DolWin5

In autumn 2025, following completion of the offshore installation campaign, TenneT and its contractors Aibel, Seatrium, Hitachi Energy, and Prysmian carried out commissioning and dynamic testing of the 900 MW DolWin5 HVDC offshore grid connection, during which ancillary systems were put into operation, converter and high-voltage components underwent undervoltage setting and dynamic tests, and the system was fully energised and ready to transmit power from Borkum Riffgrund 3 to the Emden/East onshore station.

By August 2025, the DolWin epsilon offshore converter platform for the DolWin5 project had been completed and commissioned, with consortium partners Aibel and Seatrium constructing the 27,000-ton platform and Hitachi Energy designing, delivering, and installing the HVDC equipment including converter valves, transformers, and high-voltage switchgear, ready to support 900 MW power transmission in the German North Sea.

In June 2025, TenneT installed the 27,000-tonne DolWin epsilon 900 MW HVDC offshore converter platform at its final location in the German North Sea, marking the start of offshore commissioning works for the DolWin5 grid connection. The platform was built by Seatrium (Singapore) and outfitted by Aibel (Haugesund, Norway) with Hitachi Energy HVDC equipment.

Prysmian commenced DolWin5 cable installation: land portion completed 2022, Wadden Sea and nearshore 2022-2023, offshore segment completed 2023, project wrapped January 2024. First project where Prysmian executed full submarine installation in-house using Barbarossa I barge.

On 15 October 2023, the 900 MW DolWin epsilon offshore converter platform for the DolWin5 grid connection departed Seatrium’s shipyard in Singapore aboard the heavy‑transport vessel Mighty Servant 1 for shipment to Aibel’s yard in Haugesund, Norway, after around three years of construction and more than ten million man‑hours, marking a major fabrication and delivery milestone prior to final outfitting and HVDC equipment installation.

In 2022, TenneT reached a key construction milestone on the DolWin5 offshore grid connection when a topping-out ceremony was held at the Emden/East land station, marking substantial structural completion of the onshore converter station buildings that will receive and reconvert power from the DolWin epsilon offshore platform before feeding it into the extra‑high‑voltage grid.

During 2022, nearshore cables for the DolWin5 grid connection were laid and the ongoing land cable installation progressed, advancing construction of the 130‑kilometre HVDC route linking the DolWin epsilon offshore converter platform with the Emden/East onshore converter station.

In spring 2021, TenneT began foundation works for the DolWin5 onshore converter station at Emden/East, marking the start of onshore construction for the 900 MW HVDC grid connection that converts power from the DolWin epsilon offshore platform back to AC and feeds it into the extra‑high‑voltage grid.