ACER publishes its Opinion on the Summer Supply Outlook 2025 prepared by the European Network of Transmission System Operators for Gas (ENTSOG).

The Summer Outlook evaluates the ability of the EU’s gas system to meet demand and handle storage injections during the upcoming summer and winter seasons.

The expected gas demand and supply projections are modelled under a reference scenario, which is complemented with various challenges to the gas system (such as cold winters and disruptions in Russian gas supply). 

What are the 2025 Summer Outlook’s main highlights?

The Outlook examines the EU’s dependence on Russian gas supply:

• In all scenarios, gas imports via the TurkStream pipeline (running from Russia to Turkey) are minimised.
• Two additional Russian gas disruption scenarios are modelled: a complete disruption of TurkStream and a 20% reduction of liquefied natural gas (LNG) supply.

In all scenarios, the Outlook concludes that the current European gas infrastructure is adequate to ensure security of gas supply.

These scenarios broadly align with the recent proposal by the European Commission to coordinate a gradual phase-out of Russian gas imports by stopping existing spot contracts by mid-2026, with the aim of ending all remaining gas imports by the end of 2027.

What’s in the ACER Opinion?

ACER welcomes the timely publication of ENTSOG’s Summer Outlook (April 2025), the modelling updates to reflect recent changes in infrastructure (e.g. new LNG terminals and cross-border capacities) and to cover the potential EU gas transit via Ukraine. ACER also suggests further improvements to the Outlook’s future editions:

• Include a gradual phase-out of Russian gas supply in a sensitivity scenario, reflecting the roadmap of the European Commission.
• Focus on LNG import trends, as the increasing global LNG market expansion is influenced by geopolitical instabilities (e.g. the current conflict in Iran may impact gas supply and price due to the country’s strategic location for energy exports).
• Review transmission system operators’ demand estimates by comparing them with past demand, political and economic trends, as well as with third-party projections.
• Explore the impact of gas prices on gas supply and storage filling, as it may alter the typical supply pattern. This would provide a more realistic assessment of the gas system in the coming year.

ACER publishes a new report and updates its interactive dashboard to showcase main gas balancing trends in the EU for the 2023-2024 gas year. 

Keeping Europe’s gas systems balanced efficiently

The Gas Balancing Network Code establishes market-based rules to ensure efficient balancing of gas supply and demand in European gas balancing zones. For example, it establishes rules that enable and incentivise network users to balance their positions. It also promotes the development of short-term markets by prioritising the use of standard wholesale products when transmission system operators (TSOs) need to manage any remaining system imbalances.

What’s the role of ACER?

Each year, ACER analyses data collected by the European Network for Transmission System Operators for Gas (ENTSOG) to monitor the implementation and effects of the Gas Balancing Network Code across Member States, focusing on:

• TSOs’ balancing activities;
• network users’ imbalances;
• neutrality (i.e. the cost or revenue generated by the balancing regime).

What does ACER monitoring show? 

• TSOs’ balancing actions have declined across most EU gas balancing zones: These interventions accounted for a decreasing share of the physical gas market at EU level.
• The changing gas market may be reducing the need for balancing. Lower gas consumption and a smaller physical market may have reduced the need for TSOs to actively balance the system. At the same time, higher gas prices may further incentivise users to stay in balance and avoid charges.

What does ACER recommend? 

ACER encourages national regulatory authorities to:

• Periodically review the performance of their balancing regimes and assess whether their design should be refined or revised.
• Ensure that incentives for commercial balancing are adequate and explore enhancements to information systems to facilitate network users’ participation.

ACER monitoring, together with market participants’ views (identified through public consultations) and regional cooperation can support regulators in these processes.

ACER releases today its Opinion on the hydrogen Infrastructure Gaps Identification (IGI) report 2024. ACER welcomes the publication of this report prepared by the European Network of Transmission System Operators for Gas (ENTSOG), providing recommendations to improve the underlying methodology.

What is the hydrogen Infrastructure Gaps Identification report?

