To what degree do wind turbines harm birds?

To what degree do wind turbines harm birds?

From the editors of E/The Environmental Magazine

The Times, Nov 8, 2007

Dear EarthTalk: I have heard that wind power turbines kill a lot of birds, including migrating flocks, and that some people oppose wind power for that reason. If this is true, to what degree do they harm birds, and what is being done about it? – Ken Lassman, Lawrence, KS

It is ironic that non-polluting, renewable wind energy, long touted as a potential savior in the fight to stop global warming, is getting a bad rap for killing wildlife. High profile examples such as at California’s Altamont Pass – where outdated, oversized wind turbines kill some 1,000 birds of prey each year – plague the growing wind-power industry even though more modern, better-sited wind farms kill far fewer birds.

According to a 2002 study of anthropogenic (human-caused) bird mortality conducted by researcher Wallace Erickson, birds face daily threats far more lethal than wind turbines. Erickson’s study found that between 500 million and 1 billion birds are killed annually in the United States alone from collisions with man-made structures including communications towers, buildings and windows and contact with power lines.

Hunting, cat predation, pesticides, commercial fishing operations, oil spills and cars and trucks also take a heavy toll. All this is important to realize, say wind power advocates, in putting the relative impact of windmills on bird populations in perspective: Contact with wind turbines represented less than 1 percent of the total number of human-caused bird deaths in Erickson’s study.

There are, however, steps that can be taken when constructing wind power turbines to minimize their impact on birds. The American Bird Conservancy (ABC) advises that lighting on turbines should be minimized, tension wires and lattice supports should be avoided, and wind turbine power lines should be placed underground whenever possible. Also, already more modern wind towers are being designed in ways that prevent birds from perching on them (solving one of the problems with the Altamont Pass towers) – and the turbine blades rotate much more slowly than earlier designs.

In addition, says ABC, careful reviews of potential wind turbine sites should be conducted. Known bird migration pathways, areas where birds are highly concentrated, and landscapes known for their popularity with birds should be avoided “unless mortality risk has been analyzed and the likelihood of significant mortality has been ruled out.” Wind farms should be situated on already disturbed land, such as in agricultural areas, so as not to displace existing bird habitat or travel corridors. Sites should also be reviewed for use by birds listed under the Endangered Species Act.

Ever-growing concerns about global warming and pollution from fossil fuel use demand that we move as quickly as possible toward clean, renewable energy sources, even if they are as yet imperfect.

“When you look at a wind turbine you can find the bird carcasses and count them,” says John Flicker, president of the National Audubon Society, the world’s pre-eminent bird advocacy organization. “With a coal-fired power plant, you can’t count the carcasses, but it’s going to kill a lot more birds.”

Indeed, according to Erickson, for every 10,000 birds killed by human activities, less than one death is caused by a wind turbine. And if greenhouse gases are not reduced significantly in the next decade, we could bear witness to a large number of plant and animal extinctions in the coming years.

Altamont Pass Wind Farm

From Wikipedia, the free encyclopedia

The Altamont Pass Wind Farm is one of the earliest in the United States. The wind farm is composed of over 4500 relatively small wind turbines of various types, making it at one time the largest farm in the world in terms of capacity. Altamont Pass is still the largest concentration of wind turbines in the world, producing about 125 MW on average. They were installed after the 1970s energy crisis in response to favorable tax policies for investors.

Considered largely obsolete, these numerous small turbines are being gradually replaced with much larger and more cost-effective units. The small turbines are dangerous to various raptors that hunt California Ground Squirrels in the area. The larger units turn more slowly and, being elevated higher, are less hazardous to the local wildlife.

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