Ellen -- I'm not understanding the basis on which you are so categorical 
that turbines just cannot be turned off during migration.  the electric 
generating industry operates on the basis of modulating production 
according to demand -- mid-summer they are making as much electricity as 
they can to power our air conditioners, mid-autumn demand is at a 
relative low.  similar patterns over the course of the day.  the 
industry likes gas powered plants even tho the cost of fuel is high 
because the plants are inexpensive to build and can be turned on or off 
very rapidly, nuclear -- with extremely expensive plant but inexpensive 
fuel-- is used as baseload production.  I would need far more data than 
your assertions that it would not be a reasonable approach, acceptable 
to many power companies.   [I caveat my comment this way because I 
recognize that management at different companies will have different 
degrees of willingness to cooperate -- that is a political or a 
regulatory problem, not one inherent to wind turbines any more than any 
other industry with economic or environmental externalities]

As to the viability of using blade design to produce sound that keeps 
the birds away, this is a very intriguing idea, but I accept that good 
experimental data may not have been turned up in this discussion.  and 
we don't need the air cannons they use at National Airport.  but that 
should not be the end of the discussion. 

unfortunately I do not know of a way to generate electricity without 
serious environmental consequences.  the consequences of coal power are 
very well understood, those of ocean thermal energy or geothermal, 
hardly at all.  I have my opinions.  I think they are informed, but I 
know they are only my opinions. 

chris kessler
falls church





Tim Boucher wrote:
> It does help in the sense that it helps birds. It is effective. That isn't
> the problem.
>
> The problem - sorry, I thought I'd explained it clearly, but I guess not -
> is that it is not economically feasible to turn off the turbines for all
> those nights. It also is a problem in that people rely on a steady supply of
> power so it can be difficult to rely on wind - as I said, if there isn't
> enough wind or if there is too much wind, there won't be any wind-generated
> energy and it has to be supplied from another source. 
>
> So for both these reasons they have to minimize the amount of down-time. 
>
> It would be difficult to use existing radar systems to narrow the times when
> turbines would need to be feathered to prevent avian mortality, because
> NEXRAD doesn't tell us altitude (I think, I'm not sure) and the kind of
> radar that is used to determine altitude, which is ground-based marine
> radar, would have to be deployed at pretty much every wind farm where
> flights can be expected on any given night. And both would require real-time
> monitoring. Expensive and difficult.
>
> I think I am explaining this clearly but maybe not, so to avoid irritating
> other readers, why don't you e-mail me off-list if you want to continue
> discussing it? My e-mail is 
>
> Ellen Paul
> Chevy Chase, MD 20815
>
>
>
>