S.9.1. Security of Energy Supply

D.9.1. Security of Energy Supply

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Stakeholders seek resolution to frequency deviations in Continental European Control Area in lead-up to synchronisation of Baltic States

Monday, November 12, 2018


ENTSO-E is stepping up the provision of technical advice to TSOs in Serbia and Kosovo that are failing to resolve persistent frequency deviation issues emanating from the region. Stakeholders hope to resolve the issue before the technical process of synchronising the Baltic systems with that of Continental Europe begins in the first half of 2019.

Last week, the Regional Group Continental Europe (RGCE), which represents all TSOs operating within the 25 countries of the Continental Europe (CE) synchronous area, voted on a proposal to resolve the problem of frequency deviations, which have been affecting the transmission system since late 2017. The frequency deviations originate from the control area covering Serbia, Macedonia, Montenegro (SMM block) and can be traced more specifically to Serbian/Kosovar territory where a political dispute between the two governments has led to a decrease in electricity production. The decrease in production has in turn led to a slight decrease in the frequency average.

To ensure that the transmission system functions correctly, frequency cannot fall below 47,6 Hz or rise above 52,4 Hz. In a scenario where frequency deviation falls outside this range, all connected generation and devices would automatically disconnect. The average frequency of the period since mid-January 2018 has been around 49,996 Hz. Since late 2017, ENTSO-E has been in discussion with the Serbian and Kosovar TSOs, EMS and KOSTT, to find the best way to resolve the issue, and the onset of winter has sparked a renewal of stakeholder efforts to come to an agreement.

In March 2018, ENTSO-E reported that the missing energy amounted to 113 GWh and had produced a frequency response delay of close to 6 minutes on average for the first few months of the year. The question of who will compensate for this loss has yet to be answered.

The impending synchronisation of the Baltic States’ electricity grid with the CE synchronous area is another development that might threaten the stability of the continental grid. Although this development does not pose a significant technological threat to the system, there are a number of issues that may threaten its success.

In June 2018, EC President Jean Claude-Juncker, together with the Heads of State and Government of Poland, Lithuania, and Latvia, signed a Political Roadmap for the 1 billion-Euro synchronisation of the Baltic States’ electricity grid with the CE system (see news of 29 June 2018: ‘EC, Baltic States, and Poland sign Roadmap on synchronisation of electricity networks with CEN’). The High-Level Group on synchronisation has since given the green light to TSOs operating in the region to formally begin the synchronisation process during the first half of 2019, following the official signing of a Connection Agreement.

However, the Russian enclave of Kaliningrad, which is located between Lithuania and Poland and an exporter to the Baltics, faces grid isolation. The issue of desynchronisation has been a source of tension between the governments of Poland, the Baltic States and Russia since the Eastern enlargement of the EU in 2004.

Furthermore, at least one more link with Poland will be needed to bolster the synchronisation plan. As things stand, LitPol is the only HV line connecting the Baltic States with CE. The line operates at a capacity of 500 MW. According to the Roadmap agreed in June, stakeholders will evaluate the feasibility of an alternative to LitPol link 2, specifically, a submarine HVDC cable between Poland and Lithuania.

Baltic TSOs will require on-going technical and financial assistance from ENTSO-E and the EC if the CE system hopes to avoid further disruption.