ACER publishes today its biennial gas congestion report, covering 2024 and 2025. The report assesses contractual congestion in EU gas markets, in line with the recast Gas Regulation.

ACER finds that contractual congestion eased in 2024 and 2025, pointing to a new equilibrium in the EU gas market following the 2022 market crisis.

What does congestion mean in gas markets? 

Gas network congestion can be either contractual or physical. Physical congestion occurs when gas flows reach the system’s technical limits. Contractual congestion occurs when demand for capacity rights exceeds the capacity offered in the market, even if the system may not be physically constrained.

In practice, contractual congestion means that network users may not be able to secure all the capacity they need to transport gas, forcing them to compete for it.

What are they key findings? 

The 2022–2023 crisis, followed by the EU’s gradual phase-out of Russian gas, rapidly reshaped the EU gas market. Liquefied natural gas (LNG) imports surged while demand fell sharply, leading to a reconfiguration of cross-border gas flows, with stronger west-to-east and coastal-to-continental flows. 

The optimisation of existing infrastructure and new investments helped absorb the shock. However, parts of the network still face residual congestion, reflecting the market’s continued adjustment to new supply and demand patterns. 

In particular, ACER finds that:

• 24 exit/entry sides of interconnection points were contractually congested in 2025 and 23 in 2024 (down from 35 in 2023 and 50 in 2022). 

• Network congestion persisted on key west-to-east routes and selected interconnection points in Southeast Europe.

• Congestion revenues stabilised at EUR 140 million (similar to 2023 levels).

• The capacity surrender scheme surpassed the oversubscription mechanism as the most used congestion management procedure. Surrender schemes allow users to return unused capacity for reallocation, while oversubscription allows additional capacity to be offered above technical limits based on potential unused capacity.

Possible ways forward to ease congestion

• Continuous coordination between neighbouring transmission system operators (TSOs) to jointly maximise available firm and interruptible capacities. 

• Regular updates by TSOs and ENTSOG on interconnection points characteristics and network usage. 

• Fully applying the Capacity Allocation Mechanism Network Code and congestion management procedure guidelines to retain the benefits and flexibility of capacity allocation at interconnection points.

• Careful assessment of investment needs where physical bottlenecks persist, taking into account the risk of asset stranding and considering the use of congestion revenues to help finance these investments.

What are the next steps?

ACER’s results can support national regulatory authorities when deciding whether to apply congestion management procedures.

REMIT is the EU-wide framework that detects and deters market manipulation and abuse in wholesale energy markets. It enhances transparency and trust in the integrity of Europe’s energy markets.

The Regulation was revised in 2024 to keep pace with evolving market dynamics. To make the framework fully operational, REMIT secondary legislation was updated in spring 2026 with a recast REMIT Implementing Regulation and a new Delegated Regulation.

ACER’s REMIT Quarterlies provide updates on REMIT related activities, helping stakeholders stay informed. 

What is in the latest REMIT Quarterly?

The 44th edition covers the first quarter of 2026, including insights into the updated REMIT framework and details on the upcoming ACER and European Commission REMIT workshop (11 June 2026).

The report also highlights:

• ACER’s ongoing efforts and next steps in implementing the updated REMIT data reporting framework (April 2026).  

• Updates on market surveillance and statistics on the 453 REMIT breach cases under review at the end of Q1 2026.

• An overview of algorithmic trading and its implications under REMIT obligations. 

• 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.

Get involved!

ACER is consulting on a new guideline on REMIT transaction reporting. Interested stakeholders have until 12 June 2026 to participate.

Read more and share your views.

ACER has launched the first edition of its electricity network tariff repository. 

Why network tariffs matter

Network tariffs are a key part of electricity bills, used to recover the costs of investing in, maintaining and operating electricity networks. As Europe’s power system evolves, the grid needs to support more electrification, more renewable energy and new patterns of grid use. Based on sector estimates, investments in electricity networks could reach up to €2,600 billion by 2050 to integrate the rise of renewable energy (see ACER’s 2024 infrastructure report). With the ramp-up of grid investments, network costs are a big driver of overall electricity costs.

