Wednesday, March 5, 2008

A Compromise on Wind Turbines ?

The meeting of the Zoning Board last Wednesday night marked a turning point for the wind energy debate in Ellis County. It was the first time some form of compromise seemed remotely possible. If turbines are kept far enough away from residents opposed to them, opposition to the project could be withdrawn.

The proposed Wind Energy Ordinance, drafted and submitted by myself on behalf of the ECEAC, sets out responsibilities for any developer of an industrial scale wind project in the county. The regulations provide residents with reasonable assurances that their rights and environment will be protected with respect to both inevitable and potential impacts. Only two of these were discussed at the meeting: noise and setbacks.

We heard much confusing discussion about noise and decibels, sound and infrasound - a highly technical subject that few people present, if any, were able to fully comprehend. I would like to respond to remarks made by Dick Klaus who suggested that any noise ordinance should apply to all sources of sound, not just wind turbines. I agree that a general noise ordinance for the county would be a progressive step forward. However, the impulsive, aerodynamic nature of the sound produced by wind turbines cannot be compared to the sounds produced by farm equipment, transient traffic noise, or other forms of machinery.

Normal motorized machinery does not sweep more than an acre of air at a height of 400 feet with blade tips approaching speeds of 200 mph. It does not create pulsating, aerodynamic disturbances that result in penetrating, low frequency wave forms that can propagate more than a mile, under suitable atmospheric conditions. This is not noise you can hear as much as vibration you can feel. We are talking about waves of energy that can penetrate buildings and cause objects to resonate, depending on their unique resonation frequency, just like crystal can be shattered by a sound wave that matches its resonation frequency. Any discussion of decibels measured in the auditory range is completely irrelevant to these concerns. However, a consistent audible hum (single tones in the frequency of 100-600hz) can also propagate from wind turbines as a result of resonation of the gear box and torque arm bring transferred to the rotor and then radiated into the environment. This is similar to the hum of a large transformer, only on a much greater scale.

Lance Russell asked me for some evidence that people had been adversely affected by turbines placed too close to their residences. In response, I have submitted a package of material at the Environmental Office that contains the testimony and personal diaries of families who have been driven from their homes by turbine noise in Canada, United Kingdom, Denmark, Sweden, Italy and Maine. I have also included 5 selected abstracts of papers presented at the 2nd International Conference on Wind Turbine Noise held in Lyon, France, September 2007. This conference was attended by 150 presenters from 24 different countries. I have further included another abstract and two complete papers published in peer-reviewed journals that explain the unique nature and behavior of wind turbine noise under various atmospheric and topographic conditions. I can make copies available to anyone who is interested. It is my hope that the zoning board will take the time to review this material.

Anyone who doubts that turbines pose sufficient risk to require setbacks of half a mile from property lines should watch the video posted last week of a turbine exploding in Denmark due to its brakes failing under high wind conditions: The turbine was only 200 feet tall, but debris was thrown as far as 1,600 feet.

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