Asso.subsea has secured a significant contract for the nearshore cable installation scope on three of TenneT’s flagship offshore wind transmission projects: BalWin4, LanWin1, and LanWin5. Located off the northwestern coast of Baltrum Island, Germany, the projects are part of the transmission system operator’s 2 GW Program, aimed at accelerating Europe’s energy transition.
The award marks the start of a new collaboration between Asso.subsea and Jan De Nul, the main contractor, with TenneT serving as the end client. This nearshore scope is part of TenneT’s larger 2GW tender framework, involving a consortium of companies focused on accelerating the deployment of high-capacity offshore grid connections across Europe. The projects will be executed over three consecutive years: BalWin4 in 2027, LanWin1 in 2028, and LanWin5 in 2029.
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Each project involves the transportation and nearshore installation of a four-cable bundle consisting of two high voltage direct current (HVDC) power cables, one metallic return cable, and one fiber optic cable. The cables will be transpooled from load-out ports in Germany or the Netherlands, followed by complex nearshore operations carried out by the cable laying vessel (CLV), Atalanti, which will be specially modified to handle the multi-cable configuration. The vessel will undergo significant deck modifications and be equipped with customized cable-handling tools to manage the bundled cables in challenging shallow-water conditions safely.
Key installation activities include precision beach landings using spud can technology, cable-free lay in intertidal zones, and wet storage of cable ends. Operating within the ecologically sensitive Wadden Sea region, a UNESCO World Heritage Site, the project will adhere to strict environmental and permitting regulations to ensure minimal impact on the surrounding marine habitat. Due to the challenging tidal conditions in the area, operations will require high levels of planning and technical execution.
The BalWin and LanWin projects are considered key building blocks in creating a unified North Sea energy corridor, positioning the 2GW Program as a model for future offshore grid standardization across Europe.
This latest contract highlights Asso.subsea’s growing role in Europe’s offshore energy infrastructure, reinforcing its capabilities in delivering engineered cable solutions for complex marine environments.
