As more and more wind turbines are placed in navigable waters, questions have arisen about their negative effects—everything from bird strikes to electronic interference. In this article, originally published in the MV Times of Martha's Vineyard, Massachusetts, the author has reached out to an electronics expert well known to PassageMaker readers and TrawlerFest attendees. Thanks, MV Times, for permission to reprint.

Furuno, a global leader in marine radar systems, does not consider offshore wind turbines an interference threat to maritime radar navigation, according to its U.S. and European representatives. Furuno radar domes are a common sight atop Massachusetts motor yachts and commercial fishing vessels. Furuno also outfits the U.S. Coast Guard and U.S. Navy with radar systems, according to Eric Kunz, senior product manager for Furuno USA, who said Furuno radar is “on almost every Coast Guard vessel.”

Eric Kunz

Eric Kunz

In telephone and email conversation with The Times, Kunz said his company has not encountered radar interference from wind turbines.

“While hypothetically multi-path and other issues could theoretically occur,” Kunz emailed, “in practice and application, our signal processing is sophisticated enough that there have been no issues that anyone in our organization is aware of with respect to turbine blade interference on Furuno marine radar systems.”

Kunz later said the issue of marine radar interference with wind turbines has drummed up “hype” but he’s not seen credible evidence it is real.

“A bunch of hooey,” he said. “I don’t think there’s any serious issues with marine radar.”

Asked specifically if radar is reflected off turbine blades or reflected from one blade to another, or if other issues could arise due to sea topography, Kunz emailed no.

“Nothing detectable to the radar operators,” he wrote. “Furuno and the marine radar industry have dealt with these kinds of radar interference issues for decades. The wind turbines present nothing new or unusual in terms of interpretation or interference. There was a lot of hype, but no strange performance behavior has been observed. Furuno arguably manufactures more marine radar systems and has won more industry awards than any two or three other marine radar manufacturers combined. If there were issues, we would be well aware of them.”

Further pressed on interference potential, Kunz, an engineer, reached out to his European colleagues on the subject, and found they too did not believe it was an issue for marine radar.

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“Hi Eric, we have fitted lots of boats which service the wind farms; there is no interference from them on our x band radars, NXT or MAG,” Daniel Conway, Furuno U.K. sales manager, wrote in a social media message to Kunz.

X-band refers to radar operating at frequencies between 8.0 and 12.0 gigahertz. “The majority of marine radars operate on X-band,” the Furuno USA website states. ”X-band is widely used because of the ability to utilize smaller antennas that fit on most boats and to provide better target resolution.”

“All that I have heard is that wind farms make long-range Air Force radars to have blind sectors, never heard anything related to marine radars,” Jarkko Pakkanen, product sales manager for Furuno Finland, wrote in a similar social media message.

“[W]e got feedback that it is having on weather radar and aircraft radar. For marine radar I fully agree to Dan,” Rudiger Engel, senior product manager for Furuno Germany, wrote in a similar message.

Block Island wind farm radar returns.

Block Island wind farm radar returns.

“The wind farms present no strange radar interference issues for marine radar systems,” Kunz emailed. “Of course, we don’t have as much experience with other marine radar systems, but I highly doubt that their products have issues of which we are not aware. Marine radars show the wind farms in all cases as normal targets.”

Kunz shared a photograph from a vessel close to a wind farm off the U.K. coast. The image shows the wind turbines out the vessel windows as well as on the radar screens in the wheelhouse. The images suggest the radar screen is clear of problems. Kunz also provided a radar image of the Block Island Wind Farm which similarly suggests no problems, interference or otherwise.

Capt. Dave Aripotch, a trawler captain out of Montauk, Long Island, shared a photograph he and his wife, Bonnie Brady, head of Long Island Commercial Fishing Association, said shows a marine radar screen taken in the vicinity of the Block Island Wind Farm that allegedly depicts interference or scattering. Another image provided by Capt. Dave Tuma of Montauk allegedly showed radar anomalies too.

