Dwarfed by Turbines

Dwarfed by Turbines

Monday, August 17, 2009

August 17th - met with Kruger representatives

On Friday afternoon, we were visited by two representatives from Kruger wind energy regarding the noise testing they had done months ago. Unfortunately, my husband was at work, however, I sat at my kitchen table with the two representatives Jo Boland and Ron Anderson (Ron used to work for the municipality of CK and is now the Rural Development Manager for Kruger Energy). The report consisted of a cover letter referencing the Aercoustics (independent engineering firm) study as well as technical notes from Siemens (the company that builds and services the turbines I believe). The last paragraph of the cover letter reads "The report concludes that "the wind-farm is now operating within the sound-level limits set by the MOE". In an effort to better understand and confirm the noise levels being experienced presently at this location, KEPA will proceed with noise measurements at the site".

A second letter attached was to Kruger Energy from Jakob Skjoeth, Seimens Engineer and David Janigan, Kruger Energy. It states that .."on june 2nd, 09, Seimens engineer Jakob Skjoeth, on request from Kruger Energy performed a test at the Port Alma wind site in order to investigate a perceived irregularity in the noise level coming from the turbines in low wind conditions.Based on this test, Seimens made an adjustment to the Seimens turbine converter parameters. This effectively eliminated the irregularity in the noise from the turbines. Mr. Skjoeth notes that the control loop settings were possibly too aggressive and created torque variations in the power-train, causing the unwanted noise. The adjustment that was implemented is being analyzed by Siemens engineers in Denmark to determine the final solution to this issue."

Then of course was the attached report. Joe read through the report, which was quite technical and I am not sure I understand all of the sound readings. To sum up, what was indicated was that a. Kruger found an odd noise and fixed it, and b. the turbines were running within allowable limits. The report contained several graphs and charts, but the actual readings were not attached, merely a summary of data charted. It seemed to me like the main focus was "averages" and "trends". My experience leaves me a bit skepical as I know that graphs, charts and trend lines can be laid out in various ways to show what the author would like them to show and omitting or camaflouging other details. I am sorry to sound distrustful, but I really feel like "the little fish in the big pond - expendable".

One odd thing in the report was that one paragraph indicated that the sound inside of our home did not correlate with the sound outside of our home.

On the bottom of page 2 "Review of the resident initiated recording.." this is where we heard the turbines very loudly and manually pressed the record button showed a similar distribution, some levels exceeding MOE limits, more falling below MOE limits. It should be noted that the noise may, in part, be due to sound emanating from inside the residence..." this is not likely due to sounds in our home as nearly every time we pressed the button it was the middle of the night and the house was silent except for the turbines ...When one compares the sound pressure levels inside the residence with the correspoding ones outside(figure 8), one sees that there is no linear correlation. Also, not all the sound recorded by the outdoor microphones are wind turbines noise. Sounds from road and farm vehicles are included as well..."
Then on page 3...."A 120 Hz tone can be idenitified on all spectra of the indoor sound (figure 11). Is is especially noticeable during periods when the turbines were generating little or no power. This tone does not appear on the coherence data, indicating that the sound is generated inside the dwelling and not associated with the sound from the wind turbines. It is well known that superposition of different tones of comparable amplitude will render the low frequency tones more audible, and annoying. There is little published data that would permit one to quantify the effect of this psycho-acoustic phenomenon on subjective response such as loudness and annoyance."
In the final minutes of the discussion, my questions were pretty basic. It seemed to me that they are working on averages and that would mean that they are in fact at times over the allowable limits of noise. I believe much more often than the report seems to indicate. I asked quite directly what we were supposed to do now since we still suffer symptoms, although they seem to have lessened with the milder weather, of sleeplessness, dizziness, and extremely dry morning eyes.

Joe asked me if I believed that all of that could be attributed to the wind turbines. He went so far as to provide examples of how he himself does not sleep well for example if he is stressed out from work, and that sometimes when the pressure changes his eyes can feel dry as well. I explained that we had none of these symptoms prior to the erection of the wind turbines and also that a sleepless night or two is nothing compared to weeks and months on end with little relief.

Of course, my next question was about the "extra" noise they say we have in our house. I asked what could cause a 120 Hz tone that seemed to be rather consistent. Niether could answer that question but suggested that if we could find out what it is, we could eliminate it and that might eliminate the enhanced effects we feel we are getting from the turbines. They promised to ask about it and see if there were any suggestions as to what could be causing it. My immediate thought was that since the microphone was placed directly behind the computer, perhaps the computer (which is one of the few things that is usually always on at our home) could be the cause. However, when the microphone was being installed by the technicians in our home, I remember asking them if I needed to shut down the computer at night and they said that this type of noise would not be picked up....

I could not really say much. What could I say? They were here to tell me that the turbines are not too loud, nor causing us any discomfort. I said to both of them that I would really like it if they could come here when the turbines are bad and spend time in the house and then tell me that there is no noise. Joe offered to come anytime during the day if I called, but as I told him, the problems are most noticeable at night... I thought it was ironic that Joe mentioned that he had told me to call him with problems and questions on our last visit and that he had not heard anything from me.... I found this funny. Did he want me to call him every day with the same complaint? Was he actually asking that I pester him with the same questions, which of course his only answer would likely have been that they were still waiting for the results. I could not help but feel like I was being "blamed" for not doing my part in calling and reporting each incident, day after day.

