The Martha’s Vineyard Commission last night imposed a moratorium on large-scale wind generation in waters within three miles of the Island.

By a vote of 12-1, the commission accepted a nomination made by two towns and supported by the other four, to have all the Vineyard’s offshore waters designated as a district of critical planning concern (DCPC).

But it deferred consideration a similar nomination which would cover wind generation on land, out of concern that it might interfere with wind projects already in the pipeline.

The move is in response to a state draft Oceans Management Plan which provides for the siting of as many as 166 turbines, each 450 feet high, as close as three miles from the southwest corner of the Island.

Town and county officials have expressed concern about the environmental and economic effects of such large-scale development so close to the Island, and also about the prospect that local planning agencies, especially the regional MVC, could be largely cut out of any role in regulating development.

The nominations for the DCPC were made by the Chilmark selectmen and the Chilmark planning board on Sept. 17, and the Aquinnah selectmen and planning board on Sept. 22.

Three of the four nominations refer to “land and waters,” while the fourth, from the Chilmark planning board, refers only to “waters.”

But as presented at last night’s MVC meeting, the nominated area includes: “that portion of the air space over all lands and waters within the county of Dukes County, except the Elizabeth Islands, the Indian Common Lands . . . and the Settlement Lands, which exceeds two hundred and twenty feet in height above mean natural grade (for land areas) and/or mean sea level (for water areas).”

There was a complication, however. While support for a DCPC over water was universal, there were practical objections to one on land.

The Edgartown selectmen, in a letter to the commission said that while they believed it important for the Vineyard to have some control over the development of commercial wind generators “that could potentially devastate the views and vistas we have so carefully protected all these years,” they already allowed “small local use windmills” and felt it unnecessary to designate all of Edgartown a DCPC at this time.

In another letter Joe Alosso, the town wastewater facilities manager was more specific about projects which might become collateral damage in a DCPC on land.

Edgartown is currently awaiting approval from the Federal Aviation Administration for a 328-foot turbine at the wastewater plant. Mr. Alosso also said the up-Island school district is planning a turbine.

Mr. Alosso said while he fully supports the intent of the nomination, the projects have “been in the works for some time and have had much public finances applied to them.”

He asked to commission to “figure out a way to either exempt those two turbines from the moratorium or structure it in a way that would not affect these projects from moving forward.”

Vineyard schools superintendent Dr. James H. Weiss also sought similar accommodation for a turbine planned for the West Tisbury School.

The school district already has received a grant for a feasibility study, he said, which was expected to be completed within weeks.

Correspondence from the other towns and from the county strongly supported a moratorium over land and sea.

In identical letters, the Tisbury selectmen and planning board called on the commission to exercise its powers to immediately promulgate the DCPCs.

A letter from county manager Russell Smith said “it appears that the Oceans Act will usurp and forgo any local input or control,” and said county commissioners felt decisions over inshore waters could not be left solely to the discretion of the state.

So, how was the commission to reconcile the differing positions?

Chilmark commissioner Bill Bennett proposed splitting the DCPC into two

parts: one for water and one for land. The water one could be voted immediately and the land one deferred until Nov. 5. Fellow commissioners were initially broadly supportive, with some minor quibbles.

Holly Stephenson of Tisbury who had suggested at the outset that the DCPC should expanded to cover sustainable energy in general, wanted to be sure her vision of using this as an opportunity to make the Vineyard a “model of sustainable living,” would not be left out later.

There were technical considerations too. Given that the commission has planning power but not regulatory power over the Elizabeth islands, would the regulated waters be measured from the Vineyard or the Elizabeth Islands?

No one knew for sure.

There was some talk about amending the height restriction for land-based structures.

But there was no great opposition to the idea, except from Peter Cabana of Tisbury, who said the commission should deal with both land and water simultaneously.

He argued the state was intent on overriding local planning power, and that five of six towns wanted a moratorium on land and water.

“And we’re saying no,” he said.

He rejected the argument that the commission was merely taking a little time to think through the complexities of a DCPC on land.

So when the vote was taken, he was the one dissenter.

The decision triggers an immediate 60-day moratorium on turbine development in Vineyard waters. On Nov. 5, the commission will decide whether to accept a DCPC nomination over land; last night the indications were that an amended nomination will be accepted over five, if not six Island towns.

From the time the MVC accepts a nomination, it has 60 days to hold a public hearing and decide whether or not to designate a DCPC. If it does, the vote triggers a one-year period for towns and the commission to come up with development regulations.

Meanwhile the state will finalize its oceans plan. The final version is due by the end of this year.