ACER’s 2025 Monitoring Report on security of EU electricity supply looks at whether Europe had adequate electricity supply in 2024, including risk preparedness, cross-sectoral electricity-gas interactions and the total cost of national support measures such as capacity mechanisms and flexibility schemes that help keep the lights on.

What trends did ACER find in 2024? 

• The EU’s interconnected power system helps keep the lights on.
  • In 2024, power outage levels averaged under two hours per year across the EU, and none were due to inadequate electricity supply.
• Fragmented support measures come with an annual price tag of €11 billion.
  • Almost €11 billion was spent in 2024 across the EU on a fragmented set of nearly 40 security-of-supply measures.
  • Capacity mechanisms are justified if the annual European Resource Adequacy Assessment (ERAA), or alternatively a national assessment, identifies a risk of inadequate supply. Any capacity mechanism must be cleared by the European Commission under State aid rules. These mechanisms rely on a broad range of technologies from dispatchable gas-powered generation to batteries and demand response.
  • Member States can also introduce flexibility measures, again if cleared under EU State aid rules.
• Capacity mechanisms have yet to become cleaner, gas will still play a role.
  • Only 29% of capacity support was directed to low-emission technologies in 2024, while natural gas will lead in long-term contracts until 2035.
  • Although EU gas demand is expected to fall by 15% by 2035, gas-fired power plants are projected to cover 30% of peak demand.
• Capacity mechanisms have yet to become more efficient, coordination can help.
  • Capacity auction prices vary more than tenfold across the EU.
  • In 2024, capacity mechanisms cost €6.5 billion (more than double the cost in 2020). Stronger cross-border coordination could reduce additional capacity needs, lowering overall system costs.
  • Limited coordination in Member States’ adoption of capacity and flexibility measures could risk duplication and inefficient investment.
• Regional and cross-sectoral coordination on risk preparedness remain weak.
  • Only 10% of national risk preparedness plans include joint measures to mitigate the impact of electricity crises and assist neighbouring countries.
  • Cross-sectoral dependencies (i.e. between gas and electricity) are often overlooked.

What are ACER’s recommendations? 

• Make capacity mechanisms cleaner by removing barriers to distributed energy, enable demand response and disclose how much capacity support goes to fossil-fuels.
• Make capacity mechanisms more efficient, coordinating capacity planning at EU level and reassessing the design of capacity auctions, particularly in markets with consistently high prices.
• Integrate flexibility measures into capacity mechanisms or better align them to reduce overlaps and inefficiencies.
• Strengthen regional cooperation on risk preparedness through exchange of best practices, shared templates and joint implementation monitoring.

Today, ACER releases its Opinion on Spain’s National Resource Adequacy Assessment (NRAA). This national assessment complements the European Resource Adequacy Assessment (ERAA) 2024, reflecting recent developments in the country’s electricity system, including the integration of the Balearic Islands and Ceuta.

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, and the Member State informs ACER, ACER must issue an opinion on the differences between the national and European assessments.

What did ACER find?

Overall, ACER finds the Spanish assessment clear, robust and well executed and notes that most differences with the ERAA 2024 are justified by national specificities and local factors.

Spain’s assessment shows higher electricity adequacy risks for 2030. While results for 2028 are in line with the European assessment, the NRAA estimates that by 2030 the country could experience periods when electricity demand exceeds available supply for more than two hours per year, above the national reliability standard that sets the target level of supply adequacy.

These higher projected risks are linked to two differences identified by ACER between the Spanish NRAA and the ERAA 2024:

• Lower storage capacity: The NRAA assumes that only storage projects already planned or under development will materialise. As a result, Spain would have around half the storage capacity estimated in the ERAA for 2030, limiting the system’s ability to balance variable renewable generation and meet peak demand.
• Stricter gas generation assumptions: Spain’s assessment applies lower generation availability for gas turbine fleet based on historical data, including fixed maintenance schedules. This reduces the generation capacity expected to be available during periods of high demand.

ACER finds the assumptions of lower storage capacity and fixed gas turbine maintenance insufficiently motivated for 2030, as they could better reflect the expected evolution of the electricity system. However, their impact on the overall results of the NRAA is limited, as the modelling approach used (based on a resource expansion calculation) tends to compensate for the missing storage capacity. 

