Next to labor, energy represents the biggest expense associated with running a data center. On Wednesday, Interop attendees learned ways to reduce those costs and save thousands of dollars.Most companies could realize some big savings by implementing energy management best practices in their data centers, said Eaton Electrical product manager Chris Loeffler, speaking Wednesday at Interop. "There's some low hanging fruit to be had," said Loeffler.

With that, he outlined a seven-step path to a greener data center.

Step 1 is straightforward: turn off idle IT equipment. "For every idle moment, that's money in, nothing out," said Loeffler. The solution: power down or retire underutilized servers and storage devices.

Step 2 means taking advantage of IT's hottest buzzword: virtualization. Loeffler said putting workloads onto 'virtual machines' dramatically improves capacity utilization because it eliminates the need for specialized devices -- say, a server that houses a critical but infrequently used application.

Step 3 involves leveraging dense configurations like blade servers to consolidate workloads onto as few systems as possible. Blade servers also are more efficient than traditional gear because they take advantage of common power supplies, fans, and other components, Loeffler noted.

Step 4 is simple: Most CPUs have power management features that regulate energy consumption -- make sure they're turned on.

Step 5 may not be obvious, but it's important. Loeffler said standard power supply units are highly inefficient -- bleeding off as much as 20% of energy before it even gets to the server. A data center with 1,000 servers could save as much as $130,000 annually simply by switching to power supplies that operate at 90% efficiency and voltage regulators that operate at least at 85% efficiency.

Step 6: Loeffler said companies need to play it cool if they want to cut data center energy costs. That means using "blanking panels" so air from hot aisles doesn't mix with air from cold aisles. Loeffler also suggested orienting air conditioning units close to enclosures and perpendicular to hot aisles to maximize cooling.

Step 7: Lastly, Loeffler said, data center managers need to audit their facilities regularly to gain a better understanding of energy inflows and outflows. Data center managers should, at the very least, be able to determine how much of their power budget is devoted to IT systems, and how much to support systems.

Being green may not be easy, but it can be a big money saver.