Clear and comparable tariff information is therefore important for understanding how network costs are allocated, how tariff structures differ across countries and how tariff design may support efficient use of the grid. This supports broader EU efforts to improve energy affordability and ensure electricity grids are fit for the future, including the European Commission’s upcoming network charges plan, which is part of its energy package expected on 10 June. 

Network tariff repository 

This new ACER repository brings together tariff information from EU Member States in one centralised platform. It complements national transparency efforts and supports access to electricity network tariff data at European level.

The dashboard aims to improve comparability and understanding of national approaches to network cost recovery and tariff setting.

Who can use ACER’s network tariff repository?

Whether for analysis, benchmarking or strategy the repository offers easy access to electricity network tariff information from across Europe to national regulatory authorities, policymakers, network operators, researchers, analysts, and consumer and industry organisations. 

Use case 1 – Electricity bills: An analyst comparing electricity bills across Europe could use the repository to check whether network charges are mainly fixed, capacity-based or energy consumption-based in different Member States and therefore understand the underlying cost drivers. 

Use case 2 – National tariff methodologies: A regulator reviewing its national tariff methodology could compare how other Member States structure and allocate network charges for households and businesses.

What’s next?

The repository will be progressively updated with data and additional information, including tariff practices and relevant studies underlying key network tariffication choices. 

The dashboard will also provide input for ACER’s future analytical work, including the next edition of ACER’s report on electricity network tariff practices, expected in 2027. 

Disclaimer: This electricity network tariff repository is published as a work-in-progress tool. The repository is intended to improve access to tariff-related information and will support ACER’s future analytical work.

Check ACER's new dashboard.

In summer 2024, Southeast Europe¹ experienced a sustained period of electricity price spikes. In response, the European Commission asked ACER to assess which measures could help prevent or mitigate similar episodes across the region in the future. 

Today, ACER publishes its Monitoring Report to the Energy Union Task Force, setting out recommendations to increase cross-zonal capacity and system flexibility across Southeast Europe.

What did ACER find? 

• The 2024 price spikes were driven mainly by a lack of flexible resources to replace solar generation in the evening, during periods of high demand. 
• Limited cross-border capacity, including due to planned network maintenance, reduced the region’s ability to import lower-priced electricity from the rest of the EU.
• Although prices in 2025 did not reach the same levels as in summer 2024, the price gap between Southeast and Central Europe² persisted into early 2026. This suggests deeper structural challenges in the region. 

ACER found that a better use of the existing network could have helped ease regional system stress in 2024. But increasing interconnection alone is not enough – greater system flexibility is also key. 

What does ACER recommend?

Addressing the challenges observed in Southeast Europe’s electricity markets requires both immediate and long-term action by Member States, national regulatory authorities, transmission system operators and other market actors:

• Faster deployment of grid-enhancing technologies (such as dynamic line rating and advanced line conductors).
• Improved regional coordination, including on outage planning and curative remedial actions in capacity calculation. 
• Continued implementation of EU market integration rules (minimum 70% cross-zonal capacity requirement, flow-based approach across Southeast and Eastern Europe, and market coupling with non-EU neighbours).
• Accelerated network investment projects to strengthen interconnectivity of Southeast Europe.
• Measures to unlock system flexibility by removing market barriers for small market participants and supporting investments in flexibility.
  
  ^{1. For the purpose of this assessment, Southeast Europe refers to the group of Member States affected by the price spikes: Slovenia, Croatia, Hungary, Romania, Bulgaria and Greece. 2. Central Europe refers to Austria and Slovakia.}

Today, ACER publishes a policy paper exploring how Europe could improve the way costs and benefits of cross-border electricity infrastructure projects are shared. The paper aims to support the grid investments needed for a more integrated European electricity market and a more efficient use of Europe’s electricity system. 

