ACER releases two reports assessing whether the proposed reference price methodologies for the Croatian and Finnish natural gas transmission tariffs comply with the EU Network Code on Harmonised Transmission Tariff Structures.

The reports are addressed to:

• the Croatian national regulatory authority (NRA), Hrvatska energetska regulatorna agencija (HERA); and
• the Finnish natural gas transmission system operator (TSO), Gasgrid Finland Oy (Gasgrid).

ACER finds that Croatia’s proposal makes only minor adjustments to the previous well-functioning methodology (last updated in 2019), while Finland’s proposal retains its existing approach (2020) without addressing some of ACER’s earlier recommendations.

What is proposed?

Croatia proposes to:

• Keep the current postage stamp reference price methodology, with a 60/40% split between entry and exit points.
• Phase out the current tariff discount at the Krk LNG terminal entry point to the transmission system.
• Continue recovering all transmission revenues through capacity-based tariffs.
• Pre-set tariffs for a five-year period, with different tariff levels each year.

Finland proposes to:

• Keep the current postage stamp reference price methodology at domestic exit points.
• Remain in the Finnish-Estonian-Latvian (FinEstLat) market area, applying common entry tariffs and zero tariffs at interconnection points within the area.
• Establish a commodity-based connection capacity charge to recover costs fairly from users that consume gas only during peak periods. 
• Maintain the flow-based charge.
• Apply two non-transmission tariffs: a datahub charge and the Balticconnector underutilisation fee (charged when network users cut back their planned gas flows at short notice, beyond an allowed limit, on days of congestion).

What are ACER’s key findings and recommendations? 

Croatia 

After analysing the consultation document, ACER concludes that:

• The proposed methodology meets EU requirements on transparency, avoidance of cross-subsidisation, non-discrimination, volume risk and prevention of cross-border trade distortions.
• Compliance with the requirements on cost-reflectivity cannot be fully assessed, as it is unclear how the applied economic efficiency justification parameter affects the cost-reflectivity of the allowed revenue.
• The tariff methodologies for non-transmission services (the connection service and the 24 proposed non-standard services) lack sufficient details.

ACER recommends the Croatian NRA to:

• Ensure that the economic efficiency justification parameter does not compromise the principle of cost-reflectivity.
• Clarify how non-yearly bookings are handled in tariff setting.
• Align the tariff period with the Network Code’s requirements.

Finland

After analysing the consultation document, ACER concludes that: 

• The proposed methodology meets EU requirements on non-discrimination, volume risk and prevention of cross-border trade distortions.
• It partially meets the transparency requirements.
• Compliance with the requirements on cost-reflectivity and avoidance of cross-subsidisation cannot be fully assessed, mainly due to a lack of clarity on the effects of the market merger.
• The proposed connection capacity charge does not meet commodity charge criteria due to multiple factors, including its partial application to non-system user entities (e.g. distribution operators and their end-users).

ACER recommends the Finnish TSO to:

• Reconsider the new connection capacity charge to ensure it meets commodity charge criteria.
• Categorise the Balticconnector underutilisation fee as a balancing service, since it falls within the scope of the Network Code on Gas Balancing.

What are the next steps?

ACER encourages the Croatian NRA and the Finnish TSO to take these recommendations into account before adopting the final tariff methodologies.

See all ACER reports on national tariff consultation documents. 

For the second consecutive year, ACER has approved the European Resource Adequacy Assessment (ERAA 2024) proposed by the European Network of Transmission System Operators for Electricity (ENTSO-E). This approval confirms the ERAA as a reliable tool in assessing EU’s security of electricity supply. As its relevance grows, so does the need for continuous improvements in future editions.

What is the ERAA?

The ERAA is ENTSO-E’s annual assessment on the risks to the EU’s security of supply. It provides a 10-year outlook to help policymakers take informed and timely decisions on security of electricity supply. The next edition, ERAA 2025, will be released in November 2025.

What does ACER say about ERAA 2024? 

ACER’s second approval confirms ERAA is a trusted tool for monitoring the adequacy of electricity resources (see ACER’s communication on the ERAA 2023). It highlights how shortages in one Member State can impact others and emphasises the importance of regional solidarity, showing the value of cross-border cooperation in managing scarcity.

The approved ERAA 2024 reflects ongoing efforts to ensure better alignment with the established ERAA methodology. ACER finds that this year’s edition largely meets expectations due to several improvements:

• More robust estimation of cross-zonal capacities using a flow-based calculation method, in line with current industry practice.
• A more representative selection of weather scenarios.
• Closer alignment with the National Energy and Climate Plans (NECPs) for renewable assumptions.

