The electricity consumed by a server over its lifetime is likely to cost as much as the server itself if energy costs continue to rise, according to one analyst. That should make energy efficiency a key concern for data center managers--and it’s a concern that server vendors are increasingly addressing.

"If you take a server where the processor is using 80 to 90 watts, and factor in all the other hardware to support that--air conditioning, storage and so on--the cost of the electricity used by that server is on a par with the cost of the server over its life," said Steve Prentice, vice president and director of research at Gartner, speaking at the International CeBIT Forum in Hanover, Germany, last week.

"I don’t see IT managers replacing servers just for environmental reasons, but if it’s to slash 40 percent to 50 percent off electricity costs, that’s serious money," Prentice said.

As technology evolves, indirect energy costs such as cooling are increasing, according to Prentice. "In the data center, as the density of hardware increases, then heat is a bigger problem," he said.

Vendors’ experience of customers’ concerns at the CeBIT trade show bears that out.

"They are asking more in the area of small blade servers, because they want to calculate the total power consumption in their blade server farm," said Bernd-Dieter Heise of Fujitsu-Siemens Computers GmbH.

Making that calculation can require a detailed knowledge of a server’s specifications.

Fujitsu-Siemens has long prided itself on the energy consumption of its servers. A PrimeQuest 400 with 32 Itanium processors and 1T byte of memory consumes 10.7 kilowatts of electricity and, fully equipped, has a list price of around €900,000 (US$1.08 million), according to Heise. A comparable system from a rival vendor consumes 16 kilowatts, he said.

Sun Microsystems, too, touts the reduced power consumption of its newest servers, equipped with Sun’s UltraSparc chips.

The power and space savings that can be realized by using such servers can be a tough sell, though. "The marketing teams just want speed. They don’t think of power, space and cooling," said Steve Campbell, Sun’s vice president of datacenter insight.

That could change as more customers realize how much they spend powering their data centers. The University of Tokyo recently found power to be its largest budget item, at over $1 million a year, according to Campbell.

Not everyone is worried about their IT electricity bill, though, according to Fujitsu-Siemens’ Josef Zitzlsperger, also working on the company’s stand. "For mainframe customers, it’s not a priority," he said.