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Power Science

Radar Could Save Bats From Wind Turbines 116

Posted by kdawson
from the holy-pressure-drop dept.
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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  • More geeky (Score:2, Informative)

    by Lorens (597774) on Wednesday July 22, 2009 @02:15AM (#28778719) Journal

    The guy who noticed this was using a device that detects the ultrasonics emitted by bats.

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

  • by RsG (809189) on Wednesday July 22, 2009 @02:38AM (#28778807)

    Nah, nothing so direct.

    Radar pulse hits bat. Pulse generates heat, which produces sound waves, inside the bats head (sounds scary, but we've been operating proximate to radar machines since WWII). I've heard of this effect elsewhere, and can readily believe it might be more pronounced in bats than humans. Sound confuses/diverts/drives off bat - they're not sure how exactly, but any number of theories might explain this behaviour.

  • by Schrockwell (867776) on Wednesday July 22, 2009 @02:56AM (#28778891)
    The rise of wind farms has already led to complications with current NEXRAD weather radars, and these radars don't even scan that close to the surface â" 0.5 degrees is the lowest tilt. I can only begin to imagine the complications of wind farms interfering with military radars which scan much closer to the Earth's surface.

    Now they want to point some sort of radar at a complicated source of ground clutter that's already difficult to detect and remove? I don't see how that's going to fly (no pun intended).

    For more information: http://www.roc.noaa.gov/windfarm/how_turbines_impact_nexrad_user.asp [noaa.gov]
  • by MichaelSmith (789609) on Wednesday July 22, 2009 @03:01AM (#28778925) Homepage Journal

    I can only begin to imagine the complications of wind farms interfering with military radars which scan much closer to the Earth's surface

    Turbines are a problem when they reflect signals back to the radar with sufficient Doppler shift to get past filters for static reflections. The emission from this device won't be near the frequency of the military radars (you would think) so there is unlikely to be a problem.

  • by shut_up_man (450725) on Wednesday July 22, 2009 @03:03AM (#28778931) Homepage

    You have to be very careful with sonic systems and creatures like bats and flying foxes. There are arguments afoot here in Australia that many sonic systems are waayyyyyy overpowered, causing bats to freak out and drop their young, or fall straight out of the sky and hurt themselves. Although technically this is a deterrent, it isn't really a good thing for the bats, which is the main point of the system. It might be like trying to keep humans away from an area by blasting our optic nerves with a near-blinding psychedelic lightshow and being a little miffed when the human falls over backwards in shock, tumbles down a hill and breaks their legs. Whoops.

  • by Plunky (929104) on Wednesday July 22, 2009 @04:09AM (#28779185)

    Intrigued, I did some google searching about bladeless wind turbines and there are some links but perhaps not any actual real life comparisons. Do you know of any such?

    It seems to me though, from what I've heard recently, that a bladed wind turbine extracts power from the area that the blades cover whereas a rotating cylinder [ecofriend.org] would only extract power from the area near the cylinder, even if the cylinders were arranged in a more traditional configuration [ecofriend.org] and the catavent [bloggingthegreen.com] system would seem to intercept even less wind

  • by blind biker (1066130) on Wednesday July 22, 2009 @04:25AM (#28779247) Journal

    Here you an find a plethora of companies making such devices [ecobusinesslinks.com], I hope this helps.

  • by drinkypoo (153816) <martin.espinoza@gmail.com> on Wednesday July 22, 2009 @08:29AM (#28780219) Homepage Journal

    Actually some bladeless turbines make power through some different principles than bladed ones. For example, the Savonius Vertical Axis Wind Turbine (the romans were using it to pump water using a screw) derives power from planetary swing-by, like a pelton wheel.

    A bladed turbine DOES only generate power from what the blades cover. However, it's from what they cover at any given time. They don't magically catch wind they're not in front of. It's very much based on their area (among other factors) and the same is true of VAWTs.

  • by Anonymous Coward on Wednesday July 22, 2009 @10:31AM (#28781511)

    Provide a link and you might get an Informative instead of a Funny.

    From Wikipedia: [wikipedia.org]
    "Bat bombs ... containing a Mexican Free-tailed Bat with a small timed incendiary bomb attached. Dropped from a bomber at dawn ... open to release the bats which would then roost in eaves and attics. The incendiaries would start fires in inaccessible places in the largely wood and paper construction of the Japanese cities that were the weapon's intended target."

Stupidity, like virtue, is its own reward.

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