I once attended a Republican club meeting to ask why our county was pursuing Industrial Wind Turbines (IWTs). I questioned a commissioner about impacts of 500′ turbines the height of the tallest skyscraper in downtown Indianapolis. He uttered “sound bites” often heard, “Have you ever stood under a wind turbine?” “They don’t make noise.” “I stood a half hour under one!”
I repair aircraft for a living that are more complicated than wind turbines operating across the US. Wind companies, when demonstrating wind turbine sound, often place people directly beneath turbines for a reason. They convince people that (IWTs) quietly run unnoticed 24/7.
Imagine the turbine fan as a propeller of an average airplane. Stand to the side of the airplane propeller as it idles. You are in line with blade tips just as you stand beneath the wind turbine. It’s “whisper” quiet no matter how long you remain there. Now, place yourself directly in front of the propeller. If you could levitate yourself 500′ to the front of the IWT, you will hear percussive thumping of blades as they gather air and force it backwards like the airplane. Walk to the rear of the aircraft and stand behind the propeller. Percussive thumping plus the force of pulsing air beats against you. Furthermore, like many aircraft propellers, IWTs can rotate their blades to “low pitch” moving less air at lower torque. “Low blade pitch” also “promotes” people into reasoning IWTs are quiet. Imagine the airplane propeller is now attached to the IWT hub and its blades stretch to the length of a football field. This propeller operates slower than the airplane at idle speed to keep the blades from separating from the hub. Although, at 20mph wind speed, the rotating blades appear to be moving very slowly but the blade tips are actually averaging 125 mph+. Simple physics.
The beating of the blades elevated 150′ is no longer felt anywhere around the turbine base. The sound emanates downwind from the fan in a cone shape. Depending upon the size of the turbine, the ‘cone of sound’ may not hit the ground for a distance of 1,000’ downwind of the IWT. But residents at 1000′ and further away will experience effects from the cone of sound and pressure pulses with varying degrees of seriousness.
It does not take a turbine expert to learn IWT basics or become wise to wind company propaganda.
To parrot “sound bites” from any wind company insisting there are no effects of IWTs when their contracts explicitly state they are NOT responsible for noise, air turbulence, wake effects, vibration, shadow flicker, electromagnetic interference or ice throw is IRRESPONSIBLE. Thank you to officials WHO investigate BEYOND the wind companies veil. It’s your job.
BTW, go to an IWT area on a windy day when the blades are high pitched and torqued backwards, it’s noisy. Organized wind tours are methodical and systematic for a reason.
Kelly Wilson
Henry County, IN
URL to article: https://www.wind-watch.org/news/2019/08/12/why-do-wind-companies-place-people-beneath-turbines/