Wind Energy - Friend or Foe?

More studies are needed to combat fatalities.

With the rise in global warming making news headlines in recent months, supporting the development of renewable energy sources is a high priority for energy companies and environmentalists alike — and wind energy has become the fastest growing energy source in the United States. Yet wind farms located on ridgelines along the East Coast may operate at the expense of the lives of many bats and birds.

"I think any biologist or scientist who opposes the development of renewable energy would be acting hypocritical," said Ed Arnett, a conservation scientist specializing in wind energy at Bat Conservation International (BCI). "But it all has to be done responsibly. There's no impact-free energy." Most people know fossil fuels can harm our health and the earth with their toxic emissions, but the suffering wind farms cause bats and birds is a recent discovery.

Bat Deaths Spark Concerns

As part of an ongoing study, BCI's Ed Arnett inspects a bat who was just killed by a turbine at the Mountaineer Wind Energy Facility.

Like birds, whose wind turbine-related perils have been publicized in recent years, some species of bats migrate south for the winter. As they pass the mid-Atlantic region, wind farms pose numerous death risks. In 2003, at the 44-turbine Mountaineer Wind Energy Center near a major Appalachian ridge in West Virginia, 475 bat carcasses were found, according to the organization SafeWind. But that's not even a conservative estimate, the researchers said; it's merely a small percentage of the actual total, which may have exceeded 3,000. The cumulative impact of the wind turbines on the East Coast could cause irreversible losses to several bat species over time, as 11 of the 46 known bat species have been found dead at wind farms over the past few years.

Arnett's group began on-site wind farm studies in summer 2004, but has not found a concrete solution to the problem—or even a true explanation for why it happens in the first place. "At this point, we just don't know," he said, but added that possible future remedies may be discovered once researchers find out more about the bats' attraction to wind turbines. They may be attracted to the moving blades of the windmills or run into them while chasing a food source, he explained. The audible and ultrasonic sounds the wind turbines produce could also be attracting bats.

Still, these preliminary observations could be a savior for many bats in the mid-Atlantic region. "There are potentially predictable time periods when the most fatalities occur," Arnett said. During the late summer and the fall, when bats begin to migrate, there appear to be more deaths, but studies need to look at other times of the year as well. Mortality rates seem to be higher following a storm front and whenever there is a low wind current, his group noted. "It suggests there may be opportunities to curtail operations and reduce mortality during periods when higher deaths are predictable," Arnett said of the patterns. Since low wind currents yield little wind power anyway, he said it could be a good solution for everyone.

Not surprisingly, "additional studies are needed" is the type of phrase often heard in connection with wind turbine-related bat fatalities. Deaths have also been documented outside of the United States—in Australia, Canada, Germany, Spain and Sweden at the very least—but the issue of bats and wind turbines has not been well explored, according to Greg Johnson of Western Ecosystem Technology, Inc.

In the United States, only about a dozen studies have been conducted, despite the fact that fatalities have been reported at almost every wind energy plant in our country, Johnson reported. And on the East Coast, at the heart of the problem, only two studies have taken place. That's a big reason groups like BCI are working so hard—in 2003 they formed the Bats and Wind Energy Cooperative with the US Fish and Wildlife Service, the American Wind Energy Association and the National Renewable Energy Laboratory of the US Department of Energy. The cooperative worked proactively with the wind industry to understand the issues and solve problems related to bat deaths until it lost its industry funding last spring.

Habitats at Stake

The relationship between small songbirds, who have higher reproductive rates than bats (these small mammals only produce one pup per year), and wind farms has already been examined. Previously, it was believed that wind turbines posed an even greater risk to their welfare, but recent evidence suggests bats may be more vulnerable than birds at sites on the East Coast. Migration through this area is also a danger to the lives of birds, and of even greater concern is the disruption of birds' natural habitats due to the construction of wind farms.

