Jan de Nul to repair offshore cables to ensure electricity supply

Cable laying vessel Willem de Vlamingh. Jan De Nul
Cable laying vessel Willem de Vlamingh. Jan De Nul

Electricity transmission system operator TenneT has awarded a framework agreement to Jan De Nul Group for repairs of TenneT’s offshore high-voltage cables in the German Bight. TenneT’s mission is to ensure a reliable and uninterrupted supply of electricity in its high-voltage grid and therefore, Jan De Nul Group has been appointed by the leading European electricity transmission system operator to mobilise in the event of high-voltage cable system faults or failures within the contractual period.

The scope entails repairs of all TenneT’s existing HVAC cable systems connecting individual wind farms to the offshore converter stations or directly to the onshore grid, as well as repairs of all TenneT’s HVDC cable systems connecting the offshore converter stations to the onshore grid. In addition, any future connections commissioned within the duration of the agreement will be added to Jan De Nul’s scope. The contract covers a period of 24 months with two optional extensions of 12 months each.

Jan De Nul Group has initiated the preparatory engineering works required to perform the cable repairs. In the event of a HV cable system fault or failure, Jan De Nul will mobilise one of its offshore cable laying vessels, either Isaac Newton or Willem de Vlamingh.

In 2018, the Willem de Vlamingh installed HV cables to connect the Trianel Windpark Borkum and Borkum Riffgrund II wind farms to TenneT’s DolWin Gamma and Alpha offshore converter stations. These cables are also subject of this framework agreement.