TenneT Awards Massive Transport and Installation Contracts to Heerema and Allseas

TenneT has signed multi-year framework agreements with Allseas and Heerema Marine Contractors for the transport and installation of at least fourteen 2 GW offshore platforms.


The fourteen 2 GW converter stations will be installed in the Dutch and German parts of the North Sea.

The framework agreement will cover at least twenty-eight slots until 2031; fourteen slots for the transport and installation of jackets, and fourteen slots for the transport and installation of topsides.

Heerema will deploy the Semi-Submersible Crane Vessel (SSCV), Sleipnir, and its own floatover barge, and Allseas will use its single-lift installation vessel, Pioneering Spirit, for the installation of the jackets and topsides.

Both vessels have been used several times in recent years for the installation of jackets and topsides for TenneT in the Dutch and German North Seas.

Heerema has been allocated about 60 per cent of the available slots and Allseas about 40 per cent.

Jeroen van Oosten, Chief Commercial Officer of Heerema, said: ”We are proud to have been selected to supply clean energy for the Netherlands and Germany together with TenneT. The award of this framework agreement is an important example of the benefits of trust-based partnerships between clients and contractors. To ensure that clean energy demand is met, the focus should continue to be on cooperation and forward-looking agreements that recognise the need to secure transmission and installation capacity.”

Slots for future projects after 2031 can be added to the contracts awarded, TenneT said. The slots allocated are not linked to specific 2 GW projects. The HVDC suppliers who build the jackets and topsides for TenneT, Hitachi Energy/Petrofac, GE/Sembcorp, GE/McDermott and Siemens/Dragados, can choose from the suppliers where Heerema and Allseas can install both jackets and topsides.

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”When my father, Edward Heerema, came up with the single-lift concept in 1987, no one could have imagined that four decades later it would be used for a groundbreaking offshore energy project of such strategic importance,” Pieter Heerema, President at Allseas, said.

”The Pioneering Spirit’s unique transport and installation capability has been used with great success to deliver critical assets for offshore wind projects across Europe. Thanks to the large lifting capacity and the high working capacity of the vessel, the installations can be carried out safely all year round, creating maximum flexibility in the huge and complex construction schedules. We look forward to strengthening our relationship with TenneT and getting started on this prestigious project.”

Boskalis to Build Transport Vessels

Boskalis will act as a subcontractor of Allseas and build one or two new transport vessels especially for the 2 GW program that will meet the strictest future legal standards on sustainability and emissions, TenneT said.

”With this agreement, we are securing global sea transport and the heaviest offshore installation capacity in the market for our HVDC partners and at the same time expanding the transport capacity in the market,” Tim Meyerj├╝rgens, COO at TenneT, said.

”We are proud to have signed the framework agreements with these Dutch and Swiss-Dutch suppliers. These European partners prove once again that they are the global market leader in the field of offshore transport and installation. They have the equipment to carry out projects of this size safely and successfully.”

TenneT has recently awarded framework contracts for the civil works for the land stations in the Netherlands, offshore and onshore converter stations, and the cable connections of the fourteen 2 GW projects in the Netherlands and Germany.

The new tendering approach accelerated the process, whereby agreements were made with all suppliers in a short time, the transmission system operator said.

Marco Kuijpers, Director Large Projects Offshore at TenneT, said: ”With the cooperation values in these long-term agreements, we offer a strong basis for the successful implementation of the projects. These contracts give planning certainty and predictability to our suppliers, which they need to be able to invest.”


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