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Alternative Energy
Selling the Wind
Wind power is pollution-free, combats global warming, and is a boon to small farmers. The biggest drawback—its lethal impact on birds and bats—is driving creative ways to ensure that this fast-growing energy source can coexist with wildlife.

On the Emick family ranch in far southeastern Colorado, a row of antique windmills adorn the entrance road, their delicate wooden blades stilled for the moment. These windmills, some more than a century old, once helped prairie homesteaders pump water out of the ground, sustaining both families and farms. Throughout the Great Plains, such windmills are still a proud symbol of survival—of pioneer persistence in a land often too hot or too cold, too dry or too windy.

Today a very different sort of windmill is helping the Emick family survive on the blustery western edge of the Great Plains. In every direction, lines of cylindrical steel towers rise from the landscape, each white column topped by three sleek, swooping blades. These modern wind turbines, which measure more than 300 feet from their base to the tips of their blades, are more than 10 times taller than the frontier-era windmills at their feet.

The 108 turbines in this neighborhood comprise the Colorado Green project, the largest wind farm in Colorado and among the 10 largest in the nation. The project, a joint venture of Shell Wind Energy and PPM Energy (a subsidiary of ScottishPower), produces roughly enough electricity each year to supply more than 52,000 average homes.

Though the Emicks and other families who lease land to wind-power companies can’t divulge the details of their agreements, typical payments range from $3,000 to $6,000 per turbine per year, and generally allow farmers to continue raising crops and livestock among the towers. For agricultural families, which face the vagaries of rainfall and commodity prices, the reliable additional income is welcome. It can help them keep their farms afloat—and keep land relatively undeveloped, in some cases preserving both wildlife habitat and open vistas. 

Small farmers are far from the only fans of wind energy. Wind farms in the United States now have a combined capacity of more than 9,000 megawatts, generating enough electricity to power approximately 2.3 million homes. (A rough rule of thumb is that one megawatt produces enough power for 250 to 300 homes.) While wind currently provides less than 1 percent of the country’s total energy needs, many states are looking to increase their supplies of renewable energy, helping to make wind the nation’s second-fastest-growing source of electricity (natural gas is tops).

Multinationals continue to make significant investments in wind power. GE Energy built well more than half of the new turbines in the United States last year, and Goldman Sachs, one of the world’s largest investment banking firms, recently purchased a wind-power development company now called Horizon Wind Energy. Meanwhile, the U.S. Department of Energy has set a goal of helping at least 30 states increase their wind-power generating capacity to 100 megawatts each by 2010. 

While consumers have long paid a premium for wind power, high natural gas and coal prices are enhancing wind’s appeal. Last year in Colorado and in Austin, Texas, the price of wind power dipped below the price of traditional energy sources, and utility customers of all political stripes flocked to sign up for it.

If wind power dilutes our diet of coal and other fossil fuels, it will reduce air pollution, and even cushion the devastating, and increasingly apparent, effects of global warming. “It’s critical to have a sense of urgency about dealing with global climate challenge in general, and about displacing coal in particular,” says Ralph Cavanagh, an expert on renewable energy at the Natural Resources Defense Council (NRDC). “Wind is a very important part of that equation.”

For many conservationists, however, wind power remains an uncomfortable subject. It’s well known that wind turbines kill both birds and bats, though exactly how often—and why—these deaths occur remains poorly understood. Wildlife advocates hope they can push for more research, better planning, and more stringent oversight of wind farms without sabotaging the industry’s hard-won momentum.


Much of the current controversy over wind power and wildlife stems from a place called Altamont Pass, a line of golden, oak-studded hills on the eastern outskirts of the San Francisco Bay Area. The Altamont Wind Resource Area, established in the early 1980s, was one of the first modern wind farms in the nation, and a visit to Altamont is a one-stop tour of the history of wind power.

On one grassy hillside stands a row of closely spaced “eggbeater” turbines, each with three busily spinning blades mounted on a latticed steel tower. Arrayed on another slope are the smooth, solid towers of newer turbines, much like those on the Emick family ranch in Colorado. Although the blades of these turbines turn more slowly than those of their smaller predecessors, each enormous turbine can generate 1.5 megawatts of power, more than twice that produced by older models. In all, more than 5,000 turbines crowd into Altamont Pass, generating enough electricity to serve some 100,000 homes.

