Last
February, BP acquired the assets of Acciona’s St. Lawrence wind farm and they
are progressing with a larger combined wind project, having recently
notified the Public service commission of their intention to proceed through an
article 10 process. In a letter to the Public Service Commission Development
Director Richard Chandler wrote BP has already
been engaged with the local community for years on the Cape Vincent Wind Farm
project and such work should not be discounted, or required to be reproduced.
However, some of their work has
been proven to be flawed.
At the second Wind
Committee Workshop February 2010, , Mr. Elliot from Cavanaugh Tocci Associates
(The consultant hired by the Planning Board) told members of Cape Vincent's
Town Council, Planning Board and Wind Committee that the sound study results
produced by Acciona /BP’s consultant, Hessler did not statistically support the
correlation between wind speed and noise.
To get a stronger
correlation, the wind speed and noise levels would have to be taken at the same
location. Additionally, Tocci and Associates were not the only acoustical
experts to question Hessler’s findings.
Paul D. Schomer of
Schomer & Associates Inc., Dr. Schomer is chairman of the International
Organization for Standardization working group on environmental noise and
chairman of the American National Standards committee on noise, among other
leadership roles in noise measurement. A group of residents commissioned Dr.
Schomer; NY to evaluate the pre-construction noise studies conducted by Hessler
and Associates. His findings contradict the studies done by Hessler Associates
Inc.
The executive
summary of his report is reproduced on this page. His full report can be
accessed by clicking on the link below.
Background sound
measurements and analysis in the vicinity of Cape Vincent, NY
May 11, 2009 by
Paul Schomer, Ph.D., P.E.
Summary:
His full report
can be accessed by clicking on the link below.
--------------------------------------------------------------------------------
Executive Summary
The acoustic
consulting engineering firm Hessler Associates, Inc., Haymarket, Virginia
produced two sound level assessment reports for two wind projects proposed for
Cape Vincent, New York: the first report in 2007 for BP and the second report
in 2009 for AES-Acciona.
Because there were
concerns early on among local citizens that the BP reports was misleading, the
Wind Power Ethics Group (WPEG) contracted with Schomer and Associates,
Champaign, Illinois to conduct an independent background sound survey of Cape
Vincent. Hessler's BP study for the Cape Vincent Wind Power Facility appears to
have selected the noisiest sites, the noisiest time of year, and the noisiest
positions at each measurement site. Collectively, these choices resulted in a
substantial overestimate of the a-weighted ambient sound level, 45-50 dB
according to Hessler.
This study was
designed to address a number of flaws noted in Hessler's BP study. First, a
summer survey was planned so it would not coincide with the emergence of vocal
adult insects (e.g., fall crickets and cicadas on August 1). Two monitoring
sites were selected within the Town of Cape Vincent. One site was a rural
residence and the other a small dairy farm. At each of these sites, two sound
level meters and a single small weather station were run for one week of
continuous data collection. At each site one meter was set up close to the
house or farm building and a road. This site was called the "Hessler"
position, because it was typical of sites selected by Hessler for his studies
in Cape Vincent. The other position was called the
Community position
and it was located back away from the noise influences of roads, houses and
farm operations. The Community position also reflected guidelines adopted by
the Cape Vincent Planning Board whereby sound levels were to be measured at the
property lines, not residences.
The analysis of
the spectral (frequency) content of the sound showed that much of the
difference in sound levels between Hessler's study and this study was
attributable to insect noise, sounds near 5000 Hz. Hessler failed to remove
insect sound from his data and recalculate A-weighted sound levels, even though
he previously (2006) recommended this procedure to other scientists and
engineers in a professional journal publication. Had he followed his own
advice, ambient sound levels would have been more comparable to the results in
this study.
Furthermore, and
more importantly, wind turbine sound spectra are low frequency and mid
frequency phenomena; therefore, higher frequency insect noise will not mask
wind turbine sounds. So even if insect noise was present year round instead of
for a few weeks it should still not be included in the ambient because it
provides little or no masking of the wind turbine sound.
