Sound specialist offers expertise on industrial wind installations
Batavia Daily News - Mary Kay Barton
- February 7, 2008
"Understanding Sound Associated with Industrial Wind Developments",
was the theme of the presentation by Rick Bolton, Engineer & Sound
Specialist, and sponsored by Citizens for a Healthy Rural Neighborhood
(CHRN), on Wednesday, January 30, [2008] at Perry's Masonic Temple. Though
Wednesday's inclement weather prohibited attendance by many from
outlying areas, citizens and Town Board members from Perry, Gainesville,
Leicester, and Orangeville were there. Mr. Bolton's presentation was
designed to convey a basic understanding of the complexities of sound,
effects on humans, and flaws in current analysis standards being
employed by wind developers in the U.S.
Mr. Bolton began by
explaining that sound associated with wind turbines is an extremely
complex issue, and one that needs thorough analysis. "Sounds are waves -
just like light and water," he said. These sound waves are measured in
deci-Bels (dB, or dBA - A-weighted deci-Bels - most closely imitate the
human ear).
"Human audibility is extremely sensitive," he said.
"In fact, far more sensitive than anything we can use to record sound
electronically. While the human ear can detect to 0 dBA, the lowest
range even the most expensive noise meters can measure is 14 dBA."
Elaborating on the factors that can amplify sound, Bolton pointed out:
1.) Sound can propagate for over a mile, and even further over water;
2.) Sound gets worse in water (i.e. - ice, fog);
3.) Low frequencies can double sound by refraction off hard surfaces (hillsides, snow-pack);
4.) 'Wave Coherence', created by a number of turbines together, amplifies sound;
5.) When the wind is blowing, it can refract noise from the elevated source-point downward;
6.) Sounds below 30 Hz, termed 'infrasound', create serious health
problems (turbines have been indicated as being a strong source of
'infrasound')
7.) Ice-loading on the front edge of turbine
blade tips disturbs air flow around the blade, creating turbulence, and
increasing sound.
8.) Modulation occurs when the blade
compresses air as passing the mast of the turbine, and is worsened by
large groups of turbines' blades not operating in sync. (Bolton has
never seen modulation addressed in any wind developer provided studies.)
Bolton explained the many ways wind developers methodology is
flawed. Field measurements are not done correctly (i.e. - improper
microphone placement, no justification for sampling sites, etc.);
accurate samplings need to be done for a full year to account for
seasonal variations, but aren't; and computer prediction models wind
developers rely on are inadequate because they don't account for
modulation, coherence, refraction, and icing.
Facts contained
in Perry's DEIS from the sound study done by Horizon for Perry were
brought up that highlighted Bolton's point that sound studies being done
are totally inadequate: "5 monitoring locations; Survey was carried out
over roughly a 3-week period; Unfortunately, 3 primary & 2 backup
instruments were destroyed by water infiltration, so octave band data
could not be collected for ALL positions for the entire 3-week survey;
There were a number of periods of either inclement weather or low wind
speeds - conditions that are not generally useful; General conditions of
temperature, barometric pressure, & wind for the survey period are
shown in plots below as observed at DANSVILLE, NY - some 20 miles
southeast of the site."
Illustrating and explaining his points
with numerous charts and graphs that were part of his presentation, he
also included examples and measurements from homes that had been
abandoned by their owners due to the resulting life-altering health
effects of living too close to turbines. Not surprisingly, these health
problems have been linked to sleep disturbances.
The World
Health Organization (WHO) guidelines recommend that sound level should
not exceed 30 dBA for a good night's sleep. WHO also unanimously agrees
that noise levels greater than 42 dBA create sleep disturbances, and
that disturbed sleep has serious health effects.
Bolton
explained that rural country settings currently enjoy extremely quiet
night-time noise levels of 20 - 30 dBA. However, wind developers
typically propose 50 dBA as acceptable noise levels at property lines of
neighboring homes to their industrial wind installations. They do so
despite the fact that the NYS DEC recommends no more than a 6 dBA
increase over existing night-time ambient noise levels.
"Every 6
dBA is a perceived doubling of sound, or loudness," Bolton said. When
you understand this, you can begin to understand the problems that are
occurring from siting these facilities far too close to people's homes
in rural areas. Bolton's research suggests that 3,000' - 5,000' setbacks
from the nearest property line should be the rule of thumb.
Neither citizens, nor the town officials being rushed through zoning,
siting, and approval processes by wind developers truly understand the
vast difference between 30 and 50 dBA until it is too late. Bolton
stressed the importance of "getting it right" before allowing industrial
wind facilities to be built, since mitigation after the fact is not
available. He has yet to see wind developers do any follow-up studies
for those now experiencing problems. They simply ignore them.
Bolton also explained that NY Townships are perpetuating flawed methods
by accepting, and placing in their ordinances, the 50 dBA sound levels
being submitted by wind developers, without demanding justifications -
despite the fact that this is contrary to SEQR rules. NYS DEC's
Environmental Conservation Rules for SEQR state that the noise pollution
potential must be evaluated at each affected "receptor".
NYS
DEC's Program Policy, "Assessing & Mitigating Noise Impacts",
states: "When a sound level evaluation indicates that receptors may
experience sound levels or characteristics that produce significant
noise impacts, or impairment of property use, the Department is to
require the permittee or applicant to employ necessary measures to
either eliminate, or mitigate, adverse noise effects."
If our
townships fail to hold developers accountable to required standards, "we
will lose the privilege, and precious asset, of having the peace and
quiet of the country," he said.
Mr. Bolton then took questions
from the crowd. In response to questions asking what he thought of being
"surrounded" by up to 23 turbines within 1.5 miles of their homes, he
answered, "I would be VERY concerned if I were you."
http://www.windaction.org/news/14054
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