Singaporean engineering group Seatrium has officially awarded a contract to heavy lifting and transport specialist Mammoet to execute the critical load-out operations for two high-voltage direct current (HVDC) offshore converter platforms. These massive structures are the centerpiece of the IJmuiden Ver Beta and Nederwiek 1 offshore wind grid connection projects, commissioned by the Dutch transmission system operator TenneT. This agreement ensures the logistical viability of TenneT’s ambitious 2GW Program, a standardized infrastructure initiative designed to accelerate the European energy transition. By securing Mammoet’s expertise early, Seatrium de-risks the final stage of fabrication, ensuring that the finished assets can be safely transitioned from the shipyard to the heavy transport vessels destined for the North Sea.

Technical Precision on the Tuas Quayside

The operation will take place at Seatrium’s Tuas Boulevard Yard in Singapore, where the platforms are currently under construction. Unlike smaller offshore modules that can be lifted by gantry cranes, these 2GW converter stations are behemoths, with each expected to weigh approximately 26,000 tonnes. To move this immense mass, Mammoet will deploy a vast array of Self-Propelled Modular Transporters (SPMTs). This is not merely a trucking job; it is a hydraulic engineering feat. The SPMTs feature computerized suspension systems that equalise the weight distribution across thousands of wheels, ensuring the platform remains perfectly level while moving. This stability is crucial to prevent structural twisting or stress that could damage the sensitive high-voltage switchgear and transformers housed inside the hull before they even leave the yard.

Seatrium / Mammoet Load-Out: Factsheet

Fabricator/Client: Seatrium (Singapore)

Heavy Lift Contractor: Mammoet

End Client: TenneT (Dutch TSO)

Projects:

IJmuiden Ver Beta

Nederwiek 1

Location: Seatrium Tuas Boulevard Yard, Singapore

Asset Type: 2GW HVDC Offshore Converter Platforms

Estimated Weight: ~26,000 tonnes per platform

Transport Method: Self-Propelled Modular Transporters (SPMTs)

Key Technology:

HVDC: Converts AC from wind turbines to DC for low-loss transmission.

2GW Standard: Standardized design to reduce costs and speed up rollout.

Jobsite Challenge: Moving a structure weighing equivalent to 3.5 Eiffel Towers without damaging internal electronics.

Enabling Efficient Long-Distance Transmission

The successful load-out of these stations is the gateway to efficient power delivery for the Netherlands. These platforms utilize HVDC technology, which is essential for transporting electricity over long distances—specifically from far-shore wind farms like IJmuiden Ver—without significant power losses. By adopting the 2GW standard, TenneT effectively doubles the capacity of previous 900 MW models, allowing a single platform to service more wind turbines while requiring fewer export cables to be trenched into the seabed.

Once Mammoet rolls these units onto the transport vessels, they will eventually serve as the “sockets” connecting gigawatts of green energy to the Dutch national grid—a next-generation connectivity paralleled by current milestones, such as TenneT energizing the 900 MW DolWin5 HVDC link in Germany. This newly activated connection, utilizing the DolWin epsilon platform, will transmit power from Ørsted’s Borkum Riffgrund 3 offshore wind farm to the German mainland, supporting the country’s goal of reaching 30 GW of offshore capacity by 2030.