There are, however, important issues that, at a county level, we can and must address. Handling noise pollution and something called “blade flicker” are things within our control and both have effects on the community’s health and welfare.
Looking at what has happened in other communities is helpful.
The experience in Maine – a state that has already sited windmills in low density population areas – has shown that the noise pollution issue becomes very real only after a project is operational.
The culprit is the noise made by the rotating blades. Blade tip noise is low frequency; between 200 and 300 Hz depending on the size of the installation. Low frequency sound travels much further and, when created “up in the air,” travels a much greater distance.
Here in Pamlico County we already have experience with this: The helicopters from Cherry Point. We all know that you can hear the rotor blades “whumping” several miles away but we only hear the engine noise when the helicopter is close at hand. Unlike our helicopters, however, the source of the turbine blade noise pollution does not fly away: It stays in place and generates the rhythmic ‘whumping’ as long as the blades are turning.
Maine’s experience with is instructive. While everyone was worried about the “visual” pollution of 450-foot tall white towers sticking up four to five times higher than the surrounding forest, the most invasive aspect of wind turbines has actually been the incessant low frequency “thuds” that come from the blades as they rotate.
This has caused issues for the people who live within the sound’s radius which, even in forested areas, is significantly further away than the quarter mile setback recommended by the wind energy industry, and approved by the State of Maine.
People report sleeping problems, irritability, headaches and even cardiac problems related to stress. Some have even been forced to move from their houses. The popular term for this is “Wind Turbine Syndrome.”
“Blade flicker” (another new term) is caused by shadows cast by the blades as they pass between the observer and the sun. Most people who are unfortunate to be plagued by this have reported that the persistent dark “flashes” is annoying at best. They say that they have to shut the blinds to escape while indoors. But, outside there is no escape. This is also a reported health issue. Blade flicker has been associated with epileptic attacks.
The flicker shadow moves with the sun and, coupled with the blade diameter, affects a large area. Regulations minimizing the impact of this must be incorporated in county regulations concerning wind turbine siting.
A search of PubMed, whch is a complete database of scientific articles, reveals many relevant studies on humans, animals, fish, and even marine mammals, all pointing to the fact that the low frequency noise is both persistent over long distances and has measurable effects on health and behavior.
In Maine, there has been an outcry against the noise pollution caused by windmills. In September 2011, the Maine Department of Environmental Protection voted to lower the allowable decibel level to 41db between the hours of 7 p.m. and 7 a.m. The industry is appealing the decision but also points out that the new, lower sound level limits will not apply to existing approved projects.
The Netherlands, with a longer history of living with wind energy generation, has decided that the most viable alternative is to move future wind generation development offshore.
The Maine experience demonstrates that the initial setback requirements were inadequate to deal with the low frequency blade tip noise. Recommendations of as much as 2 kilometers (1.2 miles) have been suggested to minimize the effects of the blade noise and flicker.
The town of Eastbrook, Maine, just passed a 42-page ordinance with a one-mile setback, maximum exposure to blade flicker, and a maximum allowable sound level of 40db at residential structures.
With this information available, would it be wise for Pamlico County to adopt limits that are significantly more lenient than current recommended parameters designed to protect personal, environmental and public health?
To view a copy of Eastbrook’s wind energy ordinance, download the attachment at the end of this article.
It is also important to remember that, given the nature of noise pollution generated by the wind turbine blades, setbacks should be not only from existing structures, but also from property lines as well.
Towers 450 feet high that generate persistent low frequency pressure waves are a material intrusion on neighboring property owners and the zoning laws must protect them from both from degradation of their property as well as from falling structures!
Finally, no matter what Pamlico County decides as far as zoning is concerned, provisions must be made for a decommissioning and removal bond to be posted by the builder so that, at the end of the tower’s useful life or, in our coastal location, in case of catastrophic structural failure in a hurricane, the county has the funds to adequately remove the structure and restore the land to its original condition.
There are already too many instances of abandoned towers left as standing junk. We do not want this for Pamlico County nor do we want the landowner or the county to become financially responsible for removal and cleanup. Decommissioning and removal is a cost of construction and should be borne by the company promoting the project.
No matter what personal opinions are about wind energy, Pamlico County must consider the health, safety, and welfare of both individuals and the community when establishing regulations for these projects, no matter how attractive they may seem from a financial standpoint. Let us not become known as “Pamlico County, where land and sky are assaulted by wind turbines.”