After more than seven years of investigation and controversy, Cape Wind’s proposal to build 130 massive turbines across 25 square miles of Horseshoe Shoal in Nantucket Sound now seems all but sure to go ahead, following a favorable environmental assessment.

The final Environmental Impact Statement from the federal Minerals Management Service (MMS) found the project posed no serious environmental threat. The 2,800 page final report differed little from a draft report, released almost exactly a year ago, which identified no lasting major adverse impacts on wildlife, navigation, fishing, tourism or recreation.

Some minor regulatory hurdles remain to be cleared, and the prospect remains of delaying legal action from the project’s opponents, but the MMS report was the most significant hurdle the project, which would be sited in federal waters, had to clear.

Certainly the proponents believe the wind is now blowing strongly their way. In a press release issued after the MMS report was released Friday, Cape Wind Associates LLC said it hoped all remaining necessary permits would be in place by March.

That being the case, construction of the $1 billion wind farm could begin by year’s end, and electricity could begin flowing into the state grid by early 2012.

But that all hinges on the MMS now issuing a formal Record of Decision, granting a lease to Cape Wind. That could happen in as little as 30 days, although opponents of the project continue to argue against it, saying the report was released prematurely.

The main opposition group, the Alliance to Protect Nantucket Sound, has already appealed for a further public comment period of at least 90 days on the report.

It also cited a number of concerns which it said should be addressed before final approval is given.

Chief among them are that the Federal Aviation Administration has yet to finish investigating potential aviation hazards, that the MMS has yet to complete consultations with tribal interests and historic preservation agencies, and foot-dragging under the former Bush administration, which had failed to complete a promised regulatory regime for offshore energy projects, which should have been done by May, 2006.

The alliance also stressed that the MMS report found that the turbines would result in a moderate impact to marine radar. Its complaint, however, failed to mention that the Coast Guard, in a recommendation appended to the report, found the effect on radar could be mitigated.

“We ask that the final ROD not be released until the above concerns, and additional issues that may arise under more detailed analysis, be fully addressed and reviewed by the public,” said an alliance press release.

It also noted the ROD is one of about 20 federal, state and local permits and authorizations that Cape Wind must secure to begin construction.

“Cape Wind has already received one permit denial from the Cape Cod Commission, which is currently under appeal,” the alliance said.

Alliance president Glenn Wattley said he and other opponents still were hoping the new Obama administration would want to see the loose ends tied up.

The politics of the situation could be ticklish. Sen. Edward M. Kennedy, a longtime opponent of Cape Wind, issued a statement saying the MMS report has “virtually assured” years of public conflict and litigation. He is close to President Obama.

But so is Gov. Deval Patrick, a strong advocate of the Cape Wind project.

Public opinion, according to numerous polls, is mostly behind the wind farm. President Obama campaigned strongly on the need to harness renewable energy and the project promises to create hundreds of jobs and generate more than $500 million in nonlabor purchases in Massachusetts and Rhode Island — possibly an attractive prospect in a weak economy.

The final impact statement is, if anything, even more favorable to the development than the draft last year. It includes, for example, new findings from the National Oceanographic and Atmospheric Administration that the survival of key wildlife would not be threatened.

“This report validates the project will create new jobs, increase energy independence and fight global warming while being a good neighbor to the ecosystem of Nantucket Sound,” said Cape Wind president Jim Gordon in the press release.

“Massachusetts is one major step closer to becoming home to America’s first offshore wind farm and becoming a global leader in the production of offshore renewable energy,” he also said.

The press release claims that of the 42,000 odd written public comments received in response to the draft EIS, more than 40,000 were in support of the project.

The final EIS found only negligible to minor impacts in most categories it studied, including fish stocks, recreation and tourism, marine and air traffic.

To define their terms: negligible means effectively none; minor means impacts that are either short-term or capable of mitigation; moderate means impacts which are unavoidable and irreversible although no threat to the viability of the resource; and major means the affected resource would not recover completely, regardless of mitigation efforts.

The report found there would be moderate impacts during construction and operation on some bird species, and some types of commercial fisheries. Marine mammals also would feel moderate impacts during construction, because of increased water turbidity due to pile driving.

The report also identified moderate to locally major impacts on visual resources, depending on whether one was viewing the turbine field from shore or close up, at sea.

What is a moderate visual impact? If a person on the beach in Oak Bluffs or Edgartown, some nine miles away from the Cape Wind development, extended an arm toward the turbines, and held thumb and finger about a half-inch apart, that’s how tall the turbines would look, out on the horizon.

For someone on a boat floating next to a turbine, however, the impact would indeed be major. Each of the proposed turbines would stand 440 feet tall.

At full capacity the project is intended to produce 454 megawatts of electricity, with average production of 182 megawatts, or about 75 per cent of total demand on the Cape and Islands, while saving some 880,000 tons of carbon dioxide emissions which would result from fossil fuel power generation.