The EU-wide framework that protects consumers and businesses from energy market manipulation and insider trading is commonly known as REMIT. This highly sophisticated framework involves many parties collecting and monitoring data, all working together to ensure the integrity of Europe’s wholesale energy markets. Ultimately, national regulators are enforcing REMIT.

For the first time, ACER publishes two reports on energy market surveillance, concerning:

• Persons professionally arranging transactions (PPATs): Analysing their preparedness to detect and report suspicious energy market activities.
• National energy regulatory authorities (NRAs): Focusing on their analysis of suspicious transaction and order reports (STORs) submitted by PPATs, their enforcement actions and penalties.

Both reports are mandated by the revised REMIT Regulation (2024) which introduces new obligations for these trading intermediaries (called PPATs under the REMIT framework) and for ACER to report on the follow-ups by the national energy regulators. 

What are ACER’s key findings and recommendations?

ACER identified the following areas for improvement in some PPATs’ surveillance practices:

• Absence of a formal surveillance function.
• Undisclosed conflicts of interest by employees.
• Undefined or unformalised market surveillance procedures to 'detect, analyse, notify and deter' as required by REMIT.
• Lack of surveillance IT system.
• Undue influence by management on the content or submission of suspicious transaction and order reports.

To address these gaps, ACER suggests:

• Structural separation: REMIT surveillance functions should be clearly separated, whether internal or outsourced, with specialised staff and tools to reduce conflicts of interest and improve performance.
• Client interaction procedures: These processes need to be updated or enhanced to ensure effective monitoring.
• Use professional and certified tools: Where possible, PPATs should use certified systems tailored to their needs, as generic tools may not be effective.
• Increase monitoring coverage: Surveillance systems should monitor all tradable products to detect cross-product manipulation.
• Regular audits: Surveillance functions should be audited more frequently, with a focus on data security and information management.

Read the report.

ACER reviewed the suspicious transactions and order reports submitted by PPATs in 2023 and 2024. Overall, their quality was satisfactory, providing enough information to assess potential breaches of REMIT on the EU wholesale energy markets.

To further improve the quality of this reporting and reinforce national regulators’ capacity to analyse the suspicious reports they receive, ACER encourages national regulatory authorities to:

• Strengthen cooperation by maintaining or establishing regular discussions with PPATs to continuously improve the STOR quality.
• Ensure adequate resources by providing adequate personnel (e.g. case handlers) and tools to manage the growing number of REMIT cases.
• Promptly communicate with ACER by notifying ACER when investigations on potential REMIT breaches are initiated and providing timely case updates to ensure a coordinated enforcement across the EU.
• Streamline case management by promptly rejecting reports of potential REMIT breaches which, upon initial review, are deemed irrelevant or that can be de-prioritised.

Read the report.

Under the EU’s Regulation on forward capacity allocation (FCA), the Baltic national regulatory authorities were required to decide on the capacity calculation methodology for long-term timeframes by 22 March 2025. This followed a proposal from electricity transmission system operators, submitted on 22 January 2025.

On 20 March 2025, the Baltic regulators (Estonia, Finland, Latvia, Lithuania, Poland and Sweden) requested from ACER a three-month extension to decide on the matter.

In their request, the regulators explained more time is needed to: 

• assess the methodology’s compatibility with existing day-ahead and intraday capacity calculation methods;
• evaluate the technical constraints of the proposed allocation; and
• consider potential updates from Poland's electricity balancing market reform.

What is long-term capacity calculation?

Capacity calculation determines how much electricity can be safely and efficiently exchanged across borders in a given capacity calculation region. It ensures that available transmission capacity is calculated in a consistent and transparent way, supporting reliable cross-border electricity trading in both short- and long-term markets.

Long-term capacity calculation focuses on ensuring that there is enough capacity in the power grid to meet future demand over extended periods (months or even years). This supports the EU’s internal energy market by enabling forward electricity trading and allowing market participants to plan ahead and manage price risks.

What are the next steps? 

ACER plans to act promptly on this request, aiming to reach a decision in June 2025.

On 28 April 2025, a large-scale blackout occurred in Spain and Portugal shortly after 12.30 CEST. There was widespread interruption in power supply in the Iberian Peninsula. Some areas in France close to the border were also affected, albeit for a very short period.

Electricity supply in the affected area has been restored, with the help of power generation resources (such as hydro-power plants) and power interconnections with France and Morocco.

Expert Panel to investigate

An expert panel is being set up by ENTSO-E to investigate the incident. This panel includes transmission system operators, regional coordination centres, ENTSO-E. The relevant national regulatory authorities and ACER are also invited to participate. 

The panel will collect the data and first prepare a factual report, followed by the final report that will analyse the causes of the incident and include recommendations to make the system more resilient.  

ACER stands ready to participate in ENTSO-E’s expert panel and to assist in identifying the root causes of this incident, including possible implications to draw going forward.

Background

Large-scale blackouts are rare in Europe, although they have occurred before:

• 8 January 2021: A disturbance split the European grid into two parts, causing frequency deviations and temporary outages across several countries. The re-synchronization of the two regions incident was resolved within an hour.
• 4 November 2006: Imperfect cross-border coordination on a planned transmission line outage led to a cascading grid failure resulting in a system split and outages across continental Europe.

