Problems prompt National Grid to suspend work reburying Block Island wind farm cable
- May 4, 2021 2:12 pm GMTMay 4, 2021 7:49 pm GMT
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PROVIDENCE – National Grid, after encountering unforeseen problems, has suspended work on Block Island to replace part of an underwater cable that delivers electricity from the nation’s first offshore wind farm to the mainland power grid.
The project was set to be completed in time for the summer tourism season starting Memorial Day, but will instead go on hiatus until the fall so the company can conduct a full assessment of the cause of obstructions in a newly installed conduit pipe at Crescent Beach.
“We need to assess what is causing these obstructions, how best to get the pipe cleared, and ultimately complete the installation with confidence in the fall,” Terry Sobolewski, president of National Grid Rhode Island, said in a statement. “We’d rather get it right in the fall than try to rush completion of it now.”
It’s unclear how the difficulties will affect the $31-million cost of the replacement project and whether Rhode Island electric ratepayers will be on the hook if there’s an increase.
The surcharge that National Grid customers already pay for the cable has been the source of recent controversy. The chairman of the state Public Utilities Commission has excoriated the company for a fee that he has described as wildly inflated and unjustified. National Grid is in the midst of determining a new rate structure.
The delay announced Tuesday is just the latest complication for the Block Island Wind Farm’s transmission cable, which has been experiencing troubles almost from the time it was installed in 2016.
While there have been no problems with the cable’s landing point on the mainland, in Narragansett, where a horizontal directional drill was used to bury it in a deep trench, it’s been a different story on Block Island, where a jet plow was employed at lower cost.
Because the shoreline off the island proved to be rockier than expected, the cable was buried at shallower depths than planned. Waves soon started uncovering portions of it and the problem grew worse over time.
Last year, in response to complaints from Block Island beachgoers and concerns from state coastal regulators, both wind farm owner Ørsted and National Grid decided to rebury the affected portions.
Over the fall and winter, the companies used a horizontal directional drill to install two conduit pipes deep under the seabed.
The pipe for Ørsted’s portion of the cable, which runs from the five-turbine wind farm to an electrical substation on the island, experienced no issues. A new length of cable was strung through it and spliced into the rest of the line.
“Ørsted is nearly finished with our work to replace the Block Island Wind Farm transmission cable, and we will be wrapped up in time for the summer season, as planned,” the company said in an email. “All that remains in our scope is removing sections of the previous cable that are no longer in use. The Block Island Wind Farm continues to operate as normal.”
But in recent weeks, as National Grid started getting ready to install the new stretch of cable through its pipe, workers discovered unexpected obstructions.
The company is working with contractors to clear the blockages, but has decided to hold off on doing more until it can assess the cause, which appears to be sand, mud and other material from the ocean bed. It says it’s told the Town of New Shoreham and the Block Island Power Company of the issues.
Workers will start clearing equipment out of the parking lot near the beach. Barges will also be moved out before Memorial Day.
This article originally appeared on The Providence Journal: Problems prompt National Grid to suspend work reburying Block Island wind farm cable
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