Hydrogen is expected to play a key role in achieving the EU’s climate and energy goals. However, its market is still in the early stages, with low renewable hydrogen production and consumption, and slow infrastructure buildout. High production costs and uncertain demand are hindering market development. Unlike electricity, hydrogen also lacks a well-developed transmission network, making infrastructure planning more complex and highly dependent on policy support and demand forecasts.

To address these challenges and support coordinated planning and investments, ENTSOG published the first hydrogen Infrastructure Gaps Identification report in March 2025. This report is part of the EU’s Ten-Year Network Development Plan (TYNDP) framework and aims to identify regional gaps in hydrogen infrastructure based on demand and supply projections for 2030 and 2040.

What does ACER recommend? 

While ENTSOG’s report highlights bottlenecks that could signal potential infrastructure shortages, ACER recommends improving the methodology used to better identify these gaps by: 

• Incorporating scenario variants to understand how projected infrastructure needs change under different assumptions. This would help identify the risk of investments that do not align with future hydrogen demand.

• Refining the analysis to better determine where and how much additional cross-border infrastructure capacity is needed. 

• Seeking a more cross-sectoral modelling approach to capture the interdependencies between hydrogen infrastructure and electricity systems more effectively.

What’s next?

ACER encourages ENTSOG to start testing the suggested improvements using the data currently available, without waiting for the upcoming 2026 TYNDP scenarios. Early testing can help enhance the methodology used to identify future needs, prevent delays and reinforce trust in the ensuing results.

As Europe moves away from Russian fossil fuels, liquified natural gas (LNG) is becoming an increasingly important flexible supply source. But with future gas demand uncertain, the EU faces a trade-off: securing higher LNG volumes to ensure stabler pricing, while maintaining the flexibility to avoid over-contracting in a changing market.

ACER’s 2025 Monitoring Report highlights:

• LNG’s share of the EU’s total gas supply rose from 23% in 2020 to around 40% in 2024.
• The EU remained the world’s largest LNG importer, with 112 bcm imported despite a 17% drop from 2023.
• The US supplied nearly 50% of EU LNG imports, while Russian LNG to EU increased by 22%, despite sanctions. 
• Over 550 EU spot LNG trades with delivery were reported to ACER, totalling 45.5 bcm – 55% of which were priced below 35 EUR/MWh.
• The EU purchased 30 bcm of LNG on the spot market, more than any other major importer.
• The EU faces up to 90 bcm of demand uncertainty between Fit for 55 and REPowerEU scenarios, which could lead to 30 bcm in additional LNG demand by 2030 (compared to 2024 levels) and prolonged reliance on the spot market.

ACER recommendations

To manage future gas demand uncertainty and price risks, key actions are needed from policymakers, network operators and market players:

• Accelerate decarbonisation efforts to reduce structural gas demand through faster deployment of renewables and improved energy efficiency.
• Secure additional LNG through flexible contracts to help reduce short-term exposure to price volatility.
• Improve coordination and effective data-sharing between Member States and the European Commission to enable better monitoring of decarbonisation progress and guide LNG procurement.

What are the next steps? 

Register for the ACER webinar on the evolving role of LNG in Europe (28 May 2025).

Read more. 

Today, ACER publishes its report on trends in the European gas wholesale markets during the gas winter season (October 2024 to March 2025). The report also explores gas storage dynamics over the winter and offers an outlook for summer 2025. 

What trends did ACER monitoring find? 

European gas markets came under more pressure this winter due to higher demand and lower supply.

• Wholesale prices increased by 50% compared to last winter, though regional price variations narrowed.
• Gas consumption increased year-on-year, driven by colder weather than in the past two winters and exceptionally low wind generation. 
• Despite increased demand and the halt of Russian gas flows via Ukraine, gas networks avoided congestion thanks to full storages at the start of winter, expanded LNG infrastructure, and gas consumption remaining structurally lower than pre-crisis levels.
• Storage levels ended winter at 34% capacity, in line with pre-2022 norms but well below 2023-2024 levels. Significant injections will be needed before next winter.
• LNG imports rose seasonally but stayed below early winter 2023 levels. Later in the season, with European gas wholesale prices exceeding Asian spot LNG prices and new US liquification coming online, EU LNG imports hit record monthly highs.

