The Carlisle Mosquito Online

Friday, September 19, 2008

Carlisle looks at wind turbines

Bylaw changes to allow solar generation and small wind turbines in Carlisle are targeted to be on the Warrant at the Spring Annual Town Meeting. On September 16, the Alternative Accessory Clean Energy Generation Committee, having completed recommendations for solar, began the process of looking at wind turbines. Height, setbacks and materials were discussed, and it was clear that satisfying community preferences regarding aesthetics and safety while minimizing costs to installers may prove a challenge.

Building Inspector John Kennedy was on hand to lend his enthusiastic support to encouraging alternative energy, saying “People here are very interested, and that’s a good thing.” He noted three homes are currently installing geothermal, an accessory heating system whose newer closed-loop systems offer a seven- to eight-year payback timeframe. Committee member Keith Therrien, who thoroughly researched turbine installation for his own property but was denied a permit, said that combining geothermal with wind can have a payback of one to two years, while wind alone might require ten years. Presently a geothermal system is acceptable under town bylaws, although Greg Peterson, the Planning Board representative to the committee, noted that his board is currently reviewing all land use regulations “and could catch it in their net.”

But back to wind turbines, Peterson raised another issue: cell phone companies will argue that their towers should not be more restricted than towers for wind turbines. For a wind turbine to get above the tree line, a height of 140 feet might be required. The Carlisle height restriction on cell monopoles is 60 feet, or 90 feet with a special permit. “So far the most allowed was 80 feet and there were definite feelings from the neighborhood,” reported Peterson. “(Allowing a 140 foot wind turbine) clearly would give cell companies an argument in court.”

But without the height, “they’re useless,” said Therrien. He pointed to a wind turbine bylaw document from the Town of Hamilton which does not specify a height restriction. The committee tentatively decided to recommend a height limit of 140 feet above average natural grade at tower base prior to installation. Peterson noted this would be the equivalent of adding another steeple on top of the First Religious Society church on the Common.

The Hamilton document did specify a setback from property lines as tall as the tower. Peterson said this might rule out many lots in Carlisle. The apparent driver of the setback was fear a tower might fall onto adjacent property, but Kennedy said it would be unlikely one would break at the base. However, committee member John Dalton observed that “noise attenuation and visual screening” would also be improved by a larger set back, and given the precedent set by other towns, the tower-high setback was agreed to. Peterson noted that an easement could be obtained from a neighbor, or an appeal made for hardship.

Peterson had “difficulty with allowing a lattice tower” for wind turbines. They are not allowed for cell installations. “It will paint a picture for some townspeople that will make it hard to get a 2/3 vote at Town Meeting,” he added, noting this is a requirement to change a bylaw. Therrien said most wind turbine kits come with a lattice tower and a monopole would be extra, adding at least 20% to an installation. For the time being, the committee agreed either a lattice or monopole would be acceptable.

This led to the questions, “Should a visual impact study be required?” and “Who should be notified?” Cell tower companies are required to notify all property owners within 900 feet. But Kennedy said that that the intent of recommending bylaw changes is to make wind turbines as a right, without the need for a special permit, so there should be no notification requirement. However, he worried, “that gives all the authority to one person.” An alternative, he suggested, might be to notify those with legal standing; all abutters and abutters-of-abutters within 300 feet.

Regarding safety, the Hamilton document had many provisions that Therrien recommended for Carlisle. Towers should be able to withstand winds of 90 mph (at 70 mph, trees would be toppled). A brake or feathering would be required at wind speeds over 30 mph to avoid blade destruction. The turbine should be hinged to tilt down if gale force winds are predicted. Blades should be able to withstand unbalanced conditions that could occur with ice. Blade clearance from the ground should be at least 20 feet, and guy wires will not be allowed.

Hamilton also had a requirement for yearly inspection, which the committee endorsed. If the tower is found not to be in use, the owner will have 12 months to remove it, or the town will take it down at the owner’s expense. Rather than set up an escrow account, it was decided to have a signed agreement giving access for inspection and allowing a town lien. Fines for uncooperative owners may be considered.

Other ideas were discussed. Engineering drawings will be required for tower, base, and electrical components. Wind data must show at least a 10% threshold output. No units will be allowed that generate more than 50 KW, and no prototypes. Mechanical and electronic elements must have been tested together; no mix and match would be allowed.

Visual impact and notification will be taken up again, along with inspection fees and fines. A suggestion was made for a noise limitation, but Peterson said that noise information is hard to garner, and Therrien assured the group that the sound from a small turbine would be less than a refrigerator compressor. Also to be determined is whether a special permit will be required.

Recommendations for bylaw changes are targeted for completion in time to schedule a public hearing in January or February. ∆

© 2008 The Carlisle Mosquito