The IFA2 (Interconnexion France-Angleterre 2) Project will connect the electricity systems of Great Britain and France using high-voltage direct current (HVDC) cables from Normandy in France to Fareham. The HVDC will come ashore at Hill Head and connect to a converter station on Solent (Daedalus) Airport. High-voltage alternating current (HVAC) cables will then run from the converter station to the sea. They will be buried in the seabed to make a landfall at Brownwich then underground to a new substation at an existing National Grid site off Chilling Lane near Warsash. On the chart above the routes of the cables are marked in red.
You may recall that during 2018 the IFA2 Project surveyed and cleared the HVAC route. The main aim was to ensure that the cable route was clear of obstructions, particulary unexploded ordnance. A secondary aim was to clear two narrow corridors parallel to the cable route where the cable laying vessel would lay its anchors. These corridors are also illustrated on the chart above.
The movement of the vessels involved with IFA2 last year appeared somewhat random; on occasions OODs had to use great initiative to set a course that did not conflict. We have been reassured that this year the cable laying process will be far more systematic and, therefore, predictable. The IFA2 team have put effort into liaising with Solent users. A team from the project supported by representatives from their subcontractors gave a briefing to Seafarers on 19th March this year.
The HVAC cables will be laid during the period mid June to end September in two phases.
In the first phase the non-propelled barge NP 289 (pictured below) will move along the route from Brownwich to Hill Head (off The Shack) six times laying one AC cable on the sea bed each time. On the chart above you will see marked the path of the vessel (the cables) and the inner and outer corridors for laying the anchors. NP 289 is 80m by 24m. Its anchors will be laid progressively along these corridors and the vessel moved by tensioning and easing its anchor cables. NP 289's progress will be very slow; it will take approximately 3 days lay each cable from Brownwich to Hill Head.
In the second phase a submerged tracked vehicle will move along the sea bed to bury each cable one at a time. There will be a companion surface vessel. Cable burial would be less intrusive than cable laying; the cable burial will only take place on the centre line of the HVAC route as there are no anchor points required. Progress of the cable burier will be even slower than the cable layer; each transit between Brownwich and Hill Head will take approximately 6 days.
The IFA2 website provides updates on progress. Both the Onshore Cables and Offshore Cables webpages contain information that could be of interest to Seafarers - see menu buttons on the right.
Location of NP 289 - The Offshore Cables page includes a Marine Traffic map. If you enter NP 289 into the Search box titled "Find a Vessel or Port", it will provide the location of the barge. (At the time of writing, 26th March, NP 289 was moored in Beneden Merwede, a stretch of river in the Netherlands)
NP 289 - the AC Cable Laying Barge
Last updated 22:24 on 4 June 2019