The ceremony, which took place on 9 February 2025 in Vilnius, was attended by Minister of Climate and Environment Paulina Hennig-Kloska.

The synchronisation is the culmination of the efforts of people who, through years of hard work in negotiations, conceptual work, analysis, construction and building, made it possible for us to witness a historic event: the electricity systems of Lithuania, Latvia and Estonia, through Poland, have become a permanent part of the continental system

- said the Minister at the headquarters of the Lithuanian transmission system operator Litgrid.

Paulina Hennig-Kloska emphasised the great importance of completing the second Poland-Lithuania synchronous connection, i.e. the Harmony Link, and protecting the existing and under-construction infrastructure, to which a separate project of common interest (PCI) will be dedicated. She indicated that "the involvement of the European Commission in this work is essential". The Harmony Link will be launched in 2030.

Multi-year preparatory period

Synchronisation was preceded by a years-long preparatory period, which included the negotiation process, concept selection, technical and economic analyses. Part of the analysis was carried out by the Polish Energy Institute Gdańsk Branch. The investments necessary to ensure the safe operation of the Lithuanian, Latvian and Estonian electricity systems have been ongoing for many years. They were carried out both in the Baltic States and in Poland.
Poland's role in this process has been crucial, both at the level of government administration and in cooperation between operators. Polish TSO – Polskie Sieci Elektroenergetyczne S.A. – oversaw the preparatory process for synchronisation on the part of ENTSO-E. Key synchronisation investments received the highest possible EU financial support from the Connecting Europe Fund (75% of costs) and political support from the European Commission. The Commission has overseen and supported the process for many years and at many levels, in particular through the regional initiative Baltic Energy Market Interconnection Plan (BEMIP).
Part of the synchronisation investments, including the second Poland-Lithuania Harmony Link, will continue to be made with the support of EU funding.  
Synchronisation of electricity systems of the Baltic States with continental Europe involves aligning the voltage frequency of these systems with that of the continental European system, i.e. from the Atlantic Ocean to Poland, Ukraine and the Balkan Peninsula, and from the North Sea and Baltic Sea to the Mediterranean. Immediately prior to synchronisation, the Baltic system operators conducted an island operation test.