National Park Service Performs Major Disservice for Anti-Wind Power Activists

National Park Service Sound Levels United States Map

National Park Service Sound Levels United States Map

The National Park Service just did a major disservice to anti-wind energy activists.

NPS recently published a new map showing the estimated sound levels for the entire country. NPS developed the map as part of its efforts to protect natural sounds for both ecosystem health, as well as visitor experience. Overall, NPS’s map shows that significant portions of the country fall within 40-45 decibel sound levels.

That’s bad news for anti-wind energy activists.

Local and even state-level wind energy regulations have been enacted regarding wind farm sound levels. Anti-wind energy activists have repeatedly used sound level regulations as a means to halt wind farm development. For example, a bill was introduced in North Carolina that would have prohibited wind farms that “create an ambient noise measurement exceeding 35 decibels”.  That sound level is lower than the wind itself, or a bird chirping. 

Thanks to NPS’s new sound level mapping, it is fairly clear that a 35 decibel sound limit isn’t just discriminatory to wind farms, it’s likely impossible to achieve under already-existing conditions in significant portions of the country. By enacting sound level regulations that are below existing, ambient sound levels, anti-wind energy activists are obviously attempting to ban wind farms.

In 1972, President Nixon gave the Environmental Protection Agency a new nuisance to evaluate and potentially regulate: noise. A few years later, the agency conducted enough research to identify general guidelines to prevent hearing loss, activity interference or simply annoyance. According to the EPA, sound levels at 55 decibels outside and 45 decibels inside are unlikely to cause annoyance. Even with the science behind these figures, the EPA’s evaluations of sound “do not constitute Agency regulations or standards” and are simply voluntary suggestions. Nevertheless, many municipalities and counties across the country have established siting regulation for wind farms based on the EPA’s 55 decibels outdoors limit to prevent annoyance. By 1982, the EPA’s Noise Control Program died because of a lack of funding. But, just this month, legislation has been introduced to reestablish EPA’s Noise Control Program, citing airplane noise as a major culprit.

Not all wind farm regulation is designed to prohibit development. A quick and easy way to determine a regulation’s true intention is to see if the decibel limit is based off the EPA’s suggestion, or if the proposed level is potentially lower than already-existing background sounds. For example, if a proposed regulation is below 45 decibels (the EPA level for indoor noise), it is likely that the proposing regulator is not interested in permitting wind farm development, but is instead aiming to ban entirely by regulation. Another litmus test is whether proposed sound level regulation would be acceptable for other forms of development or activities such as coal mines, railroads, airports, roads, air conditioners, football games, tractors or refrigerators.

For the record, wind turbines have been compared to refrigerators in terms of their relative sound level. That comparison is based on a distance between a listener and turbine of about 1,300 feet. Turbine sound may average out to be about 40 decibels, but will be higher when wind speeds pick up, and lower when wind speeds drop. Even the wind itself can be very loud – and NPS actually incorporated “wind power potential” in its mapping exercise to account for the high levels of noise caused naturally by the wind.

Absent a robust sound analysis, setting sound level regulations is a one-size-fits-none regulatory approach. Locally gathered, long-term sound level monitoring provides the best picture of local conditions. Hopefully elected officials will use the National Park Service map to interject some sound reasoning in developing wind farm regulation.

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The decibel standard needs to be updated or a new standard created because the decibel standard does nothing to consider the impact of low frequencies. With many forms of noise pollution low frequencies are the most problematic for the human body and they travel much greater distances straight into peoples’ homes.

Comment by Gh0st on July 27, 2016 8:37 am

“There is no direct evidence that considered the possible effects on health of infrasound or low frequency noise from wind farms. Exposure to infrasound and low-frequency noise in a laboratory setting has few, if any, effects on body functions.” – Australian National Health and Medical Research Council, 2015

Comment by Simon Mahan on July 27, 2016 10:04 am

The Park Service map is for sound levels during a summer day. Many of these areas are much quieter at night, or in winter (when vegetation and water noise is less).

Most wind farms are permitted using noise limits that are either day-long averages or hourly averages, often with lower nighttime limits.

So to use this map in assessing whether turbines will be audible above local ambient would be comparing apples to oranges. In addition, the NPS map is a model (based on locations of key noise sources: roads, airports, rivers, and degree of vegetation). By contrast, assessing local ambient conditions, as part of a wind project planning process, must be done by recording on site, ideally in each season.

Comment by Jim Cummings on July 27, 2016 3:34 pm

Thanks Jim for your comments. Good sound regulation does exist; however, anti-wind farm activists are not interested in good sound regulation. As mentioned in the blog, a bill was introduced in North Carolina that would ban any renewable energy project (not just wind farms!) that “create an ambient noise measurement exceeding 35 decibels”. That’s not a day-long average or hourly average. That’s not dBA/dBC/dBG rated. It’s designed specifically to ban wind farms.

The NPS map isn’t perfect – and as we stated in the blog, “Absent a robust sound analysis, setting sound level regulations is a one-size-fits-none regulatory approach. Locally gathered, long-term sound level monitoring provides the best picture of local conditions.” Until additional data are available, the NPS map is the best publicly available research.

Comment by Simon Mahan on July 27, 2016 4:28 pm

The blanket statement published by the Australian National Health and Medical Research Council, 2015 like so many similar statements is in error.
There have been some scientifically controlled laboratory studies on the effects of infrasound on humans which clearly indicate that some people are measurably affected by infrasound exposure.
For one example of such a study see “Some Individual Differences to Human Response to Infrasound” by D. S. Nussbaum & S. Rienis
The above referenced study was a scientifically controlled study which included physiological measurements of 60 people exposed to infrasound with a control group of an additional 20 people. Indications were that approximately 15% of the subjects experienced motion sickness type symptoms following the 20 minute exposure. A pilot study of less test subjects showed a similar % of test subjects responded similarly at lower levels of Infrasound.
The study was completed before 1984, i.e. no anti-wind movements involved.
A more recent study indicates that motion sickness itself may often be caused by the infrasound associated with motion rather than the motion itself

Comment by Kevin Dooley on July 31, 2016 2:34 pm

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