The Carlisle Mosquito Online

Friday, February 27, 2009

Proposed wind turbine bylaw debated

Approximately 30 residents attended the February 23 public hearing on the proposed new bylaw on Wind Energy Conversion Systems. The proposed new Section 5.10 would establish standards for locating and using wind turbines in any zoning district by special permit issued by the Board of Appeals. The proposed bylaw is sponsored by the Alternative Accessory Clean Energy Generation Committee (AACEGC), a committee formed by the Selectmen in response to public interest in the topic.

Although the committee’s scope included other clean energy topics including geothermal and solar, wind turbines have proven to be the most controversial and commanded the bulk of the committee’s efforts. The Planning Board has responsibility for holding public hearings on all proposed Zoning Bylaw changes. Excerpts from the latest draft of the proposed bylaw are at the end of this article.

Major concerns expressed were visual impact, noise, and impact on property values. A consensus was reached on noise – nobody wanted it. Several representative comments were:

Amy Isaacs: “The biggest effect [noise] will be at low wind levels.”

Rhonda Sheffield: “I want to be able to hear the coyotes at night; I don’t want to hear – thub, thub, thub.”

Ray Modeen: “Having a steel lattice evokes an industrial area. This isn’t like a refrigerator that turns off. We did due diligence on cell towers and they are silent. We should hire an independent consultant to study sound effects.”

AACEGC members tried a variety of analogies to relate expected noise readings to neighborhood equivalents. Values for air conditioners, refrigerators, and suburban background noise were trotted out. The internet was prominently cited by members of the audience for studies in Europe on noise-induced stress and impact on sleep. Residents spoke of being bothered by the Routes 495 and 27 traffic drone at night. Neither proponents nor opponents were persuaded.

Planning board member Carol Nathan had perhaps the most cogent question: “Are there convenient sites where we could listen to wind turbines in operation?” Building Commissioner John Luther said that equivalent units are on private property. Nathan countered, “I would like to hear it from the property line.” Carlisle’s Administrative Coordinator Elizabeth Barnett said that she had experience with a guyed monopole wind turbine at the University of Vermont in Burlington and was impressed with how quiet it was. The committee will determine if appropriate sites are convenient.

In response to board member Kent Gonzales’ question at a prior board meeting regarding the relative cost of monopole and lattice-type towers, Luther said that a 130-foot monopole would be $42,000 compared to $19,500 for a lattice structure.

The August/September 2008 issue of the magazine “Home Power” (p. 85) offers system cost comparisons: Bergey Excel-S (10kw) 120-foot Monopole $77,720 – 90-foot Monopole $67,110 – 120-foot Freestanding Lattice $63,170 – 100-foot Tilt-up Lattice $58,600.

Chair Greg Peterson thanked the public for “keeping the decibel level down” during the sometimes heated hearing and announced that the public hearing will be continued in conjunction with the solar power hearing at 8:45 p.m. on March 9.

Wind Turbine Bylaw Exerpts: Placement of Wind Energy Conversion Systems – hereafter referred to as wind turbines – on any property in any zoning district in the Town of Carlisle shall require a special permit from the Board of Appeals, in addition to a building permit and any relevant electrical permits. Setback: The wind turbine tower shall be set back at least one tower height plus one rotor radius from any property line. [The provision in an earlier draft that would have permitted the Board of Appeals to reduce this setback has been dropped.] Screening: In all wind turbine installations, visual screening and sound attenuation shall be required where necessary to limit visual and noise impacts to neighbors. Height: The maximum total height of tower and rotor shall be limited to 140 feet above average mean grade before construction. Noise: Applicant will provide noise data that shows the noise level at any property line will not exceed 10dBA above the assumed normal ambient level of 45 dBA at ground level at the property line when the unit is operating in average wind speed conditions for the site. Tower type: Lattice and monopole towers may be allowed by the special permit granting authority. Guyed towers are prohibited. Towers must be hinged for maintenance and lowering in high wind conditions. ∆

© 2009 The Carlisle Mosquito