ACER and national regulators join ENTSO-E’s Expert Panel investigating the electricity system separation of the Continental Europe synchronous area on 8 January 2021

The Expert Panel will identify the causes and make recommendations in a Final Report

Europe’s electricity system split in two separate regions on 8th January 2021 resulting in transmission system outages.

Expert Panel begins its investigation

Based on preliminary data of Transmission System Operators (TSOs), the system separation of the Continental Europe synchronous area, which lasted just over an hour, is classified as a scale 2 (or “extensive”) incident as per ENTSO-E’s Incident Classification Scale (ICS)1.

According to the ICS Methodology, for scale 2 incidents, a final report shall be prepared by an Expert Panel, where relevant National Regulatory Authorities (NRAs) and the European Agency for the Cooperation of Energy Regulators (ACER) may be involved upon their request. ENTSO-E has created the Expert Panel, inviting ACER and NRAs to join it. The Expert Panel will first meet on 4 March.

ENTSO-E’s Interim Report published

An intensive process started immediately after the event has been resolved, in order to collect and prepare factual data. The Interim Report published today by ENTSO-E contains the data gathered, initial findings on the sequences of events and timeframes. The Interim Report is the basis for the formal investigation by an Expert Panel.

Expert Panel’s Final Report will have recommendations

The Final Report shall describe the sequence of events and violations of operational security limits. It will explain the causes and have recommendations to prevent such incidents in the future.

ACER and ENTSO-E are committed to fulfilling their legal obligations specified in the System Operations Guideline and ICS Methodology. ACER and ENTSO-E will continue together to provide timely information about the incident, published on their websites.


  1. Incidents Classification Scale: The ICS Methodology has been developed in accordance with Regulation (EU) 2019/943 of the European Parliament and of the Council of 5 June 2019. It has been updated 2019, to fulfil the objectives of Article 15 of SO GL quoted above.
  2. Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (System Operation Guideline, SO GL)
  3. ENTSO-E publications:

    • 8 January 2021:

    • 15 January 2021, 1st update:

    • 26 January 2021, 2nd update:

  4. ACER news:

    • 01 February 2021:

Press contacts:

ACER,, T: + 32 (0) 484 66 85 99

ENTSO-E,, T: +32 (0) 476 97 50 93.