Deepwater Wind cable installation begins

From Town Beach to B.I. Wind Farm
Fri, 05/13/2016 - 12:00pm
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The next phase of construction of the Block Island Wind Farm has begun, with installation of Deepwater Wind’s submarine cable portion of the project getting underway this week.

“Big Max is in the area,” said Deepwater Wind spokesperson Meaghan Wims on Wednesday, May 11. “We expect laying of the cable from Town Beach to the wind farm will begin this week, and that work will take about 10 days to complete.”

Deepwater Wind project manager Bryan Wilson told The Block Island Times that the cable-laying barge called the CLB Big Max arrived at its location off of Town Beach at about midnight on Tuesday, May 10. Wilson said the United States Coast Guard moved the landmark green buoy out of the cable-lay-zone on Monday so that the CLB Big Max would have clearance in laying what Deepwater Wind calls their “export cable” to the wind farm.

“Big Max is working off Crescent Beach with her support vessels,” noted Fisheries Liaison Elizabeth Marchetti on Wednesday. “The crew boats, Megan T. Miller, Sorensen Miller and Abigail Miller will support the Big Max with crew transfer, and they are required by the United States Coast Guard as safety vessels.”

While National Grid has been delayed in laying its 20-mile long sea2shore submarine cable that will connect the island to the mainland due to drilling delays, the company switched gears and commenced the process of laying Deepwater Wind’s eight-mile long export cable, which will link the wind farm turbines to Block Island. According to Wilson, since National Grid has completed its drilling at Scarborough Beach the CLB Big Max will begin installing the sea2shore cable after the export cable to the wind farm has been installed.

National Grid Media Relations Director David Graves told The Times that the utility company won’t be starting its sea2shore cable “installation until later this month, after Deepwater Wind finishes their work. Right now we’re looking at a likely start being during the week of May 23. Drilling at Scarborough Beach was wrapped up over this past weekend,” Graves said.

Graves said National Grid will begin its sea2shore installation process by pulling “a sleeve through the hole from offshore to the manhole in the beach parking lot. When we’re ready to start the cable installation, the submarine cable will be pulled from the barge, through the sleeve and later spliced with the underground cable which will eventually tie into our distribution system.”

As for Deepwater Wind’s cable installation process, the wind energy company expects to install its export cable from the cofferdam at Town Beach to the wind farm within the week. The route of the installation path by the CLB Big Max will be almost straight out from the Fred Benson Town Beach, before turning and heading in a southeasterly direction to the wind farm site.

Wilson said that once the export cable arrives at the wind farm site, a team of divers will aid in guiding it into a tube on jacket number one. Deepwater Wind will then begin the process of installing the four inter-array cables linking the five steel turbine foundations.

The foundations stand in approximately 90-feet of water and are spaced 2,000 feet apart. The United States Coast Guard (USCG) established a 500-yard safety zone around each of the foundations to safeguard mariners from construction hazards. Vessels are prohibited from entering, mooring or anchoring within the five specified safety zones.

Although Deepwater Wind’s export cable is different in name from National Grid’s lengthier sea2shore cable, both were manufactured by LS Cable in South Korea, are comprised of the same materials, including fiber optic strands, and are expected to have 30 to 40 year lifespans. The export cable is a component of the transmission system that will allow electrons produced by the 30-megawatt wind farm to flow to a substation at the Block Island Power Company, and then be delivered to the mainland.

The CLB Big Max is carrying National Grid’s sea2shore cable, as well as Deepwater Wind’s wind farm cable spooled on its deck throughout the cable laying process. The CLB Big Max, which is a custom, specially configured barge, is equipped with a jet plow that can liquefy the seafloor to install the submarine cable six-feet beneath the seabed.

Wilson said the CLB Big Max will remain at sea in harsh weather since the export and sea2shore submarine cables cannot be cut and then re-attached during the installation process.

Marchetti stated in her daily briefing that, “All mariners transiting or fishing in the area of the wind farm are requested to provide a wide berth to construction and support vessels. Vessels transiting in the vicinity of the wind farm foundations must operate at a no-wake speed, in a manner that will not endanger construction vessels or associated equipment.

Mariners are requested to remain clear of all work platforms and attendant vessels during wind farm construction operations, and otherwise use extreme caution when navigating in the vicinity of the Block Island Sound and Point Judith Harbor of Refuge.” 

The Deepwater Wind Block Island Wind Farm is located three miles off the southeast coast of Block Island.

Learn more about the Block Island Wind Farm’s cable installation process on National Grid’s website: sea2shoreri.com. Vessels associated with the project can be tracked at: marinetraffic.com.