Defense Department Cites Potential Radar Interference from Wind Farms

By IAN FEIN

Pentagon officials are calling for additional studies to determine whether the proposed wind farm in Nantucket Sound would impair a crucial missile detection radar system located on Cape Cod.

In a special congressional report released last week, the U.S. Department of Defense found that wind turbines located within the line of sight of military radar can adversely affect its ability to track aircraft and other aerial objects. The results were based largely on military tests conducted by the U.S. Air Force and United Kingdom Ministry of Defence between 2002 and 2005.

The Pentagon report did not specifically determine whether the Cape Wind project would have such an effect, but it did find errors in an earlier March 2004 Air Force review that suggested the Nantucket Sound project would not pose a threat to the Cape Cod radar operation. The Defense Department said it would be unable to assess the Cape Wind impact until a more comprehensive investigation is performed, and called for the additional studies to begin as soon as possible.

"The analysis that had been performed for the early warning radar at Cape Cod Air Force Station was overly simplified and technically flawed," defense officials wrote in the 62-page report released last Thursday. "A more comprehensive analysis followed by development of appropriate offset criteria for fixed-site missile early warning radars should be performed on an expedited basis."

Congress commissioned the report last year to address the accelerated rate of wind farm projects spreading across the country. Defense Department officials pledged their overall support for wind energy in the report, but expressed concern about specific impacts to national security. The report also mentioned some technological efforts initiated by the Pentagon to mitigate the potential effects of turbines on radar operation.

"The Department of Defense strongly supports the development of renewable energy sources and is a recognized leader in the use of wind energy," the report said. "However, the Department is also mindful of its responsibility to maintain its capabilities to defend the nation."

Additional radar studies will likely now be folded into the ongoing federal environmental review of the Cape Wind project. A spokesman for the Minerals Management Service - the agency within the U.S. Department of Interior with lead regulatory authority over this and other proposed offshore wind farms - said this week that the service is currently reviewing the Defense Department report.

Minerals Management Service officials hoped to make a final permitting decision on Cape Wind sometime next winter, but have said that timeline is subject to change.

The first company to propose an offshore wind farm in the United States, Cape Wind in November 2001 unveiled plans to build 130 wind turbines on 24 square miles of Horseshoe Shoal in Nantucket Sound. Supporters say it would provide roughly three-quarters of the energy needs of the Cape and Islands and serve as a symbolic step toward cleaner energy in this country, while opponents have raised concerns about a wide variety of potential impacts, from navigation issues to migrating bird populations to aesthetics.

Cong. William Delahunt, a Democrat and Cape Wind critic whose legislative district encompasses the Cape and Islands, has called for further studies on the potential radar problems for more than a year. His chief of staff, Mark Forest, praised the Defense Department report yesterday for addressing the issue.

"We had been concerned that these questions were out there, but nobody treated them seriously until now," Mr. Forest said. "Obviously the report identifies a number of concerns that ought to be addressed."

In particular, the report notes the proximity of the proposed Cape Wind project to a unique radar system located in the Cape Cod Air Force Station. One of only three early warning missile systems in the country - the other two are in California and Alaska - the so-called PAVE PAWS radar, according to Mr. Forest, plays a significant role in national defense.

The unique aspect of the early warning system is a phased array antenna technology that covers a much larger range of space than a mechanical radar, which must be physically aimed at an object to track and observe it. The Pentagon found in its report that a wind turbine could affect the PAVE PAWS tracking ability if it appears in any portion of the phased array, while the Air Force in 2004 assumed that it would only have an impact if it was located within sight of the main beam.

Mr. Forest this week also expressed continued concern about potential radar effects of the offshore wind farm on aviation and boat navigation.

The Federal Aviation Administration (FAA) has twice found that the Cape Wind project would pose no hazard to air navigation, but that determination is set to expire in February, giving the FAA another opportunity to weigh in on the matter. The FAA has indicated in correspondence to Congressman Delahunt that, like the Defense Department, it too had second thoughts about its earlier Cape Wind review, and planned to undertake additional studies on the potential effects of the turbines.

As far as sea navigation, the commandant of the U.S. Coast Guard is scheduled to issue a report as early as December specifying terms and conditions necessary to ensure navigational safety near the Nantucket Sound project.

Some wind energy supporters have expressed skepticism about the proliferation of congressionally mandated studies surrounding Cape Wind; both the Coast Guard and Pentagon reports were created by controversial amendments tacked onto military spending bills by powerful senators who oppose the project.

Senate Armed Services Committee chairman John Warner, Republican of Virginia, added the military radar study as a last-minute amendment to the fiscal year 2006 defense authorization bill last year. Senator Warner, who has long family ties on the Cape, also tried unsuccessfully in October 2004 to attach an amendment to a defense spending bill that would have authorized a moratorium on all offshore wind projects in federally controlled waters.

The Pentagon radar report generated a storm of dissent in the midwest this year after the FAA halted work on about a dozen land-based wind farm projects that were within the line of sight of any military radar. The Sierra Club sued the Pentagon in June for failing to complete the report within the mandated time period, and two Democratic Senators from Illinois, Richard (Dick) Durbin and Barack Obama, blocked a Senate vote on a Defense Department nominee in July to force the release of the report.

Cape Wind spokesman Mark Rodgers this week was reserved in his comments about the Pentagon report, and warned against prejudging the results of any additional studies specific to Cape Wind. He said even if Cape Wind was found to have an impact on military radar, the company would work with the Air Force to develop technology to counteract the effects.

Meanwhile, Cape Wind officials this week announced plans to use a newer and larger wind turbine model, which will produce seven per cent more power but at its maximum height will be 440 feet to the tip of the blade, instead of 417 feet. In addition, under new FAA guidelines, the company plans to decrease the number of red aviation lights on the top of turbines from 260 (two per turbine) to 57 strategically located sites.