Acoustics expert disputes wind company's noise study
Freedom — An acoustics investigator is disputing a recently released report that indicated Beaver Ridge Wind in Freedom is operating at noise levels below the noise limit required of similar wind projects.
Stephen Ambrose, of Windham, reported to the legislature's Energy, Utilities and Technology Committee that he felt the report, which was conducted by an independent third party, failed to take into account noise results from particularly windy days.
"The Beaver Ridge Wind noise measurement report is deficient," Ambrose wrote. "The sound protocol was hobbled by unattended survey methods and excluded measurements during wind events when the wind turbines are the loudest."
Ambrose, an acoustics expert with SE Ambrose & Associates, told the committee he thought the data had be "cherry picked" to present a more favorable result.
At the legislative hearing Ambrose reported that there was a windy period with sound levels greater than 45 dBA, which is higher than what DEP regulations normally require. According to a spokesperson for Patriot Renewables,in rebuttal to Ambrose, a representative of the firm doing the sound testing explained to the committee the higher sound levels during that period were due to the wind blowing through vegetation, and not the wind turbines.
According to Tom Carroll, Director of Government and Community Affairs at Patriot Renewables, because it was one of the first wind farms in Maine the Beaver Ridge Wind project is not regulated by the Maine Department of Environmental Protection; however, the study was conducted to show it is voluntarily adhering to sound limits that apply to similar wind projects.
"The sound testing that was done at Beaver Ridge Wind was conducted by an independent firm specializing in sound testing, and followed the Maine DEP Rules, as required by the Legislative Committee, which specifies sound monitoring under a specific set of worst-case wind conditions," Todd Presson, Chief Operating Officer of Patriot Renewables, said. "In addition, sound monitoring results were reported around 10 turbine shutdowns at higher wind speeds. The sound monitoring protocol, placement of monitors, and results were reviewed and confirmed by another independent third party noise control engineer. Beaver Ridge Wind is confident in the results, and are happy to know that we are voluntarily staying within sound limits placed on other wind projects in other parts of the state."
According to previously published reports, Beaver Ridge Wind is a 4.5 megawatt (MW), 3-turbine wind project located in Freedom. The project was commissioned in November 2008 as the second operational wind farm in Maine and the first in Central Maine Power service territory. Beaver Ridge Wind produces approximately 12,500,000 kilowatt-hours of emission-free electricity each year, enough to power about 2,000 homes.