System operation regions (SORs) are established according to Article 36 of Regulation (EU) 2019/943 of the European Parliament and of the Council on the internal market for electricity. 




7 April 2022


ACER decides on the definition of System Operation Regions


ACER Decision 05/2022 on the Definition of System Operation Regions (SOR)

The Decision replaces ACER Decision No 10/2020. With this Decision, ACER added further reasoning to its amendments and revised the definition of SORs, taking into consideration the impact of UK’s withdrawal from the EU. ACER also decided to maintain the South-West Europe as a separate SOR, as proposed by ENTSO-E.


Annex I

Annex Ia

Annex II

Annex III

Annex IV

Annex V



The document that defined the SORs was ACER Decision 08/2021 of 29 June 2021 (earlier ACER Decision No 10/2020 of 6 April 2020), however, on 19 October 2021 the ACER adopted the Decision 13/2021 withdrawing Decision No 08/2021 of 29 June 2021 on the definition of system operation regions.


See also:


Regional Coordination Centre (RCC)

The withdrawal of the decision follows the finding by ACER that the principles of good administration (access to the file) were not sufficiently respected during the administrative procedure.


In the reopened proceedings for a new decision, ACER intends to focus on the part of the SOR definition subject to appeal, namely including the South-West Europe (SWE) Capacity Calculation Region (CCR) in the Central Europe SOR and not defining a separate SWE SOR.


Article 36
Geographical scope of regional coordination centres

1.By 5 January 2020 the ENTSO for Electricity shall submit to ACER a proposal specifying which transmission system operators, bidding zones, bidding zone borders, capacity calculation regions and outage coordination regions are covered by each of the system operation regions. The proposal shall take into account the grid topology, including the degree of interconnection and of interdependency of the electricity system in terms of flows and the size of the region which shall cover at least one capacity calculation region.

2.The transmission system operators of a system operation region shall participate in the regional coordination centre established in that region. In exceptional circumstances, where the control area of a transmission system operator is part of various synchronous areas, the transmission system operator may participate in two regional coordination centres. For the bidding zone borders adjacent to system operation regions, the proposal in paragraph 1 shall specify how the coordination between regional coordination centres for those borders is to take place. For the Continental Europe synchronous area, where the activities of two regional coordination centres may overlap in a system operation region, the transmission system operators of that system operation region shall decide to either designate a single regional coordination centre in that region or that the two regional coordination centres carry out some or all of the tasks of regional relevance in the entire system operation region on a rotational basis while other tasks are carried out by a single designated regional coordination centre.

3.Within three months of receipt of the proposal in paragraph 1, ACER shall either approve the proposal defining the system operation regions or propose amendments. In the latter case, ACER shall consult the ENTSO for Electricity before adopting the amendments. The adopted proposal shall be published on ACER's website.

4.The relevant transmission system operators may submit a proposal to ACER for the amendment of system operation regions defined pursuant to paragraph 1. The process set out in paragraph 3 shall apply.



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