By 2011, the majority of U.S. enterprise data centers will face disruptions caused by rising energy costs and the need to increase power supplies and floor space, a market research firm said.

In fact, during the next five years, most large data centers will spend as much on power and cooling as they will on hardware infrastructure, Gartner said on Tuesday. "CIOs of large U.S. organizations must prepare for a period of rapid changes in their data centers," Gartner analyst Rakesh Kumar said in a statement.

More than 70% of the Global 1,000 organizations will have to modify their data center facilities significantly during the next five years, Gartner said. The reason is most facilities in use today were built more than seven years ago, and built to a design specification of 100 to 150 watts per square foot. Current design needs, however, are about 300 to 400 watts per square foot.

By 2011, power demand could rise to more than 600 watts per square foot. "The implication is that most current data centers will be unable to host the next generation of high-density equipment, so CIOs will have to refurbish their established sites, build new ones, or look for alternatives, such as using a hosting provider," Kumar said.

Future technology, coupled with growth, is expected to lead to the need for more power and cooling, more floor space, and better optimization tools and modeling techniques to manage upwardly spiraling energy costs.

One trend that may counter Gartner's predictions is server virtualization, which many businesses are now starting to use to reduce the number of physical servers in their data centers. At the recent InformationWeek 500 conference, a number of businesses reported that they had substantially cut back on the number of servers they were using because virtualization had let them operate their computers more efficiently.

Still, Gartner predicts that during the next three or more years, midsize and large data centers will be increasingly leaning on hosting services, something U.S. companies have been reluctant to do in the past. This trend will be driven by the capital cost of a new, owned data center versus the less expensive, ongoing operational costs of leased space. "We expect this hosting market to become very attractive during the next few years, so users should move quickly to secure good prices," Kumar said.

The United States has the biggest concentration of large data centers, which Gartner defines as more than 50,000 square feet.