Communicating the Noise Effects of Wind Farms to Stakeholders 

Presented at Noise-Con 2007, Reno Nevada, October 22-24, 2007:

A few [more than a few –Ed.] recent news stories have told about individuals and communities who live in proximity to wind farms in the northeast United States and in Japan [and in Canada, England, Ireland, other parts of the U.S. … –Ed.], and who started to complain about noise from wind turbines shortly after the facility began operations. The author’s own experience demonstrates that noise complaints and adverse community reaction can occur even though a wind farm is operating in compliance with local noise limits. …

Figure 3 shows the extent of people highly annoyed by wind farm noise based on the dose-response relationship given in Equation (1). As shown in the figure, within approximately 0.8 km (1/2 mile) of the wind farm, 44-percent of the population would be considered highly annoyed due to wind farm noise. At a distance of approximately 1.62 km (1 mile) from the wind farm, the percent of highly annoyed people is expected to drop to 4-percent. Such information could be useful for developers and/or regulatory authorities during the siting of a wind energy facility when deciding upon appropriate set-back distances.

The results of Figure 3 could be compared to the results of a social survey performed for this same wind farm. Figure 4 shows responses to three questions from a social survey performed in 2001. In the top chart of the figure, 44-percent of the respondents living from 800 feet to 1/4 mile of the wind farm stated that the turbines are “causing a problem with noise.” From approximately 1/4 mile to 1/2 mile from the wind farm, the percentage of respondents indicating a problem with noise increased to 52-percent. Similar trneds are shown in the responses to questions in the middle and bottom charts of Figure 4. … It should be noted that the findings of the committee with oversight of the social survey suggested that the participation of a land-owner in the project may have had an influence in the elicited response. …

Figure 4 -- wind turbine noise survey

It is generally recognized in the acoustical community that certain A-weighted noise metrics have been shown to correlate well with levels of annoyance. However, it is also recognized that A-weighted noise metrics underestimate the potential impact of low-frequency noise, since people do not hear low-frequency sound as wll as sound at other frequencies. In such cases, a comparison of C-weighted and A-weighted noise metrics will provide a rough estimate of the significance of noise in the low frequencies. It has been suggested that in cases where the C-weighted noise level generated by a source is 10 to 20 dB greater than the A-weighted noise level, the source is considered to have low-frequency components.

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