April 15, 2013
Rhode Island

Deepwater has offered to upgrade nav device at B.I. Airport; Residents debate the wind farm’s impact

In order to mitigate a potential impact that the proposed wind turbines may have on a pilot navigation device located at Block Island Airport, Deepwater Wind has offered to pay for an upgrade to the device.

This fact was pointed out by Deepwater Wind Project Manager Bryan Wilson as having been included in the language of a Feb. 1 memo issued by the Federal Aviation Administration about decommissioning the navigation unit, also known as Sandy Point VOR.

The FAA memorandum stated that it has recommended a study to decommission the VOR because the proposed Deepwater Wind turbines, once built, would “have a significant impact to the related signal” of the device. There are five turbines proposed for the Block Island Wind Farm.

The memorandum stated, as Wilson pointed out, that “two construction options were proposed to the wind farm proponent [Deepwater]: a reduction in height of the wind turbines which was rejected; and dopplerization of the existing VOR facility which was accepted.”

Dopplerization would involve upgrading the VORs radio signal to a specialized Doppler radar technology, which is what Deepwater has offered to pay for.

“If the FAA determines that it will help the signal, if the FAA says to dopplerize it, then we’ll do it,” said Wilson.

Outside of the issue of the Deepwater Wind’s impact on the signal, the FAA has also clearly stated that it plans on reducing the number of VORs across the country anyway, according to a federal notice issued last year.

That notice said that the national network of VORs costs “nearly $110 million per year to operate and maintain and recapitalization costs are estimated at over $1 billion. The FAA can no longer afford to support an entire network of legacy VORs,” said the notice.

Although the Feb. 1 memorandum from the FAA states that the services of the Sandy Point VOR “will be evaluated and retained, if necessary” it also states that the same VOR is “not listed for retention in the Minimum Operational Network of VORs.”

Private pilot Henry duPont, also a wind energy project consultant for over 30 years, said that the turbines may not significantly affect the VOR’s signal.

“There’s no evidence there will be interference from the proposed wind farm,” said duPont. “Plus, the wind farm is years away from being completed. To use it as a reason [to decommission the VOR] just doesn’t make sense.”

However, island resident Mike Delia, also a director of engine sales company B.I. Aero, said the signal would be affected.

“[W]ind turbines installed in clusters known as wind farms have significant effects on VOR performance even when these wind farms are located several miles away from the VOR,” Delia said in a statement to the B.I. Times.

Henry duPont and his former colleague Michael Wichmann, who is currently a Technical Manager for the Danish National Police, performed calculations to determine the impact of Deepwater’s proposed wind farm to the VOR.

“Most land-based VORs have much more reflection risk from buildings and other objects nearby,” said Wichmann in an email. “The amount of interfering reflections on the dominating flight paths would be very little because the turbines, if they were not in shadow, would not get much signal to reflect. The direct signal from the VOR would be much stronger and absolutely dominating.”

Wind turbine guidelines in Canada incorporate the impact of wind farms on navigational devices. According to 2010 guidelines by the Radio Advisory Board of Canada and the Canadian Wind Energy Association, “turbines can cause deflections in the bearing measured by the airborne receiver with the severity depending on the turbines proximity, elevation and size. Clustered together, each turbine in a wind farm can have a cumulative effect.”

Deepwater Wind has proposed to build a 30-megawatt, five-turbine wind farm three miles off Block Island’s southeast coast.