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Vermont lawmakers impose stricter sound limits for wind turbines

Vermont lawmakers have imposed stricter noise limits for wind turbines in order to allay public health concerns. The state’s eight-member Legislative Committee on Administrative Rules gave final approval Oct. 26 of a rule issued by the Vermont Public Service Board in May. Unpopular among both wind energy supporters and opponents, the rule restricts the sound of wind turbines on wind farms that apply for a certificate of public good.

As measured 100 feet from a neighboring landowner, the new rule restricts the daytime sound pressure levels allowed for facilities larger than 150 kW to 42 A-weighted decibels, or dBA, and nighttime levels to 39 dBA. Facilities smaller than 50 kW are prohibited from exceeding the 42-dBA limit no more than 5% of the entire day and night, while facilities between 50 kW and 150 kW are restricted to 42 dBA.

At a previous Oct. 12 meeting, the committee removed a proposed “setback” provision that would have required industrial-scale turbines be located at least 10 times the length of their height away from neighboring residential buildings. For example, a 500-foot turbine would have had to be at least 5,000 feet from the nearest residence. The PUC in an Oct. 26 meeting accepted the elimination of the setbacks.

The rule was prompted by legislation signed in June 2016 by then-Vermont Gov. Peter Shumlin that set temporary noise limits and gave “substantial deference” to local municipalities in the siting process of wind projects. Like elsewhere in New England, the move is the latest in an ongoing struggle between citizens, developers and politicians over the siting of wind turbines along mountain ridges.

According to Vermont newspaper Seven Days, despite skepticism among other committee members, the only nays in the final voice vote came from committee Chair Sen. Mark MacDonald, a Democrat from Orange, and Rep. Robin Chesnut-Tangerman, a Progressive-Democrat from Middletown Springs. During an Oct. 12 hearing, Rep. Chesnut-Tangerman had expressed concerns of hampering wind energy development with the “low” decibel levels.

“The rule is a win for the wind industry, despite their protestations that it will stop wind development in Vermont,” Annette Smith, executive director of Vermonters for a Clean Environment, an advocacy group opposed to turbines, said in an email. Smith said the audible-defined rule is deficient because it does not provide any standards for the “full spectrum” of sound levels produced by wind turbines and does not include restrictions for low-frequency noise.

“It is also deficient in that it does not apply to seasonal residences, does not set a standard at the property boundary and does not have a standard for amplitude modulation,” Smith said. In comparison, Smith said New York state, “which can hardly be considered anti-wind,” has standards for all of those, including [low-frequency noise] and amplitude modulation.