Fox Islands Wind has submitted a preliminary revised operating protocol for its Vinalhaven turbines to the Maine Department of Environmental Protection. The revised protocol was requested by the DEP after residents near the wind turbines filed complaints about the noise.

Fox Islands Wind’s proposed protocol calls for slowing down the turbines to reduce the noise level when the wind direction is out of the southwest and the surface level wind speeds are less than 6 mph.

However, after reviewing Fox Islands’ revised operating protocol, the DEP asked for more data and a trigger based on wind shear to slow down the turbines and reduce the noise level.

“[The DEP] requires additional information from Fox Islands Wind in order to establish a wind shear coefficient that can be used as the trigger mechanism by Fox Islands Wind in their revised operational protocol to be submitted to the department for approval,” wrote James Cassida, director of the Division of Land Resource Regulation at the DEP, in an e-mail to Fox Islands Wind.

In a Nov. 23 letter to Fox Islands Wind, Cassida requested a preliminary outline of a revised operation protocol by Dec. 3.

A few weeks after receiving the proposed new protocol, the DEP provided its feedback and requested the additional data and wind shear trigger. Cassida said the DEP seeks a “more finely tuned” trigger that takes into account wind shear.

Wind shear is caused when the wind blows at different speeds at the ground and higher altitudes, such as several hundred feet above the ground where the turbine blades spin.

Fox Islands Wind has a deadline of Jan. 23 to incorporate the DEP’s comments and submit a revised operating protocol.

In the Nov. 23 letter, Cassida wrote, “The department views the compliance issues identified at this facility as a serious matter. Provided that Fox Island Wind, LLC submits a revised operation protocol to the department for review and approval no later than Jan. 23, 2011, and further provided that the revised operation protocol approved by the department is fully implemented by Fox Island Wind LLC in a manner that ensures compliance with department noise standards and permit conditions, the department can resolve this matter without further action.”

The original noise complaint said the Fox Islands Wind turbines were exceeding the 45 decibel nighttime noise limit. The specific period for the noise complaint covered July 17 and July 18, 2010.