Estlink 2 Power Interconnector Sabotage

On Christmas Day 2024, the Estlink 2 high-voltage direct current (HVDC) power cable connecting Estonia and Finland had an ‘unplanned failure’, cutting approximately 658 MW of electricity transmission capacity between the Baltic states and the Nordic grid. The cable, which runs across the bed of the Gulf of Finland, was allegedly damaged by the anchor of the Eagle S, a vessel calculated by Finnish and Estonian authorities as part of Russia's 'shadow fleet' transporting sanctioned Russian oil exports.

Incident:

The Eagle S was tracked transiting the Gulf of Finland on 25 December 2024 when its anchor is assessed to have deliberately dragged across the seabed, severing the Estlink 2 cable. Finnish Border Guard and Coast Guard vessels intercepted the Eagle S in Finnish territorial waters, and the vessel was escorted to port in Finland. Analysis of the vessel's AIS (Automatic Identification System) data showed that the Eagle S had significantly reduced speed around the cable, patterns consistent with deliberate anchor dragging. The vessel was on a voyage from a Russian port carrying Russian crude oil. Several crew members were detained for questioning with Finnish authorities launching a criminal investigation for aggravated vandalism.

Impact:

The severing of Estlink 2 significantly reduced the electrical interconnection capacity between the Baltic states and the broader European grid. Estonia, Latvia, and Lithuania, countries in the process of decoupling from the Russian-controlled BRELL electricity ring and synchronising with the European continental grid, rely on interconnectors with Nordic countries as critical infrastructure for energy independence. The outage increased reliance on local generation and the remaining Estlink 1 cable, raising energy security risks during winter. Multiple data cables were also damaged in the same incident, adding telecommunications disruption to the impact. Repair of HVDC subsea cables is a complex, costly, and time-consuming process, with assessments suggesting several months for full restoration.

Attribution:

Finnish, Estonian, and Western intelligence services argue the Eagle S as a member of Russia's shadow fleet and suspected the cable damage to be deliberate sabotage linked to Russian hybrid warfare. The vessel's navigational behaviour, the specific routing over the cable, and the pattern of infrastructure damage across the Baltic region all contributed to this assessment. Russia denied involvement and characterised the incident as an accident.

Lessons:

The Estlink 2 incident highlights the vulnerability of undersea energy infrastructure to hybrid attack using commercially deniable vessels, a method that offers significant legal ambiguity. The incident demonstrates the need for enhanced seabed monitoring, improved AIS anomaly detection, faster interdiction frameworks, and greater investment in cable resilience and repair capacity. It also underscores the strategic importance of energy interconnectors for the Baltic states' independence from Russian energy infrastructure, and the risk that these assets will continue to be targeted. Finland's decision to seize the Eagle S signals a potential shift toward more assertive Western responses to hybrid attacks on critical infrastructure.