ACER’s suggestions for improving future editions

To ensure the ERAA evolves in line with the methodology and remains a reliable tool for policymakers, further enhancements are needed in three priority areas:

• Reduce the consistency gap between ERAA’s investment and adequacy modules.
• Improve national assumptions’ transparency by explaining the main drivers behind the estimates (especially for demand).
• In future ERAA editions, explain what has changed compared to the previous one, allowing stakeholders to follow the developments. 

Without these improvements, the ERAA gradually risks falling behind. A lack of alignment between its two modules could disconnect market revenues from investment, weakening the tool’s usefulness. Increased consistency and transparency, both long advocated by ACER, are key to meeting the expectations of policymakers and the wider public. For future editions, a full assessment of the existing capacity markets is necessary to contribute to the European Commission’s ‘fast track’ initiative for streamlining the capacity mechanism approval process. 

What are the next steps? 

As ENTSO-E prepares its proposal for ERAA 2025 (expected by November 2025), ACER remains actively engaged with ENTSO-E, Member States, the European Commission and the Joint Research Centre to foster improvements. ACER’s ongoing efforts include:

• Providing insights on ENTSO-E’s preliminary input data, calling for increased transparency (especially regarding demand assumptions, demand response and investment parameters). 
• Commissioning a consultancy study to explore key adequacy and infrastructure challenges in scenario development for the ERAA and the ten-year network development plan (TYNDP). ACER will hold a webinar on 11 September 2025 to present the study (expected in late August).
• Working with ENTSO-E and other stakeholders on streamlining the ERAA methodology, triggered by the related European Commission’s report. ENTSO-E shall propose revisions to the European methodology by mid-October 2025. ACER will then decide on the amendments by the end of January 2026.

Would you like to dive into the topic?

Use ACER’s updated dynamic dashboard to:

• Explore the data categories used in all ERAA’s editions, including those proposed for ERAA 2025. 
• Compare how the estimated electricity demand varies across past editions. 
• Check the estimates for power resources, such as batteries and gas-fired plants in 2030 (and beyond) for each EU Member State.  

On 9 May 2025, the Swedish and Lithuanian national regulatory authorities (Energy Markets Inspectorate and National Energy Regulatory Council, respectively) requested from ACER a six-month extension to reach a joint decision on electricity cross-zonal risk hedging opportunities at the Swedish-Lithuanian border.

On 11 August 2025, ACER has granted the requested extension. The regulators now have until 12 November 2025 to decide on the matter.

What is this ACER Decision about? 

Cross-zonal risk hedging opportunities are strategies used by electricity market participants to mitigate price volatility risks across different bidding zones. They are important for ensuring the proper functioning of EU's wholesale electricity markets and protecting market participants from price uncertainty.

Under the Forward Capacity Allocation Network Code, national regulatory authorities must assess whether forward electricity markets in their respective bidding zones offer sufficient hedging opportunities. If these are deemed insufficient, the regulators must coordinate to either:

• introduce long-term transmission rights (LTTRs); or
• task transmission system operators (TSOs) with implementing alternative measures that enhance cross-zonal hedging.

To meet this requirement, the Swedish and Lithuanian regulators asked their TSOs to propose alternative measures to improve hedging opportunities in the Lithuanian bidding zone. The TSOs submitted a joint proposal to the regulators, but since some aspects were unclear, the regulators requested more time for a thorough review.

ACER’s REMIT Quarterly provides updates on the Regulation on Wholesale Energy Market Integrity and Transparency (REMIT) and related activities, including insights into the 2024 revision of the REMIT Regulation to help stakeholders stay informed on changes that enhance transparency and integrity in the European energy market.

Today, ACER has published its 41^st REMIT Quarterly, covering second quarter of 2025 and the latest developments under the Regulation.

What is in the latest REMIT Quarterly?

This edition highlights the launch of two major transparency tools: the REMIT Data Reference Centre and the Inside Information Access Point, both introduced in May 2025. These ACER applications give public access to non-sensitive market data and inside information, supporting better analysis, oversight and research. A webinar in June presented how to use these new tools.

The report also includes:

• ACER’s ongoing preparatory work on data reporting following the revised REMIT and pending the finalisation of the REMIT Implementing Regulation revision. 
• Key takeaways from Expert Groups' meetings in April and May on Wholesale Energy Market Data Reporting and on Wholesale Energy Market Integrity and Transparency.
• An update on market surveillance and statistics on 416 REMIT breach cases under review at the end of Q2.
• A summary of market activity, showing a year-on-year increase in trading on Organised Market Places, driven by growth in natural gas forward markets.

ACER publishes today its first Recommendation on inter-temporal cost allocation mechanisms for financing hydrogen infrastructure. To ensure the recommendation is well-informed, ACER conducted a public consultation on the topic in spring 2025. 

