In July 2025, electricity transmission system operators (TSOs) submitted to ACER their proposal to amend how capacity calculation regions (CCRs) are defined across Europe.

With its Decision 10-2025, ACER has approved the proposed amendments.

What are capacity calculation regions and why are they important? 

CCRs are geographic areas across Europe that group neighbouring electricity bidding zones and their borders. Within each region, TSOs work together to determine how much electricity can safely flow across borders while ensuring security of supply.

There are currently nine CCRs in the EU: Nordic, Hansa, Core, Italy North, Central Europe (CE), Greece-Italy (GRIT), South-West Europe (SWE), Baltic and South-East Europe (SEE).

Well-defined CCRs benefit European consumers and producers by: 

• helping TSOs coordinate regional processes such as capacity calculation, redispatch and countertrading more effectively; and
• optimising cross-zonal capacity, facilitating electricity trade across borders and ensuring security of supply.

What did ACER decide?

ACER assessed whether the TSOs’ proposal supports market integration, non-discrimination, effective competition and the well-functioning of the EU electricity market.

Following a public consultation in summer 2025, ACER has approved the TSOs’ proposal to:

• Merge two existing CCRs (Core and Italy North) into the Central Europe CCR across multiple timeframes and methodologies. The Central Europe CCR, previously limited to the day-ahead timeframe, will now also cover:
  • intraday capacity calculation;
  • regional operational security coordination (ROSC); and
  • coordinated redispatching and countertrading (RDCT), along with their cost-sharing methodology (RDCT CS).

• Expand the existing South-East Europe CCR and establish three new CCRs (East-Central Europe*, Italy-Montenegro and Eastern Europe) to include the bidding zone borders and TSOs of the Energy Community Contracting Parties and neighbouring EU countries.

  *The ECE region is established as a temporary setup, with the intention to merge it with the Central Europe CCR in the future.

  These changes are necessary to reflect the growing integration of Energy Community countries into the EU electricity market and strengthen cooperation and efficiency across borders.

Next steps

Once the conditions for integrating the East-Central Europe CCR into the Central Europe CCR are met, TSOs shall submit to ACER a new proposal to formally merge the two regions. 

Today, ACER releases its Opinion on France’s National Resource Adequacy Assessment (NRAA). This assessment complements the European Resource Adequacy Assessment (ERAA) 2024, using input assumptions and modelling approaches that better reflect the characteristics of the national electricity system, drawing on historical data and recent developments.

What is a resource adequacy assessment?

The European Resource Adequacy Assessment (ERAA) evaluates electricity resource adequacy across the EU and provides a consistent framework to assess whether additional national measures are needed to ensure security of supply. ERAA is carried out annually by the European Network of Transmission System Operators for Electricity (ENTSO-E) and reviewed by ACER.

Member States can complement the European analysis through national assessments (NRAAs). While based on the ERAA methodology, NRAAs may capture new developments or national specificities not yet reflected in the latest ERAA.

When a national assessment identifies new adequacy concerns, the Member State informs ACER. In turn, ACER issues an opinion on the differences between the national and European assessments.

What did ACER find?

ACER finds the French assessment clear, robust and generally aligned with ERAA 2024 for most target years. However, unlike ERAA, the NRAA identifies an adequacy concern for 2030, estimating nearly twenty hours during the year when electricity demand would not be met (above France’s reliability standard of two hours). 

ACER notes that most differences with ERAA 2024 are justified by national specificities or methodological improvements. In particular, the NRAA introduces several good practices, including: 

• Considering revenues from ancillary services (e.g. balancing and grid-stability services), which better shows how flexible resources (such as batteries) can earn revenue.
• Ensuring consistency between investment and adequacy modules, strengthening the overall coherence and robustness of the assessment.
• Better accounting for available capacity from neighbouring countries by adjusting it to match national reliability standards, resulting in a more balanced estimate of how much France can rely on cross-border electricity.

The map displays the capacity mechanisms in place across Europe in 2025 and their expiration date. It shows how France’s neighbouring countries have running capacity mechanisms in place. Their impact should be taken into account to ensure an accurate assessment of risks in France. Source: ACER’s Monitoring Report on security of EU electricity supply, p.12.

At the same time, ACER identifies three unjustified differences that could overestimate the projected risks.

1. Conservative estimation of market revenues for adequacy resources (impacting investment prospects).
2. Not considering that the legally set maximum price may change in the future.
3. Using a simplified cross-border capacity calculation that does not reflect the actual operations of the grids. 

What are the next steps?

ACER encourages the French authorities to consider its recommendations to ensure a more accurate assessment of adequacy risks.

See other ACER’s opinions on national assessments.

In 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. After reviewing the proposal and exchanging with stakeholders, ACER has decided to amend the methodology.

What’s new in the amended methodology?

The methodology for the regional procurement of balancing capacity (first approved by ACER in 2023) enables regional coordination centres (RCCs) to assess how voluntary balancing bids can be utilised effectively across borders. Following this evaluation, RCCs provide transmission system operators (TSOs) with recommendations to reduce the volume of procured balancing capacity, hence utilising the flexibility of the EU electricity system and lowering costs. 

