As part of its REMIT mandate, ACER is strengthening transparency and reliability in the EU liquefied natural gas (LNG) market through:

• updated guidance on LNG market data reporting; and
• a new Expert Group on LNG price assessment and benchmarks.

Why does this matter?

The Regulation on Wholesale Energy Market Integrity and Transparency (REMIT) is the EU-wide framework that helps detect and deter abuse in wholesale energy markets.

Under REMIT, ACER is responsible for publishing a daily LNG price assessment and a daily LNG benchmark, providing market participants with reliable references that reflect actual trading conditions.

Reliable LNG price indicators mainly depend on two elements:

1. Accurate and consistent reporting by market participants

To support this, ACER has updated its guidance on LNG market data reporting, which clarifies how market participants should submit the data used for the price assessment and benchmark in line with REMIT requirements. The update includes additional guidance on how to report information about the facility where LNG is loaded onto a ship in case of free on board (FOB) transactions. In these arrangements, once the cargo is loaded, ownership of the LNG passes from the seller to the buyer, who then becomes responsible for transport and delivery. 

The guidance will be revised again once the recast REMIT Implementing Regulation is published in the Official Journal, to reflect any new reporting requirements and incorporate stakeholder input.

2. A robust methodology to collect and process LNG transaction data

ACER regularly reviews the methodology behind its LNG price assessment and benchmarks to reflect feedback from market participants and evolving market practices.

To further refine this methodology and strengthen its work on price assessments and benchmarks, ACER is launching a new Expert Group. Building on previous experience, the group will serve as a platform for discussion and expert input, helping improve the reliability of LNG price indicators.

Interested in joining the Expert Group? 

We are looking for professionals with experience in LNG markets, energy pricing or related fields to join and contribute their expertise.

Submit your application by 26 March 2026. 

Check the Open Letter for detailed information on the application process, eligibility criteria and other relevant information.

Today, ACER releases its report on the Slovak gas transmission tariffs directed at Eustream, Slovakia’s transmission system operator (TSO).

The report assesses the compliance of the proposed reference price methodology (RPM) with the requirements of the EU Network Code on Harmonised Transmission Tariff Structures (NC TAR).

What is the proposed tariff methodology?

The Slovak TSO proposes to:

• Change the current methodology to introduce new tariffs in the middle of the ongoing tariff period, which would result in a tariff increase of more than 70%. The TSO cites exceptional circumstances (a large drop in cross-system flows) as the reason for this change.
• Apply a uniform postage stamp reference price methodology with an ex-ante entry-exit split, covering the multi-year tariff period 2026-2027.
• Continue recovering transmission revenues through a mix of capacity-based charges (paid for reserving network capacity) and commodity-based charges (linked to the volume of gas transported).
• Adjust capacity tariffs at all entry and exit points (including domestic points) using benchmarking to lower tariffs and make them more competitive. Eustream proposes to use a wide set of European TSO tariffs, including those from Northwestern Europe, as a reference.
• Keep two commodity-based charges in place:
  • a flow-based charge paid in kind (meaning a portion of transported gas is normally used to cover the fee); and
  • a complementary revenue recovery charge, designed to help recover the costs of the Slovakia-Poland gas interconnector.

What are the key findings? 

After analysing the consultation document, ACER concludes that:

• The proposed methodology meets the EU requirement on non-discrimination.
• Compliance with the requirements on transparency, cost-reflectivity, avoidance of cross-subsidisation, volume risk and the prevention of cross-border trade distortions cannot be confirmed. This is mainly due to the proposed benchmarking adjustment, which does not meet NC TAR standards.
• The proposed commodity-based charges are also non-compliant. Specifically, the flow-based charge is adjusted by a discount for domestic flows, which is not allowed under EU rules.

What does ACER recommend? 

ACER recommends that the Slovak national regulator (ÚRSO), when adopting its final decision on the proposed methodology:

• Limit benchmarking adjustments to points with clearly identified competition between pipelines, so that tariffs reflect actual market conditions and remain predictable for network users.
• Implement measures to improve alignment with NC requirements, despite current challenges to full compliance.
• Phase out the non-compliant discount applied to the flow-based tariff.

See all ACER reports on national tariff consultation documents.

On 27 February 2026, ACER will open a public consultation on economic input data to improve electricity system modelling across Europe. The aim of this consultation is to ensure that the inputs used in European-level modelling are robust, transparent and properly grounded in national market realities.

Why are we consulting?

Realistic cost assumptions are key for effective long-term electricity system modelling, including the one used by ENTSO-E for the European Resource Adequacy Assessment (ERAA). These models are used to assess future investment needs, such as whether new power generation or flexibility resources are likely to be built, and whether existing power plants are expected to remain economically viable.

ACER has recently commissioned a consultancy study on investment parameters. As part of it, the consultant delivered a comprehensive EU-wide economic dataset for electricity system modelling. This new dataset shows estimated investments and operational costs for different power generation technologies and demand-side flexibility at Member State level.

Get involved!

Stakeholders are encouraged to review the data for their relevant Member State(s), assess whether it reflects current market and technological developments and propose evidence-based alternatives. 

The consultation will run from 27 February 2026 until 27 March 2026.

What’s next?

These figures will help shape how Europe’s power system develops in the years ahead.

ACER will examine the feedback received and revise the dataset to ensure accuracy and credibility. The finalised data will then be used to improve future ERAA modelling by ENTSO-E, as well as to help Member States in the procedure of fast-track approval of capacity mechanisms under the new State aid framework.

ACER will consult on amendments to the long-term capacity calculation methodology of the Core capacity calculation region (CCR) from 27 February until 27 March 2026.

