National Grid returning for round three

Tue, 03/01/2022 - 12:15pm
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Joe Murphy of National Grid joined the Town Council via Zoom on February 16 and reported that the cable reburial project will begin, again, in April. National Grid’s sea2shore cable, which runs from Block Island to the mainland, was not buried to the recommended depth of six feet, and subsequently became exposed near Fred Benson Town Beach. To rebury the cable, a tunnel was dug deep under the ocean floor, conduit was put through the tunnel, and new cable was run through the conduit. The new cable now has to be spliced together with the old, both on land near the beach pavilion, and out in the ocean. The new section of cable will bypass the exposed cable section, which will then be removed.
Orsted, the company that owns the wind farm and the cable that runs from the turbines to Block Island, performed a similar operation for its section of exposed
cable last year.
Murphy described the “significant success” the company had achieved on its last visit in the fall of 2021, clearing the blocked conduit and pulling the new cable
through. The conduit had been placed under the sea floor back in the spring of 2021, but somehow became clogged before the cable was pulled through. National Grid has only been able to work on the project around the busy tourist season, which has caused the project to drag on and on.
Dave Arthur, the Director of Project Management at National Grid, joined the meeting via Zoom to inform the council that the team had spent the winter months
reviewing and reassessing the equipment used for the project. Back in the fall, National Grid had attempted to splice the cable but rough seas made the work
impossible. The company had used an anchor barge, which needs fairly calm conditions of waves less than four feet and winds less than 25 miles per hour. With a sometimes uncooperative Mother Nature, Arthur said National Grid had considered other options for its return this spring.
He said the company considered a jack-barge, but rejected it as lacking the desired mobility. He also said a jack-barge has the same wave height restrictions as the anchor barge.
A dynamic positioning vessel was also considered, but Arthur told the council that those types of vessels still have difficulty in high winds above 25 miles per hour.
Orsted used the European offshore support vessel Global Symphony to splice its cable, but Arthur said that particular vessel needed 40 feet of depth to operate.
National Grid’s cable splice location is only around 22 feet deep, according to Arthur. He said that after considering these other options, it was decided that the anchor barge would be used again this spring, with hopes for better weather. The anchor barge is attached by chains or cables to four moorings anchored to the ocean floor. The moorings form a rough square, with the barge in the middle. Lengthening or shortening the cables allows the barge to maneuver within the work area while still being anchored to the moorings. National Grid needs this mobility for splicing the
sea2shore cable.
Arthur said the team has been examining historical weather patterns, looking for a window of five or six days of fair weather in which to operate. According to Arthur, seven out of the past ten years have had at least one window of clear weather during the month of April, with wave heights less than four feet and winds less than 25 miles per hour. He said the frequency and duration of these windows increase in May and June, historically.

The work requires a power outage to the island during the multi-day splicing process, during which time the island will operate on the diesel generators at Block
Island Power Company. Arthur said he had a “good degree of confidence” that the work would be completed by May 25 at the latest. He said the work on land would be concentrated around the manhole covers in the north parking lot of the Town Beach.
The parking lots have been a source of angst for many islanders, as the south lot has developed a flooding problem since Orsted used it for its part of the work.
Orsted is planning to repair the drainage issue this spring.
Council Member Martha Ball asked National Grid about the north lot, saying that it was not returned to its previous condition as it has gotten “smaller and smaller.” Ball said the berm between the parking lot and Corn Neck Road is “bigger than it’s ever been.”
Murphy responded that National Grid had worked with the town's previous Facilities Manager Sam Bird to make sure the posts were put back in place and
the berm was the same size. National Grid had to remove some of the berm to accommodate machinery, and is required to return the parking lot to its previous state.
Ball called the current restoration of the berm a “huge tactical mistake that should be fixed.”
Council Member Keith Stover said that in order to feel comfortable granting National Grid another easement to work in the parking lot this spring, he needed to
hear from the town experts, such as Town Manager Maryanne Crawford, Facilities Manager Tom Risom, and Director of Public Works Matt Moynihan. He said he
wanted them “to tell us they are comfortable with the plans for the parking lots.”
Second Warden Sven Risom said he hoped the snow fencing installed by National Grid on the berm at the north parking lot was “not reflective of the quality” of work that the town should expect. The fencing has been falling down, seemingly since it was put up.
Arthur said he expects the equipment to begin arriving on-island on March 24.