Eric Hansen, a Responsible Offshore Development Alliance (RODA) board member, sent images of a radar screen taken from a vessel near wind turbines off the U.K. coast. Hansen said the screen evidenced problematic readings. When emailed these images, Kunz did not respond to them.

Kunz did say thousands of vessels pass by European wind farms, and to the best of his knowledge, these vessels haven’t encountered trouble relative to the issue.

Kunz later wrote that while he had seen the Hansen image, it showed the screen of another radar maker (Garmin), and he is only able to comment on Furuno products, and wasn’t intentionally ignoring the email sent about the image.

This image depicts radar returns from a U.K wind farm and was provided by Eric Hansen, a member of an ocean advocacy group.

This image depicts radar returns from a U.K wind farm and was provided by Eric Hansen, a member of an ocean advocacy group.

Carly Hysell, a spokesperson for Garmin, did not immediately return a message seeking comment. Garmin previously told The Times the company would comment on radar interference, but has not followed through despite repeated inquiries.

Kunz wrote that certain large objects could create reflectivity. “Any strong radar-reflective target has the possibility of showing multi-path interference on the radar display,” he wrote. “The same phenomena can happen with nearby land or structure or large vessels, and is not just a function of a windmill or rotating windmill blades.”

Concerning Capt. Tuma’s image, Kunz admitted it looked like reflections showed.

“I see what appears to be multi-path reflections in the one image on the Furuno radar display,” he wrote. “This could be a function of how the radar is mounted or the type of vessel on which the radar is mounted. For example, does the vessel have large flat sides that could provide a strong secondary reflection? It could also be a function of the operator’s radar proficiency. Note that strong multi-path reflections could also be a function of how the vessel is oriented to the proximity and the reflective properties of any targets in view. Any marine radar signal can be reflected and cause multi-path impacts.”

The U.S. Coast Guard is still keeping cards close to its chest on the evaluation of potential radar risks from Vineyard Wind 1, or any other project stemming from the leased areas off Martha’s Vineyard and Nantucket.

“Radar impacts are a function of numerous issues, including turbine height and proximity to nearby towers, weather, vessel radar type (and quality), and operator radar proficiency,” Petty Officer Nicole Groll emailed. “Coast Guard has in the past and may on future wind projects recommend a permit condition to include that the developer conduct analysis on radar — before construction and after operation.”

Kunz later emailed that he agreed with Groll’s statement.

Vineyard Wind spokesman Brendan Moss had no update to share regarding Vineyard Wind’s radar survey, however he did offer comment on radar relative to a letter Vineyard Wind CEO Lars Thaaning Pedersen and executives from Equinor, Eversource, Orsted, and Mayflower Wind sent the Coast Guard, along with a proposal for turbine spacing.

“A study of radar will be conducted on the final configuration of any one project per anticipated USCG terms and conditions,” he emailed. “We will await the Coast Guard’s view of our proposal for the overall layout, which we expect will consider radar as well as search/rescue. Meanwhile we can say wider, uniform spacing is something USCG has previously indicated would be preferred.”

Wind turbines in service off Block Island, which is off Long Island, New York, but part of Rhode Island.

Wind turbines in service off Block Island, which is off Long Island, New York, but part of Rhode Island.

Kunz said he expects the Block Island turbines and other offshore turbines in the area will be mounted with AIS (Automatic Identification System) beacons, and between those, marine radar, and GPS systems, ships should have no difficulty navigating near or through wind turbines. He also said he believes wind farms in the lease area under development will be off-limits to fishing, but that they will nonetheless attract fish. In light of that, he said he expects fishing on the periphery of the wind farms will be bountiful.

In a follow-up email to The Times, Moss made it clear Vineyard Wind’s stance on fishing within the lease area diverged from the opinion expressed by Kunz. “Vineyard Wind has always said fishing would continue to be allowed in the lease area,” he wrote.

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