German transmission system operator (TSO) 50Hertz Transmission has selected two contractors to perform boulder removal in the Baltic Sea and North Sea.
Germany’s Heinrich Hirdes and UK-based Hughes Subsea Services have secured contracts with 50Hertz Offshore for boulder removal services on the cable route of the Ostwind 3 project and possible future projects in the Baltic Sea and/or North Sea.
This includes the provision and operation of all assets necessary for the works, removal of boulders, reporting and interfacing with the employer and other relevant parties, among other things.
The project works consist of the removal of boulders within specific areas of the Baltic Sea or North Sea, such as within the offshore site northeast of the island of Rügen close to the existing Arkona Becken and Wikinger wind farms.
According to 50Hertz, the objective of the boulder removal campaign will be to mitigate the risk of the presence of boulders in the cable installation corridor which could possibly hinder the cable installation or damage the cable installation spread.
To remind, at the end of 2022, Germany’s Fraunhofer Institute for Wind Energy Systems IWES completed a boulder detection campaign off the coast of the island of Rügen in the Baltic Sea for 50Hertz.
“For us, precise knowledge of subsoil conditions is important for avoiding possible installation risks. It allows us to avoid construction delays and thus save costs. The technique has proved that it is effective and delivers the essential measurements that we need for precise planning,” Dr. Henrich Quick, Head of Offshore Projects at 50Hertz, said at the time.