ASHFIELD – After a year of studying the impact that windmills might have on the community, an advisory committee is recommending the town develop rules stricter than the state’s to minimize noise impacts.
This report – and two minority reports from within the Ashfield Wind Turbine Siting Bylaw Advisory Committee – will be presented at an informational public forum on Dec. 8, from 7 to 9 p.m. in the Town Hall.
The committee was appointed by the Selectboard in September 2010, after the town received a proposal from Clear Sky Energy LLC to install four to eight windmills up to 466 feet tall in the Ridge Hill area. While the Planning Board is working on developing a wind turbine siting bylaw for the town, the advisory board was to investigate several specific issues – especially concerns about noise.
Andrew Wells is chairman, and members include: Health Board Chairman Duncan Colter, Brian Clark, Ron Coler, Planning Board Chairman Michael Fitzgerald, Todd Olanyk, Anne Yuryan and adjunct member Walter Cudnohufsky.
The majority report finds noise issues to be of greatest concern, and recommends limiting the noise level of windmills to lower than what is recommended by the state.
The state Department of Environmental Protection noise regulations limit industrial and commercial sound sources, including wind turbines, to within 10 decibels of “ambient noise” (dBA) – which is the quietest noise level measured in decibels at that location.
But the advisory committee is recommending that Ashfield require any turbines sited within the town’s borders not to exceed 5 decibels above ambient noise.
The committee also recommends keeping turbine-produced noise levels to under 32.5 dBA for abutting properties that are not part of the wind turbine project.
The report says the state’s sound regulations are “inadequate.”
“While the majority of wind farms do not experience significant noise complaints, many, if not most of those in more settled areas do have significant problems, ” says the report. “There is evidence that this can be a significant public health problem and therefore needs to be addressed by the Board of Health as well as by any permit process that allows wind turbines above a certain size.”
The report also recommends a setback requirement of 3,400 feet – about six-tenths of a mile – from all “non-participating” abutting properties to the wind turbine, based on current turbine technologies. “If and when there are quieter turbines, tried and tested methods for predicting sound, and/or measurement methods for amplitude modulation, then this setback might be subject to change,” says the report.
The committee also recommends a setback of at least 1.5 times the overall height of tower and blade from any residence or public way, based on ice-throw data from melting ice on the turbine blades.
The group has been meeting every other week since November 2010 to put together its 42-page finding.
A minority report written by Colter, Clark and Fitzgerald says that sleep disturbance “is the only generally recognized significant exposure to health from large turbines,” but is an important issue. This is why the report recommends a sophisticated and comprehensive sound study with multiple noise thresholds, post-installation verification, a formal complaint resolution and enforcement actions.
However, this minority report says the proposed setback “is an arbitrary and seemingly prejudicial restriction.”
A second minority report by landscape architect Walter Cudnohufsky – endorsed by Wells – recommends a 1.25-mile setback from any residence.
Cudnohufsky said the 3,400-footsetback was a political compromise, “so that Ashfield does not ‘appear to be’ banning industrial wind. I do not believe it a legitimate issue for compromise, ” he wrote.
Recently, acoustic consultants Cavanaugh Tocci Associates took ambient sound measurements of Ridge Hill, where the Clear Sky wind project had been proposed last year, and measured base-level sounds from five homes within proximity.
The findings show very low base noise levels.
The study was commissioned by Green Berkshires Inc. a nonprofit environmental group. In a letter to Coler and Wells, Green Berkshires Inc. President Eleanor Tillinghast said the purpose was to “work with a nationally recognized, independent engineering firm to develop a baseline protocol” for environmental sound measurements in rural hilltown areas.
She said Ashfield was chosen because it’s a rural hilltown that “lies along a major transmission corridor” and is likely to be the site of at least one wind turbine facility.