"When we work with vendors, we really hold them to keep their energy consumption down," he says.

Higher use, lower cost

Thornton describes a method of achieving energy efficiency in the data center that, while simple, seems to run contrary to the way data centers have been structured for years: By getting the maximum use out of existing servers, companies can avoid powering unused portions of their machines and therefore spend less money on energy. This approach -- known as high-utilization and often dependent on such technologies as virtualization, which can turn dedicated servers into multifunction computers -- means servers spend the most time possible processing tasks and the least time sitting idle, yet still on.

"What people aren't paying attention to is the idea of high utilization," says Andrew Kutz, an analyst with Burton Group. Organizations -- in particular, online ones where delays in server response times can lead directly to dollars lost -- have become so obsessed with making sure their servers are functioning at top efficiency during peak traffic times that they're not using a large percentage of the servers' processing power during off times -- yet they're still powering these servers.

Let's say an application server can handle a maximum of x simultaneous requests from users, yet that level of requests is achieved only a small percentage of the time. That means the rest of the time, a portion of the server's processing power is unused but still draws energy.

"Companies need to focus on their servers being highly utilized," Kutz adds. That can be achieved without affecting performance through such techniques as virtualization and power management.

For example, the SDSC is planning to replace about 20 dual, single-core-processor Dell servers. Each consumes about 400 watts with five dual, quad-core processor Dell servers that each consume about 300W. Thornton plans to virtualize the operating system and combine applications on these fewer servers so there is minimal impact to users.

What this consolidation means to energy efficiency -- and the bottom line -- is significant. Each of the existing 20 servers consumes 400W, with a total power draw of 8,000W; the five new servers each will consume 300W, with a total power draw of 1,500W, but will offer the same computing power.

"During less than their lifetime, [the new servers] will have paid for themselves on utilities savings alone," Thornton says. "Not to mention savings of freed-up power and cooling equipment, space, and other data center infrastructure."

In addition, the SDSC has instituted a chargeback mechanism for users who install their own IT equipment in the center, Thornton says, charging them more for high-consumption machines and less for energy-efficient architectures.

"We're trying to encourage the users of the data center to limit power use and upgrade what they have on the floor to new machines," Thornton says. "The key is aligning incentives with targeted outcomes -- in this case, energy efficiency."