Network codes are binding rules that govern electricity networks' connection requirements in an effective and transparent manner. They were established in 2009 by the EU Regulation on conditions for access to the network for cross-border exchanges in electricity  and recast in 2019 by the Regulation on the internal market for electricity. In 2023, ACER proposed amendments to two of the grid connection codes to the European Commission.

The codes are crucial for ensuring the safety of system operation and the efficiency of the European Union's power grid. ​

Grid connection refers to all the subjects establishing and maintaining a physical connection between the transmission and/or distribution grids and the grid users.  

Grid connection, or network connection, is one of the areas regulated by the specific network codes. These rules aim to develop a harmonised electricity grid connection regime, as well as efficient and secure operations. This is particularly important in view of the integration of an increasing share of sources of renewable energy in the system. European rules on grid connection also ensure a fair competition in the electricity market, and facilitate the electricity trade across the Union.

Three network codes on grid connection have been developed:

• The Network Code on requirements for grid connection of generators (RfG Regulation) establishes common standards that generators must respect to connect to the grid.

• The Network Code on demand connection (DCC Regulation) sets up harmonised requirements that demand facilities must respect to connect to the grid. 

• The Network Code on requirements for grid connection of high voltage direct current systems (HVDC Regulation) covers the definition of harmonised standards for direct current (DC) connections.​​​

The Risk Preparedness Regulation introduces important rules for the cooperation between Member States with the aim to prevent, prepare for, and manage electricity crises. It also establishes common provisions for risk assessment, risk preparedness plans, managing electricity crises, evaluation and monitoring.

Each Member State's competent authority must establish a risk-preparedness plan, based on the regional and national electricity crisis scenarios. This plan consists of national, regional and where applicable, bilateral measures planned or taken to prevent, prepare for and mitigate electricity crises.

The Regulation foresees the adoption of two methodologies during the course of 2020:

• methodology for identifying regional electricity crisis scenarios
• methodology for short-term and seasonal adequacy assessment.

In the interest of EU electricity security of supply, EU law requires ENTSO-E to identify the most relevant regional electricity crisis scenarios (following a methodology approved by ACER). The methodology is required to consider system adequacy, system security and fuel security. It also must include an analysis of all relevant national and regional circumstances, simulations of simultaneous electricity crisis scenarios, ranking of risks, as well as probability and principles on how to handle sensitive information in a transparent manner.

Following extensive consultation, including a (2019) ENTSO-E public consultation a (2020) ACER public consultation and the consultation with the Electricity Coordination Group, ACER published (6 March 2020) its Decision on the methodology for identifying regional electricity crisis scenarios. Access the methodology​.

On 8 March 2024, ACER issued its Decision on the amendment  to the methodology for identifying regional electricity crisis scenarios. This ACER Decision follows extensive public consultations by ENTSO-E (in Spring and Autumn 2023), by ACER with the Electricity Coordination Group (composed only of the Member States' representatives), NRAs and ENTSO-E. The improved methodology reflects amendments that ACER deems necessary to ENTSO-E’s proposal (submitted on 8 January 2024).

Every two weeks, regional coordination centres (RCCs) take turns performing daily assessments of potential EU-wide adequacy issues (i.e. whether the electricity system will have enough supply to meet demand) over the next seven days.

These assessments are carried out through a dedicated tool, developed under the EU methodology for short-term and seasonal adequacy assessments and approved by ACER in 2020. The tool combines probabilistic and deterministic calculations to identify potential adequacy risks. If an EU-wide assessment detects possible concerns, this can trigger a more detailed assessment at regional level.

In 2025, ACER launched an implementation monitoring exercise to evaluate how consistently RCCs apply the EU methodology. Results show uniform progress, with implementation currently at 60% across all RCCs. 

ACER’s monitoring also found that, although RCCs identified some potential adequacy concerns over the years, none were flagged as requiring further analysis. As a result, no regional adequacy assessments were initiated in 2022, 2023 or 2024.

ACER’s findings from this monitoring exercise are presented in its interactive dashboard:

​​The Electricity Regulation aims to adapt the existing market rules to new emerging market realities.

The Regulation provides a set of fundamental principles for well-functioning, integrated electricity markets.

It includes general rules for the electricity market and covers in detail network access and congestion management, resource adequacy, transmission system operators, distribution system operators, as well as network codes and guidelines.​

The Electricity Regulation foresees the establishment of Regional Coordination Centres (RCCs), replacing the regional security coordinators established by the System Operation Guideline. 

