PSE and Litgrid signed cooperation agreement to build Harmony Link interconnector as overland line

PSE and Litgrid, transmission system operators in Poland and Lithuania, respectively, on July 14, 2024, signed an agreement on cooperation on the implementation of Harmony Link interconnector as an overland line.

The agreement establishes the general basis of cooperation between PSE and Litgrid for implementing the Harmony Link project. The project involves construction of the new double-circuit 220 kV alternating current (AC) interconnection between substations Ełk Bis (Poland) and the new substation near Gižai (Lithuania) as well as two new substations in Poland on the route of the interconnection, Norki and Wigry. The existing 220 kV power line Ostrołęka - Ełk Bis in Poland will be upgraded to increase its capacity.

By the end of 2024, PSE and Litgrid will make financial investment decision, allowing to start preparations for the procurement and permitting processes. According to the initial schedule, the tender for the construction works will be launched in 2026. The new interconnection is expected to be energized by the end of 2030.

In April 2023, PSE and Litgrid canceled the procurement tenders for constructing the Harmony Link as an offshore HVDC interconnection due to a significant increase in market prices for the cable and converter stations. Both TSOs were committed to continuing the project seeking other technical approaches that would allow to reduce costs and implement the interconnector in the shortest possible time. The chosen option was the construction of the overland AC line across the border between Poland and Lithuania.

In June 2024, TSOs from Estonia, Latvia, Lithuania, and Poland obtained results of the first phase of power flows and dynamic feasibility study carried out by the Institute of Power Engineering, Gdansk Division, Poland. The study confirmed that implementing Harmony Link as an overland AC interconnector is technically viable and provides comparable stability of the interconnected systems as the subsea interconnection.