Updated July 21
One of four undersea electrical distribution cables that serve Martha’s Vineyard failed on Friday, July 16, causing a spate of brownouts across the Island. In a release limited to Island officials, Eversource stated repairs to the cable will be done “over the coming weeks.”
A utility official also wrote that the company is sending generators to the Vineyard.
“To help ensure reliability for residents, businesses, and visitors while we make the necessary repairs to the submarine cable, we are taking the extra precaution of bringing 15 extra backup generators to Martha’s Vineyard,” Eversource official Ronit Goldstein wrote. “These extra generators will be able to provide 28 MW of backup generation to the Island if needed, and will be strategically placed at the Tisbury landfill, near our Vineyard Haven substation, and near the Oak Bluffs DPW facility.”
Eversource hasn’t offered any idea about what caused the cable failure, and stated it is “assessing.” Eversource didn’t return repeated calls by The Times following the brownout, and responded to detailed email questions about the cable failure with a statement that didn’t encompass many of the questions posed.
In an email to The Times, Eversource spokesman William Hinkle stated that 2,250 people lost power in the brownout, but that Eversource restored their power in less than five minutes.
“We are currently assessing the location of the fault,” Hinkle wrote, “which could be along the cable or at an existing splice. There are many moving pieces as we continue to work toward making the necessary repairs as quickly as safely possible, which we believe could be complete in eight to 10 weeks, weather permitting. Next steps include bringing in a diver to further inspect the cable and pinpoint the fault location, and eventually a barge to pull the cable up to make repairs. The logistics for both of these are still being finalized. “
The Massachusetts Emergency Management Agency (MEMA) was unable to provide details about the cable failure, and hasn’t received requests from Vineyard officials for assistance, according to MEMA spokesman Christopher Besse. The U.S. Coast Guard’s District 1 isn’t involved in matters related to the cable, and could provide no information on it, according to Petty Officer Ryan Noel.
The cable in question makes landfall on West Chop, Tisbury Fire Chief Greg Leland told The Times. However, Chief Leland said he couldn’t comment further about the cable.
Cables 91, 97, and 75 land in West Chop, while cable No. 99 lands on East Chop. According to a slideshow presentation created by the Martha’s Vineyard Commission’s climate action task force energy working group, three of the four cables are “near or beyond their design life.” Each cable transmits a 23-kilovolt load, according to an MVC slide.
Martha’s Vineyard Commission member Ben Robinson tweeted concern about the cables in response to The Times’ initial story.
“The age of the cables servicing the Vineyard has been a topic of concern at the MVC climate action task force, and further underscores the need to stand up a strong grid to meet the electrification needs of the Vineyard as we move away from fossil fuels,” Robinson wrote.
In 2019 Eversource was planning to build a battery facility in Oak Bluffs to offset the need for backup generators, and for insurance against failure of any of the submarine cables to the Vineyard. Despite reaching an agreement with Oak Bluffs regarding the facility, several officials have told The Times Eversource has abandoned the idea in favor of sinking another undersea cable. Oak Bluffs Fire Chief Nelson Wirtz said it was his understanding that it was an economic decision.
“The capacity of that facility wasn’t going to be worth the expenditure of money,” Wirtz said.
Wirtz said the downed cable was concerning in light of the seasonal electrical draw underway.
“It’s a problem because of the numbers of people here, and the high demand,” he said.
In the past, the Vineyard’s submarine cables have been damaged by an anchoring accident. In 1980, according to court records, the Steamship Authority ferry Naushon had a boiler emergency, and dropped anchor and wound up dragging its 3,450-pound anchor into a cable crossing. The anchor damaged the cables, and cut power to the Vineyard.
Reporter Brian Dowd contributed to this story.