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Re: wind power

From:

Tim Boucher

Reply-To:

Tim Boucher

Date:

Wed, 19 Dec 2007 11:00:06 -0500

I don't want to debate the costs/benefits of wind or other alternative
energy sources, and I thank Norm for tolerating this discussion. 

However, I do think it is important that when people debate, they do so
based on as much information - as much accurate information - as possible.

Frank said that there was evidence that changing the design of the rotor
blades to change the frequency of the sound emittted from the turbines would
help birds avoid the turbines. I've been engaged in the issue of wind energy
for several years, and had never heard that. I followed up by asking Frank
for more information, but pending a response from him, I did my own
research. I did find a 2002 document from the National Renewal Energy Lab
(NREL, part of the U.S. Department of Energy) speculating that this might
work and suggesting that it be tested. I found some references to studies
conducted by the Avian Powerline Interaction Committee. As I couldn't find
any such studies, I contacted APLIC directly, and to date, their response
is, "there were some studies regarding use of noise as deterrent in our
early years but it proved unsuccessful...." I am awaiting further
information from APLIC and other sources and if it turns out that anyone has
done such studies, I'll post that info here. Suffice to say, though, that
with the controversies relating to telecomm towers, turbines, and other
obstructions, it seems likely that if this had been shown to work, it would
be in widespread use.

Also consider that detectability of a turbine blade might not be enhanced,
even if the bird associated that particular frequency with the presence of
an obstacle, because the rotor-swept area is very large. Further, turbines
are generally in large arrays. Avoiding one turbine wouldn't be sufficient.
The bird would have to be able to detect and avoid a series of turbines. 

Ellen Paul
Chevy Chase, MD