ACER publishes its report on unit investment cost (UIC) indicators for energy infrastructure, updating the reference values last published in 2023. 

What are UIC indicators?

Transparent cost estimation is essential for planning energy networks. Standardised reference values for specific infrastructure costs can improve the quality and credibility of assessments and enable consistent comparisons across the EU.

Under the TEN-E Regulation, ACER is required to develop and publish a set of UIC indicators and corresponding reference values every three years. These indicators provide a common framework for assessing the investment costs of comparable energy infrastructure projects.

What did ACER observe?

The 2026 ACER report provides updated cost information for energy infrastructure, expressed per unit (kilometre, installed power, capacity). It analyses the factors influencing infrastructure costs over time, using cost data and technical information collected from project promoters between October 2025 and January 2026. The report also includes additional indicators and a sensitivity analysis based on an alternative methodology that accounts for cross-country differences in labour costs.

ACER’s analysis shows that: 

• Infrastructure costs have increased above inflation across most categories (e.g. electricity lines, cables and substations). As the indicators are based on historical data from commissioned projects, they do not fully reflect current price levels and may underestimate actual costs.
• Cost drivers point to increased exposure to price volatility and dependence on supply chains, particularly for materials from third countries, as well as other manufacturing-related costs.
• Data representativeness remains limited for several infrastructure categories, with inputs unevenly distributed across countries, which can affect the robustness of the indicators. Future updates would benefit from data covering a wider range of commissioned projects across countries and infrastructure categories.

Despite some limitations, the indicators provide valuable insights into infrastructure costs and support more transparent and informed planning decisions.

Looking ahead

As the assessment is based on historical data from commissioned projects, the indicators may not yet fully reflect recent cost developments. Further work is needed to better capture these cost developments in future updates, for example by exploring alternative methodologies or taking into account recent tender outcomes. ACER notes that regulatory oversight, stronger cooperation on supply chains and better use of existing infrastructure can alleviate bottlenecks.

ACER's latest gas Monitoring Report covers trends in winter 2025-2026. A key is the impact of the evolving Middle East conflict and the closure of the Strait of Hormuz on European gas markets.

This analysis helps inform decision makers on strategies to ensure secure and competitively priced gas in the EU.

What did ACER’s monitoring find?

The EU is vulnerable to energy shocks. To date the 2026 energy crisis is not at the same level of magnitude as the 2022-2023 crisis.

• The Middle East conflict crisis could cut 20% of global LNG exports: EU sourced 7% of its LNG from Qatar during winter 2025/2026, equivalent to 4% of its natural gas imports over the same period. If Qatari production remains offline until December 2026, a global LNG supply shortfall of 26 bcm could arise and EU spot LNG demand could rise to around 56 bcm. Europe’s exposure to further price increases will depend on the duration of the conflict.
• Title Transfer Facility (TTF) gas prices peaked above 60 EUR/MWh after attacks on energy facilities: Price volatility is expected to remain high amid continued uncertainty.
• Competition with Asia for flexible LNG cargoes could push prices up: This could make Europe's summer storage filling more challenging, as heightened competition for flexible LNG cargoes threatens to push prices up further.
• EU underground gas storage ended winter below 30%, due to both higher reliance on gas use for power and a cold winter. EU gas stocks are near a 9-year low.
• Storage targets for the next winter, in accordance with the EU Gas Storage Regulation, may put upward pressure on prices this summer.
• Europe could achieve 80% storage levels at current LNG import rates (~11 bcm/month). Reaching the 90% target would be difficult without additional supply sources. 
• EU gas demand rose slightly year-on-year to around 2400 TWh: This increase was mainly driven by higher gas use in power generation and for heating, due to a colder-than-average winter. 
• Europe’s reliance on US LNG grew amid the phase-out of Russian gas imports. US LNG now accounts for 30% of EU gas imports and about two-thirds of its LNG imports. Russian gas flows continued to decline, falling close to 240 TWh (but still around 14% of total EU gas imports).
• In Europe, gas flows continued to shift away from eastern pipeline supply and to LNG entry points, resulting in higher west–east cross border flows. This shift was also reflected in wholesale market signals, with price spreads in Central Europe widening to over 2 EUR/MWh above the TTF benchmark.

Looking ahead

• Heightened price volatility: European gas prices will remain highly sensitive to global shocks. The Middle East conflict and strong competition with Asian markets for flexible LNG cargoes will be the main drivers of price spikes.
• Costly storage refills: While reaching the 80% storage target ahead of next winter is feasible, lower starting storage stocks and tight global supply mean that filling storage over the summer will likely come at a premium cost and be more vulnerable to sudden market disruptions.
• Geopolitics and supply shifts: Europe's structural pivot away from Russian gas supply will continue. In January 2026, the EU adopted a regulation introducing a gradual and permanent ban on Russian pipeline and LNG imports. This deepens the EU’s reliance on US LNG imports and maintains a west–east and coastal–continental gas pipeline flow in Europe.