Ron did give me his card and said I could call him when they were noisy. I had planned to do this at first opportunity - which would have been late this afternoon and early this evening as I noticed they were very loud, but to be honest, I just couldn't bring myself to give up my Sunday with my kids to spend time with a man I don't know visiting my home to hear the turbines. I am not at all worried that there will be plenty more opportunities to share these noises, but today was not that day.

As I sit here typing this blog information, I am thinking more and more about this 120 Hz sound that is in our home that is apparently amplifying the way we "feel" the turbines and it makes me wonder this: If they are saying the combination of various tones can "render low frequency tones more audible and annoying", what is the expectation? Does this mean that people who live in homes near wind turbines are to live without new technologies? Does it mean computers? cell phones? refridgerators? air conditioning? freezers? flourescent lights? I imagine that all of these things give off some sort of low frequency tone.

Further, I find it odd that the inside noise is greater than the outside noise. But as I think about it, it seems sort of true to me. When I stand outside on the porch at night, I can hear the turbines, but I can also hear other sounds in the night - the wind in the trees, the frogs, the birds sometimes, etc. When I lie in bed at night in the silence, I hear only the woosh, woosh, woosh of the turbines, and they almost seem louder, closer, more enhanced somehow - Could it be that the house itself amplifies the noise somehow? Could a home be a conductor? Could our house be positioned in such a way that we are hearing several turbines...they are after all lined up, so perhaps one amplifies another and so on until it reaches our windows....Why are all of these things not considered? Could this be a reason why some people in some locations feel the effects more than others...it is interesting that from what I have noticed, other than those who are suseptible to the turbines for health or other reasons, the affected seem to sit in 'clumps'. Could it be the topography? underground conductors, the building construction? So many unanswered questions and the only thing I know for sure is that our symptoms correlate with the turbines.

The few days before my meeting with Kruger the windmills were not running at all (apparently they were on shutdown). These past two days, especially today, I noticed I am again very, very tired. I laid beside my young son today and fell asleep for 2 hours in the middle of the day! This is not the norm for me. I account it to the fact that my rest is not proper even though I am "asleep" at night.

I don't really know what else to say at this point except that we will be waiting for answers from Kruger regarding this "tone" in our home, and we will continue to report our discomforts and the noise of the turbines. Kruger did note, as mentioned above, that KEPA will condintue with noise measurements at the site. I am going to request that these next noise measurements be done when the leaves are off the trees, and the wind is actually blowing...this may give a better representation of the actual noise we hear.

By the way, if anyone knows of a great piece of property with 15 or more acres of trees on it, not too far from Chatham and without turbines nearby - please let me know...it took us several years of looking to find this home we live in, but if another became available that was turbine free, I would move today!

Goodnight all, Nik (sorry about the spelling, fonts,bold and italic -it's far too late to sweat the small stuff)


windturbines said...

It can not avoid for the noisy problem for horizonal axis wind turbine. This is caused by the design, not the turbine problem. Vertical axis wind turbine has low nosiy but not use in the high wind speed area.

Barry Bridgeford said...

Hi Nik

The "offending" wavelength of 120 Hz could be an amplified "standing-wave".

If you refer to .. http://www.algonquinadventures.com/waywardwind/swaves.htm , you can access the "Sengpielaudio" wavelength frequency conversion tool. Enter "120" into the "Audio sound frequency field and click on "calculate".

You'll see that the resulting wavelength is 9.3777 feet.

Resonance of this wavelength can set up a standing-wave across "rooms" of half, 1x, 2x, 3x, 4x, etc. that dimension.

If your situation involves a simple "axial" standing-wave (as opposed to a more complex tangential standing wave, which would be reacting to the structure's wall at other than 90 degrees), the possible resonating "room dimensions" are 4.69', 9.48', 18.76, 23.45', etc.

A caution is appropriate here. In following this exercise, it is crucial that you are identifying an "initial receptor" of a wavelength. If a wavelength from outside the room is initially received by a different room which amplifies its own "standing-wave", then what you are dealing with could be a "secondary receptor" which has been set vibrating at its own inherent wavelength, by the "initial receptor". By this point, you can see that a detailed "sound-mapping" of each room, during a variety of conditions would be advantageous.

Proceeding with the assumption that the room in question is the "initial receptor", the wavelength's point of origin would be somewhere along the projected "axis" of the "standing-wave" either within the room or outside the room (beyond the room's end "amplifying walls" at right angles, at any distance).

However, I must express a warning here. To become pre-occupied with only 120 Hz wavelengths serves the interests of wind turbine industrialists better than any "red-herring". The people you met with made repeated reference to "MOE limits" (Ministry of Environment). These "limits" are just that. They only address the "dBA filtered" wavelengths, which filter out progressively more of the pressure energy present in lower audible wavelengths and totally fails to represent the pressure energy present in inaudible infrasound wavelengths.

The Ministry of Environment dBA filtered limits don't recognize the pressure energy and resulting health impacts of those very wavelengths that they filter out. It's my opinion that because a wind turbine industrialist complies with MOE limits doesn't make him "right". I believe it simply makes him just as self-righteously inadequate as the MOE! That's the whole focus of the health concerns!

Bubble's Mama said...

Hang in there Nikki! You have plenty of support across the province.