German TSO opens €11.7 million tender for marine warranty surveyor services

October 14, 2025, by Adrijana Buljan

50Hertz has launched an €11.7 million call for tenders for marine warranty surveyor (MWS) services for offshore wind energy projects in both the Baltic Sea and the North Sea.

The German TSO is looking to award a framework agreement(s) for MWS services through four lots, with the contract for each lot worth a little less than €3 million. The first two lots cover MWS services during installation and maritime operations on offshore converter platforms and subsea cables in the Baltic Sea, and Lots 3 and 4 concern the same work on offshore platforms and cables in the North Sea.

The framework agreement(s) will be signed for a period of four years, with two options to extend them by two years.

50Hertz’s MWS tender is open for applications until November 7, with the start date for work awarded through the procurement set to February 1, 2026.

The TSO, part of the Elia Group, has several new projects in the Baltic Sea, including the new Ostwind grid connections, Ostwind 3 and 4, and the Bornholm Energy Island interconnection.

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In the North Sea, 50Hertz is building the LanWin3 grid connection, which will connect the wind farms located in the N-11.1 area, approximately 120 kilometres to the northwest of Helgoland, inside the German Exclusive Economic Zone (EEZ), to the German grid.