But these turbines are believed to kill more birds of prey than any other wind farm in the world. Beginning in the late 1980s biologists reported that large numbers of golden eagles, hawks, and other raptors were flying into the spinning blades at Altamont, and dying as a result. Wind-energy companies tried many measures to limit the damage, such as installing chicken wire on the latticed towers to discourage perching. But a recent five-year study by the California Energy Commission estimated that every year up to 1,300 raptors are killed at Altamont, including more than a hundred golden eagles. 

For raptors, which reproduce and develop slowly, these deaths may have painful ecological effects. Grainger Hunt, a senior biologist for the Peregrine Fund who studied golden eagles at Altamont, says the losses from collisions with turbine blades could make the local eagle population more vulnerable to other stresses, such as the rapid development in the area. “What the population has probably lost is its resiliency,” he says.

For an industry that often trades on its green image, the ongoing bird deaths at Altamont are an embarrassment—and a major liability. Public concerns about bird collisions with turbines have helped delay, and even sink, proposed wind-farm projects in California and elsewhere. Last year, in response to a 2004 lawsuit filed by the Center for Biological Diversity against Altamont turbine operators over the raptor kills, wind-power companies and local county officials agreed to shut down half the turbines during winter months, and permanently remove 100 turbines over five years. Five Audubon chapters, including Golden Gate Audubon, teamed up in 2005 with Californians for Renewable Energy and pressed ahead with another lawsuit against the county, citing an inadequate environmental review.

What makes Altamont Pass so dangerous for birds of prey? The problem, many researchers say, begins with the abundance of small mammals in the area. “Altamont is a ground-squirrel refuge extraordinaire,” says Allen Fish, director of the Golden Gate Raptor Observatory. The plentiful mammals, combined with the mild California climate, attract large numbers of migrant and resident raptors; the area also has the highest density of wintering golden eagles observed anywhere in the world. Younger hawks and eagles, eager to hunt and build muscle and thus most enthusiastic about the fine dining available on the ground, seem especially prone to blunder into the moving turbine blades.

The unusually high density of turbines, along with the older, latticed towers that can serve as perch sites, may compound Altamont’s woes. But the basic issue, most observers say, is the real estate itself. “The bottom line,” says Hunt, “is that the Altamont site was a very, very bad place to build a wind farm.”


The farms and ranches of the West and Midwest are now favored homes for wind turbines, and so far they seem to be relatively safe for both raptors and songbirds. “The bird mortality we’re seeing is lower than what’s been seen at Altamont,” says Tim Cullinan, director of science and bird conservation for Audubon Washington and a wildlife biologist. Cullinan is working with the U.S. Fish and Wildlife Service and other stakeholders such as the American Wind Energy Association and the International Association of Fish and Wildlife Agencies to strengthen siting standards for wind facilities nationwide.

The exact reasons for the improvement are a matter of debate, but collisions seem far fewer when wind farms keep out of major flyways and give a wide berth to rich prey sites like Altamont and attractive bird habitats such as wetlands. Some researchers speculate that modern technology also helps reduce the risks, since newer turbines allow the same amount of electricity to be generated with far fewer turbines. Wind developers—trying to avoid another Altamont—now generally conduct some biological surveys before beginning construction, though these studies vary widely in their length and complexity.

Because of these developments, the wind industry often describes Altamont as an anomaly. “I’m continually surprised by how widespread the bird issue has become, and how long it has lasted,” says Tom Gray of the American Wind Energy Association. “A number of studies at other projects indicate that, in general, wind power is not a significant threat to birds.”

Environmentalists agree that the industry has made major progress on wildlife issues since Altamont. “I don’t think there’s any question that we’re doing a better job of siting wind power now than we did a quarter-century ago,” says the NRDC’s Cavanagh. “I’ve watched a real evolution within the industry in terms of their sensitivity to this issue.”

But the research on wind power and wildlife remains spotty at best, and the unknowns concern scientists and conservationists alike. Even when sites are regularly surveyed for bird kills, for instance, there’s always the possibility that predators have snatched up bird carcasses, in effect removing the evidence. Pete Bloom, a former wildlife biologist for National Audubon who works as a consultant for the wind industry, worries about what he calls the “poofing factor”—migrating songbirds that collide with the massive turbine blades and could simply be obliterated, leaving no evidence on the ground and thus further skewing the numbers.

