PROVIDENCE – A Senate commission wants to know who is to blame and who is going to pay to bury the exposed electric cables from the Block Island Wind Farm.
The Coastal Resources Management Council (CRMC) said its geologist recommended before construction of the offshore wind facility that Deepwater Wind, now owned by Denmark-based Ørsted, bury the two cables 6-8 feet deep using a process known as horizontal directional drilling.
Deepwater Wind, however, relied on an independent engineering report that concluded the 12-inch-diameter cable could be buried at a depth of 2-4 feet using a devise called a jet plow.
According to CRMC executive director Grover Fugate, CRMC’s governing board relied on the independent report to approve the more shallow depth using the jet plow process.
Fugate explained at a recent commission hearing that the jet plow was preferred because it uses a high-pressure spray of water to quickly create a trench and bury the cable. That worked for the sandy seafloor further offshore, but when the jet plow encountered the boulders and cobble near Block Island’s Crescent Beach it simply rose over the impediments and buried the cables at a shallow depth.
The 34,500-volt power line from the five-turbine Block Island Wind Farm reaches shore at Fred Benson Town Beach and leaves the island for Narragansett at Crescent Beach to the north. Keeping portions of the cables buried at Crescent Beach has been a struggle for the past four years.
The independent engineers didn’t do their homework on the geology of the beach area, according to Fugate.
“They did not know that was there until they went to bury the cable,” he said.
Soon after the turbines went online in 2016 the cables became exposed about 200 feet from the shore of Crescent Beach. It wasn’t until 2018 that New Shoreham and CRMC called for repairs.
By contrast, directional drilling was used to create the preferred 8-foot depth into bedrock at the cable landing in Narragansett.
In 2017, CRMC allowed the temporary use of a plastic casing for the exposed transmission lines. The agency, however, denied the use of concrete mats because of concern that they would interfere with swimming and other beach activities.
A no-anchor zone, 150 feet by 450 feet long, was established offshore. National Grid said the area was safe for swimming and other water-related activities.
To fix the problem, a half-mile section of the cable off Crescent Beach will have to be spliced and replaced, so it can be buried properly. The work will involve a complicated drilling process from a beach parking lot and run under the beach to an offshore worksite, according to National Grid.
At a Feb. 4 hearing, the Special Senate Tack Force on Fisheries wanted assurances that ratepayers will not pay for the cost for that work.
That decision, however, is before the Rhode Island Public Utilities Commission (PUC), at least for the work being done on behalf of National Grid, which owns the cable that runs from Block Island to Narragansett. Ørsted said it will pay for work performed on its cable, which connects the five offshore wind turbines to Block Island.
Fugate said fines haven’t been issued to Ørsted or National Grid because of concerns that the cost would be passed on to ratepayers.
Several months ago, CRMC turned over all of its documents related to the issue to the PUC. It’s not known yet when the PUC is expected to rule on the cost issue.
“I just hope that going forward these companies who are going to be building (wind) farms understand what happened at Block Island and they don’t make the same mistake,” Sen. Dennis Algiere, R-Charlestown, said at the recent hearing.
Fugate said CRMC is negotiating with offshore wind developers to write new regulations for burying cables. He noted that the companies objected to a first draft of regulations written by CRMC.
The reburial work for the Bock Island cables is expected to start this October and finish by spring 2021. At certain times during construction, electricity will stop running from the turbines and the Island will be powered by diesel generators.
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