Mammoet has signed a support contract with Seatrium to carry out the load-out of three ultra-heavy offshore substations for TenneT’s landmark 2GW offshore grid connection program.
The project forms part of a major North Sea infrastructure rollout that will link large-scale offshore wind farms to the European mainland. By 2032, a total of 15 high-voltage direct current (HVDC) offshore grid connection systems, eight in the Netherlands and seven in Germany, are scheduled for installation. Each system will deliver 2 gigawatts of capacity, significantly boosting renewable power transmission.
By deploying higher-capacity offshore connections, the program supports Dutch, German and wider European climate targets while reducing environmental impact. Fewer platforms at sea will be needed overall, lowering material use and offshore installation activity.
Under its One Seatrium Global Delivery model, Seatrium will fabricate the topsides across several key international yards. Each structure will exceed 30,000 tonnes, making them among the heaviest substations ever built for offshore grid use.
Mammoet will manage the on-site movement and load-out of the massive platforms. Using specialist hydraulically compensated skidding systems, the company will transfer the structures from land onto sea-going transport vessels. The equipment enables highly controlled motion while minimizing structural deflection during the transfer process.
Richard Verhoeff, Global Sales Director at Mammoet, said the partnership reflects the growing scale of offshore energy infrastructure and highlighted the role of engineered heavy-lift solutions in delivering Europe’s net-zero and energy independence ambitions.