On 22 January 2026, the transmission system operators (TSOs) of the Core capacity calculation region submitted a proposal to their national regulatory authorities to amend the day-ahead capacity calculation methodology. As the national regulators could not reach an agreement, the proposal was referred to ACER on 30 March 2026 under the Capacity Calculation and Congestion Management Regulation.

The Core capacity calculation region comprises of 13 Member States: Austria, Belgium, Czech Republic, Croatia, France, Germany, Hungary, Luxembourg, the Netherlands, Poland, Romania, Slovakia and Slovenia.

Capacity calculation regions define the geographic areas across Europe where TSOs coordinate the capacity calculation and other processes subject to regional methodologies.

What is the methodology about?

The Core day-ahead capacity calculation methodology (initially established by ACER in 2019 and first implemented in June 2022) aims to maximise the capacity made available to the market while maintaining operational security.

This methodology is based on a flow-based approach, meaning cross-zonal capacities are calculated by taking into account transmission networks’ physical constraints. This approach significantly improves the efficiency of cross-zonal capacity allocation, as it better reflects real network conditions. 

Why change the rules?

Core TSOs propose to amend the methodology to better harmonise it with other electricity market timeframes (i.e. intraday and long-term capacity calculation) operating in the same region.

The main purpose of this amendment is to remove long-term allocations from the day-ahead capacity calculation. This change is a prerequisite for the adoption and implementation of the flow-based capacity calculation methodology in the long-term timeframe (Core LT CCM), which is currently under review by ACER following its referral by Core regulatory authorities in February 2026.

Removing long-term allocations from the day-ahead capacity calculation decouples operational safety from long-term capacity volumes, allowing their determination without direct operational security constraints. This will improve the efficiency of the process, as long-term capacities will be calculated independently, reflecting the separation between the day-ahead and long-term frameworks. 

What are the next steps?

ACER, in cooperation with relevant energy regulators and TSOs, will reach a decision by 30 September 2026.

Today, ACER publishes its report on distribution system operator (DSO) investments and revenue setting. 

The report: 

• finds a major upscaling in electricity distribution grid investment trends across Europe;
• identifies some factors that may hinder efficient investments; 
• reviews the DSO landscape in Europe; 
• explores ways to address the challenges facing DSOs;
• proposes a set of 10 recommendations to optimise the ramp-up of distribution grid investment and improve services to grid user.

What are the main findings?

To accelerate decarbonisation, significantly more grid capacity is needed for electrification and renewables’ growth. This is driving a visible rise in electricity distribution grid investments across Europe. In 2024, annual distribution grid investments increased by over 50% to €35.3 billion (compared to €23.5 billion in 2021). Distribution grid investment is projected to approach €47 billion in 2027.

Beyond the investment challenge, DSOs face expanded roles under EU legislation. They must be active system operators (e.g. managing the system, utilising flexibility services, optimising electricity flows on the grid), market facilitators, data hubs, and innovation drivers – responsibilities that require new tools, specialised skills, and stronger coordination. 

Europe needs DSOs who provide high quality distribution services. As the system evolves, regulatory frameworks must adapt alongside it. 

This ACER report highlights several elements that might hinder efficient investments:

• Size matters. DSOs must be equipped to deal with evolving responsibilities for grid planning, flexibility solutions, grids’ digitalisation and resilience, to ensure all customers have equal access to high-quality and cost-efficient distribution services. Robust system planning and efficient regulatory scrutiny should not be compromised by fragmented and uncoordinated network development. 
• DSOs should adopt the most efficient solutions for network development – whether grid-based or non-grid (e.g. flexibility). The regulatory focus must expand beyond cost-cutting and maximise the benefits for society. Reducing capital expenditure (CAPEX) bias, still present in several countries, is key for improving regulatory regimes. 
• Rigid expenditure caps should not hinder nor distort key investments needed for the clean energy transition. 
• Distribution grid use and planned development should be more transparent. DSOs should strive to publish their mid-term cost trajectories and monitor grid utilisation to improve planning and operations.

ACER’s report offers 10 recommendations for legislators, regulators and system operators to optimise the ramp-up of distribution grid investment and improve services to grid users. These aim to ensure adequate competences, proper transparency and unlock efficient investments. National regulatory authorities should consider these recommendations when setting or approving their distribution revenue methodologies.

