In 2010 HFG's Zwijndrecht fabrication facility has been awarded the contract for the Engineering, Procurement and Construction of the DolWin alpha HVDC platform by ABB Sweden. The topsides are constructed at HFG’s facilities in Zwijndrecht and the jacket is fabricated at our Vlissingen yard. ABB contracted Heerema Marine Contractors for the transport and installation of the DolWin alpha platform.

The topsides consists of a 5-deck level structure. To maintain the tight schedule for the construction of the topsides it was decided to split the topsides in 2 modules, fabricated in parallel. Those modules were assembled at the assembled at the Heerema Zwijndrecht yard. The modules were assembled by means of a so-called mating operation. First, the upper deck module was moved and positioned in front of the lower deck module, followed by the jacking operation for the mating procedure. Once the upper deck module was at the required height, the lower deck section was moved out of the hall and positioned under the upper deck.

The DolWin alpha jacket is a 6-legs jacket and has been built for 40% indoors allowing a shorter fabrication period. The design started in March 2011 and in November 2011 fabrication started. Subsequently the jacket sailed to its final offshore destination in September 2012.

Client:ABB Sweden
Grid Operator:Tennet
Contract type:EPCI (Engineering, Procurement, Construction & Installation)
Location:German bight
Structures:HVDC topside
HVDC jacket
Project completion: 2013