'The [electricity] cost is one thing,' said Williams, 'but an outage is devastating and will cost me a lot more than the increase in energy costs.'

Electricity costs vary widely, depending on fuel source, with states that are dependent on natural gas paying the most for electricity, according to Robert Burns, a senior research specialist at the National Regulatory Research Institute at Ohio State University in Columbus. Nationally, electric costs are up about 8 percent this year. The states seeing the smallest increases are those in the northern Midwest, where a fair amount of the electricity is generated by coal-fired plants.

Bill Hunter, data center manager for a telecommunications company in Washington state that he did not want identified, said the most important factors in locating data centers are environmental issues -- such as the risk of experiencing an earthquake, tornado or hurricane, for example -- as well as power reliability, water supply and labor. While large companies with data centers on the order of 100,000 square feet can try to curb cost increases by negotiating their own rates, Hunter said there are other things a company can do to control electricity costs. Possible steps include the use of cooling pumps with variable frequency drives that only work as needed.

Energy spending tends to be a relatively small percentage of an overall IT budget, according to Frank Scavo, president of Computer Economics Inc. in Irvine, Calif. Facility costs and the expense of maintaining a physical infrastructure -- which would include power -- usually amount to about 4 percent of a total IT budget. That means electrical power would be an even smaller percentage of the total.

'It's unlikely that a company would decide to move a data center solely on the basis of rising local electrical rates,' said Scavo. Nevertheless, for a company that's in the process of deciding where to locate or relocate a data center, 'electrical costs could be a factor in choosing one location over another. I would say that reliability of the power supply would be more of a concern than cost,' Scavo said.