Looking ahead 

To meet summer 2025 gas needs and refill EU gas storage to 90% by next winter, ACER estimates that pipeline flows must remain high and LNG imports will need to increase by 20% compared to summer 2024. 

Today, ACER publishes its report on the Czech gas transmission tariffs directed at the Energetický regulační úřad/Energy Regulatory Office (ERO), the Czech national regulatory authority.

The report assesses whether the proposed reference price methodology complies with the requirements of the EU binding Network Code on Harmonised Transmission Tariff structures. 

What is the proposed tariff methodology about?

The regulator proposes to:

• Adopt a capacity weighted distance methodology as the reference price methodology.
• Adjust the entry-exit split from the current 9-91% to 15-85%. 
• Reduce the discount applied to entry and exit points of storage facilities from 100% to 80%.

What are the key findings? 

After analysing the consultation document, ACER concludes that:

• The proposed methodology largely complies with the requirements of the network code.
• Most required information is provided, with the exception of the calculation and components of the cost allocation assessment. 
• The proposed commodity-based charge generally aligns with Article 4(3) of the tariff network code (which sets the rules for commodity-based tariffs). 

What does ACER recommend? 

ACER recommends that the national regulatory authority (ERO), when adopting its final decision:

• Consults on any benchmarking adjustments, respecting the two-month consultation period set in the tariff network code. If this timeframe cannot be met, ACER recommends that ERO provides the longest possible consultation period, anticipating the opening and closing dates to stakeholders and ACER.
• Justifies the results of the cost allocation assessment, providing an explanation on how the outcomes vary when different assumptions are used. This should help identify the most suitable methodologies for the transmission network.
• Justifies the use of an alternative pricing mechanism for the flow-based charge at interconnection points. For this purpose, ERO should demonstrate that there is a significant risk of volatility in cross-system flows that could impact the cost reflectivity of the flow-based charge.

See all ACER reports on national tariff consultation documents.

Today, ACER releases its report on the Lithuanian gas transmission tariffs directed at the Valstybinė Energetikos Reguliavimo Taryba (VERT), the national regulatory authority (NRA) of Lithuania.

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

What is the proposed methodology about?

The Lithuanian regulator proposes to:

• Apply a postage stamp reference price methodology with flexible entry-exit splits, complemented by a 100% discount at entry points for domestic biomethane producers.
• Align entry tariffs with those of the neighbouring FinEstLat (Finland, Estonia and Latvia) zone.
• Simplify the existing tariff structure by abandoning the previously applied system based on multiple asset cost splits and differentiated tariffs.
• Use a flow-based charge (commodity-based tariff) with a fixed tariff level for the entire regulatory period.
• Offer a conditional product with limited allocability (i.e. the product can only be used to ship gas to pre-defined system points) at entry and exit points with non-EU countries.

What are the key findings? 

After analysing the consultation document, ACER concludes that:

• The proposed methodology meets the requirements on transparency, non-discrimination, and volume risk.
• Compliance with the requirements on cost-reflectivity, avoidance of cross-subsidisation, and prevention of cross-border trade distortions cannot be fully assessed, due to several design elements of the methodology.
• While the criteria for setting the flow-based charge are met, further clarification is needed on how the charge will be adjusted and reconciled. 
• Simplifying the tariff structure has made the methodology more understandable for system users.

What does ACER recommend? 

ACER recommends that the national regulator, when adopting its final decision:

• Provides a clear framework for the flow-based charge, preferably by recalculating its level annually.
• Ensures full compliance of non-EU entry and exit points with the network code. 
• Assesses regional networks and allocates their costs in a compliant way, in line with EU rules and ACER’s guidance.

See all ACER reports on national tariff consultation documents. 

