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—Katie V. Troe, The Star Tribune, 10/10/09

Industrial wind turbines, utility-scale turbines—whatever you call them, they are popping up all over the state. Minnesota is requiring utility companies to be using 25 percent renewable energy by 2025. When I ask most people what they know about turbines, most reply, “They are green energy!” When I probe for more information, they know nothing more.

I’d like you to join me on a short journey to see what it is like to live near a wind project. From about 15 miles away, we’ll be able to spot the turbines on the horizon. They’ll appear small, but as we drive closer, they’ll grow. Once we are nearer, you might say something like, “These things are enormous!” or “I feel like I am in the twilight zone.”

Most turbines, counting their blades, stand about 400 feet tall, the equivalent of a 40-story building in the middle of a corn field.

It is late in the day as we make our visit, so the sun is setting. The strobe lights start to blink from atop the turbines. These are required by the Federal Aviation Administration. They are the same lights that were used at high school dances but were discontinued because high schoolers were having epileptic seizures caused by the light. They flash every night into nearby farmyards, and for those who do not have curtains in their windows, the red light comes into the house and reflects off mirrors, crystal dishes, glass end tables, grandma’s old vase on the piano, and eyeglasses.

Those who live with the effect of strobe lights find it necessary to cover all of their windows. Some find strobe lights to cause migraine headaches and must buy special black plastic for this purpose.

The sun has now set, and the afternoon’s wind has slowed to a gentle breeze. Though most of us may not know the physics behind the phenomenon of wind, those who live near a wind project can describe its effects. For those who have stood at the base of a turbine on a clear day, the following statements may come as a surprise.

Those who live near wind projects say that the turbines are noisiest at night. This is because the wind subsides close to the ground but not above, where the turbine blades are. Some nights we can hardly hear them, especially with a television or radio on. But other nights we need earplugs to sleep.

This is the audible sound that comes from turbines. It comes from the interaction of the turbine blade with the wind, from the generator and from gears inside the turbine.

Low-frequency noise is another phenomenon of wind. It is not audible. It is being blamed for most of the health effects people experience living near turbines. It comes off the blades of the turbine. Because of its long wavelength, low-frequency sound easily penetrates house walls and actually gets trapped inside, bouncing from wall to wall. Audible noise does not enter homes as easily, so it is less noisy inside than it is outside.

Those affected by low-frequency noise will often find relief outside.

What are the effects of low-frequency sound on humans? Dr. Nina Pierpont, a New York pediatrician who has studied the health effects of wind turbines, has established a medical definition of Wind Turbine Syndrome, which includes the following symptoms: headaches, stress and anxiety, tinnitus, vertigo, nausea, visual blurring, cognitive problems and panic episodes.

Last May the Minnesota Department of Health prepared a white paper on the public health impacts of wind turbines for the state Public Utilities Commission. While making few final conclusions, the researchers noted that “human sensitivity to sound, especially to low-frequency sound, is variable,” adding that “sounds, such as repetitive but low-intensity noise, can evoke different responses from individuals.”

“Case studies,” the paper noted, “have suggested that health can be impacted by relatively low levels of low-frequency noise.”

Wind developers are currently enjoying the technology’s image as a benign industrial-scale source of clean energy. But I believe that siting turbines is a science.

Right now the PUC allows the company or individuals installing the turbines to site them. Yet the white paper also states that aerodynamic noise is often underestimated in siting.

The legislature should step to the plate and provide a law to protect Minnesotans in the future. The state should conduct more studies to find criteria to ensure proper setbacks of wind turbines, making sure they are placed far enough from the nearest homes.

We have completed our journey. Thank you for joining me.
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