System Operation

The System Operation Guideline

The Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (SOGL) sets out harmonised rules on how to ensure security of supply through efficient grid operation in a variable renewables paradigm. The implementation of the SOGL and its stemming methodologies entails several challenging tasks for TSOs at pan-European, synchronous area and regional levels. Work at the pan-European level is facilitated by ENTSO-E, whereas synchronous areas’ activities are decided by TSOs in the respective regional groups.

The following SOGL implementation activities have been carried out in 2019:

 Further SOGL deliverables in 2019Key documents and dates
Art. 75.1:Methodology for coordinating operational security analysis19 Jun 2019:decision by ACER requesting the ­submission of three amendments in 2020
Art. 84.1:Methodology for assessing the relevance of assets for outage coordination19 Jun 2019:proposal approved by ACER
Art. 39.3a:CE TSOs’ Study on minimum required inertia15 May 2019:3rd stakeholder workshop on dynamic stability assessment and studies on minimum required inertia
Art. 39.3a:Great Britain’s Study on minimum required inertia
Art. 39.3a:Nordic TSOs’ Study on minimum required inertia14 Sep 2019:proposals submitted to relevant NRAs
Art. 39.3a:Ireland’s and Northern Ireland’s Study on minimum required inertia
Art. 154.2: All CE TSOs’ proposal for additional ­properties of FCR27 Dec 2019:proposal submitted to relevant NRAs
Art. 156.11:Methodology for a cost–benefit analysis for assessing the required minimum activation time for FCR in Continental Europe and Nordic synchronous areas1 Mar 2019:1st amendment to proposal ­approved by relevant NRAs
15 Nov 2019:Stakeholder Webinar on CBA to assess the time period required for FCR with limited energy reservoirs (LERs)
Art. 184.2: All TSOs shall notify the contents of their Synchronous operational agreement to ENTSO-E for publicationThe Synchronous Area Operational Agreements for CE, GB and Nordic were published to Transparency Platform according to the different deadlines
Art. 185.4 (a): The synchronous area monitor of each synchronous area shall notify the results of the criteria application process for their synchronous area to ENTSO-E for publicationThe Synchronous Area monitors are publishing the frequency quality evaluation criteria measurements for the synchronous area from Q3 2019 in Transparency Platform
LFC Block
Art. 184.3: Each TSO of each LFC Block shall share the contents of its LFC block operational agreement with its regulatory authorityIn a voluntary effort of transparency some LFC Blocks have published on Transparency Platform the operational agreements
Art. 185.4 (a):The synchronous area monitor of each synchronous area shall notify the results of the criteria application process for their synchronous area to ENTSO-E for publicationThe Synchronous Area monitors are publishing the frequency quality evaluation criteria measurements for each LFC Block from Q3 2019 in Transparency Platform
CCR TASKSArt. 76.1:Core TSOs’ Common provisions for regional operational security coordination19 Dec 2019:proposal submitted to relevant NRAs
23 Sep – 24 Oct 2019:public consultation
Art. 76.1:Hansa TSOs’ Common provisions for regional operational security coordination20 Dec 2019:proposal submitted to relevant NRAs
18 Oct – 15 Nov 2019:public consultation
Art. 76.1:SEE TSOs’ Common provisions for regional operational security coordinationDec 2019:proposal submitted to relevant NRAs
12 Nov – 13 Dec 2019:public consultation

Table 1 – SO GL implementation activities in 2019

Implementation monitoring

Between July and September 2019, ENTSO-E released three important yearly implementation monitoring reports: the Incident Classification Scale annual report (Art. 15 SOGL), the annual report on Load-Frequency Control (Art. 16 SOGL) and the all TSOs’ scenario definition and scenario description for the year 2020 (Art. 65 SOGL).

Key dates & documents

30 Sep 2019

Publication of the “Incident Classification Scale” annual report

30 Sep 2019

Publication of the “Load-Frequency Control” ­annual report

The Emergency and Restoration Code

The Emergency and Restoration Network Code (NC ER) sets out harmonised rules on how to deal with emergency situations and restore the system as efficiently and as quickly as possible. It entered into force on 18 December 2017 and is primarily subject to implementation at a national or TSO level. Implementation should be finished till December 2022 (Art. 55 NC ER).