On 21 November 2025, the Core CCR’s transmission system operators (TSOs) submitted a proposal to their national regulatory authorities (NRAs) to amend the long-term capacity calculation methodology. As the NRAs could not reach an agreement, the proposal was referred to ACER on 4 February 2026 under the Forward Capacity Allocation Regulation. 

The Core CCR comprises 13 countries: Austria, Belgium, Czech Republic, Croatia, France, Germany, Hungary, Luxembourg, the Netherlands, Poland, Romania, Slovakia and Slovenia.

What is the methodology about?

Long‐term cross-border capacity calculation promotes efficient long‐term cross‐zonal trade. By providing reliable capacities to market participants early, it enables long-term planning and hedging opportunities.

The Core CCR’s long-term methodology covers both yearly and monthly processes, using the flow-based approach.

Why change it?

In their proposal, TSOs recommend to:

• Introduce a benchmark process for available transfer capacity, adjusting the flow-based capacity calculation to better reflect historical cross-border transmission capacities.
• Integrate the Ireland and Northern Ireland single electricity market - France bidding zone border into the Core CCR’s long-term capacity calculation process, once the Celtic interconnector is commissioned.

The proposed changes aim to improve long-term capacity calculation in the Core CCR by enabling the implementation of the flow-based methodology. As a transitional measure, the benchmark for available transfer capacity would be applied at the end of the process. This would allow the yearly auction at the end of 2026 (for delivery in 2027), as well as the monthly auctions in 2027, to take place.

The inclusion of the Ireland and Northern Ireland single electricity market – France bidding zone border reflects its recent integration into the Core CCR. 

What are the next steps?

ACER aims to reach a decision by 4 August 2026. The Core TSOs shall implement the long-term capacity calculation methodology by the end of 2026.

On 11 February 2026, ACER issued its Opinion on the Winter Supply Outlook 2025/2026, published by the European Network of Transmission System Operators for Gas (ENTSOG). 

What’s in ENTSOG’s Outlook?

This year’s Outlook is particularly timely in light of the recent EU measure phasing out Russian gas imports. Against this backdrop, ENTSOG’s Outlook evaluates the gas system readiness for winter 2025/2026, considering a gradual phase-out of Russian gas. 

• EU entered winter with lower gas storage (83%) than last year (94%), but still has sufficient gas to meet demand.
• Storage levels are expected to remain above 30% by the end of winter, even if remaining Russian flows via TurkStream are fully disrupted.
• LNG availability is the main supply risk, as LNG now covers around 40% of EU gas demand.
• In a low-LNG scenario, gas storage could be depleted by the end of winter, potentially requiring demand reduction measures.

What does ACER say?

ACER welcomes ENTSOG’s extensive testing of the gas system, including cold winter scenarios, supply disruptions and updated infrastructure data. It also recognises the clear inclusion of the Russian gas phase-out in the Outlook, as well as consideration of the remaining gas dependency in the electricity sector, as highlighted in ACER’s security of supply Monitoring Report (November 2025).

However, ACER notes that a more holistic assessment of security of supply requires shifting the focus from infrastructure (which is currently not the main bottleneck) towards supply challenges and diversification. 

What does ACER recommend?

ACER recommends that ENTSOG, in its future outlooks, adjust its analysis to better reflect supply risks and market dynamics by:

• Shifting the analysis towards gas supply availability and LNG market dynamics, rather than infrastructure resilience.
• Assessing LNG supply based on EU regasification capacity and destination-free global LNG volumes, as reflected in the high-LNG scenario, rather than capping LNG supply in the reference and low-LNG scenarios only based on historic averages.

The European Commission is inviting applications to appoint new members and alternates of ACER’s Board of Appeal. Successful candidates will serve on the Board for its next mandate, starting on 18 October 2026.

Applications are open until 31 March 2026 (midnight Brussels time).

See the call for interest for details and instructions on how to apply.

About the Board of Appeal

ACER’s Board of Appeal operates as an independent body to address complaints lodged against ACER decisions. It is part of ACER but at the same time independent from its administrative and regulatory structure. As such, its members and alternates act independently and in the public interest. 

The Board is composed by six members and six alternates serving for a 5-year mandate (renewable once). Members and alternates are selected among current or former senior staff of the national regulatory authorities (NRAs), competition authorities or other national or EU institutions with relevant experience in the energy sector.​

In August 2025, ACER has received a proposal from Nominated Electricity Market Operators (NEMOs) to amend the harmonised maximum and minimum clearing price (HMMCP) methodologies for the EU day-ahead and intraday market coupling.

On 4 February 2026, ACER has approved NEMOs’ proposal.

Why is market coupling important?

Before market coupling was introduced in the EU, electricity and cross-zonal transmission grid capacity had to be purchased separately. Today, market coupling (of day-ahead and intraday markets) allocates scarce cross-zonal transmission grid capacity efficiently by coupling wholesale electricity markets across the EU, while taking into account physical grid constraints.

What are the methodologies about?

The HMMCP methodologies (first approved by ACER in 2017 and amended in 2023) set the maximum and minimum price limits in the EU single day-ahead and intraday electricity markets. 

Established under the Capacity Allocation and Congestion Management (CACM) Regulation, the methodologies also define the harmonised automatic price adjustment mechanism and specify how it is triggered when the applicable price limits are reached in the day-ahead and intraday markets. 

Why amend the methodologies and what’s new?

ACER amended the methodologies to clarify how the automatic price adjustment mechanism applies in rare market conditions.

In case of partial decoupling within a bidding zone where multiple NEMOs operate but not all are decoupled, the bidding zone will remain in market coupling, potentially with low liquidity. The amended methodologies clarify that, in such cases, the harmonised automatic price adjustment mechanism cannot be triggered. 

What are the next steps? 

Following this ACER Decision, NEMOs are required to promptly implement the amendments. 

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

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

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.