Over recent years people have become concerned about the amount of electricity used by servers and other Internet infrastructure and we often have an image of data centres as being huge machines with an insatiable appetite for electricity. This isn't so, says Koomey, who estimated the amount of electricity consumed by data centres around the world using more detailed data than was available for previous studies. The data included electricity used by servers, data centre communications and storage equipment.
Koomey defines a data centre as any space that houses servers, such as data closets and server rooms. However the definition does not include telecommunications central offices that house telephone switches, routers and other large-scale network equipment. His study estimates total electricity consumed as the product of the number of servers and the electricity used per server (derived from a detailed analysis of server models reported by analysis firm IDC). Power use was based on manufacturer data.
Koomey found that worldwide electricity consumption by data centres doubled from 2000 to 2005 (see figure 1). This represents an aggregate annual growth rate of 16.7% per year. Roughly 80% of this growth can be attributed to growth in electricity used by servers, 10% to growth in electricity use associated with data centre communications, and 10% to storage equipment.
Assuming that the IDC forecast of worldwide server installed base is correct, global electricity use by data centres will likely increase by 76% by 2010 if current trends continue, says Koomey. This result also implies that the average annual world growth rate in data centre electricity for 2005 to 2010 will be around 12% compared to the 16.7% per year growth that prevailed from 2000 to 2005, he added.
Data centres in the US and Europe make up about two thirds of the world total, with Japan, Asia Pacific and rest of world each contributing to between 10 and 15% of the total, Koomey found. Consumption in the Asia Pacific region (excluding Japan) increased from around 10% of the total in 2000 to over 13% in 2005, which reflects the important economic growth in China, India and other Asian economies during this time. Indeed, data centre electricity use in the Asia Pacific region grew at an annual rate of 23%, compared to the world average of 16.7%.
"Data centres don't actually use that much power considering how important they are for improving efficiency in the broader economy," he told environmentalresearchweb.
Koomey expects companies and governments to focus their efforts on making institutional changes that will enable substantial efficiency improvements in these facilities. "Right now, data centres represent capital that is vastly underused and inefficiently operated," he added. "This will have to change if we hope to deliver the IT services embodied in the next generation of Internet applications."
He is now looking into trends in costs, performance and energy use of servers to understand drivers affecting energy consumption in the data centres of the future.
Koomey published his work in Environmental Research Letters.