ABL Appointed Marine Warranty Surveyor for Ostwind 4 HVDC Grid Connection

24 September 2026
Edited By: Haley McQueen

Energy and marine consultancy ABL has been appointed by German transmission system operator 50Hertz to provide marine warranty survey services to de-risk critical transportation and installation (T&I) operations of subsea and offshore infrastructure for the Ostwind 4 offshore grid connection project.

(Image credit: ABL)

Ostwind 4 is the fourth project in the Ostwind offshore grid development program, connecting offshore wind generation in the German Baltic Sea to the mainland. The project will provide a targeted transmission capacity of up to 2 GW, enabling the integration of large volumes of offshore wind power into Germany’s electricity network and supporting wider European decarbonization goals.

The project includes an offshore converter platform, an onshore converter station, and a 110-kilometer subsea and onshore cable route. Ostwind 4 will be the first project to deploy a high-voltage direct current (HVDC) transmission system in the German Baltic Sea, introducing new technical and marine assurance considerations for offshore installation and cable-lay operations.

“With a long cable route and the first use of HVDC transmission in the German Baltic Sea, Ostwind 4 is a unique and significant project. ABL brings independent marine assurance expertise and extensive experience supporting complex offshore energy projects in both the Baltic and North Seas. We look forward to working with 50Hertz to support risk mitigation and the safe delivery of this important transmission link,” said Tilo Klappenbach, Country Manager, ABL Germany.

ABL’s German team, based in Hamburg, will deliver independent marine warranty survey (MWS) services covering the marine T&I of subsea cables and offshore infrastructure, as well as the installation of the converter platform and associated assets.

The scope of work includes the review and approval of technical documentation and procedures, marine risk and assurance services to assess the suitability of the proposed marine spread, and on-site attendances to witness and approve all warranted operations.

“Since establishing operations in Germany nearly a decade ago, ABL has built a strong track record supporting clients with independent analysis and on-site marine assurance across offshore wind and transmission projects. We look forward to applying this experience on Ostwind 4,” Klappenbach added.

ABL is part of Oslo-listed Aqualis ASA—a global group of technical consultancies in energy and oceans.