Better Plan, Wisconsin

THE MYSTERIOUS LINK BETWEEN BATS AND WIND TURBINES

Source: Minneapolis Star Tribune

November 2, 2011

By Josephine Marcotty

For years researchers have been puzzled by the number of bats killed by wind turbines. Birds, yes. But bats, in theory, should be able to avoid the towers because of their innate sonar systems that orient them in space. Nonetheless, they die in the thousands, in far greater numbers than birds. Some research found that they died because the enormous changes in pressure as the blades sweep through the air ruptured their delicate ear drums, causing a hemorrhage known as barotrauma. Now, a new study based on bat autopsies from the University of  Wisconsin found that the problem is far more complicated.

X-ray of a bat killed by a wind turbine at a southeastern Wisconsin wind energy facility during fall 2009.  Note the compound fracture of the right arm and the dislocation of the right shoulder joint

The scientists found 41 dead bats over three months beneath 29 turbines in Wisconsin. They conducted autopsies, including X-rays, on the animals to determine precisely why they died.

"Half the bats had trauma to the inner ear -- their ear drums blew out," said David Drake, one of the researchers on the study published this week in the journal of Mammology. And three fourths had broken bones, primarily wings, he said.

Why does it matter? Because knowing why they die might help in designing towers and blades that are not quite so lethal, he said. For example, changing the  shape of a blade could reduce the pressure gradient enough to prevent trauma to their ear canals, he said. Maybe changing the height of the tower would help avoid fatal collisions.

But the science is in its infancy, Drake said. in addition, not much is known about bats, much less about how they behave around wind towers or why they get close to them at all.

In the Midwest, migrating tree roosting bats are the ones that are killed most often. Drake said one theory is that they look for the tallest thing on the landscape -- often a wind turbine -- in which to roost and mate.  There are also studies that correlate bat deaths with low wind, perhaps because that's the best time for bats to feed. "They are so focused on feeding that they don’t pay attention to the blades until it's too late, Drake said. Even so, the bats need 20 meters to sense to a moving object. But the blades of a turbine move so fast they have only a quarter second to move out of the way. 

Drake said no one has a good estimate of how many bats are killed by wind turbines. But now it matters more than ever because bats are being decimated by a disease called white nose syndrome that destroys whole colonies. The disease is common in east, and is steadily moving west. So the total impact on bats is worrisome.

"With white nose syndrome  coming, all bets are off," he said. "When they are suffering 100 percent mortality from white nose, then added mortality from wind farms, it's hard to tell."

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GROUP REPORTS BIRD KILLS AT WEST VIRGINA WIND FARMS

Source: augustafreepress.com

October 31, 2011

With the deaths of nearly 500 birds at the Laurel Mountain wind facility earlier this month, three of the four wind farms operating in West Virginia have now experienced large bird fatality events, according to American Bird Conservancy (ABC), the nation’s leading bird conservation organization.

“Wind energy has the potential to be a green energy source, but the industry still needs to embrace simple, bird-smart principles that would dramatically reduce incidents across the country, such as those that have occurred in West Virginia,” said Kelly Fuller, ABC’s wind campaign coordinator.

There were three critical circumstances that tragically aligned in each of the three West Virginia events to kill these birds. Each occurred during bird migration season, during low visibility weather conditions, and with the addition of a deadly triggering element – an artificial light source. Steady-burning lights have been shown to attract and disorient birds, particularly night-migrating songbirds that navigate by starlight, and especially during nights where visibility is low such as in fog or inclement weather. Circling birds collide with structures or each other, or drop to the ground from exhaustion.

At the Laurel Mountain facility in the Allegheny Mountains, almost 500 birds were reportedly killed after lights were left on at an electrical substation associated with the wind project. The deaths are said to have occurred not from collisions with the wind turbines themselves, but from a combination of collisions with the substation and apparent exhaustion as birds caught in the light’s glare circled in mass confusion.

On the evening of Sept. 24 this year at the Mount Storm facility in the Allegheny Mountains, 59 birds and two bats were killed. Thirty of the dead birds were found near a single wind turbine that was reported to have had internal lighting left on overnight. This incident stands in stark contrast to industry assertions that just two birds per year are killed on average by each turbine. Data from Altamont Pass, California wind farms – the most studied in the nation – suggest that over 2,000 Golden Eagles alone have been killed there.

On May 23, 2003 at the Mountaineer wind farm in the Allegheny Mountains, at least 33 birds were killed. Some of the deaths were attributed to collisions with wind turbines and some to collisions with a substation.

“The good news is that it shouldn’t be hard to make changes that will keep these sorts of unnecessary deaths from happening again, but it’s disturbing that they happened at all. It has long been known that many birds navigate by the stars at night, that they normally fly lower during bad weather conditions, and that artificial light can draw them off course and lead to fatal collision events. That’s why minimizing outdoor lighting at wind facilities is a well-known operating standard. And yet lights were left on at these sites resulting in these unfortunate deaths. This reinforces the need to have mandatory federal operational standards as opposed to the optional, voluntary guidelines that are currently under discussion,” Fuller said.

A fourth wind farm in West Virginia, the Beech Ridge Wind Energy Project in Greenbrier County, has not experienced large mortality events, likely because it is currently prohibited by a court order from operating during nighttime between April 1 and Nov. 15.

“Some West Virginia conservation groups have suggested that other wind farms in the state should shut down their wind turbines at certain times and seasons to protect birds. Given the recurring bird-kill problems, that idea needs to be seriously considered, at least during migration season on nights where low visibility is predicted. A wind farm in Texas is doing just that, so it is possible.” said Fuller.