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    Allseas, Heerema to install 14 offshore converter stations for TenneT

    May 17, 2023
    TenneT has awarded transport and installation slots for 2-GW offshore platforms to Allseas and Heerema.
    Courtesy TenneT
    Sleipnir semisubmersible crane vessel
    Sleipnir semisubmersible crane vessel

    Offshore staff

    THE NETHERLANDS — TenneT has signed multi-year framework agreements with Allseas and Heerema Marine Contractors for transport and installation of at least 14 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 covers at least 28 slots until 2031—14 slots for transport and installation of a jacket and 14 slots for transport and installation of a topside.

    Courtesy TenneT
    single-lift installation vessel Pioneering Spirit
    single-lift installation vessel Pioneering Spirit
    Heerema will deploy the Sleipnir semisubmersible crane vessel as well as an owned 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 to install jackets and topsides for TenneT in the Dutch and German North Sea.

    Heerema has been awarded about 60% of the available slots, while Allseas has been awarded about 40% of the slots. Additional work can be added to the awarded contracts. The awarded slots are not linked to specific 2-GW projects.

    The HVDC suppliers building the jackets and topsides for TenneT (Hitachi Energy/Petrofac, GE/Sembcorp, GE/McDermott and Siemens/Dragados) can choose from the suppliers whereby Heerema and Allseas can install both jackets and topsides. 

    Boskalis will act as a subcontractor to Allseas, building one or two new transport vessels specifically for the 2-GW program that will meet the most stringent future legislation standards on sustainability and emissions.

    05.17.2023