The Agency for the Co-operation of Energy Regulators (ACER) has launched its fifth public consultation, seeking views on its draft framework guidelines on system operation.

ACER's earlier consultations concerned draft framework guidelines dealing with issues including capacity allocation in the European gas transmission network and electricity grid interconnection (see our e-bulletin for further details).  

For participants in the European gas and electricity markets, ACER's consultations present the opportunity to comment on the guidelines, which will directly affect the content of the European network codes they will need to comply with.


On 13 July 2009, the European Union adopted the Third Energy Package which, amongst other legal and policy measures (for further details see our e-bulletin), provided for the establishment of ACER and the development of European network codes to define a new European regulatory framework and facilitate the effective functioning of the internal electricity and gas markets, enabling cross-border trade and competition to develop across the EU.

The European Network of Transmission System Operators (ENTSOs) are tasked with developing the European network codes in accordance with framework guidelines set by ACER. ACER's latest consultation seeks views on its draft framework guidelines on system operation.

Aims and objectives

The draft framework guidelines seek to set out clear and objective principles for the development of network code(s) on system operation, dealing with issues such as network security, technical standards, principles and procedures, and the synchronous operation of interconnected power systems. They aim to:

  • define harmonised security criteria;
  • clarify and harmonise TSOs' roles, responsibilities and methods; and
  • enable and ensure adequate data exchange.

These aims will be met by promoting:

  • the operation of the electric power system in a safe, secure, effective and efficient manner;
  • the integration of innovative technologies;
  • the application of the same principles for different systems; and
  • the full use of information and communication technologies.

Minimum standards and requirements for system operation

The minimum requirements and standards to be dealt with in the European network codes have been differentiated by topic (see below) and prioritised, with top priority accorded to operational security:

  • operational security;
  • operational planning and scheduling;
  • load frequency control;
  • staff training and certification;
  • emergency and restoration; and
  • new applications.

Operational security

Operational security relates to issues such as the intraday/extended real time security of the network, voltage control, short circuit currents and angle stability. The draft framework guidelines seek to ensure the coherent and coordinated behaviour of bulk transmission networks and power systems within each area operated by a single TSO.

Another objective of the operational security requirements is to achieve and maintain a satisfactory level of security, allowing for efficient utilisation of the power system and resources, including, but not limited to, the necessary inputs for congestion management and balancing.

The third objective is to avoid any further deterioration of operational security in circumstances where constraints have been violated and systems are not in a normal operating state.

Operational planning and scheduling

Operational planning and scheduling includes activities and tasks conducted ahead of the real time operation of a network and encompasses outage scheduling, day ahead congestion forecasts and network security contingency analysis (which could be complemented by voltage stability analysis), as well as the commercial and scheduling processes.

The draft framework guidelines aim to ensure the coherent and coordinated behaviour of transmission networks and power systems in preparation for real time operation and to achieve and maintain a satisfactory level of operational security and efficient utilisation of the power system and resources.

Load frequency control

All aspects of load frequency control, primary, secondary and tertiary, are covered by the draft framework guidelines. The real time operation of a network requires generation and load to be balanced; deviations impact on system frequency. Load frequency control is therefore a core task of system operation, with a view to:

  • ensuring coherent and coordinated behaviour of transmission networks and power systems in real time; and
  • achieving and maintaining a satisfactory level of frequency quality and efficient utilisation of the power system and resources.

Staff training and certification

The draft framework guidelines deal with specific human resource requirements for operating staff, such as the need for them to:

  • acquire skills to maintain the secure operation of the network at all times and in different network conditions; and
  • learn about market effects and have sufficient English language skills to enable them to communicate effectively and carry out tasks in cooperation with neighbouring TSO's operators.

Staff working in control rooms must be properly trained to take decisions necessary to ensure the secure and efficient operation of the network.

Common training principles and standards and certification are intended to ensure smooth cooperation and coordination at a European level. Certification shall extend primarily to the TSO organisation and lead transmission system operators (eg, shift engineers).

Emergency and restoration

The draft framework guidelines seek to promote awareness of system operating states, defence plans and how to restore the system after a major disturbance or a blackout, as well as how to analyse disturbances. Any synchronous system-wide event should be analysed by TSOs and communicated to ENTSO-E, market participants and relevant regulatory authorities (ACER and national regulatory authorities).

Remedial action may include, for example, calling on active or reactive power reserves, automatic load shedding or any other emergency measures. Network recovery or restoration should occur as quickly, effectively and in the most reliable and efficient manner as possible in order to avoid further disturbances and/or deterioration of system security.

The draft framework guidelines aim to ensure that restoration efforts following a major disturbance or a blackout are led by TSOs, and are well coordinated so that measures taken, or attempts to restore the power supply, by an individual TSO do not adversely affect the overall goal of restoring system operation as soon as possible.

New applications

The draft framework guidelines are concerned with the future development of socio-economy, technology and cross border exchanges. The European network codes should address issues such as:

  • the integration and operation of direct current bulk-power-transport lines, used for "collecting" the massive wind power generation in the North and solar thermal generation in the South of Europe that might occur in future;
  • the use of methods and tools enabling high-level and efficient TSO coordination during operational planning and real time system operation (eg, adequate operational observation capabilities);
  • the dynamic rating of power cables and overhead transmission lines;
  • the close interaction of the future integrated electricity balancing markets of Europe with intraday trade and manually activated reserves; and
  • the coordinated use of phase-shifting transformers and/or flexible alternating current transmission system (FACTS) devices for active load flow control and system stability augmentation.

Impact and outlook

When finalised, the framework guidelines and the European network codes that will be drawn up based on the guidelines will have a significant impact on national network codes and existing arrangements for electricity transmission system operators and significant grid users.

The European network codes will prevail over any relevant national and international codes. Where national codes, standards and requirements are more stringent than the European codes they will continue to apply in so far as they are compatible with the European codes.

Throughout 2011 and 2012, ACER will publish further framework guidelines on issues such as system balancing, congestion management, tariffs, incentives to increase cross border trade and investment incentives for TSOs. These will result in further European network codes which will affect national network codes and may require industry players to adjust their business practices.

Get involved

Interested parties are invited to submit a questionnaire concerning the framework guidelines. The consultation documents and the response questionnaire can be accessed here. Completed questionnaires should be submitted by email to by 15 September 2011.