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Power Science

Radar Could Save Bats From Wind Turbines 116

mknewman sends in an MSNBC piece on a promising way to keep bats from straying into wind farms — by using radar. "Bats use sonar to navigate and hunt. Many have been killed by wind turbines, however, which their sonar doesn't seem to recognize as a danger. Surprisingly, radar signals could help keep bats away from wind turbines, scientists have now discovered. ...some researchers have raised concerns that wind turbines inadvertently kill bats and other flying creatures. ... The bats might not be killed by the wind turbine blades directly, but instead by the sudden drop in air pressure the swinging rotors induce... The researchers discovered that radar helped keep bats away, reducing bat activity by 30 to 40 percent. The radar did not keep insects away, which suggests that however the radar works as a deterrent, it does so by influencing the bats directly and not just their food. Radar signals can lead to small but rapid spikes of heat in the head that generate sound waves, which in turn stimulate the ear. A bat's hearing is much more sensitive than ours. It may be so sensitive that even a tiny amount of sound caused by electromagnetic radiation is enough to drive them out."
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Radar Could Save Bats From Wind Turbines

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  • by RsG ( 809189 ) on Wednesday July 22, 2009 @02:20AM (#28778741)

    Why not just use a direct sonic system, instead of using radar pulses to generate sound indirectly? Bats have very sensitive hearing, and there are probably ways of generating noises that keep them away, either by interfering with their sonar, or simply generating unpleasant aural input. I seem to recall ultrasonic systems devised for driving off human beings, or other animal species, so it's a demonstrated concept.

    Of course, such a system could exist and use more energy, or cost more to implement. Nothing in the article about that however.

  • Re:More geeky (Score:4, Interesting)

    by waferhead ( 557795 ) <waferhead@EEEyahoo.com minus threevowels> on Wednesday July 22, 2009 @02:22AM (#28778745)

    ...Or for a tad more energy efficiency vs. using RADAR to heat up the bats skull to produce sound, put some SPEAKERS on the bloody blades.

    Or air activated "deer warnings" on the blades, except ones that work for bats.
    (Dangerously assuming those worked for Deer, but you get the idea)

  • by RsG ( 809189 ) on Wednesday July 22, 2009 @02:30AM (#28778771)

    Not the issue you might think it is. Bat's hearing includes a whole range of sounds outside of what we mere humans can hear. You could probably make an ultrasonic system that sounds like fingernails on a blackboard to bats, and nothing at all to us.

  • by GrpA ( 691294 ) on Wednesday July 22, 2009 @02:43AM (#28778827)

    No, they are actually referring to the radiation causing sound inside the bat's heads...

    They figured this out decades ago when they heard sound coming from radar systems that were appropriately modulated.

    Then a bunch of nerds (they called them "Air Control Tower Operators" back then) figured they could modulate voice into a radar dish, point it at someone walking over the other side of the field and they would suddenly hear voices in their head... Which I'm sure was really funny for a while.

    It's even patented. Microwave induced audio.

    But it causes sound by heating, so basically, regardless of the level of radiation, heat generation is needed to induce sound. Consider that for a moment and also that it's microwave radiation.

    No matter how small the radiation level is, it's like microwaving the bats.

    Fortunately, Bat's can't sue people for exposing them to potentially dangerous levels of radiation, so it's probably just fine.


  • by RsG ( 809189 ) on Wednesday July 22, 2009 @03:14AM (#28778977)

    Well, to play devils advocate for a minute, if the options are 1) no system, 40% casualties or 2) potentially dangerous system, 5% casualties, then I'd call option 2 an improvement, at least from a conservation standpoint. From an animal rights POV... not so great.

    Anyway, a bat repellent speaker doesn't absolutely have to be a brute force approach. What about broadcasting their own sonar waves back at them, such that they get the mistaken impression there's a solid object in their path, and avoid it accordingly?

  • by blind biker ( 1066130 ) on Wednesday July 22, 2009 @03:27AM (#28779031) Journal

    The trend is towards larger and slower wind turbines, because they are more efficient. At the same time, slower moving blades are safer (actually, with contemporary wind turbines, completely safe) for birds and bats. Also, bladeless designs are becoming more popular, again because they are more efficient. These bladeless designs are completely safe, regardless of size.

  • Re:More geeky (Score:3, Interesting)

    by c0p0n ( 770852 ) <copong@g[ ]l.com ['mai' in gap]> on Wednesday July 22, 2009 @05:14AM (#28779441)

    ...Or for a tad more energy efficiency vs. using RADAR to heat up the bats skull to produce sound, put some SPEAKERS on the bloody blades.

    Dude, last thing you wanna do is to introduce instability on a 4m long blade by adding uneven weight.

  • by mad_minstrel ( 943049 ) on Wednesday July 22, 2009 @05:20AM (#28779457)
    Echolocation only works when and where you sent out the signal in the first place. A signal sent out from a different location than your current, at an unknown time carries little to no data. Therefore, I don't think you can really impersonate a bat and make it think there's a wall ahead.
  • Re:More geeky (Score:3, Interesting)

    by kinnell ( 607819 ) on Wednesday July 22, 2009 @07:21AM (#28779857)

    Instead of setting a radar to pump out radio waves, why not set a device like that to send an amplified return?

    Yes, let's make bats safer around wind turbines by jamming their sonar ;)

  • by mad_minstrel ( 943049 ) on Wednesday July 22, 2009 @09:46AM (#28780885)
    Common sense suggests they can. If you go into a cave, or anywhere else there's an echo, you can easily distinguish your own voice, even in a crowd of echoes, because you know exactly what you shouted, including timbre, tone, content, rythm, little rasps, etc. You can also approximate when to expect an echo based on whan you shouted and the timing of your previous shouts. And a bat's hearing is a lot better than ours. Then again, whether bats can remember the particular way they had just screached is not certain. But if they could, it would probably raise their survivability quite a bit, so I would expect mother nature to have given them that ability, at least to a certain extent. Someone probably already studied this.
  • by apoc.famine ( 621563 ) <apoc.famineNO@SPAMgmail.com> on Wednesday July 22, 2009 @11:59AM (#28782889) Journal

    No, he's not joking [wikipedia.org].

Building translators is good clean fun. -- T. Cheatham