Estlink 1

Talks on a cable between Estonia and Finland started in 1999. For six years nothing was built, and the Baltic grid stayed almost cut off from the West, tied instead to Russia and Belarus. A harsh winter finally pushed the project forward, and Estlink 1 was completed in 2006.

It was not built by the grid operators. The owner was AS Nordic Energy Link, a company of utilities: Eesti Energia held 39.9%, Latvenergo and Lietuvos Energija 25% each, and Pohjolan Voima with Helsingin Energia the remaining 10.1%. Work was launched on 29 April 2005, the subsea cable went down in September 2006, the link was inaugurated on 4 December 2006 and it became fully operational on 5 January 2007. The Estlink article on Wikipedia puts the cost at €110 million. On 30 December 2013 the utilities sold it to the two national operators, Elering and Fingrid, who run it today.

Technically it was an early example of the voltage-source approach described on the HVDC explainer. Hitachi Energy, which built it as ABB, notes that the whole route is either underground or underwater, with extruded oil-free cables and no overhead line anywhere. The converters can also help restart the Estonian grid after a blackout, a black-start role that few links of its age were designed for.

Demand outran it quickly. The line soon became one of the most congested on the Nord Pool spot market, and that congestion is the reason Estlink 2 followed in 2014.

The older link has had its own trouble. On 1 September 2025 it tripped at 05:46 because of a fault in a reactor at the Espoo converter station. Elering said the evidence pointed to a technical fault, not sabotage, and repairs were estimated at about three weeks, as ERR News reported. Nord Pool messages gave 24 September as the return date.

The next step is a new brain for the old hardware: a MACH control and protection system, which Hitachi Energy says it will install in 2027 to extend the link’s working life.