Scaldis successfully installs two offshore substations at SeaMade with new in-house developed transportation method

Otary RS NV, Electrabel and Eneco are developing the offshore wind farms Mermaid and Seastar, collectively known as the SeaMade project. The Mermaid and Seastar fields are respectively the northernmost and central concessions of the Belgian offshore energy zone. Both offshore wind farms combined have a total capacity of 487 MW, spread over 58 wind turbine generators and will provide 485000 families with green energy. On behalf of DEME Offshore, Scaldis was responsible for the transport and installation of the Mermaid & Seastar Offshore substations.

Efficiency driven transportation concept
Having installed six offshore substations in the Belgium North Sea, Scaldis developed a new record-breaking transportation concept for the two 1200-ton topsides. We were able to improve our record due to the new in-house developed Transportation/Installation method. Both topsides where pick-up by our crane vessel in a sheltered port and seafastened on deck. A modular seafastening was designed and built to transport the topside partially suspended in the main cranes to the SeaMade offshore wind farm. The load was maintained into the cranes during transport to optimize the lean and cost-effective seafasting configuration. This innovative method eliminated the endeavor of mooring, offshore barge and the need of auxiliary tugs.

Swift installation — twice
During the challenging weather conditions of March, Mermaid offshore substation arrived in Vlissingen where it was picked up by HLV Gulliver and sailed towards the offshore field. The crew conducted the DP checks before entering the concession zone and was ready for installation before noon. The substation was lifted from deck and HLV Gulliver slowly approached the last 100 m towards the monopile in DP2 mode. On the instructions of the heavy lift supervisor, the substation was lowered gently over its stabbing guides. Mermaid was installed in a record time. However, the record stood only 11 days, as we successfully installed Seastar’s substation on 16th March.

With this new concept we were able to move 75% of all activities to a sheltered location, this increases the speed of the operation and the safety of the project. After an extensive preparation we are extremely proud how well it was executed and are positive that we will use this often in the near future for installation and decommissioning projects.