Heerema’s Thialf Soon to Install First He Dreiht Foundations Offshore Germany

May 16, 2024, by Adnan Memija

Construction work has started on one of Germany’s largest offshore wind farms, the 960 MW He Dreiht project. In the next few days, Heerema Marine Contractors’ crane vessel, Thialf, will install the first foundations at EnBW’s offshore wind farm, being built in the German North Sea.

The He Dreiht offshore wind farm is located approximately 85 kilometres northwest of Borkum and about 110 kilometres west of Helgoland.

More than 500 employees will work on this large construction site in the middle of the sea at peak times, said EnBW. Over 60 ships are involved in the construction of the offshore wind farm.

Heerema Marine Contractors, the company responsible for the transportation and installation of 64 monopiles and transition pieces under a contract signed with the developer in April 2022, will install the first foundations in the next few days using its semi-submersible crane vessel (SSCV) Thialf.

According to previous information, during the operations, Heerema will use the IHC IQIP double-walled noise mitigation system NMS-10,000 amongst other systems to reduce noise pollution.

The monopiles, manufactured by Steelwind Nordenham, have a diameter of 9.2 metres, a length of up to 70 metres, and a weight of around 1,350 tonnes.

The monopiles and transition pieces had previously been loaded onto floating platforms in Eemshaven in the Netherlands and towed to the construction site by tugboats.

According to EnBW, work on installing all of the foundations will continue into the summer.

The Vestas V236-15.0 MW wind turbines and the cables are being manufactured simultaneously for installation and laying planned for early 2025.

The Dutch-German grid operator TenneT will connect the wind farm to the grid using an offshore converter station and two high-voltage DC export cables.

The cables will be laid over a distance of 120 kilometres underwater and 110 kilometres on land. From the landfall point near Hilgenriedesiel, the electricity will be transmitted by buried cable to the future Garrel/Ost converter station in the Cloppenburg area.

EnBW will be responsible for the technical and commercial management while servicing and maintenance work will be carried out from its service base in Emden.

The He Dreiht offshore wind farm is scheduled to go into operation at the end of 2025.

EnBW is the majority owner (50.1 per cent) and the developer of He Dreiht. The consortium consisting of Allianz Capital Partners on behalf of Allianz insurance companies, AIP and Norges Bank, holds the remaining 49.9 per cent in the wind farm.