ENTSO-E has monitored the national implementation of the network code (Art. 52.1 NC ER) and supported its member TSOs in the delivery of their proposals for National Defence and Restoration Plans (Art. 6.2 NC ER). Moreover, guidelines for the rules for the situations in which the market activities are suspended and restored, which in turn are the responsibility of each TSO to implement, have been established (Art. 36.1 NC ER).

ENTSO-E has worked on the assessment of the level of harmonisation of the rules for the suspension and restoration of market activities established by TSOs, and will attempt to identify, as appropriate, the areas that require harmonisation. This report will be delivered by December 2020 (Art. 36.7 NC ER).

The implementation of the NC ER was discussed with stakeholders during meetings of the System Operation European Stakeholder Committee held on a quarterly basis in 2019.

The Common Grid Model

The Common Grid Model (CGM) finds its legal basis in three of the network codes: the SOGL (Art. 64), the Capacity Allocation and Congestion Management (CACM) Regulation (Art. 17) and the Forward Capacity Allocation (FCA) Regulation (Art. 18). The CGM, and its data exchange system the Operational Planning Data Environment (OPDE), are a prerequisite for several services harmonised in the network codes, including coordinated capacity calculation, operational security analysis, outage planning coordination and adequacy analysis.

The CGM compiles the Individual Grid Model (IGM) of each TSO, covering timeframes going from one year before real time to one hour before real time. TSOs’ individual (in most cases, national) grid models, after following a quality assessment and pan-European alignment process, are picked up by Regional Security Coordinators (RSCs), who merge them into a pan-European CGM and feed the merged CGM back into the system.

Achievements and Challenges

The CGM Programme delivered Release 1.2 on schedule in June 2019, to TSOs and RSCs. In November 2019, TSOs, RSCs and the CGM Programme jointly demonstrated the Basic CGM Build Process, respecting the process times and achieving data quality levels. The Basic CGM Build Process test was carried out for three consecutive days and it was possible to merge IGMs from 17 TSOs into a CGM. In December 2019, the CGM Programme distributed Release 2.0 on schedule to TSOs and RSCs, including the associated security elements.

The roll-out of the Physical Communication Network (PCN) is on schedule.

A joint User Group has been established to synchronise deliverables among RSCs, Capacity Calculation Region (CCRs) and the CGM Programme. The joint CGM–RSC User Group aligns requirements and timelines among RSCs and CCRs and coordinates subsequent activities with the CGM Programme.


As the implementation of the CGM needs to be consistent throughout the various processes set in the SOGL, CACM and FCA regulations, the consolidation of the three methodologies into a single document was initiated by TSOs, keeping stakeholders abreast of developments in this respect via the European stakeholder committees.

CGM Security Plan

In line with the CGM Security Plan approved during the previous year, all TSOs and RSCs performed a first compliance self-assessment in February followed by an update in June 2019. In July 2019, the ENTSO-E System Operations Committee (SOC) approved an update of the implementation timeline, defining a stepwise implementation approach, resulting in a full compliance by all participants in August 2021.

Operational Planning Data Environment

The OPDE, specified in the SOGL (Art. 114), is the information platform that will support the data exchange associated with the CGM merging process. It is also the foundation of the data exchange platform for fulfilling the five core tasks of RSCs. This platform is currently on schedule with the rollout of Release 1.2 and the distribution of the new release 2.0. With Release 1.2, a total set of 130 major changes were implemented, including a set of 68 new features and updates to the existing software packages. Release 2.0 mainly includes security updates as well as new business requirements.

European Awareness System

The European Awareness System (EAS) provides a real-time pan-European view of the state of transmission systems. All operators input a number of measurements including frequency and cross-border exchange. These measurements are then merged to provide an overall European view of each TSO on the platform. ENTSO-E has implemented the required updates to system status indications and predefined messages to ensure compliance of EAS with Art. 18 and 42 of SO GL. ENTSO-E is also working to ensure compliance of EAS with Art. 29 and 33 of the ER NC.

