Today, ACER initiates the review of its Decision 30/2020 on the electricity redispatching and countertrading cost sharing methodology for the Core capacity calculation region.  

What is a capacity calculation region?

A capacity calculation region is a set of electrically interdependent bidding zone borders, where capacity calculation, regional operational security, redispatching and countertrading costs sharing tasks are coordinated by that region’s transmission system operators (TSOs).

The Core capacity calculation region involves the TSOs and bidding zone borders of Austria, Belgium, Croatia, Czech Republic, France, Germany, Hungary, Luxembourg, the Netherlands, Poland, Romania, Slovakia and Slovenia. It is the biggest European region, involving 13 Member States, 16 TSOs and 19 bidding zone borders.

What is the methodology about? 

The cost sharing methodology allocates the costs from redispatching and countertrading remedial actions within a capacity calculation region. These actions are triggered to solve network congestions occurring within the region. 

Specifically, this methodology tracks how each action affects congested network elements and assigns the related costs to the responsible TSOs, based on the order of flow types (loop, internal, allocated and power-shifting transformer flows). Loop flows are charged first, however according to the Electricity Regulation, its portion below a given threshold is exempted.

Why amend the methodology?

On foot of the ACER Board of Appeal Decision of 31 July 2025, ACER is now revising its Decision 30/2020 and the methodology accordingly.

What are the next steps?

ACER aims to adopt its Decision by the end of January 2026.

On 26 September 2025, ACER received a proposal from the European Network of Transmission System Operators for Electricity (ENTSO-E) to amend the methodology for the regional procurement of balancing capacity.

What is the methodology about?

Transmission system operators (TSOs) must always keep the power system in balance. TSOs usually procure the balancing capacity needed at national level, but to lower procurement costs, they may opt for utilising available voluntary balancing bids from other countries (e.g. made available when local capacity exceeds national needs).  If transmission capacity is expected to be available across bidding zones during balancing, these bids can also be used to reduce balancing capacity needs. 

The methodology for the regional procurement of balancing capacity enables regional coordination centres (RCCs) to evaluate how voluntary balancing bids can be utilised effectively across borders. Following this evaluation, regional coordination centres provide TSOs with recommendations to reduce the volume of procured balancing capacity, hence utilising the flexibility of the EU electricity system. 

Why amend the methodology?

As requested by ACER, European TSOs propose to update the reliability parameters used by regional coordination centres to assess the availability of cross-zonal capacity and voluntary balancing bids. This is important as reliability parameters need to reflect the most relevant data, enabling TSOs to procure balancing capacity efficiently, and at the same time managing their operational risks. This change should foster a more transparent and coordinated process and improve the balancing of EU power system.

What are the next steps? 

ACER will decide by 5 January 2026.

Interested parties may submit comments or questions to ACER-ELE-2025-009@acer.europa.eu by 31 October 2025.

ACER encourages European associations of energy market participants to engage in stakeholder activities supporting REMIT implementation from 2026 to 2028.

We welcome associations with expertise in the areas of electricity, natural gas, liquified natural gas (LNG) and hydrogen, dealing with supply, transportation and storage, including energy derivatives (where relevant for REMIT reporting framework).

What’s behind this?

The Regulation on Wholesale Energy Market Integrity and Transparency (REMIT) is the EU framework that aims to prevent wholesale energy market abuse and support fair competition. The Regulation was revised in 2024 to keep pace with evolving market dynamics.

To ensure the revised Regulation is implemented effectively and consistently, ACER works closely with different stakeholders across the EU. European associations of energy market participants are key to bringing practical experience and sector-wide perspectives that help align implementation with real market practices.

How will associations contribute?

Associations participating in ACER’s stakeholder activities will:

• provide input on the revision of the REMIT data reporting framework, including updates to the reporting guidance; and
• exchange views on practical aspects of REMIT implementation and related challenges.

Engagement may include targeted consultations, roundtable meetings, webinars or other interactive activities, allowing associations to directly contribute to shaping REMIT implementation.

Who can join? 

ACER plans to establish two lists of associations:

1. EU associations of energy market participants, representing members from several EU Member States, to take part in regular stakeholder activities.
2. Associations of energy market participants, representing international, national or local views, to be engaged on an ad hoc basis depending on the topic.

ACER will seek balanced and diverse participation, representing different energy market segments and expertise at EU level.

Interested in applying? 

Submit your application by 31 October 2025. Late submissions will not be considered.

