Between the power needed to run the computer equipment itself and the energy used to heat and cool it, data centers can be intensive users of energy. "In a data center, energy typically is the highest cost," says Dale Sartor, a staff engineer with Lawrence Berkeley National Laboratory, a Department of Energy National Lab.
The amount of energy used by data centers captured policymakers' attention in 2007, when the Environmental Protection Agency (EPA) published its "Report to Congress on Data Center Efficiency," says Don Beaty, founder of DLB Associates, an engineering firm. In the report, the EPA estimated that by 2011, the country's data centers and servers would consume, to 100 billion kWh (kilowatt hours) of energy.
Two categories of energy savings usually are possible in a data center, Sartor says. One results from increasing the efficiency of the systems themselves, while the other comes from boosting the efficiency of the infrastructure supporting the IT equipment.