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 Block Island Wind Farm power cables at a New Shoreham beach. Both companies now likely regret that decision.
National Grid, which owns the high-voltage power line from Block Island to Narragansett, expects to pay $30 million for its share of the reconstruction, which will require horizontal directional drilling. The state’s primary electric utility will recover the expense through an undetermined surcharge on ratepayers’ bills.
“While exact bill impacts won’t be available for some time, we don’t anticipate major fluctuations to those charges with these needed repairs,” National Grid spokesperson Ted Kresse said.
The power line from the five-turbine Block Island Wind Farm 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.
Ørsted, owner of the 12-inch transmission cable from the offshore wind facility to Block Island, won’t say how much it expects to spend on the project, but the Denmark-based energy developer intends to make good on its portion of the cost.
“Ørsted will pay for the repairs to our Block Island Wind Farm cable, as our power contract does not provide for passing any such costs on to ratepayers,” company spokesperson Meaghan Wims said. “We are not disclosing our costs to make those repairs.”
Approval of the lower-cost jet plow to bury the cable at Crescent Beach was granted against the advice of CRMC’s in-house staff and former executive director Grover Fugate. CRMC’s governing board, however, 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 in 2016, portions of the cable were exposed close to the Block Island shore.
Ørsted and National Grid were issued enforcement orders by CRMC to fix the problem. Over the course of nearly two years, the companies tried several fixes and proposed others, but they eventually returned to CRMC’s original recommendation of using horizontal directional drilling to bore deeper into the rocky shoreline, a process that was used where the cables make landfall in Narragansett.
The cost of horizontal drilling will likely be higher than the original cost, because the 34,500-volt power lines entering and leaving the island will need to be spliced and lengthened – up to a half-mile – to be buried into a deeper trench.
At a Special Senate Tack Force on Fisheries hearing in February, Fugate explained that the jet plow’s high-pressure water jet was effective at burying the cables the mandated 6-8 feet beneath the sandy seafloor offshore. But the device struggled when it reached the rocky coast, riding up and over boulders.
Nearshore, Fugate said, the cables were buried in 2-3 feet of sand or less.
“It’s a mixture of sand, boulders, cobbles, those types of things and not really conducive to the type of technology they ended up using, which is called a jet plow,” he said.
Fugate noted that the drilling contractor was supposed to notify CRMC when it failed to reach the required depth but failed to do so.
“Within a matter of months (the cable) became exposed on the beach,” Fugate said.
Later, swimmers at popular Crescent Beach discovered the exposed cables in just a few feet of water.
The companies cordoned off the area with buoys and signs to create a no-anchor zone. Engineers offered several fixes, but CRMC rejected National Grid’s plan to cover the exposed cable with concrete mats. In 2017, CRMC approved encasing the cables with a plastic shell, but not as a permanent remedy.
National Grid and Ørsted finally settled on horizontal directional drilling.
“Because, after all this surveying work the companies did, they determined like we asked them several years ago that the best way to bury these cables was by horizontal directional drilling and that is what they are going to do,” CRMC’s interim executive director Jeffrey Willis said when the plan was finalized by the CRMC board at its Sept. 8 meeting.
The drilling is expected to begin in October and finish over the winter, although the order allows the work to continue until May 31.
“The sea2shore cable and Block Island Wind Farm was a unique, complex, first-of-its-kind project for the state of Rhode Island,” Kresse said. “With any complex project, which can often have unanticipated challenges, we plan for potential contingencies to help protect customers against significant bill impacts.”
The drilling operation is done offshore and bores horizontally at a depth of close to 100 feet under the beach and under Corn Neck Road and surfaces at an electrical substation owned by the Block Island Power Co. The previous installation disturbed more than 2 acres of beach and parking areas. The re-do project will require approvals from the town of New Shoreham, the Rhode Island Department of Environmental Management (DEM), the Coast Guard, and the Army Corps of Engineers.
“We feel very confident that this time around that horizontal directional drilling by the two companies will resolve the burial-depth issue of those cables,” Willis said.
Other offshore wind news
CRMC is assisting Vineyard Wind with a review of its draft consistency certification for an application that will be submitted for the second phase of the wind facility.
CRMC’s cable corridor working group continues work on cable construction regulations for Revolution Wind, a project shared by Ørsted and Eversource.
The CRMC council expects to vote on state approvals for South Fork Wind Farm by the end of January 2021.
The Sunrise and Bay State offshore wind facilities, projects shared by Ørsted and Eversource, are also preparing to submit consistency applications to CRMC.
Caitlin Chaffee has left CRMC as a coastal policy analyst for the position of program manager with the Narragansett Bay National Estuarine Research Reserve, a program run through DEM.
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