Jan De Nul Cable Layer To Wire Four Two-Gigawatt Grid Connections
A newly built cable installation vessel is fitting out at Nantong in China ahead of an opening assignment that will see her install export cables on four offshore grid connections of two gigawatts each, for the transmission operator responsible for the Dutch grid and large parts of Germany. The programme represents a step change in the capacity of individual offshore connections and in the volume of cable a single vessel is expected to lay.
The connections are rated at two gigawatts apiece, against the 700 to 900 megawatts typical of existing systems, which more than doubles the power each link carries to shore. For comparison, a conventional nuclear power station generates between one and 1.6 gigawatts, so each of these connections moves more electricity than a reactor produces. Concentrating that much capacity in one system reduces the number of cable corridors, landfalls and converter stations required for a given amount of generation, which is where much of the cost and most of the permitting difficulty in offshore wind actually sits.
The vessel's scope covers four of the connections. Because the cables are bundled and laid together, four at a time, the work amounts to more than 2,800 kilometres of cable installed along a route length of more than 700 kilometres. That ratio is the practical signature of the design: the distance to be covered is modest by offshore standards, but the quantity of product to be handled, tensioned and buried along it is very large, and it has to be done without damaging conductors whose repair at sea costs weeks.
Cable installation has been the persistent bottleneck in offshore wind rather than turbine supply or foundation fabrication. Insurance claims data across the sector has consistently shown that cables account for the large majority of losses by value, mostly from installation damage and from inadequate burial that leaves a conductor exposed to anchors and fishing gear. That record is why owners have moved from chartering installation capacity in the spot market to building purpose-designed vessels and contracting them years ahead.
The commercial logic behind the newbuilding follows from that. A contractor with a modern high-capacity cable layer secured to a multi-year programme has both revenue visibility and the ability to refuse marginal work, in a market where the alternative is competing on price for scattered single-project awards. For the grid operator the calculation is the mirror image: a dedicated vessel committed to the programme removes the risk that installation capacity is unavailable at the point four connections all need wiring at once.
