Wind turbine noise, what you can’t hear can harm you 

What do you think of when you think of an industrial wind project? Wind developers want you to think of free, green electricity. People who live near industrial wind turbines think of noise. Let’s see why. An Industrial Wind project in Swanton proposes to install seven 499-foot tall wind turbines along 6,000 feet of Rocky Ridge (elevation 323 feet). We don’t know what turbine model the developer is considering, so let’s look at the GE 2.75-120 Wind Turbine. At 475 feet, it is slightly smaller than the developer’s Swanton turbines. GE says a single one of their 475-foot monsters can produce 106 dBA of noise. Scaling up to seven turbines would increase that noise to 109 dBA. (Noise is measured as pressure on a scale that is logarithmic, so sometimes the numbers are difficult to understand, but 109 dBA is loud. For comparison, my chain saw is rated at 109 dBA. I wear ear protection when I use it.)

So, when you think of industrial wind turbines on a ridge line, envision an airport with a line of airplanes that are holding for take-off. The airplanes are powered by chainsaw engines that have run up their engines to full power. But, unlike planes at an airport, the turbines never take off. Now, imagine this at 2am in the morning.

Some people will say wind turbines are not that noisy. Well that depends on how far from the turbines (chainsaws) and how many turbines (chainsaws) there are. Sound attenuates over distance. The further you are from the turbines (chainsaws) the more the noise attenuates and thus the quieter the sound is. Noise attenuation is also dependent on many topographical and meteorological factors. For example if you are downwind from the turbines (chainsaws) the noise is greater. If the turbines (chainsaws) are located on high ground, the noise carries farther.

The World Health Organization says that noise levels greater than 30 dBA can interfere with sleep. The WHO also explains that low-frequency noise has a greater potential to disrupt sleep and that levels of low frequency noise should be kept lower than 30 dBA. Turbines produce lots of low frequency noise—the kind of noise most likely to interfere with neighbors’ sleep.

Vermont’s Department of Health says that turbine noise outside your open bedroom window should not exceed 40 dBA. The Department assumes that you have different windows than I have and that your open bedroom window will reduce a 40 dBA noise to 30 dBA. Not only that, the Department’s 40dBA limit applies to noise averaged over a year. That means that somebody could start up a vacuum cleaner (70 dBA) outside your open bedroom window every 19 minutes and still operate within the Department’s guideline.

Vermont’s Public Service Board has a different standard. The PSB says that the turbine noise outside your open bedroom window, averaged over an hour, should not exceed 45 dBA. The PSB would allow the vacuum cleaner to start up every five minutes.

Of course a standard is no good if you don’t monitor for compliance. Vermont has developed an ingenious system where the monitoring is done by turbine neighbors. When noise levels exceed the PSB’s limits, the neighbors can call a special telephone number provided by the turbine operator. Turbine neighbors say that this telephone is not answered at night. To compensate for this, some wind operators hire experienced professionals to come in for a week or two every year to monitor their noise and to assure the neighbors that they are imagining things.

The noise you can hear is not the only sound that an industrial wind turbine produces. Industrial wind turbines also produce low frequency sound that you cannot hear but you can feel. When a turbine blade passes the wind tower on a large turbine it generates a low frequency pulse. These pulses are typically below 20 Hz and are called infrasound.

Turbine infrasound can be detected inside homes as far away as six miles. We know also that very low levels of infrasound and LFN are registered by the nervous system and affect the body even though they cannot be heard. Researchers have implicated these infrasonic pulsations as the cause of some of the most commonly reported “sensations” experienced by many people living close to wind turbines. These sensations include chronic sleep disturbance, dizziness, tinnitus, heart palpitations, vibrations and pressure sensations in the head and chest etc. There is medical research which demonstrates that pulsating infrasound can be a direct cause of sleep disturbance. In clinical medicine, chronic sleep interruption and deprivation is acknowledged as a trigger of serious health problems.

Denmark, which may have the most successful renewable energy program in the world, recognizes the potential health effects of audible and sub-audible turbine noise. Vermont does not. The Vermont Department of Health acknowledges that turbine noise can disturb sleep and that disturbed sleep can impair health. It is curious that the Department is unable to connect the dots and to conclude that turbines can impair health.

There is a growing body of research that shows that industrial wind turbines can have negative effects on the health of their neighbors. Because so many indicators point to infrasound as a potential agent of adverse health effects, I respectfully ask the members of Pubic Service Board, the Pubic Service Department, the Governor, the members of the Legislature, all Elected Officials, the Media, the Industrial Wind industry and all Vermonters who care about the future of our State to please read this report that describes infrasound in detail HERE.

If not sited properly industrial wind turbines can harm public health. I therefore call for a moratorium on industrial wind turbine projects until the Legislature, Pubic Service Board, Public Service Department and the Governor develop operating standards that protect the health of turbine neighbors, reform turbine siting standards, and regulate the operation of existing industrial turbines.

Brian Dubie of Fairfield served as Vermont’s Lieutenant Governor 2003-2011