Construction, Installation and Operation of Offshore-Platforms

All-In-One Installation of an HVDC-Platform in the German bight (with the PIONEERING SPIRIT)

Sebastian Nostheide M. Sc., TenneT Offshore GmbH

The offshore HVDC converter station DolWin kappa is a key part of the grid connection system DolWin6 with 900MW transmission capacity for offshore wind power. It is TenneTs 13th grid connection system in the German north sea and thereof the 10th in HVDC technology. Consequently, it’s design has some technological developments and some site specific specialties, e.g. being the last daughter platform next to DolWin beta. But it has also one remarkable aspect on T&I (Transport and Installation). The design of topside and jacket is optimized and designed for the installation by one specific vessel: Pioneering Spirit, the biggest crane vessel in the world.
In summer 2022, the platforms main components were loaded out in Cadiz/Spain, were these have been built within three years, to the barge “Iron Lady” and transported to Rotterdam. Here, jacket, topside, piles and bridge have been transferred to the installation vessel, which then set sail to the German Bight. Vertical jacket transport in lifted condition, installation, piling and noise mitigation, grouting and topside installation as main steps and main challenges for the project will be detailed in planning and execution.