Harmony Link is a cross-border electricity interconnector project between Poland and Lithuania intended to strengthen regional security of supply, enable market trading and support integration of renewables as part of the Baltic states’ synchronisation with the Continental European Synchronous Ar...
Litgrid placed orders for 330 kV shunt reactors to support the Harmony Link land connection with Poland and associated 330 kV network upgrades in Lithuania, awarding a supply contract for these grid components.
LITGRID AB is constructing a new 330 kV onshore substation at Darbėnai in Lithuania, which ENTSO-E documentation describes as necessary for connecting the Harmony Link HVDC subsea cable along with the Darbėnai–Bitėnai line and an offshore wind farm; EU PCI materials indicate the substation is under construction with commissioning planned for 12 December 2025.
Litgrid signed a design services and construction works contract with the consortium UAB Energetikos projektavimo institutas and UAB Ener-G Design for the Harmony Link overland interconnector in Lithuania, covering design of a 220 kV transmission line and the 330/220/110/10 kV Gižai transformer substation, with a contract value of EUR 2.2 million excluding VAT and an expected design phase of 29 months until construction permits are obtained.
Upgrade to access detailed cable specifications, supply chain data, projected timeline, financial analysis, and more.
Owners
Polish–Lithuanian submarine HVDC cable, Poland–Lithuania HVDC cable interconnection, Poland–Lithuania interconnector, Harmony Link onshore AC interconnector, Harmony Link overland (double-circuit 220 kV AC) interconnector
In March 2025, Litgrid prepared the concept of the engineering infrastructure development plan for the Harmony Link overland interconnector in Lithuania and a Strategic Environmental Assessment (SEA) report, forming part of the territorial planning and impact assessment work for the new 220 kV line and associated Gižai substation.
Litgrid launched a public procurement process for design services for the Harmony Link onshore connection in Lithuania, seeking a contractor to define technical solutions and design key infrastructure elements including a 220 kV transmission line and the 330/220/110/10 kV Gižai transformer substation.
On 19 August 2024, Litgrid reported that the Harmony Link overland interconnector project between Lithuania and Poland had been granted the status of a project of special national importance in Lithuania, coinciding with the start of spatial planning and environmental impact assessment works for the land-based connection.
On 15 July 2024, PSE and Litgrid signed a cooperation agreement to implement Harmony Link as a new overland double‑circuit 220 kV AC interconnection between Ełk Bis in Poland and a new substation near Gižai in Lithuania, including new Norki and Wigry substations in Poland and an upgraded Ostrołęka–Ełk Bis line, establishing the framework for developing the reconfigured onshore project.
In June 2024, transmission system operators from Estonia, Latvia, Lithuania and Poland received results of the first phase of a power flows and dynamic feasibility study, which confirmed that implementing Harmony Link as an overland 220 kV AC interconnector would be technically viable and could provide system stability comparable to the previously planned subsea HVDC link.
Construction work started in June 2023 at the Darbėnai transmission station in Lithuania, a 330 kV switchyard required to connect the planned Harmony Link interconnector into the Lithuanian electricity system. The Darbėnai facility, located in the Kretinga region, forms part of the onshore infrastructure (converter station and switchyard) needed to integrate the direct current connection with the existing 330 kV network.
PSE and Litgrid reported that the Harmony Link project implementation study had been completed in 2021, providing a key technical and planning basis for moving the interconnector into its implementation phase and supporting preparation of tender documentation for cables and converter stations.
By October 2021, Litgrid and PSE had completed the seabed geophysical survey of the Baltic Sea route for the planned Harmony Link submarine interconnector, finalising data collection on bathymetry and seabed characteristics needed to refine the cable route and installation methodology.
On completion of the Harmony Link seabed investigation campaign reported in October 2021, the geotechnical survey work in the Baltic Sea—comprising soil investigations along the planned cable corridor—was also concluded, providing input for detailed design of cable burial and protection.
The October 2021 announcement that the Harmony Link seabed survey had been completed also marked the end of the UXO and hazardous object detection activities along the offshore route, confirming that wrecks, unexploded ordnance and other debris had been identified for consideration in subsequent cable design and installation plans.
On 1 September 2021, LTG approved Resolution No. 720, the Engineering Infrastructure Development Plan for the project of special national importance covering construction of the electricity system synchronisation Harmony Link connector and the 330 kV Darbėnai switchyard in Lithuania. This resolution established the planned area for the Harmony Link connector corridor, providing a key spatial planning approval for the project’s infrastructure.
