Work continues to make great progress on Normandie 1 (N1).
The scheme to lay Jersey’s latest subsea power cable from France through to the Channel Islands, known as Normandie 1 (N1) has made excellent progress. Once complete, N1, a £35m joint venture between Jersey Electricity and Guernsey Electricity under the oversight of the Channel Islands Electricity Grid, will become the third active power link between the Channel Islands and France, following the successful installation of Normandie 2 in 2000 and Normandie 3 in 2014.
After four years of planning, Dutch specialists, VBMS were appointed to install the 100MW cable over the same 27.5 km route as EDF1, Jersey’s first link to France that came to the end of its life in 2012 and which was removed from the seabed earlier in the year in preparation for N1.
The actual submarine install began off the coast of Surville on 9th August and was carried out by the use of the 4,000-tonne cable-laying vessel Stemat Spirit. During the install, a mobile exclusion zone was put in place around the Stemat Spirit and its support vessels. No vessel was allowed to pass within 1,000 metres of the front and sides of the 90-metre-long vehicle, or within 500 metres of the stern. Unlike N3, which took almost three months to install over a more southerly route, N1 took just six days to install because it was laid on the seabed rather than ploughed in beneath it.
The Stemat eased into St Catherine’s Bay on the rising tide of Monday 15th August to offload the cable in Jersey.
According to the Jersey Electricity plc’s official project blog, “the final few metres of the 27km cable slipped off the Stemat to a gentle ripple of applause from deck hands and onshore observers that included Environment Minister Steve Luce and his Assistant Minister, Steve Pallett and other States department officials.”
The cable was marked by 126 buoys ready to be re-floated later in the week for the beach landing operation and ‘pull in’ to Archirondel substation. This operation covered three days and fives tides. The 650 metres of beached cable was laid in a large loop around two quadrants and eased up the beach into a straight line for its final approach to the substation. With around 60 metres to spare after its journey from Surville, Normandie, the cable was cut and positioned ready for connection to the existing substation switch gear by jointers from Prysmian.
A six-strong team from Norwegian company Sea Trench, a sub-contractor of VBMS, used a special sea trencher that operates underwater to bury 1km of cable beneath the seabed. Higher up, towards the sea wall, the rocky trench in which the cable was pulled sloping up to the station was filled and the sea wall itself reinstated.
In October 2016, the project reached another important milestone, with the safe arrival of the project’s two 50-ton Voltage Regulators. The Regulators – which arrived in France at the beginning of the month – were built by ABB in Vassa, Finland and were then transported by sea to Antwerp, Belgium before being delivered by road to Saint Remy des Landes, Normandy.
N1 Project Executive and Chief Engineer, John Duquemin, said:
“The arrival of these Regulators are on the critical path for the delivery of the N1 project. Now they are safely on site we need to make all the connections and carry out commissioning tests before the circuits from St Remy can be energised later this year.”
N1 is expected to be in service from early 2017.
Jersey Electricity plc provides affordable, sustainable energy to the island of Jersey. The company has been in operation for more than 90 years and continues to invest in the island’s infrastructure to meet the needs of future generations.
For more information about the N1 project or Jersey Electricity plc, please visit: www.jec.co.uk.