DolWin6 HVDC

DolWin6 HVDC
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Capacity900 MW
Country of deliverySpain
Delivery year2023
ShipyardDragados Offshore
SubsidiaryHeinen & Hopman and Teknotherm
Vessel typeOHVS


We are proud to announce that Heinen & Hopman and Teknotherm were awarded the contract to design and deliver the complete HVAC system for Offshore High Voltage Station DolWin6. The high-voltage direct current (HVDC) converter platform will be built by Dragados Offshore in Cadiz, Spain, who is specialized in building offshore modules. The new OHVS, which will be built for German-Dutch grid operator TenneT, has a capacity of 900 megawatt and will be located in the German North Sea.

The offshore converter platform transforms power from the incoming wind turbines via 155 kV high voltage cables AC to 320kV high voltage DC. The power is exported to the converter station onshore, where the power is converted back to AC and connected to the high voltage AC grid. The platform will be bridge‐linked to the existing Dolwin beta platform.


Heinen & Hopman will design and supply the HVAC systems and will be involved during installation – onshore and offshore commissioning – into 2023. High-quality materials will be used to avoid corrosion and guarantee the 30 year design lifetime of the platform.

The contract is considered a major milestone for both Heinen & Hopman and Teknotherm Marine, who has gained valuable expertise and competence in this sector. With this prestigious contract, the companies strengthen their activities  in the offshore wind industry.

Design Conditions

The following design conditions are specified:

Design conditions summer

Outside: 30˚C/70% RH
Inside: 25-35˚C/40% RH

Design conditions winter

Outside: -15˚C/70% RH
Inside: 0-20˚C/40% RH

More information

If you want to know more about our HVAC solutions for Offshore High Voltage Stations, don’t hesitate to get in touch.

Do you want to know how our HVAC can benefit your vessel?