DEME and Prysmian have begun installing HV cables in the Veerse Meer in the Netherlands for grid operator Tennet's IJmuiden Ver Alpha and Nederwiek One offshore grid connections, the companies said on Thursday, October 29.
Each connection has a transmission capacity of two GW and uses a 525kV DC cable system. The cables run from offshore platforms through the lake and then underground to separate converter stations in the Sloegebied at Borssele. There, the electricity is converted to 380kV AC for the national grid.
Prysmian is the cable contractor. DEME is its subcontractor for the lake installation, including worksite preparation, cofferdams and preparatory dredging.
The installation is being carried out from a pontoon that DEME developed for the lake. Cable carousels aboard handle the power cables, spare cables, and fibre optics simultaneously.
Each connection comprises two HVDC power cables, a metallic-return cable and a fibre-optic cable, laid along a route of approximately 12 kilometres between the Veerse Gatdam and haven De Piet.
"To install the cables to at least three m deep, a tailored vertical installation method is used in combination with high-pressure water jets to temporarily fluidize the sand beneath the cable," the companies said.
Tennet said the coupled pontoon measures 75 metres wide and 40 metres long, with its highest component reaching 31 metres. Because the lake is accessible only through relatively small locks, the spread was delivered in sections and coupled at the lake's northern end. The first section arrived on September 1.
The installation pontoon is equipped with anchor winches, a vertical injector, water pumps, and spud poles.
Works will continue until the spring of 2027 so that the lake is available for watersports and recreation in summer. Tennet has set a completion deadline of May 2027 and lists commissioning of IJmuiden Ver Alpha for 2029.