The Site Acceptance Test (SAT) has been successfully completed, and the upgraded EAS has been fully operational since September 2019. Moreover, to ensure safety on data exchange, ENTSO-E performed a cyber security risk assessment on EAS.

Regional development

Cooperation at the regional level is a building block for ensuring security of supply and implementing the Internal Energy Market. The development of variable generation and increased interconnections render regional coordination among TSOs more important than ever.

ENTSO-E supports regional tasks where it is beneficial for the TSOs of the region. In this respect ENTSO-E provides a platform for coordinating regional deliverables which affect neighbouring regions and where addressing the matter at the pan-European level is more efficient than bilaterally.

Regional Coordination

RSCs are entities owned and appointed by TSOs to fulfil five tasks: security analysis, capacity calculation, outage coordination, adequacy forecast, and the CGM. The System Operation Guideline formalised the role of the RSCs and made it legally binding for TSOs to procure at least the five core tasks from one of the RSCs. Through their recommendations to TSOs, RSCs contribute to increasing efficiency in system operation; minimising risks of wide area events such as brownouts or blackouts; and lowering costs through maximised availability of transmission capacity to market participants.

The four TSOs, ESO–EAD (Bulgaria), IPTO (Greece), Trans­electrica (Romania) and Terna (Italy), of the South-East Europe (SEE) and Greece–Italy (GRIT) CCRs agreed in December 2019 to establish an RSC located in Thessaloniki1.

1 The South East electricity Network – Coordination Center (SEleNe CC) was officially established on 22 May 2020.

Regional Security Coordinators and the Clean Energy Package

The CEP establishes an enhanced framework for regional cooperation through the establishment of Regional Coordination Centres (RCCs). Art. 35 of Regulation (EU) 2019/943 (the “Electricity Regulation”) requires that TSOs of System Operation Regions (SORs) develop a proposal for the establishment of RCCs of their region. These should be operational by 1 July 2022 and will replace existing RSCs, adding new tasks for the RCCs.2

In 2019, ENTSO-E developed a proposal defining SORs fully compliant with Art. 36 of the Electricity Regulation3. The SOR Proposal specifies that some of the new tasks shall be carried out through a SOR configuration, and others through CCR or other configurations.

Key dates & documents

24 Oct – 20 Nov 2019

Public consultation on the SOR proposal

2 Article 37 of the Electricity Regulation mentions 10 new tasks in addition to the ones provided for by SOGL and the NC ER as adopted on the basis of Regulation 714/2009.
3 The proposal was submitted in January 2020 and ACER published its decision in April 2020. These developments are out of the scope of this Report and will be covered in the Annual Report 2020 to be drafted next year.

Other regional developments

The operational rules of the TSOs of Continental Europe have been updated in April 2019 with the entry into force of the Synchronous Area Framework Agreement (SAFA), which ensures compliance with the EU network codes and guidelines.

The European Commission welcomed in October 2019 the Technical Solution for inclusion of the Swiss transmission system in CACM and SOGL methodologies of the Core and Northern Italian Borders regions.

Future synchronisation of Baltic countries to the Continental Europe synchronous area

The Agreement on the Conditions for a Future Synchronous Interconnection of the power system of the Baltic States and the power system of Continental Europe entered into force in May 2019. The Agreement contains the conditions and steps to be completed prior to the synchronisation of the Baltic TSOs (Elering, AST and Litgrid) to Continental Europe.

The Baltic synchronisation with Continental Europe is part of the EU Energy Union strategy and will provide for the Baltic TSOs to operate their systems under the EU rules.

Key dates & documents

27 May 2019

The Agreement on the Conditions for a Future ­Synchronous Interconnection of the power system of the Baltic States and the power system of ­Continental Europe enters into force


ENTSO-E Annual Report 2019

This Annual Report covers the period from January to December 2019. It focuses on the legal mandates given to ENTSO-E. Activities covered in this report have been performed thanks to the 42 members of ENTSO-E who provide its financial resources and whose staff provides expertise to the Association.


  1. System Operation
  2. Market
  3. System Development
  4. Transparency Regulation
  5. Research, Development and Innovation
  6. Cybersecurity, Interoperability and Data
  7. TSO–DSO partnership and demand side flexibility
Download the full report (PDF, 4.2 Mb)