This is the second of three posts on how wind energy siting rules are changing in New England to address concerns about turbine noise. The last post addressed local and statewide rule changes in Massachusetts, this post discuss new rules in Maine, and the final will speak to the awkward nature of regulating noise, which we all experience subjectively.
U.S. Department of Energy
Operational wind farms (yellow), community (blue) and residential (green) wind energy installations in New England.
Maine and Massachusetts are leading New England in wind power development, and both states are bumping into the same problem: How to deal with concerns surrounding turbine noise and its potential effects on human health. While distinct siting rules are popping up on a municipal, county, and state level in Massachusetts, Maine will soon have a statewide standard for turbine noise.
On a windy day, Maine produces about 10 times as much energy as Massachusetts. The Bay State is home to dozens of small projects, mostly private and municipal turbines in collections of one to two. But the Pine Tree State hosts a small handful of industrial wind farms that far exceed Massachusetts’ capacity. Maine has more ambitious long-term political goals for wind, too. Massachusetts is shooting for two gigawatts of installed power by 2020, while Maine has called for eight gigawatts by 2030.
Of course Maine is a much larger state with far more undeveloped territory than Massachusetts, so comparisons like this are not necessarily instructive for Cape Cod. What is instructive is this: Several of Maine’s wind projects have led to the same types of noise complaints seen here on the Cape.
The Maine Board of Environmental Protection is reviewing a new threshold for turbine noise. The original proposal came from a citizen petition and would have been the strictest of its kind in New England. It proposed very tough limits on high-frequency (dBA) and low-frequency (dBC) sounds, distinguishing separate limits for daytime and nighttime. While dBA sound is commonly regulated, dBC is not; some think low-frequency turbine sound is problematic, leading to sleep loss and stress for some individuals. As originally proposed, Maine’s siting rule also called for siting turbines no closer than one mile from a residence.
After several periods of review and public comment, this proposal has been tamped down. The current draft sets daytime and nighttime limits at 55 and 42 dBA, respectively. Low frequency (dBC) sound is not addressed, but “tonal sounds” and “short duration repetitive sounds” are.
Nighttime Noise
The World Health Organization suggests a nighttime noise limit of 40 dBA (the same as what Bourne just established). Above levels of 42 dBA, WHO reports the following effects.
- Waking up in the night and/or early in the morning
- Increased average motility when sleeping
- Self-reported sleep disturbance
- Environmental insomnia*
* Essentially the same thing as “self-reported sleep disturbance,” “environmental insomnia” is diagnosed by a medical professional.
It is hard to say if Maine’s potential rules are stricter or more lenient than what is being considered on Cape Cod. When comparing Maine’s draft rules with the rules recently passed in Bourne, Maine is looking at much stricter daytime noise limits, but slightly more lenient nighttime limits. That means Maine’s turbines could be quieter than Bourne’s during the day but louder at night, when sleep is more likely to be disturbed.
Barnstable County is considering rules to regulate turbine noise, but the county has not prescribed any definitive noise limits yet. The Cape Cod Commission (Barnstable County’s legislative arm) is promising to regulate high and low-frequency sound, while Maine is currently not considering regulating low-frequency sound. Ryan Christenberry, an energy specialist with the Cape Cod Commission, says a more detailed process does not equate to a more restrictive process. For example, Maine is looking at blanket rules for the entire state, but the CCC is including waivers for small municipal projects. More details, more nuance, more room to adapt to unique situations.
At the crux of all of these rules is a sound study. Maine, the Cape Cod Commission, and the state of Massachusetts are slowly developing the details of what should be included in a robust sound study. So far the only thing everyone seems to agree on is every location is different, and therefore every proposal needs its own study. What is tolerable in one neighborhood might not be tolerable in another. So independently conducted sound studies will determine average localized noise levels. The conclusion of these studies will determine key factors in the turbine’s operation: how far should it be from homes, how loud can it be at a resident’s property line, and so on. But how you conduct a study will determine the study’s outcome, so this is still a major detail that remains unclear throughout New England.
Everyone might wind up skinning this cat differently. Cape Cod’s towns, the Cape Cod Commission, and our neighbors in Maine may all set distinct sound limits for daytime and nighttime. Maine might rely on high-frequency noise limits, while the Cape Cod Commission may use a combination of noise limits and setback distances.
But will any of these rules actually protect human health? Check Climatide tomorrow for the final installment in this series, where we will address the ethical dilemma of regulating sound.
