Normandie 3 links the Channel Islands to France and forms part of the Channel Islands Electricity Grid (CIEG) along with Normandie 2, an existing 100MW cable between Jersey and France and GJ1, a 60MW cable between Guernsey and Jersey.

The extra link will reduce the need to generate power here, which is much more expensive than buying it in from France.

Jersey Electricity CEO Chris Ambler said: "This is an important milestone in our long history of serving this Island community. Normandie 3 will double our capacity to import cleaner, low carbon supplies of electricity from France’s nuclear and hydro plants, enhancing the security of supply for our customers and helping us maintain price stability going forward. It has been an immense project, which is within its £70m budget and ahead of its 2015 schedule. I am extremely proud of the team that made it possible, particularly in this our 90th anniversary year.

"I’d like to take this opportunity to thank the Jersey public – our customers – for their patience during the installation of the Jersey land cable, which has involved some complex traffic management along its route, and the fishermen and boat owners here and in France for their co- operation during the burial of the subsea cable."