(CN) - The D.C. Circuit upheld the Federal Aviation Administration's determination that a massive offshore wind farm planned for Nantucket Sound poses no hazard to air navigation.
The $2.6 billion Cape Wind project, which would comprise about 130 wind turbines, has long been a subject of controversy in Cape Cod. Its critics included the late Sen. Ted Kennedy, whose family has a famous home on the cape.
Various legal challenges to the project -- which, if built, would be the first offshore wind farm in the United States -- have delayed construction of the project for more than 13 years.
The U.S. Department of the Interior approved the project in 2010. Shortly afterward, the FAA issued a "no hazard" determination for the project, finding that while the turbines would have some electromagnetic effect on local radar facilities, this could be easily mitigated and would therefore pose no threat to the "safe and efficient use of navigable airspace."
But in October 2011, the federal appeals court in Washington, D.C., vacated the FAA's decision, saying the agency failed to consider whether the turbines posed a danger to pilots relying on eyesight rather than their aircraft's instruments while flying through the area.
After a review, the FAA in August 2012 again issued a no-hazard determination -- the agency's fourth over the history of the project -- finding that the turbines would have no adverse effect on the use of nearby radar facilities or on navigable airspace.
With that, the Alliance to Protect Nantucket Sound and the city of Barnstable, Mass., appealed to the D.C. Circuit, which ruled on the case Wednesday.
This time, the three-judge panel sided with proponents of the project.
Writing for the panel, Judge Judith Rogers noted that by the time the FAA had issued its no-hazard determination, "the circumstances regarding radar had changed."
"In January 2012, the FAA upgraded the ASR-8 radar and beacon at Otis Airfield by digitizing the output with a TDX- 2000 processor," Rogers wrote. "The FAA had concluded in the aeronautical study that the installation of the TDX-2000 would not only address existing radar issues with 'coasting, dropped targets, and ring around,' but also reduce unwanted returns from the wind turbines."
Further, tests conducted both before and after the system was permanently installed "confirmed that the modification was effective," she wrote.
"On remand, the FAA explained that its aeronautical study had relied on multiple reports to evaluate potential impacts to the three FAA radar sites on or near Nantucket Sound. The FAA found that the Cape Wind project would have no noticeable impact on beacon, or 'secondary,' radars," Rogers continued.
The panel affirmed the FAA's detailed determination that the turbines would not adversely affect pilots flying by sight and concluded that the agency need not assess the environmental impacts of its "no hazard" determination."
Cape Wind Communications Director Mark Rodgers applauded the decision.
"The Alliance to Protect Nantucket Sound, the Town of Barnstable and their financial backer -- coal billionaire Bill Koch -- have failed yet against in their continuing campaign to use the courts to delay the financing of Cape Wind," Rodgers said in a statement issued after the ruling.
As the panel handed down its decision, opponents of the proposed offshore wind farm filed yet another legal challenge to the project, claiming Massachusetts forced NStar Electric to agree to buy high-priced electricity from the wind farm.
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