Photo credit: praatafrikaans
Are wind turbines benign carbon-free power sources or avian death traps that blight the landscape? New numbers have been tossed into the fray, yet we're no closer to achieving common ground. (No surprise there.)
It takes 30-plus turbines to reach a kill rate of one bird per year, according to a recent report by the U.S. National Academy of Sciences on the environmental impacts of wind-energy projects, based on 14 studies they felt superlative. A number of caveats were attached to the figure, however, including the acknowledgment that rates can vary by site and that endangered species such as the bald eagle are particularly worth avoiding.
However you look at it, though, birds in the United States seem to die in turbine blades at a rate no higher than 40,000 a year. Deaths by dastardly domestic felines, on the other hand, number in the "hundreds of millions."The study seems to have, well, ruffled more than a few feathers, especially those of bird-lovers who reserve a special brand of loathing for wind farms. "My personal opinion is that the evidence base is very poor," says Andrew Pullin, head of the Birmingham, UK-based Centre for Evidence-Based Conservation, in Nature.
The non-profit Royal Society of the Protection of Birds also points out that, while its members oppose large offshore developments, existing evidence on British wind farms is limited to studies of small installations onshore.
Published studies in Spain, which is the third largest wind-power-producer after the United States and Germany, also suggest that the number of birds killed is low. But at least one Spanish environmentalist, Alvaro Camiña, who monitors bird fatalities at 70 of the country's 140 wind-power farms, says that the figures don't tell the whole story; in the case of a widely accepted study published in 2004, the field work was completed a decade earlier, when turbines were much smaller.
More important, Camiña says, are the number of raptors killed—for example, 866 griffon vultures since 2000. "It's important to know the mortality of large birds because they have a lower number of offspring. Even a small number of deaths can affect a population," he tells Nature.
Rich Koebbe, the president of PowerWorks, a California firm with turbines in Altamont, counters with the assertion that the issue needs to be placed in context. "I heard that over 1,000 birds a year run into the Washington Monument. Should we tear that down? We're out here trying to do a job to save the Earth. We even save birds, since they are twice as vulnerable to pollution as humans." :: Nature