Wind bylaw revisions 

Cohasset – For nearly three years hardly a month has gone by where a wind turbine proposal or the wind bylaw has not made a headline.

As the Trustees of Reservation proposal to place an 80-meter wind turbine on Turkey Hill works its way through the Planning Board special permit process, the Alternative Energy Committee is making final rounds to various boards with a revised wind conversion facility bylaw.

The revisions address many of the major concerns brought up through the permitting process for the two-turbine project proposed by private developer CCI-Energy during 2009 and 2010.

The original wind turbine bylaw passed in a unanimous vote at the 2008 Annual Town Meeting. It is a town-wide zoning bylaw establishing regulations for commercial size wind turbines. The projects go through a special permit process, overseen by the Planning Board. The bylaw establishes the parameters for a wind turbine and the revised bylaw places clearer and in some cases more stringent regulations on turbine construction in Cohasset.

Andrew Willard, chairman of the Alternative Energy Commission (AEC), said the bylaw has been adjusted to address concerns of height, setback and noise. Over the summer the Alternative Energy Committee held two public forums on the bylaw to gather input and opinion from the public. Many of the changes clarify the bylaw and could potentially make it easier to interpret.

The maximum height for a turbine (from pre-construction grade to the highest point reached by the nacelle) has been lowered from 100-meters (350-feet) to 80-meters (260-feet) in the revised bylaw.

Setbacks have been increased substantially. A turbine cannot be sited within a distance equal to the total height of the turbine from buildings, critical infrastructure, or private or public ways. Additional protection for residential buildings is included: turbines must be sited at least three times the total height of the turbine from the nearest existing residential structure. The final setback addition is the turbine must be sited 1.5 times the total height of the turbine from the nearest property line.

“The lower height and increased setback requirement should decrease the effects on neighboring homes and businesses,” Willard said.

Other changes include a clarification of the noise requirements. An expansion on the Massachusetts state law on noise is included. A definition of “ambient” was added. The revised bylaw also calls for a noise analysis to be completed within 90 days of initial operation of the turbine. It also contains a clause to address the noise regulations as it might mean for two turbines within a half-mile of each other.

The portion of the bylaw related to shadow flicker, the blinking effect caused when the sun passes behind the moving rotors, has been quantified. The original bylaw left a lot of subjectivity in the hands of the applicant and the Planning Board. It said the “turbines shall be sited in a manner that does not result in significant shadowing or flicker impacts.”

The revised bylaw offers a concrete number for shadow flicker: “The maximum allowable worst-case daily shadow flicker for each applicable structure shall not exceed 30 minutes for each day.”

Selectmen chair Karen Quigley asked Willard if with the increased setback requirements there were still parcels where a wind turbine was possible.

“We made a conscious decision not to look at any specific parcels when revising the bylaw. We wanted to focus on coming up with verbiage that we think is reasonable,” Willard said. “We kept the discussion away from whether wind would be possible (under the revised bylaw) on this site or that site.”

Selectman Paul Carlson raised some questions about how the bylaw protects the town when the time comes to dismantle the turbine. He questioned whether more protections should be put in place so the town doesn’t end up footing the bill.

Willard said they could look into the issue a little further.

The estimated life of a wind turbine is 20 to 25 years.

The next stop for the revised bylaw is a formal public hearing before the planning board. The Alternative Energy Committee is aiming to put the bylaw before Annual Town Meeting on April 30.