Today, ACER releases its report on the German gas transmission tariffs directed at the Bundesnetzagentur für Elektrizität, Gas, Telekommunikation, Post und Eisenbahnen (BNetzA), the national regulatory authority (NRA) of Germany.

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

What is the proposed RPM about?

The German NRA proposes to:

• Apply a postage stamp RPM with uniform entry and exit tariffs.
• Use conditional products with discounted tariffs.
• Use non-transmission services, including metering at exit points (for both end-users and distribution networks) and alternative nomination procedures for gas deliveries.

What are the key findings? 

After analysing the consultation document, ACER concludes that: 

• The RPM complies with the requirements of the network code on transparency, non-discrimination and volume risk.
• Due to insufficient information on regional networks, ACER could not assess the compliance of the proposed tariffs with the principles of cost-reflectivity, avoidance of cross-subsidisation and prevention of cross-border trade distortions. 
• While the criteria for setting metering charges are met, ACER could not assess whether the proposed tariff methodologies for alternative nomination procedures comply with NC TAR principles.

What does ACER recommend? 

ACER recommends that the NRA, when adopting its final decision:

• Assess regional networks and allocate their costs in a compliant way, in line with EU rules and ACER’s guidance.
• Provide more clarity on how discounted tariffs for conditional products are calculated.

See all ACER reports on national tariff consultation documents. 

ACER kicks off its 2025 Monitoring Report series with key insights into the EU energy markets, highlighting major developments in 2024, and examining the interplay between gas and electricity markets in the energy transition.

What are the key findings?

The report highlights progress towards Europe’s transition to clean energy, persistent challenges (such as high and volatile energy prices for European consumers and businesses), and how to address them. It sets out ACER’s recommendations on how Europe can unlock a clean, secure and competitive energy future.

• 2024 recorded the lowest energy prices since 2021, but with noticeable regional differences. Gas prices averaged 34 €/MWh and electricity averaged 81 €/MWh. The surge in negative and very low prices in 2023 intensified in 2024.
• Energy market prices remained volatile (but less extreme than during the crisis), driven by gas supply risks and renewables’ variability. Frequent swings in electricity prices (within a day) persist – on 70% of days, electricity price variations within the day reached 50€ or higher. Electricity price swings reveal a need for more short-term flexibility.
• Renewables grew significantly, accounting for 35% of power generation. Solar power confirmed its leading role in the energy transition whilst nuclear and hydro came back.
• Europe’s clean energy transition faces persistent challenges. Gas supply risks and unpredictable weather later in the year kept market prices volatile. In December, a ‘dunkelflaute’ episode in Germany sent electricity prices to nearly 1,000 €/MWh (far above the 81 €/MWh annual average). 
• Gas as a flexibility provider. Fossil fuels, especially gas and coal, remain essential for meeting peak electricity demand.

ACER’s recommendations to address these challenges:

For decarbonisation and global competitiveness, Europe must place renewed effort on further expanding EU energy market integration, enhancing energy efficiency, and driving power grid innovation:

• Target new transition cost drivers: Network costs are at risk of doubling by 2050. Enhancing grid capacity (rather than new build) is part of the solution. Better network tariffs and 'efficiency first' incentives to prevent stranded assets play an important role. Ensure capacity, flexibility, and renewables remain affordable while securing long-term supply.
• Harness energy efficiency and flexibility: Use demand response, electric vehicles (EVs), and batteries to balance supply and demand, cut price swings, and strengthen grid resilience, especially at peak times.
• Expand energy market integration: Support cross-border renewable use for flexibility and security. Strengthen interconnections to cut fossil fuel reliance and build trust in Europe’s energy markets.

Looking ahead 

In its 2025 Monitoring Report series, ACER will continue to pave the way for a clean, secure and competitive energy future by shedding light on:

• strengthened cross-border cooperation;
• energy transition monitoring; and
• efficient grid investment.

Upcoming reports:

• ACER's Monitoring Report on removing barriers to demand response (to be published here on 8 April).
• ACER’s report on EU electricity tariff practices (coming on 26 March).