Dragados Offshore is pleased to announce that it will develop, in consortium with Siemens Energy, the HVDC converter platforms of both the DolWin4 and BorWin4 HVDC grid connection projects for Amprion Offshore.

The project consists of two 900 megawatt converter systems for the transmission of electrical energy, part of Germany’s Energy Transition, in which the Hanekenfähr grid access point was seen as the “technically most expedient and cost-effective solution” for the NOR-3-2 (DolWin4) and NOR-6-3 (BorWin4) connection systems. Amprion is the transmission system operator responsible for this area and for both systems.

The grid connection systems for DolWin4 and BorWin4 are set up as point-to-point HVDC transmission systems, each executed as a symmetrical monopole. The offshore stations are set up in the relevant cluster for the Offshore Wind Farms to be connected. Both the HVDC transmission converters and the necessary auxiliary systems are installed at these stations. The OWFs are connected to both offshore stations via 66 kV AC direct connection systems and convert the power to 320 kV DC voltage for transmission to shore.

The two HVDC onshore stations for DolWin4 and BorWin4 are connected to the Hilgenberg switchgear as well as being linked to the 380 kV link that is to be built to the grid access point at Hanekenfähr for the AC transmission grid.

With a total transmission capacity of 1.8 GW, these converter stations will be sufficient to supply the electricity for a major city like Hamburg of 1.8 million people.

Dragados Offshore is responsible for providing the offshore platforms, including detail design and engineering, procurement, fabrication, construction, load out, transportation, installation and hook-up of the offshore platform, and installation and commissioning of its platform systems. The HVDC systems, as well as the complete onshore converter stations, are the scope of work of our partner Siemens Energy.

The award of both systems is considered a major milestone for Dragados Offshore as it consolidates our activities for the offshore wind industry, providing low carbon emission projects for the energy market. The official start date of the project is set at 29 July 2022 and will provide workload in Dragados Offshore’s Puerto Real yard up to sail-away of the platforms, which is scheduled for 2027. Final delivery and commencement of power transmission by the HVDC systems will be in 2028.

DolWin4 and BorWin4 are the third and fourth 900 MW HVDC converter station platforms that Dragados Offshore will develop together with Siemens Energy. At the moment of this award, the DolWin6 platform is close to sailaway for offshore installation, while construction of the BorWin5 platform has started in the yard in Puerto Real, both of which were awarded previously by TenneT.