• 28 September 2003: A power line touching a tree led to other lines overheating, leading to a series of grid failures and a blackout affecting more than 50 million consumers in Italy and Switzerland.

The lessons learned from these incidents led to improvements in cross-border coordination, system operation, and market integration.

In April 2025, the European Network of Transmission System Operators for Electricity (ENTSO-E) submitted its proposal for the European Resource Adequacy Assessment (ERAA) 2024 to ACER.

What is ERAA?

Mandated by the 2019 Clean Energy Package, ERAA is ENTSO-E’s annual evaluation of the risks to the EU’s security of electricity supply for up to 10 years ahead. In line with the methodology approved by ACER in 2020, ENTSO-E must carry out an annual assessment to determine whether the EU has sufficient electricity resources to meet future demand.

At the national level, Member States set their own electricity reliability standards, which indicate the level of security of supply they require. At the European level, ERAA assesses whether the results align with the standards set by the Member States.

How does ERAA benefit the EU?

ERAA provides an objective basis for identifying potential risks to the security of electricity supply in Europe, and whether additional national measures, such as capacity mechanisms, are needed.

What is ACER’s role?

Each year, ACER reviews ENTSO-E’s proposal for ERAA, taking into account the relevant scenarios, assumptions, and results. If approved by ACER, the assessment informs national decisions on the security of electricity supply.

Following ENTSO-E's submission, ACER is conducting its review of the draft ERAA 2024 and will issue its decision in July 2025.

Amendment of future ERAA methodology 

In March 2025, ACER was mandated by the European Commission to amend and streamline the methodology for ERAA. This stems from the Electricity Market Design Reform (July 2024) and the European Commission’s report (March 2025), both calling for streamlined and simplified application of capacity mechanisms.

To initiate the process, ACER requested ENTSO-E to propose amendments to the ERAA methodology by mid-October 2025. ACER will then approve or amend the proposal within 3 months of receipt. 

Read more on ERAA.

ACER issues today its guidelines to better protect cybersecurity information exchanged under the EU-wide network code on sector-specific rules for cybersecurity aspects of cross-border electricity flows (NCCS).

These guidelines are issued for the electricity sector, including transmission and distribution system operators, generators, organised markets, nominated electricity market operators (NEMOs) and the balancing responsible parties, as well as for providers of critical information and communication technology (ICT) services and managed security services.

ACER consulted the EU cybersecurity agency (ENISA), the European Network of Transmission System Operators for Electricity (ENTSO-E), EU DSO Entity and the competent authorities under the electricity cybersecurity network code in preparing these guidelines.

Why are these guidelines important?

Entities from the electricity sector (e.g. network companies and others) are required under the binding electricity-specific cybersecurity network code to share information, including on cyberattacks, threats, risk assessments and cybersecurity expenditures. Preserving the confidentiality of such sensitive information when sharing it among themselves and with relevant authorities is important. 

What are ACER's recommendations?

The guidelines suggest:

• Usage of the Traffic Light Protocol (TLP) to exchange information. The guidelines also provide basic instructions for the electricity sector on how to apply it. In case there are no legally binding national classification schemes applicable to the shared information, the TLP can also be used to share information within a Member State.
• Several methods for anonymising and aggregating information. The guidelines also provide examples of how specific information exchanged under the NCCS could be anonymised or aggregated.

Find out more on the NCCS.

ACER has published its opinion on the amended balancing monitoring plan of the European Network of Transmission System Operators for Electricity (ENTSO-E), suggesting more flexible reporting timelines, while stressing the need for improved data quality. 

How balancing works and why it needs oversight

In balancing markets, balancing energy is used to always keep the power system stable by correcting differences between electricity production and consumption. If there is not enough electricity in the system, transmission system operators (TSOs) procure upward balancing energy. If there is too much electricity, TSOs procure downward balancing energy. In most EU countries, this is done via EU platforms for the activation of balancing energy.  

Under the Electricity Balancing Regulation, ENTSO-E is tasked with overseeing the implementation and integration of balancing mechanisms across the EU. This includes coordinating the use of key platforms for the exchange of balancing energy and providing detailed reports to ACER on progress, efficiency and market integration.

However, delays in some TSOs joining key balancing platforms could hinder the timely publication of monitoring reports, as insufficient operational data may be available for analysis. As a result, ACER has suggested more flexible reporting timelines, while stressing the importance of high-quality balancing data. 

What are ACER’s key messages? 

ACER recommends that ENTSO-E:

• Adopts alternative reporting timelines suggested by ACER.
• Prioritises the quality of balancing data published on the ENTSO-E Transparency Platform to ensure that national regulators and ACER can effectively conduct their respective monitoring and analyses. 
• Streamlines reporting and promptly notifies ACER of any overlaps between reporting obligations, without the need to resubmit the amended Monitoring Plan. 

What are the next steps?

ENTSO-E is encouraged to begin improving data quality without delay.

Looking ahead, ACER commits to working closely with ENTSO-E to progressively reduce the number of reports required, aiming for more efficient and focused monitoring processes.