The Norderney I export cable system connecting the offshore wind farm alpha ventus to the onshore substation at Hagermarsch via the island of Norderney was completed in May 2009 and entered operational service as part of the Offshore-Ist-Netz Nordsee. The system comprises a subsea and onshore cable route that transmits power from the alpha ventus offshore platform, where voltage is stepped up to 110 kV, through Norderney to the mainland grid connection point.
In 2009, during the spring to autumn construction phase, the project’s substation (Umspannwerk) was commissioned in parallel with the connection of the sea cable, as part of the grid connection works outlined in the construction overview.
During the winter of 2007–08, network operator transpower (formerly E.ON Netz) installed cable pipes and a 1.5‑kilometre empty pipe construction beneath the island of Norderney, routing them under existing roads, paths, and dunes to form a multi-duct corridor for nine three-phase and four direct-current connections between offshore wind farms, the island crossing, and the mainland substation at Diele. This trench-based installation through the Wadden Sea National Park created the core under-island ducting used as a transit corridor for multiple grid connections, enabling additional cables to be added later without complex new construction.
| Lower Saxony | Lower Saxony | |
|---|---|---|
| Landfall | Norderney, Germany | Hilgenriedersiel, Germany |
| Grid Connection | Hagermarsch substation | Hager Marsch (Hagermarsch) transformer/substation |
Lower Saxony
Lower Saxony