Soon after Russia’s invasion of Ukraine in 2022, Latvia and Estonia had ceased trading electricity with Russia, and Lithuania reduced its electricity imports. Synchronisation with continental Europe is the final step to achieving the countries’ independence in terms of electricity supply.

At present, the energy systems of Estonia, Latvia and Lithuania are still operating within the IPS/UPS (isolated power supply/uninterruptible power supply) system, where system frequency is controlled by Russia.

Operating synchronously with the energy system of continental Europe will provide the energy systems of the Baltic States with independent and secure system frequency control and increased energy supply security, while fostering the development of Europe’s internal energy market, creating new business opportunities. In addition, investments made within the framework of the project in equipment and technologies are one of the prerequisites for the transmission grid to be able to securely connect major sources of renewable energy and fulfil the objectives of the European Green Deal.

How will it happen?    
The Baltic energy system will disconnect from Russia’s unified energy system (the ‘BRELL’ transmission system which expires on 7 February 2025) and join the European system on 7–9 February 2025.

On 8 February 2025, Baltic operators will disconnect the energy system of Estonia, Latvia and Lithuania from the IPS/UPS grid, terminating the Baltic 21 connection to Russia’s energy system. From then on, the inertia and frequency of the Baltic states’ electricity system will no longer be overseen by Russia.

Afterwards, an isolated operational test of the Baltic energy system will be carried out. During this time, the Baltic states will be in ‘island mode’, where the network operation will be covered by local capabilities.

After completion of the test on 9 February, the Baltic states’ energy system will connect to continental Europe’s energy system, and synchronisation will take place along the 400 kV overhead power transmission line from Lithuania to Poland. At that point, within the energy systems of the Baltics and continental Europe, generation rotation frequencies will be balanced, making the operation of the energy system more stable. Consumers will not be able to detect synchronisation reconnections.

Fig 1: Map showing existing and new electricity grid infrastructure in (from top) Estonia, Latvia, Lithuania and Poland    
Source: Estonian electrical utility Elering

When did this all start?     
The switch dates back to an agreement between the Baltic states’ prime ministers in 2007, three years after joining the EU.  

Over the past 15 years, the Baltic power transmission system operators have carried out preparatory work. According to Elering, the synchronisation project will be split into three stages, mostly funded by public money from Europe. Stage one, €430mn, is to reinforce domestic network connections and build three synchronous condensers (see Box). Stage two, €700mn, is to build a connection between Lithuania and Poland, as well as network reinforcements, and to supply six more condensers. Stage three, €230mn, is to renovate high-voltage power lines, develop substations, pay for battery-electric storage systems in Latvia, renovate control systems in Estonia, including for the Estlink 1 and 2 submarine cables.

Latvia’s utility AST states that the synchronisation project will not affect electricity tariffs in 2025. In 2026, the overall impact of synchronisation costs on the system service tariff period will be about 1%, and 0.25% on the distribution tariff.

Likewise, the other Baltic states do not expect the synchronisation project to have a significant effect on overall electricity charges. Because the main factors affecting prices in the Baltic states are local production, fuel prices, weather conditions and the availability of network infrastructure. These factors remain unchanged throughout the year.

To ensure the stable operation of the Baltic electricity system, balancing reserves are crucial. Still, Latvia’s utility forecasts that, just like in Estonia and Lithuania, the ultimate impact on electricity bills in Latvia of the cost of the balancing reserves required by the Baltic states for the stable operation of the energy system will be less than 5%.

Chairman of the Board of Latvia’s ATS Rolands Irklis says: ‘Just like integration into the European Union and NATO, Latvia’s integration into the European energy system is a decisively important and logical next step on the road to complete energy independence. Through close cooperation, the Baltic transmission system operators have succeeded in successfully preparing this major European joint interest project with significant EU co-financing, as a result having no significant impact on the transmission tariff or electricity prices.’

And Estonian grid operator Elering remarks: ‘Estonia is acceded to carbon neutrality goals aimed at slowing global climate change. It is thus not conceivable to invest in renewable energy at home while consuming electricity of unknown environmental footprint from third countries. Carbon emissions will not decrease if the emissions merely are diverted outside the border of the EU.’

It continues: ‘Besides energy security, better integration of Estonia with the European system would improve the international competitiveness of the local economy. In the course of synchronisation, new markets and products will arise alongside existing electricity markets, and this will increase the opportunities for local electricity producers to sell electricity.’

The Lithuanian TSO adds that electricity trade with mainland Europe will increase with construction of the new Harmony Link interconnector to Poland, which is expected to be operational in 2030. Early plans for a marine cable were cancelled in 2023 for cost reasons. Now the project is intended to consist of a double-circuit 220 kV AC transmission line running onshore between Ełk Bis (Poland) and the planned Gižai substation in the Vilkaviskis district of Lithuania. The line should be energised by the end of 2030.

The Lithuanian operator points out that the disconnection will also separate it and Baltic neighbours from the 4,400 MW Belarusian Astravets nuclear power plant, about 45 km from Lithuania’s capital city Vilnius.  

According to Latvian Climate and Energy Minister Kaspars Melnis: ‘Synchronisation aims to ensure that we can maintain and control the grid ourselves, ensure stability so that we are not dependent on the actions of our neighbours.’

The three TSOs have formally agreed to continue to collaborate after the switch-over has been completed, having signed a deal in November 2024 to ensure reliable operation, optimal management and technical development. The Baltic system operation region will become a new system operation region, alongside Nordic, Central Europe, South-eastern Europe and South-western Europe.

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