Cape Wind has won another round in the battle over construction of a wind farm in Nantucket Sound, in a 4-2 split decision in the state’s highest court.

The Massachusetts Supreme Judicial Court this week rejected a challenge to the so-called super-permit given to the wind farm developers by the Energy Facilities Siting Board (EFSB) in May 2009, covering nine state and local permits related to the connection of the wind farm to the electric grid.

The case had been brought by the Cape Cod Commission, the town of Barnstable and the main community opposition group, the Alliance to Protect Nantucket Sound. Had they won, it would have caused further delays — and the project already has been almost 10 years in the permitting stage — or even killed the Cape Wind project by putting permitting power back in the hands of local and regional agencies opposed to the development.

In November 2007, after the Cape Cod Commission denied Cape Wind approval for the land transmission portion of the wind farm on procedural grounds, the company filed a petition with the EFSB for a composite certificate that would bypass the commission and state and local permitting agencies and grant the remaining necessary state and local permits.

In May 2009, the siting board granted the certificate, and it was that approval that was contested.

The high court’s majority held that the state had acted properly in delegating power to the siting board for the issuance of permits for development in tidal lands, that the siting board did have the power to override the Cape Cod Commission and that the siting board had been right to consider only issues related to the cabling, which would be in state waters, and not the wind farm itself, which would be in federal waters.

But two members of the court, Chief Justice Margaret H. Marshall and Associate Justice Francis X. Spina disagreed with part of the judgment, holding that the siting board did not have the power to issue one permit, relating to the laying of cables through state tidelands. They also argued the court should have considered some in-state effects of the wind farm itself — which is in federal waters.

An excerpted text of the dissent written by the chief justice is published on the Commentary Page in today’s edition.

The main focus of the disagreement was the issue of whether the siting board had the power to act in place of the Department of Environmental Protection in granting the permit for the cable to cross tidelands.

The majority noted the state legislature had delegated to the DEP the power to license structures in the commonwealth’s tidelands. But they held there existed an “express legislative directive to the siting board to stand in the shoes” of any and all state and local agencies with permitting authority over a proposed power facility.

“We affirm the decision of the siting board and conclude that the challenged regulation is valid,” Justice Margot Botsford wrote for the majority.

But in writing for the minority, Chief Justice Marshall said the majority decision that the granting of the permit by the siting board was proper “is contrary to existing law and seriously undermines the public trust doctrine, which for centuries has protected the rights of the people of Massachusetts in commonwealth tidelands.”

“The court’s ruling to the contrary establishes a dangerous and unwise precedent, which has far-reaching consequences,” she wrote.

“A wind farm today may be a drilling rig or nuclear power plant tomorrow.”

She continued: “The court also concludes that the siting board acted appropriately by granting the certificate without considering any of the in-state impacts of the wind farm.

“As we have recently seen in the Gulf of Mexico, the failure to take into account in-state consequences of federally-authorized energy projects in federal waters can have catastrophic effects on state tidelands and coastal areas, and on all who depend on them.”

The 4-2 decision removes one more obstacle to the building of the long-debated wind farm, planned for Horseshoe Shoal in the center of Nantucket Sound. The project site is about 5.2 miles from the mainland shoreline, 13.8 miles from Nantucket and nine miles from Martha’s Vineyard.

The proponents, Cape Wind Associates, hope to start construction on the 130-turbine project by the end of the year.

Counsel for the Cape Cod Commossion, Eric W. Wodlinger, said after the decision that he feared “We may have cause to regret the damage to the public trust doctrine.

“The SJC majority upheld the siting board’s exclusion of all evidence of adverse in-state impacts from the wind turbines in deciding whether to permit the private developer to place its electric cables on the state’s seabed.

“The siting board refused to admit evidence concerning interference with air traffic control radar, marine radar, fisheries, navigation, etc., even within Massachusetts waters and air space, because the turbines would be in federal waters.

“As Chief Justice Marshall asked, what trustee would refuse to consider potential injury to trust property from a proposed nuclear plant next door when considering whether to allow transmission cables from that plant to cross the trust property?” Mr. Wodlinger said.

“The Cape Cod Commission wanted to identify the in-state impacts from the turbines; the siting board deliberately ignored them. From the commission’s point of view, the two dissenting justices got it right.”

Cape Wind’s attorney, David Rosenzweig, however, hailed the decision.

“The SJC’s decision brings to a close 10 years of state and local permitting for this landmark clean energy project,” he said.

And Cape Wind communications director Mark Rodgers said the result brought the prospect of “hundreds of new jobs, greater energy independence and a healthier environment that much closer to the people of Massachusetts.

“The court was right to say no to the delay tactics of the oil and coal-funded opposition group which brought this lawsuit,” he said.