What are the next steps?

ACER encourages the Spanish authorities to take its findings into account as the assessment process progresses.

See other ACER’s opinions on national assessments.

On 4 November 2025, the EU DSO Entity submitted its updated statutory documents to the European Commission and ACER. This revision follows the Hydrogen and Decarbonised Gas Market Package adopted in 2024, which extends the Entity’s membership to natural gas and hydrogen distribution system operators (DSOs). 

ACER already provided an Opinion on the previous version of the statutory documents in 2024. It will now review the updated submission and consult stakeholders before delivering its new Opinion to the Commission. 

What is the EU DSO Entity?

The EU DSO Entity was created in 2019 by the Clean Energy Package to facilitate cooperation among European electricity DSOs. The 2024 Regulation broadened the Entity’s scope to include natural gas and hydrogen DSOs, making it necessary to update and resubmit the Entity’s statutes, rules of procedure and other statutory documents to ensure fair and balanced representation of all participating operators. 

This update reflects the EU’s integrated approach to energy networks, supporting system efficiency and cooperation across transmission and distribution. ACER’s role is to ensure a fair and balanced representation across all operators considering the interests of distribution system users (e.g. generators, prosumers and consumers, aggregators, suppliers, and storage operators).

What are the next steps? 

To inform its Opinion, ACER will conduct a consultation to gather inputs from organisations representing all stakeholders, particularly distribution system users (including consumers).

The consultation will run from 21 November to 19 December 2025.

After receiving the proposal, ACER has four months to provide its Opinion to the European Commission.

ACER’s 2025 electricity Monitoring Report reviews progress in integrating EU electricity markets. It examines forward, day-ahead, intraday and balancing markets, and identifies where rules and projects are delayed.

This year’s edition also highlights weather-driven price volatility, which occurs when unusually low renewable generation coincides with higher-than-normal demand due to exceptional weather conditions.

What trends did ACER find in 2024? 

• EU market integration brings value and helps mitigate high electricity prices.
• Price volatility shows that more flexibility is needed.
• Long-term markets remain illiquid, limiting investment signals.
• Cross-border integration reduces costs, but project delays persist.
• Balancing integration generated €1.6 billion in welfare gains.
• Forward markets lack depth; Power Purchase Agreements (PPAs) are growing but vary widely in design.
• Day-ahead integration is consolidating and intraday markets are evolving.

What are ACER’s recommendations? 

ACER points to several priorities that are key to resilience:

• Reinforcing flexibility by investing in demand response, storage and backup generation.
• Accelerating delivery of delayed cross-border projects through timely completion of interconnectors and adoption of flow-based capacity allocation in intraday markets.
• Broadening transmission system operators' (TSOs') participation in balancing platforms to reduce costs and volatility and ensure more efficient system balancing.
• Strengthening forward markets with more active long-term trading and well-designed PPAs and Contracts for Difference (CfDs).
• Moving to flow-based allocation in the intraday timeframe to ensure efficient capacity use and reduce congestion-related costs.
• Enhancing monitoring and enforcement to ensure rules are applied consistently and consumers benefit.

Check out ACER’s interactive electricity dashboards, with latest data up to Q3 2025. Next update in January 2026.

The Spanish energy regulatory authority, Comisión Nacional de los Mercados y la Competencia (CNMC), has imposed a €1 million fine on Enet Energy S.A. for attempting to manipulate the national organised gas market (MIBGAS) eight times from April to May 2023. Enet Energy S.A. acknowledged its responsibility and proceeded with an early voluntary payment. Therefore, in accordance with Spanish regulations, a 40% reduction was applied to the imposed fine. 

The REMIT Regulation prohibits market manipulation and seeks to protect the integrity and transparency of the EU’s wholesale energy markets.

In its decision, CNMC found that Enet Energy S.A. had breached Article 5 of REMIT for attempting to manipulate the Spanish organised gas market. The market participant inserted sell orders at low prices and significantly high volumes around 17:30, to give false or misleading signals regarding the supply and price level at which gas was being traded at that specific moment of the trading session (17:30) in MIBGAS. This is the time at which market reference indices are calculated, including the market price index for natural gas traded at the Spanish Virtual Hub (PVB) by the agency ICIS HEREN. 

