SOMERSET COUNTY, Pa. -- Bob Will stood on a ridgeline of his farm recently. Red-tailed hawks soared overhead. Songbirds twittered in the pasture. A blue-black storm approached on the horizon, pushing a stiff wind ahead of it.

As he talked about the benefits of wind energy -- namely the clean electricity it puts out on the national grid and the cash it puts in his pocket -- the shadows of huge windmill blades swept over and over these low green mountains in southwest Pennsylvania.

"It all seems like a good idea to me," said Will, who leases part of his land to Florida Power and Light, the largest generator of wind power in the United States.

Long based in the West and the Great Plains, wind energy is rapidly expanding in the East, where hundreds of wind turbines have been built and hundreds more are planned, including three possible sites in Western Virginia.

But a scarcity of definitive, long-term studies on the economic and environmental effects of wind power continues to fuel a controversy over its benefits, such as emissions-free electricity, and drawbacks, including dead birds and bats.

Among the sites being considered for wind turbines in Appalachian states is Highland County, where the first wind farm in Virginia has been proposed. Opponents say the 19-turbine project would industrialize Highland County, a pastoral and sparsely populated setting of rugged peaks and valleys where sheep outnumber people.

Supporters say the project would pump about $200,000 in tax revenue into the county's ailing economy. State officials are reviewing the proposal, which faces lawsuits from opponents.

Wind developers also are considering Roanoke County's Bent and Poor mountains and Patrick County's Bull and Belcher mountains and the Mountain View area of Meadows of Dan.

Nationwide, wind power has been hailed as a source of clean, renewable energy and a moneymaker for ailing rural communities. But its rapid expansion in the East has intensified concerns about bird and bat deaths, altered landscapes and other environmental and economic issues.

More than two decades after the first U.S. wind turbines were erected in California, supporters and opponents continue to dismiss each other's claims as biased.

Some conservationists and residents say the turbines aren't worth huge federal subsidies, or that they're so inefficient they can do little to reduce America's dependence on fossil fuels. Wind turbines work only when the wind blows, and their power can't be stored, a problem because the winds typically are weaker in summertime when electricity demand is highest.

Opponents say the turbines aren't worth the damage to ecosystems and communities in the East, an area more densely covered by people, migratory flyways and fragmented forests than the wide-open West, where turbines nonetheless kill thousands of birds a year.

The U.S. Fish and Wildlife Service recommends three years of study before a wind farm is built, but the wind industry doesn't follow those voluntary guidelines, saying it would amount to a moratorium on wind power.

"From an ecological standpoint, I think wind turbines pose the greatest threat to the forest interior in the mid-Atlantic region today," said Dan Boone, a wildlife scientist and wind policy analyst.

Wind energy supporters disagree, including some environmentalists who want stricter standards on where wind turbines can be built but who praise them as nonpolluting energy sources.

"We're contributing to home-grown, renewable power [in Eastern states], and I think the region can gain a lot of economic opportunity, too," said Frank Maisano, an energy industry spokesman.

Less than 5 percent of the potential wind energy in the country lies east of the Mississippi, according to the National Renewable Energy Laboratory, but development of wind power in the East is a high priority for the U.S. Department of Energy.

Wind produces less than 1 percent of all electricity in the United States, but the American Wind Energy Association, the industry's trade group, predicts it will increase to 6 percent by 2020.

In the mid-Atlantic region of the Appalachian Plateau, where electricity traditionally has meant coal mining, wind turbines in two communities -- Tucker County, W.Va., and Somerset County, Pa. -- offer a glimpse of what wind power might bring to Western Virginia.

Where the wind blows

Somerset County, a place of villages, farms and woodland in southwest Pennsylvania, touts itself as the Alps of the Keystone state, where the wind blows steadily through the valleys and mountains of the Laurel Highlands.

In 1997, the Somerset County board of commissioners passed an ordinance clearing the way for some of the first windmills in the East. Eight turbines and six turbines, producing a combined 19.4 megawatts, went online at two sites in 2000 and 2001, respectively.

