PUR Guide 2012 Fully Updated Version

Available NOW!

This comprehensive self-study certification course is designed to teach the novice or pro everything they need to understand and succeed in every phase of the public utilities business.

Order Now

Wind Energy: Vermont Finalizes Sound Level Rules

The Vermont Public Utility Commission has instituted final rules under which wind-powered electric generation facilities must abide by strict noise level limits. The final regulations are consistent with those announced earlier in the year by the commission’s predecessor Public Service Board.

According to the commission, the new rules will play a pivotal role in its siting determinations, which constitute part of the review process for certificate applications for the construction of new wind units. The adopted rules took effect on November 22, 2017, and will apply to any facility that files for a certificate of public good on or after that date. However, the commission said, the regulations will not apply retrospectively to any existing or pending wind generation facilities.

Under the new rules, standards are set for three categories of wind facilities: small (up to 50 kilowatts [kW]), medium (between 50 and 150 kW), and large (greater than 150 kW). For the small and medium categories, the rules limit sound to 42 decibels for units within 100 feet of nearby homes, with that cap applying day or night.
For the large category, the sound level limit differentiates between daytime and nighttime, with the limit being 42 decibels during the day but only 39 decibels at night. The daytime period was defined as 7:00 in the morning until 9:00 in the evening.

The commission included in the regulations a requirement that project developers list in their certificate applications information representing the expected sound levels of their structures at neighboring residences.

The commission said that once constructed, large wind units will be subject to ongoing monitoring to assure that they comply with the sound level standards. Medium-sized projects, however, can choose to conduct sound monitoring or simply construct their facilities at a minimum distance from nearby homes so as to facilitate compliance. The commission reported that smaller generators will not be required to meet the identified decibel limit if the distance of the turbines from the nearest home is at least 10 times the turbine’s height. For all projects, it said, a neighboring landowner may agree that the limits in the rule do not apply to his or her property.

The commission said that in setting statewide standards on wind unit noise levels, it was guided by a desire to protect neighbors’ interests while preserving the opportunity to develop wind projects as part of Vermont’s renewable energy goals. Refuting complaints that it had failed to elucidate on the particular elements it considered in choosing the standards, the commission emphasized that the rules were the product of an extensive process that included a thorough review of scientific research and practices in other jurisdictions as well as consideration of hundreds of comments from Vermonters who offered many different perspectives regarding wind projects.

The commission related that some advocates of wind power had questioned whether the new rules might prevent Vermont from attaining its renewable energy goals, impede development of wind power in the state, and possibly put the brakes on what had been growing installations of wind equipment at small residential sites and even larger utility-scale developments. At the opposite end of the spectrum, the commission said that others had complained that the approved noise level limits are still too high, despite being among the lowest in the country.

Although some parties had argued that the new rules created an unreasonable burden for project developers while others asserted that they set forth an equally unjust burden on people residing near the turbines, the commission voiced confidence that the regulations were reasonable and fair overall. It thus dismissed warnings from some that new technologies might have to be developed in order to assure that larger turbines could run efficiently both day and night while meeting the 39-decibel limit for nighttime operations. Rule on Sound Levels from Wind Generation Facilities, Rule 5.700, effective Nov. 22, 2017 (Vt.P.U.C.).