Proposed rules issued Friday by the state Public Service Board signal a significant shift in the state’s regulation of wind turbines.
The board is calling for more restrictive limits on sound emissions, which at least one renewable energy proponent said could effectively ban wind power in Vermont.
Currently, regulators measure sound emissions from inside and outside homes. Emissions outside must not exceed 45 decibels, while emissions inside a home cannot exceed 30 decibels.
The new proposal does away with inside or outside and instead measures emissions during the day and at night within 100 feet of a home. Under such standards, emissions could not exceed 42 decibels during the day and 35 decibels at night.
“That is absurdly low,” Ben Walsh, climate and energy program director at the Vermont Public Interest Research Group, said of the nighttime level in particular. “This is functionally a ban on wind large and small in Vermont ... I’m surprised the board went this far.”
The board also called for new limits on the distance between large-scale turbines and homes, requiring that structures be at least 10 times their height from a home. That’s 5,000 feet for a 500-foot turbine.
Those who’ve long argued that Vermont has been too lenient about sound emissions view the new proposal somewhat favorably.
“Someone is listening,” said Annette Smith, executive director of Vermonters for a Clean Environment and a vocal critic of turbines.
Thirty-five decibels at night is the standard used in Germany, Smith noted. But she argued that the standards won’t be sufficient if Vermont doesn’t step up its enforcement of sound violations.
The proposed rules are still subject to change, following public hearings and review by two state panels. Two public hearings will be held in Montpelier on May 4: at 9:30 a.m. at the Public Service Board and at 7 p.m. at the high school.
The changes in sound standards come after some neighbors of wind projects in Vermont — particularly those in Sheffield, Lowell and Georgia — complained that the turbine emissions are deeply disruptive under certain conditions .
Gov. Phil Scott, who took office in January, has also said he will seek to prevent new large-scale ridgeline wind projects from being constructed.