Consortium secures €7 billion German North Sea HVDC substation platform contract

A consortium of Siemens Energy and Spain's Dragados Offshore has signed a €7 billion agreement with grid operator Tennet to supply high-voltage direct current transmission technology for three connections in the German North Sea.

Converter technology is fundamental to connecting offshore wind farms to the onshore grid (pic credit: Siemens Energy)
Converter technology is fundamental to connecting offshore wind farms to the onshore grid (pic credit: Siemens Energy)

The framework deal completes Tennet's current plans for 2GW of offshore wind connections in German and Dutch waters, having awarded €23 billion of contracts, spanning 11 projects, at the end of March.

The three latest grid connections – BalWin3, LanWin2 and LanWin4 – will transport electricity from wind farms in the German North Sea to grid connection points in the north of Germany. Each of the systems has a transmission capacity of 2GW.

The substation converter platforms being supplied by the consortium will collect alternating current (AC) generated by several wind farms and convert it into high-voltage direct current (HVDC). This will be reconverted into AC at onshore stations approximately 200 kilometres away in the towns of Wilhelmshaven and Heide.

Siemens Energy will manufacture the main electrical components for the platforms – including switchgears, transformers and converter technologies - at its factories in Europe. 

Dragados is responsible for the construction and offshore installation of the platforms. Each platform weighs around 34,000 tonnes and will generate more than 2,000 jobs during construction, until 2031.


Siemens and Dragados are already working together on similar German projects. In January, grid operator Amprion Offshore awarded the consortium contracts for 2GW converter platforms for the BalWin1 and BalWin2 HVDC grid connection projects. 

The two companies are also jointly producing and installing the following 900MW HVDC platforms: DolWin 6 and BorWin 5, both for Tennet; and DolWin 4 and BorWin 4, awarded by Amprion.

Dragados will now be working on nine HVDC grid connection projects in total, all to connect wind farms in Germany. For Siemens, which has already completed five such projects in the German North Sea, 11 projects are ongoing, covering Germany, the UK and the US. 

Once all current projects are commissioned, Siemens said its HVDC technology will feed more than 19GW of wind power into high-voltage grids worldwide.

Tim Holt, executive board member at Siemens Energy, said grid expansion must keep pace with the accelerated expansion targets for renewable energies in the global race against climate change. 

“Shorter contracting processes, large-scale tenders and standardisation of solutions show how grid operators and manufacturers are already pulling together to get green energy to consumers faster,” he said. 

He added that “all levers must now be pulled” by policy makers, from raw materials to skills and permitting processes, to enable the industry to ramp up capacity.

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