On 31 May 2021, Polish and Lithuanian TSOs PSE and Litgrid each approved their final investment decisions for the offshore HVDC Harmony Link interconnector, moving the project into the implementation phase and enabling tenders for the submarine cable and converter stations for the 700 MW, ~330 km link between Żarnowiec in Poland and the future Darbėnai substation in Lithuania, with total project cost stated at around EUR 700 million.
By the time final investment decisions were announced at the end of May 2021, Litgrid had acquired a plot of land in Darbėnai, Lithuania, designated for the Harmony Link converter station, securing the onshore site needed to connect the subsea HVDC cable into the Lithuanian transmission system.
By the time of the final investment decisions in May 2021, Harmony Link was described by PSE and Litgrid as being co-financed under the EU’s Connecting Europe Facility with grants exceeding EUR 500 million, providing substantial non‑repayable capital support towards the approximately EUR 700 million cost of the offshore HVDC interconnector.
In early February 2021, the seabed survey campaign for the planned Harmony Link submarine cable between Lithuania and Poland began in the Baltic Sea, with a MEWO‑led consortium carrying out geophysical investigations along the offshore route to characterise seabed conditions and support cable route design and protection strategy.
As part of the seabed survey campaign that commenced in early February 2021 for Harmony Link’s Baltic Sea route, the MEWO, Gdynia Maritime University and Garant Diving consortium also started geotechnical surveys to investigate subsurface soil conditions needed for detailed cable installation and burial design.
When the Harmony Link seabed survey began in early February 2021, the MEWO‑led consortium also initiated unexploded ordnance (UXO) detection activities along the planned cable route in the Baltic Sea, using the geophysical campaign to locate wrecks, UXO and other hazardous seabed objects that could affect cable installation.
In 2021, a project implementation study for the Harmony Link interconnector was completed, providing a detailed assessment of how the subsea HVDC link between the Żarnowiec substation in Poland and the planned Darbėnai substation in Lithuania would be realised and supporting subsequent investment decisions.
Litgrid initiated the procurement process for seabed survey services for the Harmony Link offshore cable, launching tendering based on the prepared cable route alternatives as part of the project’s preparatory phase.
Litgrid completed the procurement of services to prepare technical specifications for the Harmony Link cables and converter stations and signed a contract with the selected supplier for this engineering scope.
By 2020, the project "Construction of Harmony Link connection and 330 kV switchyard Darbėnai" had been classified in Lithuania as a project for synchronisation of the electric energy system of special state significance, as reflected in the engineering infrastructure development plan and strategic environmental impact assessment summary prepared for Harmony Link and the Darbėnai switchyard.
PSE and Litgrid signed an agreement with a consortium led by MEWO S.A., together with Gdynia Maritime University and Garant Diving UAB, awarding them the contract to carry out geophysical and geotechnical seabed surveys along the planned Harmony Link cable route in the Baltic Sea, including UXO and debris detection.
On 26 May 2020, Litgrid and PSE signed the Harmony Link Implementation Phase Cooperation Agreement, setting an estimated project value of about EUR 680 million and defining the financial and scope split whereby each TSO would fully fund the onshore cable and converter station in its own territory while sharing offshore cable costs 50/50, with Litgrid responsible for procuring the HVDC cable works and PSE for the HVDC converter stations.
On 22 January 2020, a Harmony Link marine survey consultancy for the sea section, including landing points on the Polish and Lithuanian shores, was conducted; following spatial assessments of the marine environment, geological and oceanographic conditions, two alternative offshore cable installation sites and corresponding cable exit points P1 and P2 near Būtingė in Palanga municipality were selected.
In 2019, the European Commission’s fourth list of Projects of Common Interest (PCI) in the electricity sector included the new Harmony Link submarine power interconnection between Lithuania and Poland as one of the key infrastructure projects needed for synchronising the Baltic States’ electricity systems with the continental European network.
On 3 December 2019, the heads of Lithuanian and Polish transmission system operators Litgrid and PSE signed an agreement with the EU’s Innovation and Networks Executive Agency for EUR 10 million in Connecting Europe Facility support to fund preparatory work for the Harmony Link submarine interconnection, including route selection studies, seabed surveys, technical specifications, and spatial planning. Of this total, EUR 4 million was allocated to Lithuania.
On 21 December 2018, Lithuanian transmission system operator Litgrid and Polish operator PSE signed an agreement to start planning and jointly develop the Harmony Link high-voltage direct current (HVDC) submarine power interconnector between Lithuania and Poland, giving the project its official name and establishing their cooperation framework for this key Baltic–Continental Europe synchronisation project.
On 21 December 2018, Lithuanian transmission system operator Litgrid and Polish operator PSE signed an agreement to start planning a new interconnector between the two countries, giving the project the official name Harmony Link and formally launching its development phase.
Showing historic events only. Subscribe for the full timeline including projected milestones.