virtualisation is widespread, there is still a long way to go before all servers are virtual – many are not.
The results indicate that there is still some way to go in making servers more energy efficient. A server doing nothing can be consuming as much as 60% of the energy it needs when working flat out. Addressing that issue looks increasingly like a green IT priority.