On the morning of February 8, the Baltic countries will begin disconnecting their power lines linked to Russia and Belarus, a legacy from the Soviet Union. The process will start in Lithuania and conclude in Estonia. By the evening of February 9, Lithuania's lines will be connected to Poland's system and the Continental European grid. In the interim, the three countries will largely need to manage on their own.

The three countries are the last European Union members to connect to the European grid and the desynchronization process has been ongoing for more than 10 years.

"Imagine a private home connected to the grid, equipped with solar panels and batteries. We disconnect it from the grid and attempt to manage for a day and a half to two days using only the solar panels and batteries," said Jako Kilter, head of the Tallinn University of Technology's electrical systems research group, illustrating the process of disconnecting from the Russian frequency area.

In addition to the amount of electricity produced in the region at that time, the alternating current frequency is also a critical factor. Frequency is determined by the rotational speed of electrical machines. In Europe and many other parts of the world, it has been agreed that the frequency of alternating current in power grids is 50 hertz (Hz). This means that current flows 50 times per second in one direction and 50 times per second in the opposite direction.

"Frequency reflects the balance between production and consumption. If the grid's frequency, agreed upon between countries, is 50 Hz, production and consumption are balanced. If there isn't enough production, the frequency begins to drop. If production exceeds consumption, the frequency rises," Kilter explained.

"Why is this important? Builders of electrical devices design them based on the agreed-upon frequency. If the frequency rises or falls too much, electrical devices may stop functioning properly," he added. For instance, if the frequency drops, electric motors may rotate too slowly and fail to operate necessary mechanisms. Conversely, if the frequency increases, the motors could rotate too quickly and overheat.

Electricity producers also rely on this agreed frequency to operate their machines. For example, the windings of an electricity generator must rotate 3,000 times per minute to produce a 50 Hz current, based on this proportional relationship.

A general rule of thumb is that the larger the electrical system, the more stable its frequency. This is one of the reasons Estonia waited so long to disconnect from the Northwest Russian power grid. Larger electrical systems have greater inertia, meaning they can better absorb the temporary imbalances in production and consumption caused by the unexpected loss of a major producer or consumer. This helps prevent significant frequency fluctuations.

It is also worth emphasizing that while Estonia is connected to Russia's electrical system, no actual electricity purchases take place. "Due to the laws of physics, some flow may occur between grids, but as far as I understand from [TSO] Elering, they aim to keep the exchange capacity at zero. This means no money changes hands," Kilter noted.

There will likely be no power outages

According to Jako Kilter, there should be no issues with supply security. He emphasized that after separating their power grids from Russia, the three Baltic states will operate as a single "island." Estonia will not rely solely on its own production capacity; instead, production and consumption will be shared among the three nations. In addition to Estonia's gas turbines and oil shale power plants, Latvia's hydroelectric resources, among others, will contribute to the effort.

Estonia will also be able to exchange electricity with Finland via undersea cables, while Lithuania has a similar connection with Sweden. However, Finland and Sweden will remain part of a different frequency area. "Their electrical machines rotate at a different angle. Synchronism occurs when machines at the ends of a system rotate in the same way," Kilter explained.

Although machines in both frequency areas may rotate at 50 times per second, their phases of rotation are not identical. This can be compared to two clocks that both tick at one-second intervals, but whose second hands are not aligned at the same moment.

Even if Russia were to damage an undersea cable, Kilter believes it would not cause power outages. However, he could not predict how such an event might affect electricity prices. Should Russia decide to sever its connections earlier than planned, Kilter said the Baltic states are already prepared for that scenario. He added that Russia would find it difficult to take further action without harming its own electrical system.

"Looking at the system as a whole, there are still enough power plants in our region to meet consumption needs. Control centers use specialized software that constantly monitors the system. We can predict consumption fairly accurately and grid operators have ensured adequate reserves are in place," Kilter summarized.

According to Estonia's transmission system operator Elering, to achieve synchronization, the Baltic states have strengthened their power grids and interconnections. Elering reconstructed high-capacity 330-kilovolt power lines originating from the Narva region and extending toward Latvia near Valga. Similar reinforcements were carried out in the Latvian and Lithuanian power systems.

To ensure frequency stability, synchronous compensators have been installed in all three Baltic States to add system inertia. Additionally, electrical systems, IT infrastructure and management systems for existing direct current connections have been upgraded.

Beyond new infrastructure and systems, synchronization efforts will enhance the interoperability of the Baltic states' control centers and provide additional expertise for independently managing their power grids.

Elering states that it has contingency plans in place for various scenarios, including the coincidence of difficult weather conditions and attempts by Russia to unilaterally desynchronize the Baltics, in which case the transitional so-called energy island period will be skipped and the Baltic grids connected to the Central European frequency area in a matter of hours.

The TSO says that the entire power grid going down as a result of the desynchronization is virtually impossible. "There is a very small likelihood that short-term electricity consumption restrictions might be needed in certain areas to maintain balance between production and consumption within the power system. Elering is committed to doing everything possible to keep the entire electricity system operational. In the event of a challenging situation, it would prioritize rotating consumption restrictions to preserve the overall functionality of the system," its website reads.

An agreement has been made with Elektrilevi, the largest distribution network operator, to limit consumption by up to 200 MW at substations, if necessary. This would involve rotating restrictions at two-hour intervals in cases where production cannot fully meet consumption. While such a scenario is highly unlikely, it cannot be entirely ruled out.

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