When the Department of Energy released a report in May championing the construction of larger and more powerful wind turbines, the wind industry unsurprisingly greeted the news with enthusiasm.
With an extension of the "hub height" of turbines to 360 feet, the chief executive of the American Wind Energy Association said, wind energy could expand to all 50 states.
Less ardent was the association's response to scientists' well-documented concerns about the half-million birds that die each year from collisions with existing turbines: Some migrating birds, a spokesman said, fly too high to be harmed by rotor blades.
Indeed. Some birds do fly very high. But far more travel at the very altitudes that would put them at greatest risk of colliding with the taller turbines. The risk is especially high during spring and fall, when migrating birds take to the skies in billions, many traveling vast distances between their wintering and breeding grounds.
A new report last month from the U.S. Fish and Wildlife Service calls into question the wind industry's assertion that birds fly well above wind turbines' rotor blades. Using radar, researchers examined fall migration at two locations in Michigan. They found that the greatest density of birds and bats migrating at night occurred from 300 to 500 feet above ground. That's almost directly at hub height for the new generation of giant turbines.
Birds and bats "don't have fixed lanes up there in the sky," says Jeff Gosse, regional energy coordinator for the U.S. Fish and Wildlife Service in Bloomington, Minn., and the report's principal investigator. During poor weather, birds tend to fly lower. "As conditions change, they will change their altitude also. As the report indicates, many birds and bats are flying within the current rotor-swept zone."
Before we rush to build thousands of turbines taller than many skyscrapers, with blade tips that often spin in excess of 100 miles per hour, we should pause to examine what we already know about turbines' effect on wildlife. Concerns about birds--and bats, which turbines also kill in large numbers--have not gone unnoticed. (The Department of Energy report euphemistically acknowledges the need to address "additional interactions with wildlife.")
Yet we already know what these "interactions" are. While existing wind turbines kill hundreds of thousands of birds annually, the projections are even more sobering: Scientists have estimated that as the number of turbines increases, they could kill more than a million birds each year by 2030.
Meanwhile, an analysis recently released by the American Bird Conservancy based on federal data found that more than 30,000 turbines have been installed in areas critical to the survival of federally protected birds--with an additional 50,000 turbines planned for construction in similar areas.
There are steps we can take. Building wind turbines away from heavily traveled bird migration routes such as the Atlantic coastline or in the Great Lakes region would help to lessen fatal collisions. So would temporary shutdowns of turbines during peak migration periods in the spring and fall.
Keeping turbines away from core habitat where imperiled birds breed is also important. Another new study published by the journal Condor shows that greater prairie chickens--rare birds that gather each year for mating displays--are more likely to abandon these courtship grounds when they are close to wind turbines.
Developing renewable energy sources is important. But our policies treat birds and other wildlife as collateral damage in that quest. As the wind industry prepares to take turbines to new heights, the death toll for birds will only intensify.
Michael Parr is vice president of the American Bird Conservancy.
Editorial on 06/14/2015