BANGOR — Opponents of a commercial wind energy development project in Highland Plantation were delighted Wednesday after state regulators decided they will review the proposed wind farm under tougher scenic standards.

It was the first time Land Use Regulation Commission board members invoked an exception within Maine law to review the impact of a wind energy project’s associated facilities — basically everything other than the wind turbines — under stricter rules.

After three hours of debate and comments from people both in favor of and opposed to the project, the six state commissioners voted unanimously that developer Highland Wind LLC will have to show that its buildings, generator lead lines and miles of access roads can fit harmoniously into the landscape; it has to prove those structures will have no “undue adverse effect” on scenic character.

After three hours of debate and comments from people both in favor of and opposed to the project, the six state commissioners voted unanimously that developer Highland Wind LLC will have to show that its buildings, generator lead lines and miles of access roads can fit harmoniously into the landscape; it has to prove those structures will have no “undue adverse effect” on scenic character.

“People have made claims about adverse impacts to resources other than those of state and national significance as a result of associated facilities. That, to me, provides sufficient information that we need to look at those impacts,” Commissioner Ed Laverty said.

Public hearings on the Highland Wind project are anticipated for late June. At that point the commissioners will hear comments about the development before making their decision on whether to grant permits for construction.

The 39-turbine project would be visible from Bigelow Preserve, which was created by public referendum. It would also be visible from a section of the Appalachian Trail.

Plans for the wind farm are driven by the leaders of Brunswick-based Independence Wind: former Gov. Angus King and former Maine Public Broadcasting Corp. President Rob Gardiner.

The commissioners’ decision Wednesday was supported by the Maine Appalachian Trail Club, Appalachian Mountain Club and Friends of Maine’s Mountains, but it was the work of one grassroots nonprofit, Friends of the Highland Mountains, that brought the provision in Maine’s Wind Energy Act to light.

Under the tougher standards, Highland Wind will have to prove the associated facilities will not harm scenery beyond eight miles of the project, where Bigelow Preserve and the Appalachian Trail are. Previously it only had to focus on the area within eight miles of the project. The turbines are still subject to the eight-mile limit.

According to surveys conducted in 2010 of people hiking within eight miles of the planned project, most expressed a neutral opinion on turbines’ effect on scenic value. The surveys, conducted by the Portland Research Group in consultation with Evan Richert, a land use planning consultant for Highland Wind, also found the proposed project would have no overall effect on the likelihood of hikers returning.

Those in favor of the wind development project, however, were unhappy with the commissioners’ decision. King, who sat on a table in the back of the room at the Spectacular Event Center for part of the meeting, said opponents did not make “any showing whatsoever that would justify a different standard.” None of the planned wind facilities are unreasonable, King said; the commissioners’ ruling will simply make upcoming public hearings longer and will not change an outcome in favor of his project.

Jane West, an attorney for the Conservation Law Foundation, called the decision “baffling.”

“The unfortunate reality is that now opponents need only hint at a suggestion of an adverse impact and the commission will apply the exception to the scenic standard with no clear guidance on how they arrived at their conclusion,” said West, representing the group that lobbies for energy-efficiency related legislation.

From the vantage point of mountaintops several miles away, the development’s up to 15 miles of roads, 10 miles of generator lead lines, an operations and maintenance facility and a substation would be barely visible, argued Richert.

“Everything about Highland Wind’s associated facilities are ordinary,” Richert said. “It is hard to distinguish them as separate objects on the landscape.”

Phil Worden, an attorney for the Friends of the Highland Mountains, said more than a million cubic yards of mountainside would be removed, and each turbine would be on a two-acre leveled, cleared area, all in a place in Somerset County where there is no other development currently.