Rollins Wind: Might The Model Be Low?

Sound level versus distance on semi-log paper has been for many years one of the best ways to review noise emissions and potential impacts from a power generation facility. Yesterday I took a look at the Rollins Wind Facility predictions at nearby residences and, levels measured near the Kibby facility this year as well as the existing Mars Hill operational data compiled for the Maine DEP. The resulting chart is shown below. It raised several somewhat technical points for me right away.

– I understand Rollins will use the same wind turbine as Mars Hill, the GE 1.5MW. Is it appropriate to compare the Oakfield prediction to actual noise emissions documented at Mars Hill? Or to Kibby’s 3MW Vestas, with their similar, blade-sweep aerodynamic noise production?

– Are the predicted noise levels at nearby residences in the ranges associated with sleep disturbance, as well as adverse health impacts especially for risk groups (children, elderly, those with pre-existing conditions or disease), according to peer-reviewed medical evidence compiled and published by the World Health Organization in their Night Noise Guideline (NNG) of October 2009?

– Is the existing Maine DEP night noise limit of 45 dBA adequate to protect the public health in the area?

– Does the data comparison to WHO health thresholds suggest that a setback distance of over two miles would be needed to minimize sleep disturbance and prevent adverse health impacts for risk groups; children, elderly, those with pre-existing conditions or disease?