Nfld. & Labrador

Marine power cable nearly complete on the Strait of Belle Isle

The sub-sea cable that will bring power from Muskrat Falls to Newfoundland is nearly finished, Nalcor says.
The Flinstone is loaded with rock for rock berm installation on the Strait of Belle Isle. (Submitted by Nalcor Energy)

The sub-sea cable system that will bring power from Muskrat Falls to Newfoundland is nearly finished.

Three cables have been laid and the rock coverings have been installed between Forteau Point and Shoal Cove, Nalcor Energy says, marking the end of all "major" construction activities for the Strait of Belle Isle Marine Cable.

Nalcor said Thursday that construction vessels left the Strait on Tuesday, after installing about 540,000 tonnes of rock that stretched approximately 80 kilometres to protect the cables.

"This is the largest subsea rock installation campaign that has been performed in a single campaign in Newfoundland and Labrador, and the fastest known fall pipe vessel rock installation campaign of this quantity," Nalcor bragged in a press release.

According to Nalcor, rock covering is about one-metre tall and between eight to 12 metres long. They're built around the 10-centimetre cable.

An illustration of the protective rock berms installed along the Strait of Belle Isle. (Courtesy Nalcor)

The sub-sea cable is an integral part of Nalcor's Labrador-Newfoundland power line, a 1,100-kilometre system which runs from Churchill Falls to the Avalon Peninsula.

Nalcor said that "each cable was first laid in two pieces that were pulled through conduits on each side of the Strait by a cable installation vessel operated by Nexans. The lengths were then intricately joined together on the vessel and permanently laid on the sea floor."

Cables were first laid in July, and the protective rock installation took two months.

The Flinstone works in the Strait of Belle Isle to install sub-sea protective coverings. (CBC)