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Elering has completed the third synchronous condenser plant – the last of the planned plants – at Viru substation near Narva. The condenser plant is an important improvement for the Estonian electricity system, allowing to keep the most important parameter of the electricity system – frequency – stable even in critical situations.

The synchronous condenser will help slow down the speed of changes in frequency when the balance between production and consumption is lost upon unexpected changes in one of the aforesaid e.g. due to a failure in a power plant or the grid.

According to Arno Raadom, Project Manager of Elering: “It has been a complex and large-scale project. There is no previous experience in Estonia related to the construction of synchronous condenser plants. The completed synchronous condensers will play an essential role in ensuring the stability of the electricity system after disconnecting the Estonian power grid from Russia in February 2025.”

Elering constructed three synchronous condensers in Estonia in Püssi, Kiisa and Viru substations in cooperation with the main contractor, Siemens Energy. The Latvian and Lithuanian system operators are also building three synchronous condenser plants with similar goals.

“The successful and timely execution of the entire project has been a huge challenge and a learning experience for both the client and the contractor. Constructing the condensers also allows for increasing the proportion of renewable energy as there are gradually fewer and fewer ‘old-school’ pieces of rotating equipment,” added Raadom.

The synchronous condensers are a part of the major project for separation from the Russian electricity system and joining the European system. In addition to constructing the condensers, Elering is improving the electricity interconnections with Latvia and constructing and upgrading various control and monitoring systems within the framework of the project.

In the course of synchronisation, new markets and products are created alongside existing ones, improving the possibilities of local electricity producers for selling electricity. For consumers, synchronisation will ensure improved security of supply as well as a sense of security that Estonia itself has full control of its electricity system, not Russia.

Investments in synchronisation are financed from the resources of the Connecting Europe Facility (CEF) of the European Commission at the maximum 75 percent as a high-priority project. The remaining 25 percent of the required investments in Estonia are ensured on account of congestion income.

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