National Grid Pauses Effort to Rebury Block Island Wind Farm Cable
May 4, 2021
Unexpected construction complications are delaying the completion of the reburial of the undersea Block Island Wind Farm cable from New Shoreham, R.I., to the mainland, according to National Grid. The multinational utility said it’s pausing construction for the summer tourism season, will conduct a detailed assessment, and resume work in the fall.
The power line from the five-turbine offshore wind facility reaches shore at Fred Benson Town Beach and leaves New Shoreham for Narragansett at Crescent Beach to the north. But keeping portions of the cable buried at Crescent Beach has been a struggle.
National Grid, which owns the high-voltage power line from Block Island to Narragansett, expects to pay about $30 million for its share of the reconstruction. The state’s primary electric utility is likely to recover the expense through an undetermined surcharge on ratepayers’ bills.
The cable was to be reburied this spring through a new underwater conduit pipe that was built this past winter. As final preparations for the installation were being completed, unexpected material causing partial obstructions was discovered within the pipe, according to National Grid. The London-based corporation worked with the pipe installer and cable installer to remove the material, but National Grid determined that a more detailed assessment is needed to understand the source of the material and to ensure a successful cable installation.
“This was an extremely difficult decision, but we recognize the importance of the summer tourism season for the Block Island community,” Terry Sobolewski, president of National Grid Rhode Island, said. “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. We’re disappointed we won’t be able to get the cable completed by Memorial Day as we planned, but this is a very complex construction project. We’d rather get it right in the fall than try to rush completion of it now.”
The transmission cables were originally installed in 2016, after National Grid and Deepwater Wind, now Ørsted, were given a break by Rhode Island’s Coastal Resources Management Council (CRMC) when the agency granted the use of a cost-saving method for burying the power cables. Approval of the lower-cost jet plow to bury the cable at Crescent Beach was granted against the advice of CRMC staff and former executive director Grover Fugate.
CRMC’s governing board gave the process the green light and even allowed the cable to be buried at a depth of 4 feet; CRMC staff recommended a depth of 8-10 feet. Within months of completion, portions of the cable were exposed close to the Block Island shore.
National Grid and Ørsted were eventually issued enforcement orders by CRMC to fix the problem.
Last fall and winter, National Grid and Ørsted conducted a horizontal directional drill and installed a conduit for the new length of onshore cable, including a new access pit. The unexpected material in National Grid’s conduit was discovered during the past few weeks, just prior to the cable being pulled through the conduit.
With the project delayed, National Grid contractors will begin cleaning up the areas where construction has occurred to date, including parking lots around Town Beach. Crews and barges will also be removed by Memorial Day weekend, according to National Grid.
Block Island and Rhode Island have continued to receive electricity from the wind facility during construction.
National Grid will seek to secure extensions on permits to allow work in the fall.
Ørsted said it’s nearly finished with its work to replace the transmission line from the turbines to Block Island. Spokesperson Meaghan Wims said “we will be wrapped up in time for the summer season, as planned.”
“The new cable connecting the wind farm with Block Island has been replaced and spliced with sections of the existing cable,” she said. “All that remains in our scope is removing sections of the previous cable that are no longer in use.”