Teams deployed for cable installation
The construction of the nation’s first offshore wind farm, and its 20-mile long cable transmission system, is becoming a reality.
That was the feeling of National Grid officials at a meeting the company hosted at Town Hall on Monday, Feb. 22, when they provided the town of New Shoreham with a project status update on the cable installation process. National Grid is the company responsible for constructing and operating the $107 million cable transmission system associated with the 30-megawatt Deepwater Wind Block Island Wind Farm pilot project.
In attendance at the meeting were several National Grid representatives, as well as a number of contractors on the project. New Shoreham town officials who attended included First Warden Ken Lacoste, Second Warden Norris Pike and Town Manager Nancy Dodge, and several department heads. Members of the Electric Utilities Task Group (EUTG) in attendance were Everett Shorey and Bill Penn.
“We’ve talked about this project for a while, and now we’re going to start impacting the island. We’re almost ready to put shovels in the ground,” said Kathryn Cox-Arslan, National Grid liaison to New Shoreham and the Block Island Power Company (BIPCo). “There’s going to be a lot of activity (on the island) over the next few months. So we’re here to answer any questions that you have.”
Cox-Arslan said that the major components of construction on Block Island would include “prep work on the beach, the (upcoming) drilling effort on the beach, the underground cable (installation) from the beach to the (National Grid-owned) substation located at the BIPCo property (on Ocean Avenue), and the construction of that substation.”
“The National Grid substation installation is a major piece of work,” said Cox-Arslan. “That work will be occurring through the summer and into the fall, so that we can energize the underground cable.”
Cox-Arslan said that the substation would require delivery of two sizeable pieces of equipment, a transformer and the control building, to the BIPCo property. National Grid is trying to determine the mode of delivery to the island for the equipment.
“Kathryn, when will the plans for the substation be delivered to our Building Inspector?” asked Town Manager Nancy Dodge, referencing the need for Building Official Marc Tillson to approve and permit the project before National Grid can commence with construction.
National Grid Project Manager George Maximovich said the plans weren’t available yet, and that the utility company was in the process of drafting the design schematic for the substation.
“We want to start mobilization for the substation work as soon as possible,” said Cox-Arslan. So, drafting of the substation plan is “a major milestone that should be happening in the next couple of weeks, I assume…”
“Hopefully, a week,” said Maximovich.
Tillson asked National Grid if they would be doing additional soil sample tests “during excavation” to ensure that the soil is “contaminant free” at the proposed BIPCo substation work site. “I know you have all of your DEM (Department of Environmental Management) permits,” he said.
“Definitely,” said Maximovich. “We would like to make sure that we are in a clear area.”
According to Cox-Arslan, the schedule for National Grid’s cable installation activity on Block Island involves “mobilization and materials delivery” from February through the end of March. The site prep work for National Grid’s substation on the BIPCo property will begin after Feb. 22 and run through the fall.
Underground cable installation activity will run through May 30. Cofferdam construction is expected to begin Friday, Feb. 27 and last through March 30. The overhead cable installation will take place between March 1 to May 23. There will be five manholes and two handholes re-installed along the route as part of the project.
“We will begin land cable survey and test pit work along the route,” said Cox-Arslan, “and then, of course, begin the cofferdam and HDD (horizontal directional drilling) work on Crescent Beach. So, those are the major activities that will be occurring imminently.”
Dodge asked Cox-Arslan if a new CRMC (Coastal Resources Management Council) directive requiring National Grid to “hoist equipment” over the dunes would impact safe passage by beach-goers. “Our understanding was that when we agreed to the easement, that there would be (safe) pedestrian access up through the dunes at the beach,” said Dodge.
“Our understanding is that there is pedestrian access,” said Cox-Arslan, who noted that National Grid would review the matter.
The National Grid sea2shore cable, as it’s being called, will be installed at Scarborough Beach in Narragansett and run through 20-miles of state and Federal waters until it comes ashore at the Fred Benson Town Beach a few hundred yards north of the beach pavilion. Cox noted that the “submarine cable installation from Scarborough beach” to the Town Beach is scheduled for April through May.
National Grid engineer Dave Campilii told The Block Island Times that the ocean-bound cable installation process will take approximately one month’s time from shoreline to shoreline. Campilii said the six-mile long Deepwater Wind cable, which will be routed from the Town Beach to the wind farm site after installation of National Grid's cable, would take about the same amount of time to be installed.
The process on the Deepwater Wind portion of the project will require divers and submersible vehicles to connect the transmission cable to each of the five steel wind turbine foundations.
“Since some of the plans we have are dated 2012, in terms of the changes in the (topography of the) beach, are you up to date on the depth that that cable needs to be?” asked Dodge.
“Yes, our plans are still showing us being at least 10-feet deep. So that has not changed,” said Campilii. “We may have had some alignment modifications, but we are still holding to that 10-foot burial depth.”
Lacoste asked National Grid what the equipment associated with "the cofferdams was going to look like."
"There will be two cofferdams on the beach," said Campilii. "They're going to be about 50-feet long, and 21-feet wide. It's basically going to be driven steel that will stick out a bit in the sand. They will stay in place until the submarine cable arrives. Then the cofferdams get pulled out."
"Will there be some kind of warning light on it at night?" asked Tillson.
"It's going to be in the surf zone between the high and low water mark," said Campilii. "We'll figure out something" to make it visible.
"Is there any estimate regarding the level of noise on the beach area?" asked Dodge.
"We do have a noise restriction in our permits, and we pass that along to all of our contractors," said Campilii.
"What's the capapcity of the cable? Is it designed for 30-megawatts?" asked EUTG member Bill Penn.
"That's correct," said Campilii.
Penn said that "there's been some disscussion with ISO- (Independent System Operators) New England that they might want to have five-megawatt capacity for getting electricity back to them. Has that been taken into consideration?" ISO-NE is an independent, non-profit Regional Transmission Organization, serving New England. (For an explanation of this, see related story on page 4.)
"No. We designed the cable based on the information we have at hand," said Campilii.
Highways Supervisor Mike Shea offered assistance: "Utilize us here on the island. We can help you guys. So, if you can't get something over from the mainland, it might be right here."
"Home Depot is not down the street," added someone at the meeting, which elicited laughter.
After the meeting, Second Warden Norris Pike told The Times that "it's great to see physical construction going on. It’s been a long time coming.”
Lacoste said that National Grid seems "to have all the bases covered and a good handle on the job ahead. From a layman’s point of view it looks like a challenge logistically, but the plan seems to be in place to get it done on schedule. Now, if mother nature cooperates we’ll be all set…"
National Grid will be providing New Shoreham officials with bi-weekly updates regarding the cable installation. The Deepwater Wind Block Island Wind Farm is scheduled to be operational in the fall of 2016.