Other examples of
Hessler's misleading choices include arbitrarily discarding sound data from one
of his sites because the levels were too low. Remarkably, the levels at that
site were more comparable to this study. Also, Hessler described position 3 in
the BP study as "representative of a typical residence along NYS Rte.
12E." However, he failed to show that the trailer in the photograph was a
field office for a construction company installing a new Town of Cape Vincent
water district. Furthermore, at the back of the trailer, out of view, was a
marshaling yard for trucks, supplies and heavy equipment. The choice of this
site and suggesting it is a typical residence was very misleading.
The accurate
measurement of spectrally-relevant ambient sound is important because these
levels are used by wind developers to assess wind turbine noise impacts on
nearby, nonparticipating residents. Local Cape Vincent Planning Board
guidelines suggest these impacts should not exceed 5 dB above the A-weighted
ambient at the property lines of non-participating residents. New York State
noise assessment policy states any new sound that exceed 6 dB above the
A-weighted ambient should undergo a detailed assessment and the developer is
required to mitigate any excessive noise. Therefore, using an inaccurate,
elevated A-weighted ambient level, such as 47 dB, allows wind developers to
place wind turbines much closer to non-participating residents in such a way
that the A-weighted wind turbine noise level will be 52 dB (e.g., 5 dB above
Hessler's elevated ambient level). A much more accurate and typical ambient
level is 30 dB, which is an average of both "Hessler" and Community
positions during daytime, evening and nighttime periods from this study. Using
30 dB as a typical A-weighted ambient level would then require wind developers
to plan a wind farm where predicted noise at non-participating property lines
would not exceed 35 dB, or 5 dB above this study's A-weighted ambient level. In
summary, to adequately protect rural residents that are not participants in
proposed wind farms it is essential to have accurate, unbiased assessments of
ambient sounds.
In conclusion:
1. The Hessler
position at a measurement site systematically and significantly yields higher
sound levels than does the Community position.
2. The sound
levels measured in this study show Cape Vincent to be a quiet rural area, much
as depicted by the data for Hessler's position 4.
3. Measurements,
such as those conducted at Hessler's position 3, are not indicative of the
noise environment of typical residences in the Cape Vincent area.
4. Failure to
remove insect noise in Hessler's study violated his own recommended survey and
analytical techniques and substantially misrepresented typical ambient sound
levels.
5. In assessing
potential noise impacts from wind turbine development, rather than using 45-50
dB A-weighted levels as suggested by Hessler, a more accurate level would be 30
dB, which is the average value for the daytime, evening and nighttime L90 sound
levels observed at both the "Hessler" and Community positions for
sites A and B in this study. Arguably, the level should be down at 20 to 25 dB,
since an A-weighted L90 of 20 dB occurs during the quietest nighttime hours,
and the A-weighted L90 for the whole 9-hour night is 25 dB.
3 comments:
No doubt we will hear from Chandler and BP that sound studies were comprehensive, professional and complete. They will also tell us these studies were accepted by the Cape Planning Board. What they won't tell you is that when Edsall accepted Acciona's FEIS he also mentioned that they couldn't resolve the noise issue between the town's consultant and Acciona/BP's noise consultant. How did Edsall propose to deal with this uncertainty? Set up a complaint commission comprised of BP affiliates that had the final say. Remarkable how BP bought off the Planning Board chair, Edsall ignores the town's own consulting engineers, and then engineers his own program whereby BP/Acciona gets to review complaints. Just thinking about this bit of outreach history has made my house stink - I think I'll go outside for a walk and a breath of fresh air.
I talked to Mr. Hessler one on one.
He questioned the professionalism of Schomer and talked down to me insulting my intelligence. I believe he brought Cape Vincent a mis-leading message that was supported by local pro-wind.
Edsall once made the comment that doing a sound study in the winter was a waste of time.
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