TenneT Hires Asso.subsea for Cabling Work off Germany

July 29, 2025

Subsea cable services company Asso.subsea has secured the nearshore cable installation contract for three key projects under TenneT’s 2 GW grid program, including BalWin4, LanWin1, and LanWin5.

The projects are located off the northwestern coast of Baltrum Island, in northern Germany, and mark the beginning of a new collaboration with Jan De Nul, acting as the main contractor, with TenneT as the end client.

(Credit: Asso.subsea)
(Credit: Asso.subsea)

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

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

The scope of work includes cable transpooling from load-out ports in the Netherlands or Germany, nearshore installation operations using the cable laying vessel (CLV) Atalanti, which will be specially modified to accommodate the four-cable bundle configuration.

Also, Asso.subsea will be involved in precision cable landing via beaching operations with spud cans, and cble free-lay in intertidal zones and wet storage of cable ends

“These nearshore operations are highly sensitive to tidal conditions, requiring detailed planning and precise execution. Our in-house capabilities, vessel adaptability, and commitment to engineered solutions ensure that we’re ready to meet the unique demands of these technically challenging works,” said Asso.subsea.

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