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As Wind Power Expands, So Do Threats to Bat Population

November 29, 2010 at 12:00 AM EST
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Ed Jahn of Oregon Public Broadcasting looks at the deadly effect wind power turbines can have on migratory bats in the Pacific Northwest.
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TRANSCRIPT

This segment was originally produced for OPB-TV’s ‘Oregon Field Guide.You can watch the full version here.

GWEN IFILL: For those stations not taking a pledge break, The NewsHour continues now with an unexpected windmill problem in the Pacific Northwest. It’s part of our series, NewsHour Connect, which showcases the work of our colleagues in public media.

Ed Jahn of Oregon Public Broadcasting, reports.

ED JAHN, Oregon Public Broadcasting: Not a lot is known about bats in Oregon, but there’s a big push to find out more. And net capturing is one way to do it.

CRIS HEIN, ABR Incorporated: So we had a bat in the net. It’s a big brown bat. And these guys are usually pretty feisty. Look at that.

JINA SAGAR: Look at that face.

ED JAHN: Chris Hein and his colleague, Jina Sagar, will note what they’ve caught, take measurements and then set this bat free.

But this research is on the being done for government or university study. Cris works for ABR Incorporated; Jina for a company called Tetra Tech. Their client is the wind energy industry.

CRIS HEIN: This bat has been found at wind facilities. It can make up roughly a quarter of fatalities at some locations.

ED JAHN: It turns out that bats are dying by the thousands at wind farms like these. At one wind farm on the East Coast, an estimated 2,000 bats were killed in just six weeks. Infrared video shot by Boston University showed the bats, looking here like small dots, getting knocked out of the sky time and again.

Oregon Fish & Wildlife’s Mark Hersh couldn’t understand why it was happening.

MARK HERSH, Oregon Fish & Wildlife: We were just absolutely flabbergasted that something as agile as a bat, with the excellent echo location capabilities that they have, would ever come in contact with a turbine blade. It would be just like a person walking into a wall in a fully lighted room.

ED JAHN: The deaths are a blow to wind energy’s green reputation. And the problem for bats could get worse. The federal government wants a fifteen fold expansion of wind energy nationwide by 2020. Oregon will be a big part of that future. In fact, tens of thousands of acres that looked like this just a few years ago now look like this.

The wind industry is hoping to find ways to avoid more bat deaths. The first step is simply learning what’s out here.

CRIS HEIN: So this is an acoustic monitoring set up. We can set up the detector to begin recording at sunset and stop recording at sunrise. And then once it’s one, it’s recording everything. So if a bat’s calling in the area, then we will pick it up.

ED JAHN: When Cris downloads the actual recording, he’ll match the sound to specific species, giving wind companies an idea of what bats are passing through. Some companies use this information to adjust their turbine siting plans. But one theory pins the problem on the turbines themselves, which generate heat, which attracts insects which are then followed by hungry bats.

Jina Sagar says the deaths often occur during seasonal migration.

JINA SAGAR: The species that are primarily killed at wind turbines are the migratory tree bats. And so these are bats that are roosting in either the foliage of trees or in the cavities of trees and then they need to migrate. So one of the theories is that they are seeing the turbines as a potential roof site.

ED JAHN: The bats don’t even have to get hit by the turbine blade to die. Researchers have discovered one other surprising cause of death.

CRIS HEIN: The other is called barrel trauma (ph) and this is a phenomenon in which, when the bat is passing through the air space adjacent to the moving blade, there’s a pressure differential. And as they pass through that, their blood vessels and organs rupture and cause death.

ED JAHN: Approximately two bats die for every megawatt produced by wind in the Northwest. Take the 8,200 mega watts approved or already on line, and you’ve got nearly 17,000 dead bats. That’s fewer than are killed back East, but it still gives pause to Blue Mountain Audubon’s Mike Denny.

MIKE DENNY, Blue Mountain Audubon: What we’re looking at is what we call the wall effect. What appears to be forming is almost the same impact that dams have on salmon, only this is wind turbines on birds and migrating bats.

ED JAHN: Mike is not against wind power as a whole. His main concern is that wind companies are expanding out of the farm country of the gorge and into wildlife rich habitats like Oregon’s Blue Mountains.

Only a few wind projects have been stopped to protect bats.

MIKE DENNY: This is an industry that is killing wildlife and it’s killing bats. And the whole issue is, are you going to produce enough energy to overcome the amount of wildlife that you’re going to kill?

ED JAHN: Portland-based Iberdrola Renewables is the largest provider of wind power in the world. Iberdrola’s Andy Linehan says the industry has been working to fix the problem ever since the first bat showed up dead on the East Coast.

ANDY LINEHAN, Iberdrola Renewables: My job is to make sure we’re not into those areas which are going to raise risk for us and which we can continue to call green development. The wind industry as a whole, I think it’s going to be challenging to get to the kinds of numbers that we expect from wind energy without getting into areas in which either we have new questions, biological questions, or we’re going to run into pure visual issues.

ED JAHN: Iberdrola is testing new techniques to reduce bat deaths.

One technique is to start up the turbines only after wind is blowing strong enough that most bats aren’t flying anyway.

ANDY LINEHAN: That’s one approach. The other approach is to create a white noise around the turbines with an — an ultrasound device, which is kind of like a sound which interferes with their echo location. And that, presumably, will either make it difficult for them to hunt insects or maybe it will just make them — make it unpleasant to be around turbines.

ED JAHN: The wind industry is working closely now with groups like Bat Conservation International. More money and manpower are being poured into research than ever before.

CRIS HEIN: A little bat like this can eat up to 600 insects an hour, small sized insects. And a lot of the insects that bats feed on are agricultural and forest pests.

ED JAHN: No one we talked to said they want to bring an end to wind power.

CRIS HEIN: Off to eat more bugs.

ED JAHN: Wind turbines provide power, emit no pollution and the energy source — wind — is both clean and unlimited. But the bat issue does make our energy choices more complicated.