Wind Turbine noise complaint predictions made easy
Stephen Ambrose and Robert Rand |January 28, 2013
This straightforward, easy to understand analysis by acousticians Stephen Ambrose and Robert Rand provide insight in to predicting whether wind turbine noise will result in community complaints. The report has four parts. Part 1 is shown below. The full report can be accessed by clicking on the links at the bottom of this page.
This straightforward, easy to understand analysis by acousticians Stephen Ambrose and Robert Rand provide insight in to predicting whether wind turbine noise will result in community complaints. The report has four parts. Part 1 is shown below. The full report can be accessed by clicking on the links at the bottom of this page.
Acousticians have known for decades how to predict the community reaction to a new noise source. Wind turbine consultants have chosen not to predict the community reaction as they have previously done for other community noise sources. If they had, there would be far fewer wind turbine sites with neighbors complaining loudly about excessive noise and adverse health impacts.
In 1974, the USEPA published a methodology that can predict the community reaction to a new noise. A simple chart can be used that shows the community reactions (y-axis) versus noise level (x-axis). This chart was developed from 55 community noise case studies (black squares). The baseline noise levels include adjustments for the existing ambient, prior noise experience, and sound character. The predicted wind turbine noise level is plotted on the ‘x-axis' and the predicted community reaction is determined by the highest reaction, indicated by the black squares. Here are some examples: 32 dBA no reaction and sporadic complaints, 37 dBA widespread complaints, 45 dBA strong appeals to stop noise and 54 dBA vigorous community action, the highest.
The International Standards Organization (ISO) determined that 25 dBA represents a rural nighttime environment. The World Health Organization (WHO) found that noise below 30 dBA had no observed effect level (NOEL) and 40 dBA represented the lowest observed adverse effect level (NOAEL) for noise sources that excluded wind turbines. Wind turbines produce strong low frequency energy that may reduce the WHO cautionary levels by 5 dB, thereby showing closer agreement with the 33 dBA recommendations.
Pederson & Waye (2004) research found that when wind turbine noise levels reached 35 dBA, 6% of the population was highly annoyed, and this rapidly increased to 25% at 40 dBA. Independent researchers recommend that noise levels should not exceed 33 dBA, which is near the upper limit for sporadic complaints, or a maximum increase of 5 dB, whichever is more stringent.