Why cost and benefit sharing of energy infrastructure matters

Building an integrated European electricity market requires substantial cross-border grid investments. An effective cost-sharing framework is a key enabler of such investments, especially when infrastructure in one country brings benefits beyond its borders.

However, the current framework does not always ensure that costs are shared fairly when a project benefits several countries (for example, when one country bears most of the investment costs while others receive a significant share of benefits). 

As a result, projects with clear European or regional value might not be realised if costs are largely borne at national level while benefits are distributed more widely across borders.

Several mechanisms currently aim to address this challenge: 

• congestion income distribution, which shares revenues from cross-border congestion; 

• the inter-TSO compensation (ITC) mechanism, which compensates for costs related to hosting cross-border flows; and 

• cross-border cost allocation (CBCA), which allocates costs of new infrastructure based on expected cross-border benefits. 

While each plays an important role, gaps and overlaps remain in how effectively they align costs with benefits. This can make it more difficult to develop infrastructure that is valuable from a European or regional perspective.

What is in ACER’s policy paper?

Already in July 2024, ACER committed to strengthening and improving the existing mechanisms to better reflect the costs and benefits of cross-border network infrastructure. 

As part of this effort, ACER’s 2026 policy paper assesses the current mechanisms, their gaps and overlaps, and explores how they could be improved or redesigned to better align national investments with European and regional needs. 

It sets out several policy options, ranging from targeted improvements to the existing mechanisms to broader changes to the overall cost-sharing framework. These include improving the current mechanisms separately, combining some of them into a single ex-post mechanism, or exploring a new framework with common EU financing for infrastructure used for cross-border trade. 

The policy paper also provides a qualitative evaluation of these options, with the common objective of strengthening investment incentives for cross-border electricity infrastructure.

The policy paper does not provide definitive solutions to the identified challenges. Instead, it aims to inform and stimulate further discussion on how the cost-sharing framework can better support investment in projects of European and regional value. 

ACER has published its 2026 Monitoring Report on European liquefied natural gas (LNG) market developments, reviewing key market trends in 2025 and the implications for Europe’s energy security, including the risks linked to tensions in the Middle East.

Worth highlighting, given there is much talk of EU data gaps, that ACER has the overview of EU LNG market. This annual ACER report shows that LNG has become central to the EU gas system as Europe continues to move away from Russian gas. At the same time, it highlights growing exposure to global LNG market risks, including supply concentration, spot market volatility and geopolitical disruptions.

Main highlights

• The EU imported a record 146 bcm of LNG in 2025, confirming LNG’s key role in Europe’s gas supply. The EU is the world's largest importer of LNG.
• Global LNG production increased by 36 bcm, the strongest annual growth since 2022.
• The United States supplied 58% of EU LNG imports in 2025, equivalent to around a quarter of total EU gas demand.
• ACER’s daily LNG price assessments (based exclusively on actual spot transactions) provide much needed transparency on the EU LNG spot price discovery. More than 980 spot LNG cargoes for delivery in the EU in 2025 were reported to ACER in 2025, up from 550 transactions in 2024.
• TTF, the Dutch gas trading hub, remained the main benchmark, used to price 74% of EU spot LNG trades.
• In a full-year Strait of Hormuz closure scenario in 2026, the global LNG market could face a net supply shortfall of 27 bcm compared with 2025, intensifying competition for spot cargoes.

ACER’s recommendations

Recent tensions in the Middle East show how quickly geopolitical crises can disrupt energy flows and drive up prices. In response, ACER underlines the continued strategic importance of REPowerEU and its three pillars for Europe’s energy security:

• Energy savings and efficiency, to reduce gas demand and lower vulnerability to external shocks.
• Diversification of supply sources, to avoid overreliance on individual suppliers or transit routes.
• Faster roll-out of renewable energy, to strengthen resilience by reducing dependence on imported fossil fuels.

For punchy overview of related issues like the impact of Hormuz on EU gas storage filling for winter 2026, see also the recent ACER key developments in European gas markets report (April 2026).