Their tasks include: 

• coordinated capacity calculation;
• coordinated security analysis;
• creating common grid models;
• supporting the consistency assessment of transmission system operators' defence and restoration plans, ensuring an effective application of the Emergency and Restoration Network Code's procedure;
• supporting the coordination and optimisation of regional restoration;
• post-operation and post disturbances analysis;
• regional sizing and facilitation of procurement of reserve capacity;
• regional system adequacy assessments;
• regional outage planning coordination;
• identification of needs for new transmission capacity;
• calculation of the maximum entry capacity available for the participation of foreign capacity in capacity mechanisms; and
• reporting and identifying regional electricity crisis scenarios.

Ahead of their entering into operation by 1 July 2022, the geographical scope of the RCCs had to be defined through a proposal for system operation regions. 

The proposal had to be submitted to ACER by the European Network of Transmission System Operators for Electricity (ENTSO-E) and specify 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 had to take into account the grid topology, including the level of interconnection and interdependency of the electricity system in terms of flows and the size of the region (covering at least one capacity calculation region).

The activities of RCCs are coordinated across regional boundaries, while the day-to-day coordination within and between the RCCs is managed by cooperation processes among the transmission system operators of the region, as well as by arrangements between the RCCs.

​On 8 April 2022, ACER published the adopted decision (ACER Decision No 05/2022) on the definition of system operation regions on its website.

The revised ACER Regulation introduces new tasks for ACER in the regulatory oversight of Regional Coordination Centres (RCCs).

Specifically, ACER is responsible for monitoring and analysing the performance of RCCs in close cooperation with the national regulatory authorities (NRAs) and the European Network of Transmission System Operators for Electricity (ENTSO-E). To this end, ACER established a project group with the concerned stakeholders.

To monitor and analyse the performance of RCCs, ACER must take into account the reports submitted by each of them pursuant to their reporting obligations under the Electricity Regulation.

To carry out its monitoring tasks, ACER has to:

• issue approvals for any new advisory tasks of the RCCs;
• request information from RCCs where appropriate in the context of monitoring and reporting obligations of RCCs;
• issue opinions and recommendations to the European Parliament, the Council and the Commission; and
• issue opinions and recommendations to RCCs.

Monitoring plan

As of 2023, ACER is monitoring the regular reporting obligations of the RCCs and plans to deliver an annual report on the submissions made by each of them, in accordance with their reporting obligations under the Electricity Regulation.

In 2025, ACER asked for more detailed information on 4 specific RCC tasks:

• week ahead to at least day-ahead adequacy assessments;

• outage planning coordination;

• seasonal adequacy assessments;

• training and certification of RCC staff.

The results are published in the ACER RCC Monitoring Dashboard. 

ACER monitoring reports on RCCs' reporting obligations

Following the revision of the Electricity Regulation, Transmission System Operators (TSOs) have the obligation to reach a minimum level of cross-zonal capacity to facilitate electricity trading across countries.

When Member States or TSOs cannot comply with their obligations, they can establish an action plan, or ask for a derogation.

Derogations allow TSOs more time to implement the necessary measures and be compliant; and they are granted for a maximum of two years. Action plans provide time to address structural network constraints – possibly requiring investment – over a longer time horizon (5 years). National regulatory authorities can grant derogations, while action plans are provided by the Member State.

To facilitate the monitoring of the European electricity market, the Agency is compiling all the derogations and action plans granted and also collecting relevant documents.​

The Electricity Regulation envisages the development of European network codes in different areas, based on a priority list established by the European Commission every three years.

The latest priority list for the development of harmonised electricity rules for 2020-2023 period includes the rules on demand side flexibility - including rules on aggregation, energy storage and demand curtailment rules.

To seek a diversified expert advice on these topics, ACER has established a dedicated Expert Group on demand side flexibility.

On 21 October 2022, the European Commission invited ACER to carry out a scoping exercise for the coming Framework Guideline on this topic. ACER’s conclusions were delivered to the European Commission on 1 February 2022.

On 1 June 2022, the European Commission invited ACER to submit non-binding framework guidelines setting out clear and objective principles for the development of a network code on demand response. ACER ran a public consultation from 2 June to 12 August 2022. The resulting Framework Guideline on Demand Response was submitted to the European Commission on 20 December 2022.

The European Commission cleared ACER’s framework guideline in March 2023, and asked the DSO Entity and ENTSO-E to draft the proposal for the new binding EU rules. On 8 May 2024, ACER received electricity system operators’ proposal for an EU-wide network code on demand response. 

ACER ran a public consultation in autumn 2024 on the ACER-revised draft proposal. ACER organised a webinar during the consultation period, on 1 October 2024.

ACER submitted the final proposal to the European Commission on 7 March 2025. On 27 March 2025, ACER held a webinar to present its proposal for the new EU-wide network code on demand response. To support the code’s implementation, ACER also committed to establishing a dedicated European Stakeholder Group.