Large companies with data centers on the order of 100,000 square feet can try to curb energy cost increases by negotiating their own rates, Hunter said. He added that there are other things data center managers can do to control electricity costs, such as using cooling pumps with variable-frequency drives that work only as needed.

Users in the Northeast, in particular, are seeing big energy-cost increases. In Connecticut, for instance, electric rates for both commercial and residential customers have so far risen more than 17 percent this month -- and they're scheduled to go up by another 5 percent in April. Electricity costs vary widely depending on fuel sources, with customers in states that rely on natural gas typically paying the most, according to Robert Burns, a senior research specialist at the National Regulatory Research Institute at Ohio State University in Columbus. For instance, power costs have always been high in the Northeast because of the region's dependence on fuel supplies from elsewhere.

Connecticut officials believe that the state's higher rates "are right in line" with increases elsewhere in New England, said Beryl Lyons, a spokeswoman for the Connecticut Department of Public Utility Control in New Britain.

"I don't care where you go -- the price of generating electricity has gone through the roof because for the most part, it uses fossil fuels," Lyons said. "There wasn't anything we could do on this one."

Nationally, electric costs are projected to go up about 8 percent this year, Burns said. The states seeing the smallest increases are those in the northern Midwest, where coal-fired plants generate much of the electricity.