TenneT Picks Asso.subsea for 2 GW Cable Installation Work in Germany

July 29, 2025, by Adnan Memija

Asso.subsea has been awarded a nearshore cable installation contract for three projects under TenneT’s 2 GW programme in Germany.

Asso.subsea TenneT — *Source: Asso.subsea*

The projects are BalWin4, LanWin1, and LanWin5, located off the northwestern coast of Baltrum Island, in northern Germany.

The contract marks the beginning of a new collaboration with Jan De Nul, acting as the main contractor, with the German transmission system operator (TSO) TenneT as the end client.

Each project involves the transportation and nearshore installation of a cable bundle comprising 2xHVDC power cables, one metallic return cable, and one fiber optic cable.

The cable transport will be carried out from load-out ports in the Netherlands or Germany, while the nearshore installation operations will be conducted using the cable-laying vessel Atalanti.

The scope of work also includes precision cable landing via beaching operations with spud cans and cable free-lay in intertidal zones and wet storage of cable ends.

Installation will be executed in 2027 (BalWin4), 2028 (LanWin1), and 2029 (LanWin5), respectively.

The consortium of Jan De Nul, LS Cable, and Denys will realise the cable connections in Lower Saxony to BalWin4 and LanWin1, both to be connected in the Unterweser area, and LanWin5 in the Rastede area, Germany.

The first steel for BalWin4, Germany’s first 2 GW offshore grid connection, was cut in March this year. The commissioning date for BalWin4 is 2029, while LanWin1’s fabrication, installation, and commissioning follow a year later, reaching completion in 2030.

The planned commissioning date for LanWin5 is 2031.