Even if biologists underestimate the number of birds killed by turbines, the damage is surely smaller, in orders of magnitude, than the numbers killed in other ways. While a 2001 study surmised that some 10,000 to 40,000 birds die in wind turbines each year, the U.S. Fish and Wildlife Service contends that these numbers are out of date and that the true mortality figures are much higher. Still, an estimated 100 million birds are killed a year by hunting housecats, and as many as 60 million die from collisions with cars and trucks.

Yet if the wind industry continues to boom, turbine numbers multiply, and the gaps in research persist, it is possible that collisions with turbines—and construction associated with wind farms—will become a more widespread and substantial threat, particularly for threatened and endangered species. “The fear is that with all the new wind farms rolling out, there is a new Altamont being created today,” says Greg Butcher, National Audubon’s director of bird conservation. “But because we don’t have the data, we just don’t know about it.”


When wildlife researchers have looked closely at wind farms, disturbing numbers have emerged. One 2003 study spent seven months compiling bat fatalities at a wind-power site in the West Virginia mountains. Researchers found, to their surprise, that the 44 turbines killed as many as 4,000 migratory bats. Similarly grim findings have since been reported at wind farms in Pennsylvania and Tennessee, raising the possibility that significant bat kills are a regional or even national phenomenon.

The three wind farms in question stand on forested Appalachian ridges, and Ed Arnett, a conservation scientist for Bat Conservation International, speculates that tree-roosting bats hunt insects in the clearings around the turbines. But because the wind industry has only a handful of bat studies to draw on, the reasons for the kills are unclear, the number of species involved uncertain, and no one is sure how to mitigate the impacts at existing or future sites. “There’s a huge dearth of research,” Arnett says. “What we do know is that these are long-lived species with low reproductive rates, so a new source of mortality could drive them into serious declines very quickly.” 

Other researchers are concerned that proliferating wind turbines will take a heavy toll on night-migrating songbirds or ground-nesting birds. A 2004 study, led by Robert Robel, a biology professor at Kansas State University, found that roads and other infrastructure disturb ground-nesting species such as the lesser-prairie chicken, a candidate for federal listing as an endangered species. Again, though, the questions far outnumber the answers.

In a 2005 Government Accountability Office report to Congress summarizing the research on wind farms and wildlife impacts, the authors describe “significant gaps in the literature” that “make it difficult for scientists to draw conclusions about wind power’s impact on wildlife in general.”

Laws and regulations governing wind-power development rarely encourage new research. Federal and state agencies oversee the development of wind farms on public land, and they regulate offshore wind farms, which have been proposed—but not yet built—along the Atlantic Coast and in the Gulf of Mexico. Such federal laws as the Migratory Bird Treaty Act and the Endangered Species Act are designed to protect wildlife from human intrusions on both public and private land. But the federal government has not prosecuted any wind-power companies for violations of environmental laws, relying instead on a set of voluntary guidelines developed by the U.S. Fish and Wildlife Service. Although some state governments have established their own permitting processes and guidelines for wind-farm development, oversight remains weak and haphazard.

“It’s very ad hoc,” says David Klute, bird conservation coordinator for the Colorado Division of Wildlife, of his agency’s involvement with wind-power development. “The technology is so new, and the potential impacts are so new, that a lot of our biologists just haven’t dealt with them.”

Most of the authority over wind farms rests with local governments, which rarely ask probing questions about wind turbines and wildlife. In the small southeastern Colorado town of Lamar, just a few miles from the Emick family ranch and the Colorado Green project, wind has been welcomed as an economic lifesaver. The county planning and zoning commission, which handled the permits for the Colorado Green development, approved it quickly and unanimously in March 2003, and local residents were almost uniform in their support.

The Colorado Green developers voluntarily commissioned some very general bird and other wildlife surveys before beginning construction, though the details of those surveys are not available to the public. The companies’ report on the environmental impacts of the project stated that while some birds and bats would be killed by the Colorado Green turbines, the deaths “will not result in significant adverse effect on populations of birds.” The report suggested that the site would be broadly similar to a large wind farm in northeastern Colorado, where several years of monitoring conducted by experienced biologists has recorded only one raptor death and very few songbird and bat kills.

