Update on Wind Sound Standard

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As the 2016 energy siting and planning bill was going through the final steps at the legislature last spring, the issue of setting statewide limits for sound from wind projects became a hot topic. Historically these limits had been set for each project individually. The bill, in its final form, tasked the Public Service Board with coming up with a new, statewide standard instead.

This summer, the Board started proceedings to create that rule, due July of 2017. VPIRG has been heavily involved in this proceeding this fall. We wanted to share an update on its status and our position on what the new sound standard should be.

First, why did VPIRG choose to get involved?

  • Having reviewed the wealth of independent peer reviewed and government sponsored public health studies on wind turbine sound, we were confident that current levels of wind turbine sounds do not pose a risk to human health. At the same time, we recognized issues with existing sound standards set for individual wind projects that had led to a lack of trust in the standards and future wind projects from some Vermonters.
  • We know wind is critical to reaching our 90% renewable energy by 2050 goals. If the final sound standard is more restrictive than it needs to be, it could drastically limit or halt all wind development, and we could fail to meet our goals. This was one of the main reasons Governor Shumlin vetoed the original version of the bill – an oversight in the language around the sound standard would have inadvertently caused a moratorium on wind power.
  • We knew that a balance existed – a standard that addressed the concerns being raised by Vermonters and allowed for wind power to continue to thrive in Vermont. We wanted to make sure there was an independent voice in the room that was advocating for a standard that would work for all stakeholders: potential project neighbors, wind developers and all Vermonters.

Since no one at VPIRG is a trained acoustic engineer, we decided to bring in an outside expert to help us wade through the wealth of scientific study on the topic to identify this balance. After interviewing several experts, we chose to work with Scott Bodwell from Maine. Scott has worked on wind turbine sound cases from every perspective – including working closely with the Maine Public Utilities Commission and Department of Environmental Protection, acoustic analysis for wind developers, and representing a group of landowners with complaints about sound from wind turbines.

We wanted somebody with experience in Maine because Maine and Vermont are actually pretty similar – mountains, trees, and a largely rural population that cares a lot about keeping the state beautiful. It’s also true that folks in Maine had raised some similar issues to the concerns being raised by Vermonters, but that those issues had been largely resolved thanks to the sound standard Maine put in place.

So what did VPIRG propose?

  • A standardized way to forecast how much sound wind projects would make at neighboring houses before they’re constructed. This model is based on specific information about the turbine and hypothetical scenarios (weather, the way sound travels over different types of land) that might affect sound levels at neighboring homes.
  • A standardized way to test the turbines once they’re constructed to ensure they’re at the predicted levels (or lower).
  • A sound limit of 45 decibels outside neighboring homes. For acoustic wonks, that’s 45 dB(A) Leq measured over 10 minutes. For non-acoustic wonks, here’s a handy chart of how loud some common sounds are, and how this level compares.

What we proposed is very similar to what’s currently in place in Maine. Projects tested in Maine were found to produce sound well below the set limits once they were constructed, even at the highest sound levels. That’s because this method plans for the worst case scenario, which rarely actually happens. Given the public health studies and scientific research on reactions to different sound levels, we are confident that any level of sound 45 decibels or below will be fully protective of public health, and confident that the method we’ve proposed will keep sound well below 45 decibels for the large majority of the time.

The Board is expected to issue a draft rule in the next few months, and VPIRG will continue to stay involved to ensure the rule works for all stakeholders as we move forward on wind power to meet our renewable energy goal of 90% by 2050.

To learn more about our proposal and the proceeding, read below:

VPIRG Initial Comments and Proposal (October 24, 2016)

VPIRG Reply Comments (November 16, 2016)

Public Service Board Webpage, with links to comments by other stakeholders and information about the proceeding

VPIRG’s FAQ on Wind Power

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