America’s first offshore wind farm, Block Island, faces a spell offline later this year to resolve power cabling issues that a senior Rhode Island official claimed are down to a wrong choice made during the project’s build phase.
Work will need to be done sometime from the autumn to lengthen and rebury part of two cables serving the Block Island wind farm off the state’s coast, after they became exposed in the approach to a popular swimming beach, a hearing of the Rhode Island Senate’s special task force on fisheries was told.
Senators sitting on the taskforce demanded that the state’s ratepayers are not left liable for any costs involved – and that the US’s emerging offshore wind sector learns from “mistakes” made.
The 30MW Block Island project, still the only US offshore wind farm in operation, made history when it was brought into service in 2016 by Deepwater Wind, which was subsequently acquired by global offshore wind giant Orsted, using 6MW Haliade turbines from General Electric.
But Grover Fugate, director of Rhode Island's Coastal Resources Management Council, said up to half a mile (800 metres) of cabling will have to have new sections spliced in and be reburied in the approach to Crescent Beach, with two cables affected – one running from Block Island and owned by Orsted and a second export line owned by power offtaker National Grid.
Fugate told the state senate hearing that the cabling concerned ended up not being buried deep enough during the wind farm’s construction phase, and it has since become exposed by the elements. Fugate claimed the project team rejected advice given by officials to use directional drilling during cable burial, and instead used a jet plow.
The problem arose, claimed Fugate, when an unexpected concentration of boulders and pebbles led to the cable achieving burial depth of less than 2ft, rather than the 4-8ft specified by state officials during the permitting process.
“If they’d done as we originally asked and directionally drilled it, we wouldn’t be in this situation,” Fugate told the hearing.
“They ran into boulders and cobbles. They had not done enough geotech work to pick those areas up,” he claimed.
Directional drilling will be used in the reburial process, said Fugate.
Senators demanded that state ratepayers aren’t left bearing any costs, and that the rest of the fast-emerging US offshore wind sector takes note of any lessons that need to be learned.
Taskforce member Dennis Algiere said: “I just hope going forward the companies that will be building these [wind] farms understand what’s been going on so they don’t make the same mistake.”
Fugate replied: “There have been learnings on both sides.”
Orsted said in a statement sent to Recharge: “We expect the work to begin in fall 2020, and be completed by Memorial Day 2021. We are working together with National Grid and Block Island Power Company to limit the amount of time that the Block Island Wind Farm will need to be offline to accommodate this work.
“We’re still finalising the plan for the repair, but we expect the wind farm will only need to be offline during the splicing and testing of the cables.”
Note: Update adds Orsted quotes