Wind Power:
Clean Source of Energy or Blood-Tainted Killer?
by Molly Absolon
 In 1997, when the libertarian think-tank the Cato Institute quoted a Sierra Club representative for calling wind turbines the “Cuisinarts of the air,” defenders of wind power groaned. It was a colorful, graphic quote that did not represent the club’s position and oversimplified the problem of birds and turbines. But it did grab headlines.
Today, eight years later, some people still question whether the bird mortality linked to wind turbines is worth the power they generate. The idea that wind turbines are killers has stuck. The question is how accurate is this perception?
Birds do die from collisions with turbines, but the numbers are far less than one might expect. The Cheyenne-based research organization Western Ecosystems Technology Inc. (WEST-Inc.) put out a report in 2001 on avian mortality stating that from 100 million to as many as one billion birds are killed annually from collisions with human-made structures such as vehicles, buildings and windows, power lines, communications towers and wind turbines. Of these numbers, WEST’s report states that between 10,000 and 40,000 can be attributed to wind farms. In comparison, collisions with buildings kill anywhere from 98 to 980 million birds each year. [These numbers were based on a study of fatalities from birds colliding with house windows. The study found 1 to 10 birds were killed per house per year. There are approximately 98 million residences/buildings in the U.S. according to census figures, hence the range of 98 to 980 million.]
Collisions aren’t the only thing killing birds. Domestic cats account for approximately 100 million bird deaths annually, while habitat loss and global climate change are having a devastating impact on many species. Furthermore, no research has been done to determine how birds are affected by other forms of electrical generation. But 10,000 to 40,000 birds is not insignificant, particularly with bird numbers declining worldwide, so increasingly wind energy companies are paying close attention to where they place their turbines.
“Information is now available to help in micro-siting turbines, which means determining specific locations for individual turbines at a wind farm, as well as in determining appropriate sites for the farms themselves,” says Wally Erickson, a statistician for WEST-Inc. who has been the lead author on several reports on wind power.
At the Foote Creek Rim Wind Power Project near Arlington, Wyo., WEST-Inc. determined that an average of 1.5 birds are estimated to be killed per turbine each year or approximately 100 birds. These numbers are in marked contrast to Altamont Pass in northern California where one of the nation’s earliest wind
farms is located. Here between 880 and 1,300 birds of prey and more than 3,000 passerines are estimated to be killed each year according to California Energy Commission and National Renewable Energy Laboratory-funded research.
WEST Inc.’s report ‘Avian and Bat Mortality Associated with the Initial Phase of the Foote Creek Rim Wind Power Project’ explains, “Early wind energy facilities in the U.S. such as those at Altamont Pass were placed without regard to factors such as avian use, and some of the sites were located where birds are abundant and the risk of turbine collisions high.”
Turbine design has also changed since Altamont went in. The original wind turbines stood on an open-lattice structure that served as an attractive perch for birds. The blades rotated rapidly making them difficult for birds to see. Early research suggested these factors might be related to higher raptor mortality. Today’s turbines are tubular offering no spots for perching and the blades move slowly. How these changes affect bird mortality remains debatable, however.
“The general belief is that the new turbines are less risky for raptors,” says WEST’s Erickson. “However, to date, there are few wind projects that have both old generation and new generation turbines that have been studied concurrently. So until we have good empirical data comparing the risk of old and new turbines within the same wind project, we cannot say anything conclusively. Differences in risk of collision between old turbines and new turbines likely vary by bird groups as well.”
What WEST-Inc. has found is that Altamont’s high raptor mortality numbers are not the norm. Nationally, WEST found that there are an average of 2.19 avian fatalities per turbine per year for all species combined and 0.033 raptor fatalities. The majority of the raptor deaths have occurred in California where approximately 11,500 turbines exist including those at Altamont.
Wind power opponents like the Cato Institute have seized upon the blood, however. An advertisement in the New York Times by the Washington Legal Foundation, a perennial critic of so-called “environmental radicals,” asked, “How many acres of land must be despoiled to erect enough windmills—and how many birds must be shredded flying through their giant blades—to keep California from becoming a third world country?”
