Vattenfall completed the installation of a new submarine electric cable between Gränsö and Viddviken northwest of Arkö in the northern Baltic Sea, leading to the Swedish Hydrographic Office updating chart 621 to show the new cable alignment and marking the previous cable route as out of use as of the situation date 26 November 2025.
A Swedish Notice to Mariners issued for the area northwest of Arkö near Gränsö records that an electric submarine cable has been established between positions a) and c), while the previous cable between positions d) and e) is now classified as not in use, with the situation effective from 26 November 2025 and published by Vattenfall on 10 December 2025.
Swedish Notices to Mariners (Ufs) No. 964, notice 17573(T), published 2023-05-24, states that submarine cable works (sjökabelarbete) by Vattenfall are taking place northwest of Arkö between Gränsö and Viddviken in the Northern Baltic during the period 29 May–4 June. This confirms that cable installation activities in the specified area began on 29 May 2023.
| Stockholm County | Stockholm archipelago | |
|---|---|---|
| Landfall | Gränsö | Viddviken |
| Grid Connection | — | — |
Stockholm County
Stockholm archipelago