The Public Service Board has issued its draft rules on wind turbine sound that, if adopted, would put much stronger restrictions on wind development in the state.
Advocates on both sides of the debate say they're surprised by the strong standards the board has proposed.
Vermont has been setting sound rules for each wind project as they're being developed. The Legislature asked the Public Service Board to come up the new rules so developers have a consistent basis on which to consider new projects
Vermonters for a Clean Environment is an environmental watchdog group that opposes industrial wind projects. Director Annette Smith says the draft rules set noise levels that are below the current standards, as well as a setback distance that would force developers to locate large turbines farther away from homes.
"So if there were these setbacks, and if the noise standards could be enforced at these levels, it would very much be helpful to the people of Vermont who have to live around these things," Smith says.
Under the proposed rules released last week, turbines would have to be located at a distance of 10-times the height of the turbines away from the nearest home. In other words, a 500-foot turbine would have to be at least 5,000-feet from the nearest home.
And the noise levels were set at 42 dBa during the day and 35 dBa in the evening.
Both of those levels are below what is now allowed in the state. Smith says they match similar rules set in Europe.
"Both of those standards are defensible, as 35 dBA night is the German standard, and 42 dBA is the highest standard allowed in Denmark," she says. "Both countries have lots of wind turbines. Both countries also have lots of wind turbine opposition."
And she says that while the rules are an improvement, the board didn't go far enough to consider low frequency sound, which some opponents say affects human health.
And she says wind developers will try make changes as the draft rules are debated at additional public hearings.
"I expect the industry to go into overdrive to try to overturn these rules," Smith says. "They have a lot of money, and they will do what they can to try and water down this rule, which is not adequate in my opinion anyway. So it's going to be a fight just to keep what's here, let alone make it better."
But while Smith says there's a lot to like about the draft rules, supporters of wind power say the rules could prevent any future projects from moving forward.
"This is functionally a ban on wind power, large and small, in the state of Vermont," says Ben Edgerly Walsh, climate and energy project director at VPIRG.
He was just as surprised as Smith that the Public Service Board proposed the stringent standards.
And he says he's going to fight just as much as the other side to relax the allowable noise limits.
"Vermonters understand that wind needs to be part of the solution," says Edgerly Walsh. "We're going to continue to be involved as an organization in the proceedings as they go forward. And [we] are going to be urging the board to come up with a standard that is rigorous, but still allows wind to be built in the state."
When the new energy siting bill was passed by lawmakers last year, then-Gov. Peter Shumlin vetoed the bill partly because of the sound issue.
The Public Service Board began looking at the new sound standards in July. The complex testimony grappled with just how much noise might impact human health, as well as what were the best methods to both model for and measure the sound produced by wind turbines.
Measuring noise, and also agreeing on how the sound impacts human health, proved contentious, as both sides dug in their heels with their hired experts.
During the hearings, Vermont's former health commissioner Dr. Harry Chen said there was no scientific evidence linking turbine noise with health effects. Edgerly Walsh it's hard to understand why the board made such drastic changes to the noise standards and setback distance.
"If you look at the actual science on sound, and what does and doesn't have an impact on human health, this is coming in at about half of the level that would necessary to be protective," he says. "In particular on a technology that is so essential to our renewable future. It just seems inexplicable."
The Public Service Board's draft rules will now go to the Interagency Committee on Administrative Rules and additional public hearings will be held this spring.
The rules are expected to be finalized by July 1.