What is inter-temporal cost allocation and why an ACER recommendation?

The EU aims to build a cost-effective hydrogen network to meet its climate goals. However, high infrastructure costs and demand uncertainty pose significant investment challenges, especially in the early stages of market development.

To address this issue, the EU Hydrogen and Decarbonised Gases Regulation (2024) grants Member States the authority to allow hydrogen network operators to recover infrastructure costs gradually over time through inter-temporal cost allocation mechanisms. These aim to ensure a fair and balanced distribution of costs between early and future consumers, ensuring that the former are not disproportionately burdened.

The regulation also assigns new hydrogen-related tasks to ACER, including issuing a recommendation to guide the development and implementation of inter-temporal cost allocation mechanisms. ACER’s Recommendation provides practical advice to support the rollout of hydrogen networks and ensure fair cost-sharing over the long term. 

What does ACER recommend? 

ACER’s Recommendation identifies key investment risks in hydrogen infrastructure and suggests ways to address them. It offers high-level guidance on designing fair and effective inter-temporal cost allocation mechanisms to support the development of the hydrogen market. ACER also highlights the need for Member States to promptly establish clear hydrogen regulatory frameworks and develop flexible national rules to accommodate the future EU-wide hydrogen network codes.

Given the early stage of the hydrogen market and the lack of established best practices, ACER does not yet propose a single, standardised EU-wide approach. Instead, it calls for:

• Regulatory authorities to:
  • ensure that inter-temporal cost allocation mechanisms and national market rules are developed in a coordinated manner;
  • strengthen cross-border coordination to avoid market fragmentation in the initial stage of the hydrogen market; and
  • establish clear and robust mechanisms that guarantee full cost recovery and fair cost distribution over time to support market growth.
• Network operators and planning bodies to:
  • ensure hydrogen network development is based on transparent, data-driven and realistic assumptions.

What are the next steps? 

ACER will review and update its Recommendation at least every two years, incorporating more refined guidance as the market evolves. The next publication is planned for 2027.

On 2 July 2025, ACER received a proposal from all electricity transmission system operators (TSOs) to amend the methodology for intraday cross-zonal gate opening and closure time. 

What is the methodology about?

Established under the Capacity Allocation and Congestion Management (CACM) Regulation, the methodology sets harmonised rules across EU Member States for when electricity trading can begin (gate opening time) and end (gate closure time) in the intraday market.

The intraday market is a short-term market where electricity is bought and sold on the same day as delivery (e.g. a few hours before), after the day-ahead market has closed. It allows participants to adjust their positions based on updated forecasts and balance supply and demand closer to real time. 

By coordinating these timings across different bidding zones, the methodology supports market integration and the efficient use of cross-zonal capacity within the European electricity market.

Why amend the methodology?

TSOs propose harmonising the gate closure time at 30 minutes before real-time delivery, replacing the current standard of 60 minutes. The gate opening time would remain unchanged. This amendment aims to align the methodology with the requirements of the Electricity Market Design Reform (2024), which seeks to improve the efficiency of short-term markets.

Shortening the gate closure time is expected to:

• allow market participants to trade electricity closer to real time, giving them more time to respond to last-minute changes in demand and supply;
• support the integration of renewable energy sources and flexibility solutions; and
• help TSOs maintain system balance and security of supply.

What are the next steps?

ACER expects to decide on the amended methodology by 2 January 2026.

Interested parties are encouraged to submit comments or questions to ACER-ELE-2025-007@acer.europa.eu by 26 September 2025.

Europe’s clean energy shift is accelerating, and electricity distribution networks must keep pace. From integrating solar panels and electric vehicles to connecting heat pumps and storage, grids need to become more modern, flexible and resilient. To support this, the European Commission’s Action Plan for Grids tasked ACER and the Council of European Energy Regulators (CEER) with providing guidance on electricity distribution planning. 

This guidance provides practical recommendations to help national distribution grid operators align with Europe’s decarbonisation goals and turn grid development into a driver, not a barrier, of the clean energy transition. By promoting more coordinated and inclusive planning, the guidance supports the EU Affordable Energy Action Plan, helping ensure the shift to clean electricity is not only sustainable and secure, but also fair and affordable for all Europeans.

Why grid planning needs a rethink

Distribution networks link homes, businesses and renewables to the wider power grid. Yet most were built for one-way power flows, not today’s decentralised, more flexible generation and fast-growing demand for electricity.

As electrification and renewable growth accelerates, so do the risks of grid bottlenecks and infrastructure development delays. That’s why EU law requires distribution system operators to publish distribution network development plans to outline medium and long-term flexibility needs and investments planned for the next 5-10 years so that the full potential of renewables can be integrated. 

