Science

System could detect – and prevent – eagle strikes on wind turbines

System could detect – and prev...
According to the US Fish and Wildlife Service, there are roughly 143,000 bald eagles and 40,000 golden eagles in the United States
According to the US Fish and Wildlife Service, there are roughly 143,000 bald eagles and 40,000 golden eagles in the United States
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According to the US Fish and Wildlife Service, there are roughly 143,000 bald eagles and 40,000 golden eagles in the United States
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According to the US Fish and Wildlife Service, there are roughly 143,000 bald eagles and 40,000 golden eagles in the United States

It's a shame when any bird is killed by colliding with the spinning blades of a wind turbine, but it's particularly sad when that bird is a protected species. With that in mind, scientists are developing technology that could both deter eagles away from turbines, and detect when they hit the blades.

The main component of the system, designed by an Oregon State University team led by Prof. Roberto Albertani, incorporates a video camera mounted at the base of the turbine tower, vibration sensors mounted at the base of each blade, and an acoustic sensor located on the turbine's generator housing.

The idea is that when a bird strikes one of the blades, the impact is detected by the vibration sensor on that blade. Footage recorded by the camera at that time, along with audio of any bird cries recorded by the acoustic sensor, is then used to determine what sort of bird (or bat) was involved.

While this won't stop eagles from flying into the blades, it will at least let wildlife officials know exactly how many of the birds are being killed by individual turbines. Currently, this sort of knowledge is gained by inspecting carcasses located on the ground beneath the turbines, although there are problems with this approach – carcasses can be dragged away by scavengers, plus such surveys aren't feasible in remote locations, in areas with dense shrubbery, or at offshore turbines.

In tests of a basic version of the system, eagle strikes were simulated by shooting tennis balls at wind turbine blades. "General results from 29 field tests with blade strikes showed positive detection and confirmation 14 times," says Albertani. "Likely the impacts not detected were low-energy events. It is strongly believed the success rate can be significantly increased."

But what about keeping those eagle strikes from happening in the first place? Well, that's where another component of the system comes into play.

Using a computer-connected turbine-mounted camera, it would automatically determine if an approaching bird was an eagle, and if it was heading towards the blades. If that was deemed to be the case, then the computer would activate a ground-based deterrent consisting of randomly moving, brightly-colored facsimiles of people. It is hoped that based on eagles' aversion to humans, this would cause the birds to alter their course.

Source: Oregon State University via EurekAlert

7 comments
Bob
Given that I have had eagles in my yard and hovering over my head while being out working in the yard, I don't think that brightly-colored facsimiles of people will be much of a deterrent. Perhaps some form of loud ultrasonic sound would work better.
Deres
Don't the eagles have an alarm shriek when they are in couple raising childs in their nest ? It could be used to prevent them approaching a turbine. The best way would anyway to put permanent better visual signalling of the blades ...
Martin Winlow
Given your typical eagle can spot a mouse (in cover) from 100m or more away, I can't help feeling that they can probably see a 50m long wind turbine blade long before the hit it (and they have ears, too!). Has anyone done any research to see how much of a problem this really is? In the UK the RSPB have allowed wind turbines to be erected on their bird reserves. I'm assuming they don't want to see a budgy massacre any more than any of the rest of us. Ergo, is this a solution looking for a problem?
Brian M
@Martin Winlow You might be right, and birds do learn to avoid hazards, as you say these can be seen and heard by them. Although I'm getting a visions of rabbits sitting on the downwind side and laughing!
Subtle
Get rid of the wind turbines. Beyond the hazard to birds they are uneconomic. That's when you take the amount of material and energy used in making them. And then considering the amount of energy delivered over their operating lifetime. Then there will be the costs of recycling them when no longer serviceable.
Catweazle
Alternatively we could just stop Alternatively, we could scrap the "Green" virtue signallers' worthless bat and bird mincers and build real generators that worked 24/7...
MichaelGray
@Martin Winlow This is a very serious issue. We are seeing a high number of bird strikes by turbines. The problems with your example of the mouse in cover are too numerous to count. A mouse in cover is stationary on the ground, a wind turbine is moving through the air in a rotational motion. How do you expect a bird to anticipate the circular movement of a turbine blade when it is traveling at up to 180 miles per hour? A 2016 article estimates that 140,000 to 328,000 birds are killed in North America each year (http://www.audubon.org/news/will-wind-turbines-ever-be-safe-birds). More will die as additional turbines are brought online. Wind turbines are horribly inefficient, and never recoup their cost of production - this is easy to research. We should look at different wind turbine designs, or alternative green energy sources.