DolWin Alpha HVDC offshore platform

DolWin Alpha

The project

Some 60 kilometres off the German coast in the North Sea is the DolWin Alpha platform, an 800 MW offshore HVDC converter station that converts alternating current into direct current to connect offshore wind farms. The DolWin Alpha platform was designed to provide a robust solution for connecting offshore wind farms to the onshore electricity grid.

The challenge

The challenge of this project was to efficiently convert alternating current to direct current for long-distance transmission without energy loss. Iv undertook the complex technical task of designing the DolWin Alpha platform. A detailed design of the platform and the necessary facilities was drawn up with the main contractors, Siemens and Heerema Fabrication Group. This included the conversion from 155 kV AC to 320 kV DC and the integration of control and protection mechanisms.

The impact

The platform enables the efficient transfer of electricity from offshore wind farms to the mainland, thus contributing to the increase of sustainable energy capacity. This strengthens the position of offshore wind energy as a reliable and clean energy source while supporting the transition to renewable energy sources and helping to reduce dependence on fossil fuels.

Technical data

Topside: 62 x 43,3 x 40m (excluding helicopter deck)

Jacket: 45 x 42 x 44m



Topside: 11,000 mT

Jacket: 4,000 mT       


Water depth: 27m

Accommodation: 24 persons

Input: 8 cables of 155 kV AC

Output: 2 x 320 kV DC

Throughput: 800 MW

Electricity generation: 2 x 3050 kV A/ 10 kV Diesel

Curious about the possibilities for your project?

Fedor, managing director of Offshore & Energy/Infra and also COO of Iv, would be delighted to discuss this with you! Get in touch via +31 88 943 3300 or send a message.

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Fedor van Veen