Arkona Completes Electrical Offshore Substation Assembly


Fewer than three weeks after laying the first block, the STX France team has laid the third and last block of the Arkona project (a joint venture of E.ON and Statoil with transmission system operator 50 Hz) electrical offshore substation topside onto the transportation barge in the dry dock of the yard in St.-Nazaire.

In the meantime, the offshore works at the Arkona wind farm site have started with the installation of the four piles of the substation jacket foundation.

The substation is one of the biggest HVAC (high voltage alternating current) substations ever built — 5,000 tons (4,000 tons topside and 1,000 tons jacket), transmitting a total of 385 MW power – and will be delivered in 2018. The project is running according to schedule.

The three blocks of the topside are now assembled on the barge, which will be used for the transport offshore in spring 2018. Equipment installation and commissioning will continue until 2018 on the barge in the dry dock in St.-Nazaire. The jacket fabrication is in progress in a dedicated workshop in Saint-Nazaire.

Recently, with STX and subcontractor SHL, the first part of the offshore installation was in the Baltic Sea. SHL heavy-lift vessel Oleg Strashnov has installed the pile foundation for the jacket. Due to close collaboration of all involved parties, the project is on schedule.

A full EPCIM contract makes STX France one of the major European industrial stakeholders of the energy transition. From the contract award in July 2015 up to the fabrication start, STX France team has carried out the design of Arkona electrical substation. Building of the topside and the jacket has been realized in the offshore-energy dedicated workshop of STX’s St.-Nazaire yard. The contract includes the transport, the installation, and one-year maintenance period.

Finally, the biggest single lift for an HVAC substation so far — 4,000 tons — will be carried out next spring. This will be a key achievement in the offshore wind market. 

Source: 4C Offshore

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