Last year, Prysmian completed submarine power cable installation along a 200 km route beneath the English Channel. The Group took care of turnkey design, manufacturing and installation of a 1 GW submarine and land power cable link between Normandy, France and Hampshire, UK. The assignment was part of a joint venture between major Prysmian clients RTE France and the UK’s National Grid.
Project Director
Submarine installation was carried out by Prysmian’s cable-laying vessel Cable Enterprise. Roughly half of the length across the sea bed was jettable, here cable was buried using Prysmian’s Sea Mole jetting tool. For the remaining length, specialised trenching equipment was used. The project also required HVAC cables for a ten-kilometre route in the UK, linking two substations on the coast.
Crossing the channel, which has some of the world’s heaviest marine traffic, was a big challenge. Furthermore, this was a ‘fast track’ project, to be completed in a limited, tight time frame. However, several interesting challenges that weren’t part of the tender! The on-shore route demanded special attention to protection of wildlife including badgers, dormice and birds, for example. Furthermore, the converter station in the UK is near Solent Airport in Hampshire, which meant the cable had to cross the airfield. That meant factoring in height restrictions at the landfall interface with the runway, limiting use of cranes.
Owners of small aircraft were worried electromagnetic interference from cables might affect compass systems. Prysmian had already done a study into this during the tender phase, but the mathematical results were not clear for the aircraft owners. So several meters of cables were buried, and the aircraft owners were asked to pass over them and check whether they saw any effect on their compasses – which remained unaffected. A UK yacht club that sailed near where the work was being carried out was also visited, to explain the planned activities and which areas were to be avoided at certain times. Communities living near the shore were also taken into account as special measures were taken to avoid noise
What’s more, in Northern France measurements along beach had to carried out quickly without leaving a trace before June, when large number of tourists visit for D-Day celebrations.
Owners of small aircraft were worried electromagnetic interference from cables might affect compass systems. Prysmian had already done a study into this during the tender phase, but the mathematical results were not clear for the aircraft owners. So several meters of cables were buried, and the aircraft owners were asked to pass over them and check whether they saw any effect on their compasses – which remained unaffected. A UK yacht club that sailed near where the work was being carried out was also visited, to explain the planned activities and which areas were to be avoided at certain times. Communities living near the shore were also taken into account as special measures were taken to avoid noise
What’s more, in Northern France measurements along beach had to carried out quickly without leaving a trace before June, when large number of tourists visit for D-Day celebrations.
Marco De Donno adds: “There was another vast challenge we hadn’t predicted: Covid 19! Suddenly, at the end of February 2020, our ways of working changed completely. We couldn't visit the site every week anymore and had to stay at home and work through Teams. Prysmian soon defined and put in place new Health & Safety rules and precautions and adopted very strict Covid mitigation measures worldwide, that went far beyond local government rules. I’m happy to say that in the end the project was completed in time and according to specification!”
“During execution of IFA 2 we were awarded the vast Viking link project, connecting the UK to Denmark. Prysmian was awarded all offshore lots and UK land lots that were part of the tender - a clear indication of the customer’s trust in our technical execution capabilities. I’m very proud that before any tender activity we were asked to hold workshops on the latest developments in cable technology and installation capability.”
Head of Product Management
“I think clients recognize that Prysmian is globally flexible and fast-reacting making us the ideal partner for fast-track projects. Apart from global presence and subsea expertise we have our own design and manufacturing capacity so we’re less prone to supply chain and delivery issues. Feedback has been very positive; the client is very satisfied with the overall result. Next, we’ll be focusing on numerous new projects connecting France to Ireland, Spain and the UK.”
Over 200 km submarine cable plus 40 km of HVAC cable to be manufactured in one year and installed in the following year.
Submarine cable was all manufactured at Prysmian’s centre of excellence in Pikkala Finland
Land cable was manufactured at Prysmian’s centre of excellence in Gron near Paris
Optical submarine cable was manufactured at Prysmian’s centre of excellence in
Drammen Qualification process including 6 loop test was executed at Prysmian’s facilities in Milan and HV lab in Bishopstoke UK
Accessories DC components were supplied by the Livorno IT factory
Accessories AC components were supplied by the Delft NL factory
