Amprion Breaks Ground on DolWin4 and BorWin4 Offshore Grid Connections

German transmission system operator Amprion has started construction work on the DolWin4 and BorWin4 offshore grid connection systems with a groundbreaking ceremony on Norderney Island’s North Beach.


The drilling to cross below the island of Norderney marks the start of construction work for Amprion’s first offshore projects, which are scheduled to go into operation in 2028 and 2029.

DolWin4 and BorWin4 will connect offshore wind farms in the North Sea with the onshore transmission grid. The transmitted power corresponds to the demand of a major city like Hamburg, Amprion said.

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“The expansion of offshore wind energy is a central pillar of our energy transition. Lower Saxony plays a special role in this,” said Lower Saxony’s Environment Minister Olaf Lies who participated in breaking the ground.

”We are becoming the gateway and hub for climate-friendly energy for all of Germany. Particularly in view of the current major energy policy challenges, we need not only expansion, but also grid connection. That’s why dates like today send out an encouraging signal. Because progress is also being made with grid connection. That’s why I’m particularly pleased to be able to congratulate Amprion on the first construction activities in the offshore sector. We need wind power in particular to ensure a free, clean and independent energy supply.”

This summer, Amprion will drill the first four of a total of twelve horizontal wells in the coastal sea.

”For the first time, we are bundling the drilling for two projects within one construction window,” said Dr. Carsten Lehmköster, one of the two managing directors of Amprion Offshore GmbH.

”This allows us to accelerate the projects while minimizing the intervention.”

The drilling will be carried out using the so-called horizontal directional drilling (HDD) method. In this process, cable protection tubes are inserted into the drilling channels, into which the direct current cables are subsequently pulled.

For the construction work, Amprion is using a construction window set by the authorities between mid-July and the end of September.

This summer, Amprion will drill a length of around 1,100 metres from the center of the island in the direction of Nordstrand. In 2023, the borehole will be drilled from the center of the island in a southerly direction, before the coastal protection dike near Hilgenriedersiel is finally crossed in 2024.

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The DolWin4 and BorWin4 offshore grid connection systems, which run largely in parallel, are among the most important energy transition projects in Germany, Amprion said. From the North Sea wind farms, the cables will initially run 60 and 125 kilometres at sea. They cross below the island of Norderney and reach the coast in the Hilgenriedersiel. From there, they run for around 155 kilometres as underground cables toward the Hanekenfähr substation in Lingen, where Amprion will connect them to its transmission network. There, the Emsland nuclear power plant will be taken off the grid at the end of 2022. The generation capacity will be replaced by 1.8 gigawatts of offshore wind energy via DolWin4 and BorWin4.

Amprion is currently planning five offshore grid connection systems. Others have already been confirmed in the grid development plan.

”In the future, the large power plants to supply the industrial regions and citizens will be located in the North Sea,” said Amprion CTO Dr. Hendrik Neumann.

”DolWin4 and BorWin4 are at the beginning of a series of offshore grid connections that our company will realize in the coming years.”

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