Energy

Active wind turbine control aims to cut bird deaths by 80%

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Norwegian researchers say they've found a potential way to cut down the numbers of birds killed by wind turbines
Norwegian researchers say they've found a potential way to cut down the numbers of birds killed by wind turbines
The SKARV system detects and tracks incoming birds, and attempts to slow the turbine rotors to let them through unchopped
SINTEF

One inconvenient truth for the clean energy industry – and a source of seemingly great concern to the fossil fuel lobby – is the indisputable fact that wind turbines kill birds. Researchers say smarter turbines could dramatically cut the toll.

It's hard to ascertain how many birds fly into the spinning blades of wind turbines and die as a result – and indeed, the topic is so politically charged that I'd recommend a radiation suit before even googling it. The American Bird Conservancy has waded through some of the available evidence and come to the conclusion that at least one million bird deaths a year in the US alone is likely to be an underestimate.

Now, that's substantially less than the estimated 25.5 million birds a year that kill themselves by flying into overhead power lines, or the estimated 980 million per year that die crashing into buildings, or the 1.4 to 3.7 billion per year killed by domestic cats. But it's still an unacceptable number, and a problem that needs to be addressed – because a fully green energy network will need more and more turbines over the coming decades.

Researchers at SINTEF and the Norwegian Centre for Environment-friendly Energy Research believe they have an idea that could help in a lot of cases.

The idea is fairly simple: each turbine will have cameras fitted, capable of spotting birds flying directly into the path of the rotors. Software will automatically calculate their predicted trajectory, and if it looks like they're in danger of being hit, the system will send control signals to slow the blades down, by adjusting the generator moment and blade twist.

The SKARV system detects and tracks incoming birds, and attempts to slow the turbine rotors to let them through unchopped
SINTEF

In simulations, the system – known as SKARV – is able to avoid the vast majority of collisions with single birds moving in a predictable path, coming toward the turbine head-on, spotted with at least five seconds until impact. This, of course, doesn't describe all situations. It won't stop them smacking into the central nacelle or the tower, and it won't help if they come flying in from the sides, or if they're circling around the turbine.

"It’s difficult to predict a bird’s flight trajectory, and the new system will not resolve this problem entirely,” says researcher Paula B. Garcia Rosa. “For example, if a young, inexperienced bird approaches a turbine displaying irregular flight behavior, it will not be possible to predict exactly where it will be a few seconds later. Prediction is also more difficult if several birds approach at the same time.”

The system can be set to shut turbines down altogether if a large number of birds are approaching – although the team notes it can take up to 20 seconds for a large turbine to stop completely from a normal rotation speed.

“On the basis of our simulations, we believe that the SKARV project can help to reduce the number of fatal collisions by up to 80%,” says Garcia Rosa. “The next step is to further develop existing strategies for controlling blade rotation speeds and to integrate these with methods for identifying bird flight trajectories. Then we will be looking to implement a practical demonstration. We believe that the SKARV technology could be commercially available within five years, and perhaps even earlier if we see sufficient interest from the industry."

This is one of those funny issues that turns coal magnates into environmentalists. If flocks of birds are going to regularly interrupt clean energy generation, the SKARV system may well also turn clean energy magnates into hard-hearted mercenaries. Some researchers even contend that birds are learning to avoid turbines of their own accord. But if more than a million birds a year – just in the USA – haven't got the memo yet, it's still a problem worth solving. We look forward to hearing how trials progress.

Check out a short video below.

Source: SINTEF

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9 comments
kwalispecial
I'm glad to see people trying to address this problem, but I'm skeptical that this is the right solution. It seems too complicated, and slowing the blades will be a big hit to the windmill's efficiency, so producers would probably fight it. I would think some kind of passive system to deter birds (and bats) with visual or sound signals would be a lot cheaper to implement without affecting the function of the turbine - if a solution like that can be found...
Rick O
I agree with kwalispecial. If the system works at all, I don't see it being effective enough to be worth the efficiency loss. Something that alerts the birds to the impending blade coming at them sideways would be much more effective. Just duct tape some deer whistles to the blades, that'll do it, lol
TechGazer
If they've got the bird detection system working well, why not have it trigger something to scare the birds? Bright lights or noise might work, and be cheaper and less inconvenient than changing rotor speed, and be faster-reacting. Physical deterrents, such as a sheet that unrolls and flaps around before being rolled back in again, would be more complex, expensive, and heavy, but maybe someone can come up with a simpler/cheaper solution.

Putting a tube down each blade provides cheap presssurizing of a fluid, so little valves releasing "smoke" might work.
CraigAllenCorson
Why not simply paint stripes on the blades to make them more visible to birds? Birds will avoid flying into objects, provided that they can SEE them. Birds are often seen flying into windows, but NEVER into walls.
paul314
So what kinds of systems are available to prevent skyscraper bird kill? Even reducing it by 10-20% (or not building in migration paths) could do more than making turbines entirely bird-safe.
Dave Holland
Anyone worried about birds being killed (and we all should be) would be better focussed on cats. In Australia "Pet and feral cats together are killing over two billion reptiles, birds and mammals per year in Australia” - 1.3 billion of these are birds. (https://www.anu.edu.au/news/all-news/cats-kill-more-than-15-billion-native-animals-per-year).
ClauS
One thing that is not mentioned neither in the article or comments is that windmill are killing more large birds than the others factors. While cats by themselves manage to extinct around 60 species, they had (I guess) a smaller impact on large birds, and here lies the issue with the windmills.
rgbatduke
Between between 89 million and 340 million birds die per year due to collisions with cars. Reducing the number of cars on the road by 1 or 2% would suffice to offset the loss to turbines. Implementing cheap commuter rail combined with inexpensive rechargable end point transport (so you get off the commuter train and step into a self-driving "golf-cart" scale commuter car that takes you to your office and returns), eliminating auto traffic from the streets altogether, fueled by wind turbines, would be a net win in bird deaths. But honestly, we'd be better off breeding "better" (read: less likely to kill birds) cats.
Lee Pannett
Great to see researchers are looking for ways to this problem but this is not the only solution that can be considered. At Scarecrow Group we are working with members of the wind turbine industry to use bioacoustics technology that deters birds from coming towards the wind turbines by omitting bird calls to scare them away. This is an effective way of preventing the birds even getting close to the turbines in the first place, negating the need for them to shut down at all.