Surrebuttal Testimony of Richard R. James on Behalf of the Coalition for Wisconsin Environmental Stewardship
(Wisconsin Public Service Commission docket 6630-CE-302: Wisconsin Electric Power Company (WEPCO) Glacier Hills Wind Park)
I am testifying in response to the rebuttal testimony of George Hessler, Mark Roberts, and Geoff Leventhal, filed on behalf of Wisconsin Electric Power Company. …
I have organized my responses into three sections: Ambient Sound Measurements, Validity of Noise Modeling, and Sleep Interference. …
Numerous studies have shown that wind turbines can be operating at nominal or higher power production during conditions when the ground level winds are calm and there is no noise from vegetation and turbulence around ground structures to mask the wind turbines. … I have also confirmed that many of the complaints made about excessive wind turbine noise by residents living in the footprint of operating wind generators are made when wind speeds at the ground level are calm. …
A level of 30 dBA is reasonable in light of the current nighttime background sound levels of less than 30 dBA (LA90). A level of 40 dBA or higher would clearly put the public’s health and well being at risk. Mr. Hessler’s contention that the criteria should be even higher than 40 dBA is based on his incorrect assumption that wind turbines do not produce significant low frequency sound, and thus will not be an indoor noise problem. Given the information showing that low frequency sounds are the dominant form of sound emitted by wind turbines (as stated in my direct testimony), it seems unusual that Mr. Hessler would reintroduce his opinion that the walls of a home would be effective in reducing the low frequency rumble that is experienced inside homes, especially evident at night when the bedroom is quiet. The subject of low frequency noise is addressed on pages 9-12 of the Kamperman-James “How to… Guide,” which is included in exhibit 809. Low frequency noise was also highlighted in the 1990 NASA study [Hubbard, H. H., Shepherd, K. P. “Wind Turbine Acoustics,” NASA Technical Paper 3057 DOE/NASA/20320-77 (1990)] by Hubbard and Shepherd (See: Noise Exposure Inside Buildings, page 35-39) to the effect that low frequency turbine sounds can resonate inside a home leading to even higher levels of low frequency sound inside the home than outside. Mr. Hessler’s focus on only dBA values, which do not include the low frequency sounds, discredits Mr. Hessler’s contrary argument.
Mr. Hessler also comments on the need to limit low frequency sound to levels of 60 to 65 dBC is a valid upper limit. The criteria proposed in the Kamperman-James paper uses Mr. Hessler’s paper on that topic as a source for its not-to-exceed limits. However, the reports of adverse health effects, especially those of the type described for Wind Turbine Syndrome also occur during the daytime when sleep disturbance is not an issue. Tests I have taken inside the homes of people reporting such effects found low frequency sound pressure levels exceeding 60 dB in the 6.3 Hz 1/3 Octave Band. The graph below illustrates this situation.
The slope of the spectrum increases as frequency decreases. Thus, the sound pressure levels in the infrasound region below 10 Hz may be higher yet. These measured levels are consistent with the sound emission spectrum of wind turbines. Although wind may play some role in raising the sound pressure level in the lower frequency, the wind turbines are by themselves significant contributors that should not be ignored by continued use of A-weighting to measure and display wind turbine sound data.
Adverse health effects are being reported that may be linked to vestibular and balance functions. Whether these are a result of the simple average sound pressure level or whether some other characteristic of the acoustic energy such as the dynamic modulation of the sound in these lower frequencies is responsible is not known. Following the precautionary principle, the K-J criteria proposed that in communities without significant man-made sources of low frequency sound to mask the ILFN sounds from the turbines that there also be limits to any increases in over-all ILFN. Thus, the recommendation for applying a second limitation for ILFN using the criteria of LCeq = LC90 +5 for additional sound from wind turbines. …
In my opinion, there should be at least a mile and 1/4 [2 km] between turbines and homes. I say this not to restrict wind energy as a source of renewable energy, but instead as a temporary condition until the questions of adverse health effects can be addressed in independent research that can be used as a future guide to either continue the large setbacks or to set new setbacks that are founded on knowledge and not speculation.
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