The amended methodology:

• Updates the reliability parameters used by RCCs to assess the availability of voluntary balancing bids and cross-zonal capacity. This change will foster a more transparent and coordinated process and improve the balancing of the EU power system.
• Allows RCCs and TSOs to decide on the geographical area where their assessment on the use of voluntary balancing bids will be performed. This will better align the process with the local context and allow for a more effective and coherent practice across Europe. 

What are the next steps? 

RCCs are tasked to assess and provide recommendations on how the use of voluntary balancing bids can be optimised by 19 January 2026.

Interested in learning more about the role of RCCs? Access the latest report on the monitoring of regional coordination centres, published today.

Today, ACER publishes its third monitoring report on the reporting obligations of Regional Coordination Centres (RCCs) for 2024, and its new RCC monitoring dashboard.

Regional Coordination Centres (RCC) were introduced in 2022 with the Electricity Regulation to facilitate coordination among electricity transmission system operators (TSOs) across regions. They contribute to grid stability, security of supply, and the EU’s energy and climate goals. RCCs are required to report on the outcome of their activities, including:

• operational performance;
• coordinated actions;
• issued recommendations; and
• designated tasks.

What is in the ACER monitoring report?  

This report covers RCC’s self-reporting efforts in 2024 and, for the first time, more detailed information on 4 tasks requested by ACER: 

• week-ahead to at least day-ahead adequacy assessments;
• outage planning coordination;
• seasonal adequacy assessments;
• training and certification of RCC staff.

With this dashboard, stakeholders are able to assess implementation progress of RCCs’ tasks and compare the RCCs in Europe. The monitoring will be expanded over time to cover all 16 RCC tasks.

What did ACER monitoring find?  

RCCs continued advancing their activities in 2024. Currently, 7 tasks are in operation across all RCCs:

• common grid model;
• short-term adequacy;
• outage planning coordination;
• defence and restoration plan consistency;
• training and certification;
• post-disturbance analysis; and
• crisis scenarios.

This compared with 4 tasks in operation for 2023 and none in 2022. ACER welcomes this progress.

However, ACER finds that: 

• key performance indicators (KPIs) remain difficult to compare across RCCs due to regional differences in the KPI design, and data quality issues;
• Supporting restoration, the optimisation of inter-TSO settlement, seasonal adequacy assessments, needs for new infrastructure remain at an early stage of development or have not yet been requested by transmission system operators.

In terms of performance, ACER encourages RCCs to:

• swiftly implement all their tasks and improve data quality;
• expand capacity calculation and security analysis across different timeframes and regions;
• focus on improving common grid model results to facilitate long-term readiness;
• enhance the scope of short-term adequacy, outage planning and training and certification of staff;
• align key performance indicators (KPIs) across regions; and
• issue recommendations as well as oversee their implementation. 

In terms of improving their reporting practices, ACER calls on RCCs to: 

• clearly distinguish between regional processes and pan-European ones;
• use common criteria and overview tables to present task implementation status; and
• further explain how the “rotation principle” is applied for pan-European tasks.

What are the next steps?

The next ACER monitoring report is scheduled for December 2026.

ACER intends to expand its monitoring to additional RCC tasks in the future. 

Check out ACER’s new RCC dashboard. 

With the adoption of the 2024 EU hydrogen and gas decarbonisation package, ACER is tasked with carrying out a periodic cost comparison assessing the efficiency of gas transmission system operators (TSOs) across the EU. 

To kickstart this work, ACER engaged a consultant to propose a methodology to benchmark the efficiency of gas TSOs. ACER has taken into account the previous (voluntary) benchmarking studies of gas TSOs, and has consulted stakeholders extensively, including an ACER public consultation, a workshop and engaged experts to conduct an independent assessment (Expert Review) of the proposed methodology.  

The consultancy study, published today, provides general guidance for ACER in designing the methodology and procedures for phase II (data collection and validation) and phase III (modelling) of the ACER efficiency comparison. Some elements of the methodology have been adapted based on the input received from third parties.

Why does the cost-efficiency of gas TSOs matter?

Ultimately, gas consumers pay the costs of natural gas transmission networks through their bill. The TSOs’ allowed revenue is set by the national regulatory authority (NRA) and is recovered from network users through network tariffs, in line with the EU-wide Network Code on Harmonised Transmission Tariff structures.

Benchmarking compares the costs of a TSO (a monopoly) to other operators in the EU. ACER’s efficiency comparison, which is mandatory for all EU TSOs, will help ensure that TSOs’ costs and the resulting tariffs across Europe are efficient. 

Why is TSO cost-comparison increasingly relevant in a decarbonised gas context?

The gas sector is evolving, with lower gas demand, the rise of renewable gases and planning for hydrogen. This may require new investment while the decreasing use of existing gas infrastructure is already driving gas network tariff increases across Member States. This ACER tool aims to provide efficiency scores in a reliable and transparent manner, reflecting different national realities and allowing for different regulatory approaches.

What’s next?