See how to apply.

Today, ACER publishes its biennial Opinion on the draft lists of proposed projects of common interest (PCIs) and projects of mutual interest (PMIs) for 2025. 

The PCIs/PMIs lists include energy infrastructure projects prioritised at EU level given their impact to significantly enhance the cross-border links among the energy systems of EU countries (and third-party countries in the case of PMIs). These projects can benefit from accelerated permitting procedures, regulatory treatment and funding, as they are identified as key contributors for integrating renewables, boosting cross-border capacity and advancing Europe’s climate and energy goals.

What is the role of ACER?

ACER’s role in the PCIs/PMIs selection process, as defined by the TEN-E Regulation, is to verify that the relevant methodologies and criteria are applied consistently and transparently across regions in the projects’ selection process. A fair and credible process ensures that the most beneficial projects are prioritised in developing trans-European energy infrastructure. ACER’s role is not to give a ‘second opinion’ on the merits of the different projects nor to help decision makers rank such projects for ultimate selection.

What are the key conclusions?

In its Opinion, ACER found:

• Delays in the availability of Ten-Year Network Development Plans (TYNDPs) data and their cost-benefit results, which hindered the projects’ assessment.
• Infrastructure needs have been identified only per Member State, without sufficient identification of capacity needs per border.
• Unclear distinction of monetised and non-monetised benefits in the ranking of projects, reducing clarity on how these are prioritised.
• Lack of justifications of the projects added on top of the formal proposals from the Regional Groups. The Regional Groups are chaired by the European Commission and include representatives from Member States, transmission system operators, project promoters, energy regulators and ACER. Their role is to assess the projects' potential contribution to EU energy priorities.
• Difficulty for regulators, due to insufficient data, to properly assess several hydrogen project candidates, including their underlying benefits, in the lists. 
• The draft PCIs/PMIs lists do not clearly distinguish between mature and less mature electricity projects.

As these obstacles may affect the credibility and robustness of the selection process, ACER recommends to:

• Deliver the TYNDP data on time and in good quality for the PCIs/PMIs selection process.
• Introduce an assessment of capacity needs per border per each energy vector, thus improving the needs assessment methodology.
• Clearly distinguish between projects’ monetised and non-monetised benefits.
• Ensure greater transparency in complementary project evaluations, if these can’t be avoided.
• Ensure that the complete set of project data is made available for the national regulatory authorities’ assessment in due time, to allow them to conduct thorough and consistent analyses.
• Introduce maturity criteria for electricity projects to clearly distinguish between mature and less mature projects on the electricity PCIs/PMIs lists. This would ensure transparent prioritisation and allow support for less mature projects when they are ready for construction.
• Consider multiple scenarios, in line with ACER’s Scenario Guidelines, to test the robustness of results.

What are the next steps?

By addressing these issues, the PCIs/PMIs selection process will become more transparent, consistent and credible, ensuring Europe invests in the right infrastructure to meet its energy and climate goals.

On 27 March 2025, ACER received the transmission system operators’ (TSOs’) proposal to amend the harmonised allocation rules (HAR) for long-term electricity transmission rights.

The harmonised allocation rules apply to all long-term transmission rights allocations conducted within the European Union, specifying criteria for their auctioning (including use and curtailment of long-term transmission rights, eligibility criteria, etc.). 

The TSOs’ proposal included various updates related to arrangements with market participants, reflecting upcoming market changes (e.g. introduction of 15-minute market time unit in the day-ahead electricity market) and recent incidents (e.g. single day-ahead market decoupling in June 2024). 

To take an informed decision, ACER consulted stakeholders during Spring 2025.

What did ACER decide?

ACER approves the TSOs' proposal, while adding some clarifications and proposing further reviews on the:

• Usage of the day-ahead price for remunerating long-term transmission rights in case of decoupling: ACER recommends TSOs and national regulatory authorities to review the arrangements among nominated electricity market operators (NEMOs), which should set transparent rules for defining the single day-ahead reference price in case of decoupling. 
• Relevant rules for the nomination of physical transmission rights: ACER recommends TSOs and national regulatory authorities to review the applicable nomination rules, considering the introduction of 15-minute market time unit in the day-ahead market.

ACER agreed with TSOs to tackle improvements to the collateral requirements in long-term flow-based auctions separately. 

What are the next steps? 

TSOs and regulatory authorities should now review nomination rules and multiple NEMOs' arrangements to reflect the latest updates introduced by ACER.