Continental European TSOs announce completion of synchronisation project with AST, Elering and Litgrid
The electricity transmission system operators (TSOs) of Continental Europe have confirmed the successful synchronisation of Estonia, Latvia, and Lithuania with the Continental Europe Synchronous Area. This milestone means Elering, Augstsprieguma tīkls (AST), and Litgrid, the TSOs of Estonia, Latvia, and Lithuania, now meet all key technical requirements for permanent interconnection with Continental Europe’s power system via Poland.
The successful trial synchronisation of Estonia, Latvia, and Lithuania was confirmed by the Regional Group Continental Europe (RGCE) of the European Network of Transmission System Operators for Electricity (ENTSO-E). Since 9 February 2025, the Baltic States have been operating in trial synchronisation mode, during which all the parameters of the synchronous connection were monitored and evaluated.
As of 25 November 2025, AST, Elering and Litgrid are members of ENTSO-E's Regional Group of TSOs from Continental Europe.
The Baltic synchronisation project formally began on 29 May 2019, when TSOs in Poland, the three Baltic States and the supporting countries of the Continental Europe Synchronous Area signed a Connection Agreement establishing the technical connection conditions that would make Lithuania, Latvia and Estonia part of the Continental European Network. Today’s announcement signals the full implementation of the conditions included in this Agreement.
The synchronisation enables the Baltic States to manage their electricity grids in close cooperation with all other Continental European countries, with stable and reliable frequency control, significantly enhancing regional energy security. Previously relying on the Russian system for frequency management, the Baltic States have joined the synchronous grid of Continental Europe, which serves over 400 million customers.
This process followed years of thorough preparation and cooperation among the Baltic transmission system operators and their counterparts in the Continental Europe Synchronous Area. A particularly important role of the Polish TSO Polskie Sieci Elektroenergetyczne (PSE) was the overall coordination and project management, as a direct neighbour and as the system which physically connects the Baltic States’ systems to Continental Europe. Extensive infrastructure upgrades in the Baltic states and Poland were essential for this achievement. Amprion as Continental European Coordination Centre North supported the planning and coordination of synchronisation.
This synchronisation has been strongly supported by the European Union and ENTSO-E, thanks to the co-financing of the European Union. Their contributions included technical guidance, operational and legal expertise.