This negative press taints the industry. In addition, many supporters who consider themselves conservationists find themselves torn between their desire for clean energy and their concern about wind power’s wildlife impacts. But the American Bird Conservancy says their concern, while well intentioned, is misplaced at least with regard to birds. According to conservancy’s newsletter, if people really want to save birds, they should keep their cats indoors.
Bats and Wind Power
In late summer of 2003, it was estimated that several thousand migrating bats had been killed by wind turbines lined up along the crest of Backbone Mountain in northeastern West Virginia. Researchers hoped the high number was a fluke, but in 2004 a more thorough study came up with a similar estimate.
“Take the most conservative estimates of mortality and multiply them by the number of turbines planned and you get very large, probably unsustainable kill rates,” Merlin Tuttle, the president and founder of Bat Conservation International told the Washington Post in January 2005.
Researchers from a variety of organizations working together as the Bats and Wind Energy Cooperative began to theorize about what was going on. Infrared imagery showed that bats were actually attracted to wind turbines. Evidence also indicated that mortality rates were much higher on low-wind nights, perhaps because of higher insect activity. Scientists hypothesized that shutting down turbines on calm nights or creating some kind of deterrent might cut mortality rates, but these ideas need to be tested.
However, in 2005, Florida Power and Light (FPL)—the largest generator of wind power in the United States with 45 wind farms in 15 states—denied access to its wind farms by scientists working with the Bats and Wind Energy Cooperative.
“I’m not going to answer why I think FPL made this decision,” says Ed Arnett, a researcher for Bat Conservation International. “But I would guess that they saw it as a slippery slope. If they shut down turbines for bats, why not for other creatures?”
“I’d like to believe there are safe places to put wind turbines,” Arnett continues, “But the jury is still out. Personally I feel curtailment or shutting down select turbines under certain conditions looks promising, but we need the data to support it. We need to test it.”
Steve Stengel, a spokesman for FPL, says it frustrates him to hear Arnett frame FPL’s decision as a lock out.
“We feel we’ve been very cooperative,” Stengel says.
FPL has been generous in its funding and support of bat research in the past, something Arnett is quick to agree with. According to Stengel, the reason for this year’s decision was that FPL wanted the first research projects to focus on using deterrents to keep bats away from turbines as opposed to testing experimental shutdowns. When this was unacceptable to the researchers for the Bats and Wind Energy Cooperative, FPL declined to allow the proposed studies to take place.
Arnett says they need to do more than just test deterrents. He says there is a bit of a “gold rush” in wind energy going on right now and his concern is that the science on the effects of wind farms on wildlife, particularly bats, is not adequate to make the best decisions. Bats are particularly vulnerable to large losses because they are long-lived and have low reproductive rates. Waiting to see if deterrents work without testing other options simultaneously seems shortsighted in Arnett’s opinion.
WEST-Inc.’s Erickson says turbines appear to be less of a problem for bats in open, prairies sites like those found in Wyoming.
“People haven’t raised the same concerns about bats in open-habitat wind farms. In general their levels of mortality are low in the West and Midwest. Much lower than the three specific wooded ridge tops studied in the East,” Erickson says.
Arnett agrees that the current research supports the contention that bat mortality at wind farms in open prairie and farmland habitats is lower than along timbered ridges in the East. However, he says this contention is based on a handful of studies and he isn’t ready to say the evidence is conclusive. He says that tree-roosting bats have been killed at a wind farm in northeastern Colorado where there isn’t a tree in sight. What bats are doing there he doesn’t know. What it tells him is that more research is imperative.
“It would be hypocritical for any biologist to be against renewable energy development,” Arnett says.“We need energy. But wind energy is not a panacea. It needs to be part of our energy portfolio, yes, and right now it seems to me as if the science is lagging. We need sound science and responsible development for all forms of energy.”
|
Privacy Policy