On Bob and Tomalee Will's dairy farm, one of the last few small farms in the county, they do more than milk cows to pay the bills. In a hay field they once leased out for a coal strip mine stand several cellular telephone towers and four wind turbines.

Atop the 2,600-foot ridgeline, the turbines stand 325 feet, from the base to the tip of the blades, so big that they're visible from 10 miles away to motorists on the Pennsylvania Turnpike.

As tall as they are, the windmills -- which include the steel towers and fiberglass blades -- take up little ground space, sunk into concrete pits 16 feet deep by 16 feet wide.

The Wills receive roughly $14,000 a year from the turbines.

"With the price of milk going down, we might be out of the farming business if it weren't for those windmills," said 68-year-old Bob Will, a sprightly man with a sun-reddened face who's farmed for five decades. "I'd take more of them if I could."

The turbines bear no resemblance to the picturesque windmills of old Holland, but the Wills say they are quiet and beautiful, the sunrises and sunsets glinting off the grayish-white blades, creating a mechanical elegance that complements the natural landscape.

They said they have found no birds or bats killed by turbine blades. They welcome scientists who want to conduct studies.

"If I said no, people would be suspicious," Bob Will said.

In 2003, Somerset County added 20 more wind turbines when the Meyersdale Wind Energy Center went on line atop a high forested ridge. The land was clear-cut to allow construction of the 345-foot turbines, which produce 30 megawatts and a handful of jobs.

Overall, the county receives about $30,000 a year in tax revenue from the wind farms, according to tax records. Developers plan to build another 20 turbines in the county.

Local officials say the windmills have helped tourism in Somerset County, which received national attention when United Flight 93 crashed there on Sept. 11, 2001, and a year later when nine coal miners were rescued from an underground mine.

Many people who live near the Meyersdale turbines oppose them. The Hutzel family's beef cattle and hog farm is less than a mile below the ridgeline.

Todd Hutzel, a short, muscular man whose workdays start at 4 a.m., said the turbines have caused a range of problems, including ruined views, decreased property values and hard feelings among residents.

"The biggest thing for us is the noise," said Hutzel, whose brother had to take sleeping pills because of the turbines' whooshing sound. "The vibrations just penetrate the house, the barn, everything."

Whoosh

About 50 miles down the road is Tucker County in northeastern West Virginia, a place of high mountains, rivers and gritty little towns, where a few thousand families depend on the charcoal plant, sawmills and tradesmen and truck-driving jobs for a living.

In 2002, the Mountaineer Wind Energy Center went on line with 44 turbines, making it one of the largest wind farms in the East. The 345-foot-tall turbines generate 66 megawatts, or enough electricity to power 22,000 homes.

The turbines run along six miles of Backbone Mountain, the 150 mile-per-hour whooshing of their blades pulsing through the forest like the sound of a giant dishwasher. Nearby are a coal-fired power plant and a rock quarry.

Mountaineer is West Virginia's only wind farm, but four more wind centers with hundreds of turbines are planned.

The turbines are at an elevation of nearly 3,000 feet, towering above a swath of clear-cut forest ridgeline owned by Western Pocahontas Properties, a Texas-based coal-mining company.

Robert Burns, the county's former economic development director, said tourists often ask questions about the windmills. He said property values haven't been hurt by the turbines.

The wind center contributes about $93,000 a year in local property tax revenue -- an amount that decreases each year with depreciation -- and a half-dozen jobs.

Burns said most local residents have accepted the wind farm.

"Change is confusing to people and it scares them," he said. "But as far as being a substantial issue here, most people just see them like power poles -- just another part of the community."

At the Tallyho Mountain Lodge, clerk Malinda Carr said the turbines' clean energy outweighs any effect on the environment.

"Birds and bats are a concern, but I'm sure with a little bit of thought, they can find a way not to scrap all the windmills," she said.

Paula Stahl, an artist who lives a few miles from the windmills, described them as "mechanical monsters" that have scared off wildlife and blighted the mountains.

When she walks along ancient tribal paths in the woods near the turbines, Stahl thinks of her American Indian ancestors and the westward expansion of the transcontinental railroad in the 19th century.

"It's like watching the iron horse coming," she said, sadly. "It offends me, but there's nothing you can really do."