Fewer birds are killed at new wind power stations than at older wind developments. Of 15 new projects examined, even deaths at the wind farm with the highest raptor mortality were three to seven times less than at the sprawling wind farms built a decade ago and more at the Altamont Pass in California. The far fewer bird deaths reported in a recent study of avian mortality means there is likely to be less opposition and more collaboration with environmentalists in developing future projects.
"The study documents that new, carefully sited wind projects have lower impacts on birds than older projects," says George Darr, who recently retired as head of wind projects at the Bonneville Power Administration (BPA). The federal power marketing agency commissioned the study. He says the large fields of turbines located within bird flyways that have a history of killing birds, particularly raptors at California's Altamont Pass, tarnished the whole industry. Wind turbines situated there kill approximately 30 to 70 golden eagles every year, a figure, says John Bianchi of the National Audubon Society (NAS), that has contributed to the tension between bird advocates and wind power development.
Things have changed, however. Even the Foote Creek Rim plant in Wyoming using Mitsubishi 1 MW turbines -- with the highest raptor mortality of 15 projects in 30 study areas in the West and Midwest -- kills three to seven times fewer raptors per 100,000 square rotor swept area than do those at the Altamont Pass. About 3000 of the 5400 turbines in the pass are Kenetech 56-100 turbines. The high density of the turbines in the landscape, their lattice towers, fast-spinning downwind blades, and rotor tips close to the ground (where they can pick off raptors approaching their prey) are all features which are hard on birds.
In contrast, the capacity of turbines installed in the US today is typically ten to 18 times greater. The larger sizes reduce their density on the landscape and the rotors spin more slowly -- at about 20 instead of 60 revolutions per minute -- giving birds that are inclined to tilt with wind turbines a chance to avoid the blades. And with tubular towers, underground transmission wires and changes to turbine nacelles to remove any small niches where birds can find a foothold, there are almost no places left where birds can perch near spinning turbine blades. "The new technology is making real inroads regarding the impact of wind turbines on birds," Bianchi says. "Now wind is the most viable alternative to fossil fuels we have and you will find us very much in support of projects."
The statement may come as a surprise. Although the organisation's Minneapolis office released a message to other Audubon chapters in the early 1990s that wind power is good, the message was never official and few people knew about the declaration, Bianchi says. A call for a moratorium on wind power development by a rogue Audubon scientist, made a year before, received more attention and tainted how the public viewed the Audubon's relationship with wind development.
That does not mean, however, that NAS will support every project just because using wind energy is environmentally better than using fossil fuel. In 1999 and 2000, the Audubon chapter in California posted signs asking "Kill the Condors?" in a public campaign to oppose an Enron Wind project destined for a site near an endangered condor nest. To save the bird from the threat of wind turbine rotors, NAS went so far as to lobby Congress to amend requirements for the production tax credit (PTC) to remove its availability from projects built within ten miles of critical habitat containing any endangered species. The issue was settled amicably, says Bianchi, with Enron Wind swapping wind sites to one without nesting condors, but it clearly revealed the tide of feeling on the subject.
Since then, NAS has gone on public record supporting wind projects as well as the PTC. But with an organisational structure that allows its local chapters to make their own decisions, support can look different depending on a local chapter's interests. One such chapter in Walla Walla, Washington, worked with FPL Energy to help resolve bird flyway issues at the developer's 300 MW Stateline wind farm (Windpower Monthly, November 2001). Some turbines were removed, some just moved, but the project went forward. In western Maryland, where there are seven Audubon chapters and a state office, only the Maryland Ornithologist's Union is opposing a wind project, while the others are working with the developers and believe the projects pose little danger to birds. US Windforce, in partnership with Padoma Wind Power and Clipper Windpower, is working on projects in the state (Windpower Monthly, October 2002).
"Our chapters are independent and able to make their own decisions and have their own points of view," Bianchi says. "Some will look at the data. Some will act on emotion."
The data in the BPA report shows the wind industry has made considerable strides in its efforts to improve the record on birds. Raptor mortality at new wind farms is nearly absent. More than 80% of birds that die after a collision in a wind farm are songbirds, like the Mountain Plover at the Foote Creek Rim project. Wind plant that have a year-round population of waterfowl, such as at Buffalo Ridge wind farms in southwest Minnesota, have the highest bird mortality. Bat mortality is low and occurs mostly when bats migrate, not when they nest.
The reduced mortality, coupled with the detailed information buried in the report entitled Synthesis and Comparison of Baseline Avian and Bat Use, Raptor Nesting and Mortality Information from Proposed and Existing Wind Projects, could ultimately help reduce the cost of new wind energy projects. Even at the 50 MW Condit wind farm in Oregon, one of the cleanest projects environmentally, says Darr, the cost of avian studies approached $300,000 and took an entire year to complete data collection. And that is by no means the entire cost of all the environmental work. Typically, developers must also perform other biological and environmental studies in order to complete a full environmental assessment for each potential project.
Pre-construction surveys are some of the most time consuming of environmental requirements in the wind farm siting process, Darr says. He predicts, however, that with the findings from the study, the cost and time to put together environmental studies for approval by state wildlife agencies are likely to be halved. According to the report, if studies are done in either the spring, the summer or the fall, there is a good chance that just one season's worth of data is all that is required to provide adequate wind plant direct-impact predictions.
The same baseline information could also provide enough data to "micro-site" within a wind project, something that was done at the Foote Creek Rim project to site individual turbines away from nesting raptors.
New techniques and technology will likely continue to reduce the number of birds killed by wind turbines, but however careful the siting, or however advanced the technology, wind turbines installed across natural landscapes will probably always kill some birds. Dennis White, local Audubon member in Klickitat County, Washington, took a stand that no bird mortality was acceptable when he opposed Michael Kitchen's 1 MW Mariah Energy Project in Columbia Hills (Windpower Monthly, November 2001). Kitchen eventually won in court.
Bianchi says the NAS is not generally that hard-line and points to the organisation's lack of a position on hunting as an example. "We're not against legal hunting, but sometimes we're against it when the species being hunted is not doing so well," he says. "It comes down to what is the species, where is it located and how many birds are there?"