Estlink is a set of HVDC submarine power cables between Estonia and Finland. Estlink 1 is the first interconnection between the Baltic and Nordic electricity markets followed by Estlink 2 in 2014. The main purpose of the Estlink connection is to secure power supply in both regions to integrate the Baltic and Nordic energy markets. Estlink 1 History First plans for a submarine power cable between the Baltic and the Nordic regions were proposed in 1990s. Negotiations between Eesti Energia, Pohjolan Voima, Helsingin Energia, Graninge (now E.ON Sverige), Latvenergo, Statkraft and TXE Nordic Energy, a subsidiary of TXU (now Energy Future Holdings Corporation) started In 1999, and on 9 October 2001 a contract was signed in Tallinn. However, only after the harsh winter of 2002–2003 which resulted in an increased demand for power, the project of the submarine cable between Estonia and Finland got a boost. The letter of intention for underwater sea cable was signed between Eesti Energia, Pohjolan Voima, Helsingin Energia and Latvenergo on 31 March 2003. In May 2004, the Lithuanian power company Lietuvos Energija agreed to participate in the project, shortly after which the project company AS Nordic Energy Link was established. On 29 April 2005, the Estlink project was launched. Construction of Harku converter station and land cable installation begins on 5 April 2006. The submarine cable was laid in September 2006. The Estlink cable was inaugurated on 4 December 2006 and it became fully operational on 5 January 2007. The Estlink 1 cable was operated by AS Nordic Energy Link company, founded by Baltic and Finnish power companies. The main shareholder was Eesti Energia with 39.9% of the shares, Latvenergo and Lietuvos Energija had 25% each, and the remaining 10.1% was divided between Pohjolan Voima and Helsingin Energia (operating through their joint project company Finestlink). On 30 December 2013 the interconnector was sold to the transmission system operators Elering and Fingrid. Description The long (including under water) +/-150 kV, 350 MW HVDC link cable is connected to the Estonian electrical system at the Harku 330 kV converter station and to the Finnish transmission network at Espoo 400 kV converter station in Järvikylä using HVDC Light transmission technology. The installation of land cable began on 4 May 2006 in Harku. The submarine cable was laid on the seabed of the Gulf of Finland in the autumn of 2006. The cable's maximum depth on the seabed