The Continental European (CE) Power System -a large synchronized area stretching from Spain to Turkey and from Poland to Netherlands; encompassing 25 countries- is experiencing a continuous system frequency deviation from the mean value of 50 Hz, and this since mid of January 2018.

The power deviations are originating from the control area called Serbia, Macedonia, Montenegro (SMM block) and specifically Kosovo and Serbia. 

The power deviations have led to a slight decrease in the electric frequency average.

This average frequency deviation, that has never happened in any similar way in the CE Power system, must cease. The missing energy amounts currently to 113 GWh. The question of who will compensate for this loss has to be answered.

The decrease in frequency average is affecting also those electric clocks that are steered by the frequency of the power system and not by a quartz crystal: they show currently a delay of close to six minutes.  

ENTSO-E, the association of the European TSOs, is exploring all technical options to address the deviation issue with the concerned TSOs.

As there is also a political dimension with impact on the functioning of the electricity system, ENTSO-E is urging European and national governments and policy makers to take swift action. These actions need to address the political side of this issue, supporting ENTSO-E’s and the TSOs’ actions to deliver a technical solution.

Frequently asked questions

What is a synchronous area?

A synchronous electricity grid is a wide area grid covering different countries or region which operates at a synchronized frequency and is electrically tied together during normal system conditions. In Continental Europe, the synchronized frequency is of 50 Hz.

Which countries are part of the Continental Europe synchronous area?

The area is made of 25 countries and covers most of Europe’s continent. Here is a link to the map of the interconnected European Power system:

Download the map

By how much has the frequency decreased?

You can find updated information on the decrease in the average frequency and the time deviation it causes on the website of the Swiss TSO, Swissgrid, that is in charge of monitoring the frequency for the Continental Europe.

When does security of supply get affected?

For the system to properly function the frequency cannot go below 47.6 and above 52.4 Hz. At the extreme values of 47.5 (under frequency) and 52.5 (over frequency) all connected generation and devices would automatically disconnect. The average frequency of the period since mid-January 2018 until today was around 49.996 Hz.

Where can I see the current frequency?

The transmission system operators in charge of monitoring the frequency in the Continental Europe area are the Swiss TSO, Swissgrid and the German TSO, Amprion. They act as Coordination Centers for the synchronous, continental European Grid. You can see the actual measurement of frequency at the website:

How are devices like clocks impacted by the frequency average decrease and when would the impact stop?

Some clocks are based on the frequency of the power system, and thus run late when the frequency decreases, or run too fast, when the system is in over-frequency. Such clocks are typically radio-, oven clocks or clocks for programming the heating system. These types of electric clocks show now a delay around six minutes. The clocks can be taken back to normal manually, with a second reset needed once the Continental European power system recovers its normal frequency. Alternatively, the clocks will get all back to normal when the deviation has ceased and the frequency is restored to normal.

How and when can the situation be put back to normal?

The first step is to cease the deviation. The second step is to compensate for the missing amount of energy. It is foreseen to solve step 1 this week, while the timeline for step 2 has yet to be decided. Taking the system back to normal could take a few weeks.

Why do you mention in your press release a political issue and solution?

The political disagreements opposing the Serbian and Kosovar authorities have led to the observed electricity impact. If no solution can be found at political level, a deviation risk could remain.

For media enquiries: please contact the ENTSO-E Communication Team

Susanne Nies,, ++32475697895 / Claire Camus, ++ 32476975093