Dept of Health releases Wind White Paper
June 5th, 2009
Iff we could harness the energy of Katie V. Troe! Her work on the Bent Tree Wind Project has a measurable impact. Here’s one example — the long awaited Minnesota Dept. of Health Wind White Paper has been released, and here it is:
Here’s the short version:
The Minnesota nighttime standard of 50 dB(A) not to be exceeded more than 50% of the time in a given hour, appears to underweight penetration of low frequency noise into dwellings. Different schemes for evaluating low frequency noise, and/or lower noise standards, have been developed in a number of countries.
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Unlike low frequency noise, shadow flicker can affect individuals outdoors as well as indoors, and may be noticeable inside any building. Flicker can be eliminated by placement of wind turbines outside of the path of the sun as viewed from areas of concern, or by appropriate setbacks.
Prediction of complaint likelihood during project planning depends on: 1) good noise modeling including characterization of potential sources of aerodynamic modulation noise and characterization of nighttime wind conditions and noise; 2) shadow flicker modeling; 3) visibility of the wind turbines; and 4) interests of nearby residents and community.
VII. Recommendations
To assure informed decisions:
- Wind turbine noise estimates should include cumulative impacts (40-50 dB(A) isopleths) of all wind turbines.
- Isopleths for dB(C) – dB(A) greater than 10 dB should also be determined to evaluate the low frequency noise component.
- Potential impacts from shadow flicker and turbine visibility should be evaluated.
Any noise criteria beyond current state standards used for placement of wind turbines should reflect priorities and attitudes of the community.
This seems to me to be recommending either local control of siting criteria that actually addresses these issues (and what county government will?) or state criteria change reflecting issues raised by local communities and recommendations that the people have brought forward.