What are the main findings?

The investigation showed that, in eight trading sessions of the Spanish day ahead gas market between 24 April and 18 May 2023, Enet Energy S.A. placed a large volume of sell orders around 17:30. Their low prices (ranging from -2.50 €/MWh on 2 May to -16.00 €/MWh on 17 May, compared to the sell price of the immediately preceding orders) caused a drop relative to the prevailing market trend in an attempt to influence the price references at that specific time. Seconds later, the market participant introduced new sell orders at higher prices (with a price increase over their offer at around 17:30, ranging from +2.00 €/MWh on 24 April to +12.00 €/MWh on 11 May), modifying in just a few seconds the price signal previously transmitted to the market.

CNMC concluded that Enet Energy S.A., through its sell orders at low prices and significantly high volumes, attempted to manipulate the Spanish organised gas market prices at the reference time used for calculating market indices, including the PVB reference price published by ICIS HEREN.

This is the fourth decision from CNMC sanctioning the manipulation or attempt of manipulation of a reference price on the Spanish gas market (see previous decisions in 2018 here and here, and in 2024).

Access CNMC’s Decision and press release (both in Spanish).

See the latest table of REMIT breach sanction decisions adopted by national regulatory authorities.

Check the ACER REMIT Guidance (6.1^st edition) for more information on trading practices that could constitute market manipulation under REMIT.

Interested in further information on enforcement decisions under REMIT? Check out ACER’s REMIT Quarterly reports.

This report on gas network use provides a comprehensive overview of capacity booking and usage trends in the EU, exploring how diversified supply, demand shifts and evolving capacity booking strategies are reshaping gas flows across the EU.

This monitoring report compares gas capacity use and booking data from 2021 to mid-2025 and analyses the main market shifts triggered by the energy crisis in 2022 (e.g. phase-out of Russian natural gas, increase in liquefied natural gas (LNG) imports, and lower gas demand). It also examines the impact of ending Russian gas transit via Ukraine as of 1 January 2025 on flow dynamics and capacity use across Southeast Europe.

What are the key findings? 

The EU’s integrated gas system has proven resilient to the energy crisis, reconfiguring its gas flows in response to changing supply and demand patterns. 

• Europe’s reliance on Russian gas pipeline imports has fallen from circa 40% to 6% of total imports since 2021.
• Since the end of 2021, gas flows have reversed direction at 40% of gas interconnection points across the EU, driven by the phasing out of Russian pipeline gas.
• Lower gas demand and increasing LNG’s supply reduced transit flows in some countries, leading to fewer capacity bookings and putting upward pressure on tariffs.
• Capacity bookings are adapting to new gas market conditions. Many long-term legacy contracts are expiring or have been terminated due to the Russian invasion of Ukraine. Instead shippers are now securing capacities on alternative routes through auctions underpinned by the EU-wide capacity allocation mechanism (CAM) network code.
• Lower pipeline congestion at EU level, but some supply bottlenecks persist. Infrastructure upgrades and lower gas demand have eased the peak congestion that affected Northwest Europe in 2022. Since 2024, high network use in Southeast Europe (including increased gas volumes to Ukraine in 2025 following the end of Russian gas transit), created significant congestion risks at several interconnection points in the region.

What are ACER’s recommendations?

• Transmission system operators (TSOs) should enhance transparency and coordination in gas capacity optimisation.
• National regulators should ensure a full and consistent application of the EU rules (CAM network code) without exceptions to maintain a transparent, predictable, and standardised capacity allocation process, fostering competition and integration of EU gas market.
• Future gas infrastructure investment by Member States should be targeted to solve persistent bottlenecks, align with the EU’s energy and climate goals and ensure security of supply. Regulators must ensure transparent and efficient distribution of congestion revenues to reduce and stabilise tariffs for European network users.

What are the next steps?

ACER will provide its next key developments in European gas wholesale markets report in early 2026. See the Q3 2025 monitoring report, also published this week.