With both Internet services and power costs soaring, big technology companies are scouring the nation to secure enough of the cheap electricity that is vital to their growth.

The search is being led by companies including Microsoft Corp., Yahoo Inc. and IAC/InterActiveCorp. Big Internet firms have been adding thousands of computer servers to data centers to handle heavy customer use of their services, including ambitious new offerings such as online video.

But that is feeding a thirst for more power. One large data center can consume enough juice to power a small city of 30,000 to 40,000 people -- and also requires a fat Internet linkup to stay connected to the outside world. The power-guzzling centers are such big energy users that shaving as little as a penny per kilowatt-hour from electricity rates can knock off millions of dollars in annual expenses.

Some Internet executives say electricity has become a closely watched expense and can even be a factor when they consider rolling out new services. While always a concern, the cost of power has become more important amid a recent run-up in energy prices and increased use at data centers.

To satisfy their power needs, Internet companies are exploring options ranging from building facilities in former defense bunkers -- which already have rugged grid connections -- to plunking themselves down near hydroelectric plants to get a slice of the inexpensive power. Anticipating demand a decade from now, some executives even are mulling whether proximity to nuclear-power plants could be a plus.

The scramble serves as a reminder of the strategic physical issues facing companies whose most visible presence is on the Internet. For all the popularity of on-screen features of Yahoo's or Google Inc.'s Web sites, their long-term prospects could increasingly depend as well on how they manage such physical considerations as power. The push echoes similar scrambles decades ago by heavy manufacturing companies, such as aluminum producers, to locate in the Northwest where there were large supplies of inexpensive electricity for their smelters.

For the big Internet players, "it's a limiting factor to their growth," says Jason Shepard, a practice leader at CB Richard Ellis, a commercial real-estate brokerage in El Segundo, Calif., who advises some of those companies in their searches for data-center sites.

At Microsoft, for instance, data-center power consumption has roughly doubled over the past four years and Debra Chrapaty, vice president for Windows Live Operations, predicts it will triple or more over the next five.

In their search for power, many companies have recently turned to eastern Washington. Prices there are among the lowest in the nation. But most of the power from big federal dams like the nearby Grand Coulee is tied up under complicated, long-term arrangements.

Over the next decade, however, re-licensing of a handful of utility-owned dams is set to occur in three counties -- loosening contractual arrangements for the first time in a half-century. The public-utility districts will be able to lay claim to power they have been furnishing to other utilities such as Seattle City Light and Portland General Electric Co.

This has created room for watchful companies to swoop in and lock up supplies of cut-rate electricity in what may be a once-in-a-generation opportunity.

Microsoft and Yahoo recently delivered a jolt to locals in the tiny farming community of Quincy -- population 5,044 -- when both announced plans to build big data centers in the Grant County town, which lies a few hours east of Microsoft's headquarters, on the dry side of the Cascade Mountain range.

Together, the companies will consume as much as 90 megawatts of electricity, local officials say, pushing up total electricity consumption by about 32 percent in the county of 81,000 people. (A megawatt equals one million watts.) Until now, the area's big energy users have been frozen-food-processing plants.

Microsoft, based in Redmond, Wash., initially will pay 1.8 cents a kilowatt-hour for power at its Quincy plant -- one-third or less of the cost of power at its other data-center locations. (A kilowatt-hour is the amount of power consumed in an hour by 10 100-watt bulbs.) When its facility is complete, it will consume up to 48 megawatts of electricity at prices expected to bump up to 2.6 to 2.9 cents a kilowatt-hour, say local officials, but that price should remain fairly constant for years.

That is a substantial savings. Nationally, the average industrial price of electricity was 5.1 cents a kilowatt-hour in 2004, the most recent year for which figures are available. The amount almost certainly has increased since then due to rising natural-gas prices.

Microsoft's Ms. Chrapaty says the company expects a cut of 30 percent to 40 percent in data-center power costs company-wide over the next two years, thanks partly to the low hydropower rates in eastern Washington. "The way we manage that has an enormous impact on our bottom line," she says.

In Wenatchee, Wash., noted for its apple cold-storage facilities, Yahoo has signed a 10-year lease at the Confluence Technology Center and intends to install a data center there. Currently, industrial customers pay 1.8 cents a kilowatt-hour for power in Chelan County, Wash. The price could drop even further once existing contracts expire on dam projects after 2011. Though it is limited to five megawatts at that price, the utility is exploring lifting that restriction.

Yahoo also has bought 50 additional acres of land in Quincy to build a separate data center. At the same time, the company plans to move out of a number of other facilities elsewhere in the U.S. when its leases expire, partly because they are located in areas where electricity costs are higher.

Yahoo Chief Financial Officer Susan Decker says power cost and supplies have become a growing consideration over the past few years with the explosion of consumer use of the company's services. Today, electricity represents roughly 20 percent to 50 percent of the total cost of running a data center, she estimates. "We watch it carefully," says Ms. Decker. She notes, however, that power remains a minor part of Yahoo's overall costs, one of a number of expenses that together represent less than 20 percent of its revenue.

IAC's Ask.com search division also decided last year to set up a data center in eastern Washington, in large part because of the availability of low-cost power, and local officials predict other technology companies will follow. But Dayne Sampson, senior vice president of information technology and operations at Ask.com, says it is tricky predicting future power needs amid the rapid growth in services. "Trying to forecast five years from now is really just sticking a finger in the wind," he says.

Bill Riley, director of the Big Bend Economic Development Council in Moses Lake in Grant County, says Google and others have been looking over the area. "The minute they talk about going in, the prices go up on everything," says Mr. Riley. "So it's understandable they don't want to discuss their plans until they have contracts."

Google declines to comment on any such interest, or any specific existing or planned data centers. Its senior vice president for operations, Urs Holzle, says power is one factor the Mountain View, Calif., company considers when deciding where to locate data centers, and in some cases high power rates discourage Google from expanding existing facilities. But he says the company isn't very concerned with the supply or cost of electricity today.

Google is preparing to power up a new data center on a 30-acre tract at The Dalles, Ore., but it is getting the electricity from a small utility that depends on the federal hydropower wholesaler Bonneville Power Administration, say officials at the small utility supplying Google. If Google keeps its data center's use below 10 megawatts of juice the first year and holds annual increases to 10 megawatts or less thereafter, its utility will be able to procure electricity at about 3.4 cents a kilowatt-hour. If use outstrips that amount, the price could double, according to Dan Bloyer, a Bonneville account executive.

Mr. Holzle says the "power inefficiency of computing and networking equipment," if not adequately addressed, could make the cost of electricity a concern for Google within five to 10 years. Semiconductor companies and other hardware companies have recently sharpened their focus on reducing power consumption, largely in response to demands of big corporate and academic customers wrestling with growing electricity bills.

Data-intensive firms are scouting for sites in other states like Texas. Michael McCluskey, senior vice president of Austin Energy, says the utility has more than 200 megawatts of demand from data centers now, about 8.5 percent of its total customer demand, and it is in talks with firms that could push up data-center use by another 120 megawatts. "We're seeing that business pick up quite a lot," he says. "When they approach us, we have a whole package ready to offer them now."

And the search for data-center power is taking tech companies to some truly unexpected places. Microsoft says sites it has examined include a former urinal warehouse and underground caverns two miles below the earth. When its staff looked at a candidate site outside the U.S. recently, the power went out. Microsoft decided against locating there.