Are wind turbines good or bad for those living around them?
It is a good question, and the answer really depends on who is doing the reporting.
A proposed wind farm near Harrisburg is at the center of a local discussion on wind energy and the noise pollution created by the generators and blades of the wind turbines.
Some groups are saying that the noise causes everything from headaches and nausea to sleep disruption and anxiety.
Those promoting wind generation, like General Electric, say the noise from the windmills at 500 meters (1,640 feet) is equivalent to a refrigerator — less than 40 decibels.
The residents of Harrisburg and the Boone County Planning & Zoning Commission want to know exactly what the situation is before committing to E.ON Climate & Renewables, a German company proposing to build a 30,000-acre wind farm.
The effects on taxes and land values should also be considered.
It is not how loud the windmills are that worries people but the sounds that are too low-frequency to be heard by the average person. Like the Cuban “sonic attack,” the noise citizens are worried about is below the audible range of most individuals but still may cause damage.
The World Health Organization has taken a look at the growing problem of noise pollution and the problems reported. The WHO guidelines, however, do not consider the wind turbines as a stand-alone source of noise pollution. They include aircraft, rail and road traffic in an October 2018 study.
Ontario, Canada’s Ministry of the Environment and Climate Change has published a report on how and where wind facilities may be built in the province.
The report not only looked at wind turbines but also included “similar details of the transformer substation(s) used for transforming the power from the wind turbine units” to AC power.
The report includes information on the expansion of the noise frequencies from 31.5 Hz to 8,000 Hz, well within the normal hearing range. It also considered the location of the residential unit(s) in relation to the noise source.
One of the conclusions of the report: “Tonal noise is caused by components such as meshing gears, non-aerodynamic structural resonances, or unstable flows over holes or slits or a blunt trailing edge of a turbine blade.
“In any event, as the distance between the turbine and the point of reception increases, these effects are reduced.
“Tonal noise is not usually a problem in modern turbines as evidenced by examination of numerous acoustical test documents from the manufacturers.”
Of course, the level of the sound increases as the wind increases to the rated level of the wind turbine’s maximum energy output. All submissions for a wind facility must include “the hub height sound power levels, octave band frequency spectrum from 31.5 Hz to 8,000 Hz, and tonal audibility at related wind speed bins” to a distance of 1,500 meters (about 5,000 feet) from the sound source.
WHO has set the European target limit of outdoor night noise levels at annual average of 40 decibels, which includes all road, rail and aircraft noise as well as noise generated inside the home.
Yet, a study by Health Canada found no link between exposure to wind turbine noise and negative health effects in people, including:
- Symptoms such as dizziness and migraines.
- Chronic illnesses such as heart disease, high blood pressure and diabetes.
- Measures of stress levels, such as heart rate, blood pressure and cortisol.
- Self-reported or measured quality of sleep.
The study included some 1,200 households and “4,000 hours of wind turbine noise in order to calculate indoor and outdoor noise levels at different homes in the study.”
A separate study conducted by the government of Prince Edward Island indicated no risk to public health.
The Harrisburg opposition to the wind farms may just be another version of “Not In My Backyard” syndrome. As a country, we want to be energy independent, and cities like Columbia are committing to increasing levels of renewable energy use.
If the setbacks for wind turbines are designated to be approximately 500 meters from residences, there should be no problems with noise pollution.