Construction of the longest subsea power cable in the world, that will connect the UK and Norwegian electricity grids, has now passed the halfway point. The cable is now well on its way to helping power Norway’s and the UK's zero-carbon hydro energy.
North Sea Link, a joint venture project between National Grid and Norwegian system operator Statnett, took on this ambitious project and it was no easy feat. First, the team had to maneuver the cable through a lake that could not be reached by ships.
The team came up with the ingenious solution of transporting the materials piece by piece in order to build their own floating platform. The operation required an average of 25 people a day for 11 days and was the first of its scale in Norway.
The end resulted was a platform the size of two tennis courts and the weight of two Being 757 airplanes. The team then worked at depths of up to 210 meters to lay down parallel subsea cables of 2.8km in length. The platform also had to withstand 150 tonnes of cable.
“The engineering that has taken place to lay high-voltage cables below the seabed is remarkable. The difficult terrain, the depth of the waters, and all in amidst of operating during a pandemic has made it extremely challenging. Nevertheless, we have powered through and remained on track with our project timelines," said in a statement Nigel Williams, Construction Director for National Grid North Sea Link.
Now the team has to lay the cable out from the fjords in Suldal, to the North Sea. This work is planned through the end of 2020.
It is estimated that by 2021 the two parallel 720km cables between Cambois, Northumberland in the UK and Kvilldal, in Norway will have been completed. Once this has been achieved, North Sea Link will be the world's longest subsea power cable interconnector.
The 1.4-gigawatt electricity interconnector will then allow Britain to produce enough clean energy to power up to 1.4 million homes. In fact, the North Sea Link will allow both the UK and Norway to maximize the use of their natural resources.
When wind generation is high and electricity demand is low in the UK, the cable will allow up to 1,400MW of power to flow from the UK to Norway. When demand is high in the UK but wind generation is low, the same amount can flow from Norway to the UK.