The Colorado Green report was hardly an exhaustive analysis, but it was enough to satisfy local authorities. Now the company wants to build 100 new turbines in the Lamar area, and plans for several new wind farms are forming in other parts of Colorado, thanks to a new state constitutional amendment requiring large utilities to purchase 10 percent of their electricity from renewable sources by 2015. Congress recently extended a significant federal tax credit for wind power through 2007, boosting the confidence of wind-power developers and investors throughout the nation.

Randy Udall, director of the Community Office for Resource Efficiency in Aspen, Colorado, and a regional renewable-energy expert, expects turbines to keep sprouting from the prairies. “In the future,” he says, “I think we’re going to be planting these things like trees.”


So conservationists find themselves in a tough spot. How can they support and encourage the rapid spread of wind power—our most promising source of clean, renewable energy—while ensuring that the industry minimizes its damage to birds and other wildlife?

“We can’t lose sight of the larger benefits of wind,” says Audubon Washington’s Tim Cullinan. “The direct environmental impacts of wind get a lot of attention, because there are dead bodies on the ground. But nobody ever finds the bodies of the birds killed by global warming, or by oil drilling on the North Slope of Alaska. They’re out there, but we don’t see them.”

The solution to this dilemma, say many conservationists, begins with early, consistent involvement in project planning. “Once those turbines go in,” says biologist Pete Bloom, “they don’t come down.” To encourage early consideration of wildlife, environmental groups have developed guidelines and policies for wind development. Audubon Washington’s guidelines, for instance, call for several seasons of bird surveys and other in-depth wildlife studies at proposed wind-power sites, and support statewide or multi-state planning efforts for wind facilities.

Some wind-energy companies willingly abide by these and other recommendations, contributing money and time to research and adjusting their activities in response to new findings. In southern Wyoming, for instance, a wind-power company changed the layout of turbines at its Foote Creek Rim site when biologists determined that the proposed project would pose a significant risk to raptors. Several wind companies have also invested in a long-term study of ground-nesting birds at wind-power sites in the Midwest.

But wildlife surveys, especially multiyear studies, are expensive and time consuming, and the wind industry is reluctant to shoulder the scientific burden alone. The National Wind Coordinating Committee Wildlife Workgroup, a collaborative of scientists, conservationists, and wind-industry representatives that formed in 1994, has worked to standardize and summarize the disparate existing research on wind and wildlife and to find ways to satisfy the demands of both business and science. 

In 2002 California legislators passed a state law requiring investor-owned utilities to double their use of renewable resources to 20 percent by 2017. With this ambitious target in mind, California environmentalists, renewable-power activists, and industry representatives have taken their cooperative work one step further. At a meeting last January, sponsored by Audubon California and the American Wind Energy Association, participants agreed on the need for a comprehensive statewide study of wildlife issues at potential wind-power sites. Audubon and industry representatives have since met with state officials, agreeing to develop a set of wind-power siting guidelines, to secure additional funding for the state’s cash-strapped wildlife agency to conduct research, and to move forward on a five-year, $25 million study of birds and bats at prime wind resource areas. 

Participants hope this proactive approach will help wind developers identify and avoid sensitive areas from the start; this would not only reduce ecological impacts but could also head off late-stage lawsuits and bad publicity. “If we can do an overarching baseline study of bird migration and habitat use in the state, it could have a huge impact,” says Glenn Olson, director of Audubon California. “It would provide the biological information we need, and wind companies need, to do projects right.”

By asking the right questions at the right time, conservationists can help wind power continue its growth and fulfill its promise. They can also share in the building enthusiasm for wind’s wide-ranging benefits. Farmer and rancher Greg Emick, who grew up on his family’s land, guesses that his ancestors—immigrants from Germany who arrived in Colorado nearly 100 years ago—would be pleased by the towering wind turbines that rise from the land they once homesteaded. “They always thought the prairie would be good for more than just raising cattle and growing a little bit of crop,” says Emick, as he listens to the steady swoosh of the gigantic turbine blades above his head. “But I don’t think they ever imagined we could sell the wind.”


What You Can Do

Learn the latest about wind power and wildlife on Audubon California’s website. The National Wind Coordinating Committee website offers a wealth of detailed information about wildlife research and ongoing collaborative efforts among conservationists, scientists, and the wind industry. To read more about the wind industry’s position on wildlife issues, visit the American Wind Energy Association online.

Michelle Nijhuis is a freelance writer based in Colorado.

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