What are the key recommendations? 

• Look ahead: Plan at least 10 years ahead and adopt a proactive approach to avoid grid bottlenecks and enable timely investments.
• Holistic approach: For strategic and efficient results, base electricity grid planning on three pillars: scenario development, network needs assessment and project identification.
• Balance infrastructure and flexibility: Address flexibility needs cost-effectively and ensure national distribution plans provide the necessary input for EU-wide flexibility needs assessment methodology (adopted by ACER today).
• Enhance transparency and public trust: Improve stakeholder engagement through structured publication, open consultations and inclusive communication practices.
• Coordinate: Strengthen cooperation among other system operators and align with broader spatial and sectoral planning to ensure system-wide consistency and efficiency.
• Regulatory oversight: National regulators should scrutinise distribution network development, including monitoring the implementation of plans. 

In a further step towards Europe’s clean energy transition, ACER approves the methodology to be used nationally for identifying non-fossil flexibility needs. This is an important step in developing a common European basis for integrating more renewable energy into the electricity grid and meeting the EU’s decarbonisation targets. This ACER decision directly supports the EU’s Clean Industrial Deal by laying the groundwork for a more resilient electricity system that can power a competitive, low-carbon economy.

The flexibility needs assessment methodology (FNAM), developed by the European Network for Transmission System Operators for Electricity (ENTSO-E) and the EU Distribution System Operators Entity (EU DSO Entity), and approved by ACER, will guide Member States' electricity network operators in identifying how much clean and flexible energy their country needs to handle the variability of demand and supply in their power system. 

What is power system flexibility and why does it matter?

Clean flexibility is the energy system’s ability to adapt quickly to changes in electricity supply and demand, without relying on fossil fuels. It enables:

• Demand response, storage or flexible generation to balance the grid in real time.
• Shifting renewable energy from periods of excess (e.g. windy nights) to times of high demand. 
• Reducing renewables curtailment (wasting renewable energy when the grid can’t absorb it).

Unlocking clean flexibility will cut reliance on gas, enable energy transition in a cost -effective manner and help Member States deliver on the EU’s binding 2030 renewable targets (42.5%) and climate neutrality by 2050. 

What is the purpose of the national flexibility needs methodology?

The methodology distinguishes between two main types of flexibility needs: network flexibility needs and system flexibility needs. Network flexibility reflects the flexibility needed to adjust for grid availability, whereas system flexibility refers to the ability of the electricity system to adjust both power generation and consumption in response to signals from the market.

The flexibility needs assessment methodology provides a harmonised approach for transmission and distribution system operators (TSOs and DSOs) in analysing the national flexibility needs in terms of:

• the data they must collect; and
• how they should assess their national electricity flexibility needs.

This harmonised and unified approach serves both national and EU-wide estimations of flexibility needs, with results feeding into reports that will identify how much flexibility is needed, where and at what cost. 

Each EU Member State shall now:

• Conduct a national flexibility needs assessment (FNA) using the new methodology.
• Submit it to ACER and the European Commission (by July 2026).
• Use the findings to define indicative national targets for non-fossil flexibility (by January 2027).

ACER will then publish an EU-wide report to estimate the flexibility needs including a set of recommendations on issues of cross-border relevance at EU level (July 2027). 

What’s novel about this national electricity flexibility needs methodology? 

This new methodology brings several important advancements to how Europe plans for flexibility, as it:

• Builds on existing studies, such as the European resource adequacy assessment (ERAA) and national resource adequacy assessments (NRAAs), to ensure consistency and prevent overlap. 
• Covers distribution and transmission networks, enabling a full-system view of flexibility needs.
• Relies on distribution network development plans (DNDPs) to bring transparency to local flexibility gaps.
• Quantifies the amount of non-fossil flexibility needed per country to meet EU decarbonisation targets by identifying how much renewable energy can be cost-effectively shifted from periods of surplus to times of high demand – maximising clean energy use and reducing curtailment.
• Accounts for cross-border potential and the role of interconnections in meeting flexibility needs.
• Mandates the EU DSO Entity to issue a guidance, taking into account the ACER-CEER guidance on distribution network planning (issued today), to harmonise flexibility assessments across the EU and align with the EU Action Plan for Grids. 
• Identifies regulatory and market barriers, echoing ACER’s No-regret actions to remove barriers to demand response.

This coordinated approach is essential to delivering a climate-neutral power system, ensuring renewables are fully used.

What’s next?

Member States now have 12 months to prepare their national flexibility assessments. These reports will become vital tools in shaping clean energy investment decisions, grid expansion and modernisation and designing EU policy to accelerate flexibility deployment across borders. 

Learn more about flexibility and ACER's work in this area.