The report’s estimates, although based on reputable data, still contain some uncertainties. One of these, Koomey says, involves measuring the number and type of Google’s servers. Google–and potentially other companies–uses servers that don’t fall into any of the three main categories of server that the report includes: volume-class servers (which cost less than $25,000 per unit), mid-range systems (between $25,000 and $500,000 per unit), and high-end systems (more than $500,000 per unit). The company instead buys motherboards, the main circuitry of a PC, and uses them to custom-design servers. “Those wouldn’t come under the IDC definition of ‘server,’” says Koomey. “They fall under the PC category.” To estimate the potential impact of Google’s servers on the findings, Koomey used a New York Times-reported estimate of 450,000 Google servers. Assuming this and other power estimates are correct, Koomey claims that Google’s servers would increase electricity consumption in the volume class of server by about 1.7 percent.
Still, the starting point is solid enough for researchers to use the findings as input for a study on data-center power consumption mandated by a recent Congressional bill. In December 2006, the Senate approved legislation introduced by Representatives Anna G. Eshoo, D-California and Mike Rogers R-Michigan, requiring research into reducing the power consumption of servers and data centers. “This will be used to inform that process,” Koomey says.
Koomey expects that the report will spark industry-wide improvements, from energy-saving microprocessors and chip architectures to more-efficient cooling technology and software that helps distribute the workload in data centers more resourcefully. “I think in the data-center area, there is a lot of opportunity for improvement,” Koomey says.