Summary
The undersea Estlink-2 power cable linking Finland and Estonia experienced an outage on Wednesday, prompting an investigation, Finnish Prime Minister Petteri Orpo announced.
Authorities stated the disruption will not affect electricity supplies in Finland or Estonia.
Concerns are heightened due to recent incidents involving undersea infrastructure in the Baltic, including severed data cables in November and the 2022 sabotage of the Nord Stream pipelines.
The cause of the Estlink-2 outage remains unclear.
I think they have the right suspect - that ship did some maneuvering which was very odd. Pekka Lund has posted an animation of how it behaved:
https://bsky.app/profile/pekka.bsky.social/post/3le5jowncic2t
Edit: one can consider this almost solved. Motivation and who paid whom remain to be figured out, but when the border guard asked the ship to lift its anchors, it lifted an anchor chain without an anchor attached.
https://news.err.ee/1609560763/finnish-police-ship-at-the-site-of-estlink-2-s-breakage-missing-anchor