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January 10th : RTE calls on interruptible industrialists

Source: RTE - DIESE 16/01/2019

As mentioned in the press in recent days, the frequency of the European transmission system experienced a drop in frequency to 49.81 Hz on Thursday 10 January 2019at 21:00. RTE wishes to shed light on the events that contributed to this drop in frequency, which are by order of importance:


  • Firstly, the amendment of cross-border exchange schedules between the different European countries is the factor which had the greatest influence on the frequency on Thursday 10 January at 21:00. It is important to note that these periods of schedule changes on the hour are the most difficult to manage for the network because they concurrently induce the stop, start and the change in generation of power plants across Europe. During these time changes, transmission system operators therefore handle the reconciliation between the market and the physical operation of the electricity system.

  • Secondly, a measurement error of cross-border exchanges between Germany and Austria has affected the frequency. This error has distorted the adjustment of the German control area, thus contributing to a frequency drop.

  • Finally, since the beginning of the year 2018, the Continental Europe Synchronous Area has been facing a permanent frequency deviation linked to the situation in Kosovo and in Serbia.

  • In all European countries, the frequency containment reserve in particular provides the means to contribute to this real-time management of the frequency. In France, the interruptible load programme is defined by legislative texts and implemented by RTE. This system complements the tools used by RTE by functioning as a complement to the frequency containment reserve, thus contributing to the restoration of the frequency by automatically amending the level of consumption of consumers connected to the transmission grid. These consumers are paid for this service.


    In any case, it is important to clarify that a frequency deviation of 190 MHz does not cause a blackout risk on the European system on its own. However, such a deviation requires mobilising resources in order to help rapidly bring the frequency back to 50 Hz. In France, the use of the interruptible load programme has shown that the mechanism is able to react correctly in real time and to contribute to the support of the frequency.