• January 2026: The second phase of the ACER efficiency comparison will start. ACER will request TSOs to submit the data that will be used for modelling in the third phase, as well as carry out a validation process to remove any reporting errors and ensure a high data quality. As part of the validation, TSOs or NRAs are expected to audit the reported data. ACER will consult with TSOs on the data that will be requested and the overall process.
• Between late Q4 2026 – early Q1/2027: The third phase will be launched to focus on the modelling of the ACER efficiency comparison. Stakeholders will be consulted on the model specifications and process in the course of 2027.
• By 5 August 2027: Completion of the first ACER efficiency comparison. Following the first publication, ACER should repeat the calculation every four years. 

Further updates will be provided along these process steps. 

On 3 December 2025, the national regulatory authorities of the Continental Europe Synchronous Area submitted to ACER a joint request for a six-month extension to decide on the transmission system operators’ proposal. This concerns the minimum activation period that frequency containment reserve providers with limited energy reservoirs must ensure in order to remain available during the alert state.

The countries of Continental Europe Synchronous Area are Austria, Belgium, Bulgaria, Croatia, Czechia, Denmark, Estonia, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, the Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia and Spain.

What is it about?

EU’s electric power systems operate at the frequency of 50 Hz. Any imbalance between electricity supply and demand causes the frequency to deviate. If not corrected quickly, this can lead to blackouts.

Frequency containment reserve is the first line of automatic response to such deviations. It is activated within seconds to stabilise the frequency and is provided continuously by power-generating or consuming assets (like batteries, hydro plants or demand response systems). 

Some of these providers, especially batteries or demand-side resources, have limited energy reservoirs and can only respond for a short duration. The System Operation Regulation therefore requires a minimum activation time to ensure these resources remain available during the alert state. 

What are the next steps? 

ACER will review the regulators’ joint request and issue its decision by the end of January 2026. 

Update of 2 February 2026: On 30 January 2026, with its Decision 01/2026, ACER granted the extension requested by the NRAs, who have until 17 June 2026 to reach an agreement on the TSOs’ proposal.

ACER’s 2025 European hydrogen markets Monitoring Report looks at the latest sector developments and highlights the main regulatory and market challenges for the EU.

This year’s edition shows progress in electrolysers build-out and in advancing the EU’s regulatory framework. Yet, renewable hydrogen costs in 2024 remained four times higher than those of conventional hydrogen. This cost gap, together with incomplete national transposition of EU rules, is hindering market development. To overcome this, lower regulatory risks and more targeted funding are needed. 

What are the key findings? 

• Market growth remains insufficient to meet EU and national targets. Despite a 51% increase in electrolyser capacity to 308 MW in 2024, deployment remains way behind the 6 GW target for 2024 and 40 GW for 2030.
• Renewable hydrogen remains costly (four times higher than hydrogen from fossil fuels), with uncertain near to mid term cost reduction prospects.
• Delays in transposing EU rules at national level persist. Only 2 Member States have transposed the amended Renewable Energy Directive.
• A decarbonised electricity sector is key to renewable hydrogen. Electricity supply costs (excluding grid tariffs) may account for up to 50% of renewable hydrogen’s production costs.
• Rising electricity network tariffs may add pressure on costs. ACER’s 2024 Monitoring Report on electricity infrastructure development shows that electricity network costs could rise by 50-100% by 2050, also depending on how investments will align with evolving electricity grid demand. As electricity tariffs represent a significant share of renewable hydrogen’s production costs, this trend poses a substantial risk.
• Network development should align with evolving demand to reduce forecasted risks. Hydrogen networks are key to expanding the market, but infrastructure should be built gradually to match actual demand development.
• Low-carbon hydrogen could support market development, yet cost and technical uncertainties should be carefully assessed.
• The European Commission has already allocated over €20 billion to hydrogen through various programmes, and Member States have announced numerous additional support schemes. Accelerating the allocation of funding to advanced projects is key to increasing scale-up.

What are ACER’s recommendations?

• Accelerate the national transposition and implementation of the amended Renewable Energy Directive to ensure regulatory certainty and accelerate market development.
• Implement the (2024) Hydrogen and Gas Decarbonisation legislative package without delay to facilitate the deployment of infrastructure and a well-functioning hydrogen market.
• Prioritise and target funding towards projects in hard-to-abate sectors that are ready to transition to renewable and low-carbon hydrogen.
• Facilitate renewable hydrogen production through faster permitting and grid connection for both electrolysers and renewable electricity projects.
• Speed up decarbonisation of the power sector to lower electricity costs and enhance electrolyser utilisation.
• Enable flexibility in the electricity market, rethink electricity grid tariffs and grid incentives, as they can optimise electrolyser location and performance.
• Assess the risks of methane-based low-carbon hydrogen, including its underlying costs, infrastructure uncertainties and lock-in effects.
• Align hydrogen network development with market realities to manage market uncertainties and reduce the risk of stranded assets.

What’s next?

Register for ACER webinar: Progress in Europe’s hydrogen markets (Tuesday 9 December 2025 at 11:00 CET).