Drew asked a very interesting question regarding why wind mills couldn’t be netted in to keep birds out. I asked the question to some experts on the issue and here’s the most cogent response.
“a. Wind turbines already involve high capital costs ($1.0 to $1.5 million per MW) about 75% of which is for the tower, turbine and blades.
b. Erecting a “screen” would require another tall tower, plus the screen which, from an engineering point of view probably could be constructed but at huge cost.
c. Apart from the impaling issue (dolphins in tuna net), the screen would have to be relatively fine to keep out small birds and bats. Such a screen would:
(1) Involve lots of wind resistance, requiring a very strong tower — which might be very difficult from an engineering point of view. Keep in mind that the span of the blades is roughly the same as the length and wingspan of a 747. (If possible, I’ll attach a neat diagram of this published by the Scotsman.)
(2) Reduce the amount of wind reaching the blades thus sharply reducing the “fuel” for the wind turbine and thus reducing the electrical output and making the things even less cost effective than they already are.
In short, a screen to keep birds and bats out of windmills is one more good idea that doesn’t make engineering, economic, or environmental sense.
It is useful to keep in mind that windmills are a niche technology that is good for pumping water (which can be stored) and for producing electricity in remote areas that are beyond the reach of electric distribution lines — or where the owner is willing to purchase expensive battery storage — or have electricity only when the wind is blowing in the right speed range.
The problem with windmills to produce electric begins when central planners try to force a niche technology into wide scale usage with dictates subsidies.”
