AST and Elering Begin a Feasibility Study for the Fourth Estonia–Latvia Electricity Interconnection

To increase transmission capacity between Estonia and Latvia and to support the development of renewable energy sources (RES) in Latvia, Estonia, and the whole Baltic Sea region, it is necessary to continue reinforcement of the electricity transmission network, including the development of new interconnections. The fourth electricity interconnection between Estonia and Latvia is planned as an offshore project in the Baltic Sea between Saaremaa Island in Estonia and the Kurzeme shore in Latvia. To assess the feasibility of such interconnection, the technological solutions and the cost–benefit aspects of the project must be evaluated. For this purpose, the Latvian and Estonian transmission system operators (TSOs) – AS “Augstsprieguma tīkls” (AST) and AS “Elering” together with international energy consultancy companies will begin the technical and economic studies this autumn.

“The power systems of the Baltic States are well interconnected through several high-capacity interconnections. Latvia currently has three interconnections with Estonia, two of which were reconstructed as part of the Baltic Synchronisation Project. Considering the expected increase of renewable generation and future electricity demand, it is essential to continue investing both in strengthening Latvia’s internal transmission network and in the development of new interconnections. The fourth Latvia–Estonia interconnection will increase system security and stability and support the integration of higher RES amounts into the Estonian and Latvian transmission networks, thus contributing to both countries’ climate targets. The studies initiated together with the Estonian transmission system operator will help identify the optimal technological solution and more precisely determine the project’s costs and benefits for both countries,” said Arnis Daugulis, Member of the Management Board of AST.

As part of the studies, a technical and economic analysis will be carried out for various interconnection configuration options, considering three potential connection points in Latvia and two in Estonia, to identify the optimal technical solution. The technological study will be performed by the Italian energy consultant CESI S.p.A. by February 2026 for EUR 165,000, while the cost–benefit study will be prepared by the French company Artelys SAS by March 2026 for EUR 79,000. The TSOs selected the consultants during a joint procurement procedure, and the costs will be shared equally between both TSOs.

In parallel with the interconnection feasibility studies, each TSO is actively developing internal grid reinforcements for secure and stable operation of interconnection. AST is preparing an Environmental Impact Assessment (EIA) for the 330 kV transmission line Ventspils–Brocēni–Varduva in territory of Latvia, in accordance with the EIA programme issued by the Energy and Environmental Agency. EIA in Latvia to be completed by the summer 2026. In Estonia, Elering is conducting spatial planning activities, including EIA, for a new planned 330 kV transmission line from Saaremaa Island to the onshore transmission network of Estonia.

In October 2023, AST and Elering signed a Memorandum of Understanding on cooperation in development of the fourth Estonia–Latvia electricity transmission interconnection. The new interconnection is planned as a hybrid project – in addition to connecting the power systems of both countries, it will also allow for the connection of planned offshore wind farms in Latvia and additional renewable energy projects in Estonia. Based on the previous assessment and technical analysis, the planned capacity of the interconnection is 1,000 MW. The interconnection is expected to be commissioned by 2035, following the necessary investments in transmission infrastructure.

The TSOs plan to implement the construction of the project with the European Union (EU) co-financing from Connecting Europe Facility (CEF) grants, ensuring financial support for both the feasibility studies and construction of the interconnection. The TSOs of both countries have completed all preparatory steps to include the project in national and EU development plans. Following the approval of EU co-financing, the operators will decide on the next steps of project implementation.

About AS Augstsprieguma tīkls

AST is Latvia's power transmission system operator, which ensures continuous, secure and sustainably efficient power transmission throughout Latvia. Its vision is to become the region's leading transmission system operator, which implements development-oriented changes efficiently and successfully. AST owns 68.46% of shares in the natural gas transmission and storage system operator AS Conexus Baltic Grid.