Animals are not the only ones upset about the gigantic wind turbines marring the natural landscapes they call home; some nearby human residents aren't thrilled with the structures either, saying they destroy environments with their presence. The issue was discussed in Congress, when Representatives Nick Rahall and Alan Mollohan, both West Virginia Democrats, asked the General Accounting Office (GAO) to look into the effects of wind turbines on migratory birds. "The issue is not a few windmills," Mollohan said in an interview. "It is thousands of windmills erected on every ridge." The GAO agreed to the request, but there has not been much progress.

Many West Virginia residents fear the construction of wind farms will destroy the area's natural landscape. The Mountaineer Wind Energy Facility was built on the densely forested Backbone Ridge.

The wind farm industry needs to have a good reputation to keep environmentalists as customers for its higher-priced form of energy. Dan Boone, spokesperson for National Wind Watch, says he fears that behind their apparent support, wind energy companies are not as concerned as they should be. But one thing is for sure: as wind energy grows in popularity, solutions to the issue of wildlife fatalities are needed urgently to ensure this vital source of energy is animal-friendly. "We really ought to view wind energy as the first step to living sustainably on our planet," Boone said.

The option of offshore wind energy, currently in practice in Europe, may be an improvement, but could put marine mammals at risk—still, Boone thinks it may be a better bet, since it would be subject to legal policy under the National Environmental Policy Act. The reason bat and bird fatalities have been overlooked for so long is because they lack much real legal protection. Additionally, offshore wind turbines are placed far out in the ocean, where they are less of an aesthetic threat to natural landscapes.

Researchers agree that the best solution for now is to place wind energy plants in areas wildlife experts deem optimal for avoiding animal habitats. Using the "precautionary principal" (to err on the side of protecting animals), developers and companies must study locations before erecting turbines, making sure high-risk areas such as ridge tops are avoided. Our earth's health depends on sustainable energy, and if it is done responsibly, wind energy has the potential to provide a remarkable amount of "green" power.

Altamont Pass:
A Death Trap for Protected Raptors

East Coast wind farms have been the most recent targets of criticism, but California's 50-square mile Altamont Pass Wind Resource Area is the deadliest of all for birds. The wind energy megasite produces 820 million kilowatt hours of pollution-free electricity annually—enough energy to power 120,000 homes for a year—while its 5,000 turbines kill 1,700 to 4,700 birds migrating through the mountainous region between the San Francisco Bay area and San Joaquin Valley. The California Energy Commission reported last year that between 880 and 1,300 birds who die after flying into the turbines are federally protected raptors, including red-tailed hawks and golden eagles. Facing legal threats, Altamont operators agreed to shut down half of their turbines for two months beginning Nov. 1. In January 2006, the other half was temporarily halted to minimize deaths this winter.

Telecommunication Towers Threaten Birds

Unfortunately, any tall structure impeding the path of migrating birds, from wind turbines to large buildings, poses a risk to the animals' safety. Yet the masts of telecommunication facilities that relay cell phone signals cause the most deaths; millions of birds of around 230 different species die each year after colliding with the poles or being electrocuted. In fact, these are the main known causes of mortality in storks.

Like the mysterious wind turbine accidents, no one really knows why birds are attracted to the structures. Studies show that collisions tend to happen with the highest occurrence at night and in the fog or other bad weather. However, there is a solution: "bird-friendly" alterations to power lines such as plastic caps and tubes can prevent deaths, and they can be fitted quickly and cheaply to existing pylons, poles and cables to prevent or reduce electrocution (guidelines are available at

Telecommunication towers may harm birds in more problematic ways as well. Researchers in Madrid recently released a study claiming electromagnetic fields emitted from these towers have caused problems for the white stork in Spain. These birds tend to build their nests at high altitudes in places with high electromagnetic contamination, including mostly urban areas. Exposure affects the birds' reproductive activity, and some populations have declined as a result. We are encouraging federal funding for research on the biological effects of cell tower emissions, as both animals and humans could be at risk.