What are the next steps?

ACER will continue to:

• facilitate best-practice sharing among national regulatory authorities; and
• engage with stakeholders to gather insights.

In 2027, ACER will publish the next edition of its report on network tariff practices. ACER’s next report on revenue setting practices will be in 2028.

Europe has an EU-wide framework (called 'REMIT') to detect and deter market manipulation and abuse in wholesale energy markets. The Regulation was revised in 2024 to keep pace with evolving market dynamics. To make the framework fully operational, REMIT secondary legislation has also been updated with a recast REMIT Implementing Regulation and a new Delegated Regulation, both entering into force on 29 April 2026 (i.e. 20 days after their publication today in the Official Journal).

This reinforced REMIT framework enhances transparency and trust in the integrity of Europe’s energy markets. To support understanding and compliance with the new obligations, ACER has published two open letters (one on the recast Implementing Regulation and the other on the new Delegated Regulation).

In the coming weeks, ACER will also seek stakeholder input, via a public consultation, on a new guideline to help REMIT data reporting parties comply with their new obligations.

Key changes

1. The recast Implementing Regulation sets out updated rules for reporting energy market data to ACER, directly affecting all reporting parties (e.g. market participants, organised market places, registered reporting mechanisms and others). It aims to reduce reporting burdens while enabling more effective market monitoring and detection of potential abuses.

ACER’s open letter explains what has changed, focusing on the provisions that will enter into force first and on how to ensure compliance with the new act. It covers:

• new ‘exposure reporting’;
• new reporting timelines; and
• new obligations for organised marketplaces.

See also ACER’s evaluation of responses to the recent public consultation on the usefulness of ISO standards for exposure reporting.

2. The new Delegated Regulation introduces authorisation and supervision processes (including withdrawal and orderly substitution) for: 

• Registered reporting mechanisms (RRMs): Entities authorised to report energy data to ACER, either on their own behalf or on behalf of companies.
• Inside information platforms (IIPs): Online platforms where companies publicly disclose inside information (like power outages or capacity issues) so that all market participants can access it at the same time. IIPs are also officially authorised to report this information to ACER on behalf of companies.

ACER’s open letter on the Delegated Regulation explains: 

• the transitional period and the status of registered RRMs and IIPs during this period;
• the authorisation of new and registered RRMs and IIPs, including the requirement to be established in the EU; and
• key changes for ‘clients’ of RRMs and IIPs (e.g. market participants submitting or accessing energy data) under the new authorisation regime.

Together, these two acts aim to improve standardised data reporting, strengthen the supervision of REMIT data reporting entities and help ensure transparency and integrity in EU wholesale energy markets. 

Why does this matter?

The updated REMIT framework helps ensure that energy markets operate fairly, preventing market manipulation and insider trading, and ensuring important information is shared so that all market players compete on an equal footing. 

What’s next?

• ACER public consultation on a new guideline on REMIT transaction reporting to reflect evolving obligations under the revised framework (16 April - 12 June 2026).
• ACER and European Commission webinar: New REMIT implementing rules for energy market integrity and transparency (23 April 2026).
• ACER and European Commission annual REMIT workshop (11 June 2026).
• ACER consultations with targeted stakeholders on guidance documents for data reporting (including on the revised electronic formats). The revision process will be gradual, in line with the phased entry into force of new obligations, and will involve stakeholder consultation.

Today, ACER releases its report on the Latvian gas transmission tariffs, evaluating compliance of the proposed reference price methodology (RPM) with the requirements of the EU Network Code on Harmonised Transmission Tariff Structures. 

What is the proposed methodology?

The Latvian regulator proposes to:

• Apply a uniform entry tariff of 142.77 €/MWh/d/y at all entry points within the Finnish-Estonian-Latvian (FinEstLat) market area, while removing tariffs at interconnection points within the area. 
• Apply a reference price methodology to set tariffs for domestic exit points and for renewable and low-carbon gases’ injection points.
• Grant full tariff discounts (i.e. zero tariffs) for entry points from and exit points to storage facilities.
• Set the exit tariff to Lithuania using the same FinEstLat entry tariff (142.77 €/MWh/d/y).
• Replace the current commodity-based tariffs (linked to the volume of transported gas) at domestic exit points with new capacity-based tariffs (charged for contracted network capacity).

What are the key findings? 

ACER concludes that: 

• The consultation document does not provide all required information, including on the:
  • comparison with the capacity-weighted distance methodology;
  • impact of the FinEstLat tariff structure on cross-subsidisation; and 
  • method used to forecast contracted capacity. 
• The proposed methodology complies with EU requirements on non-discrimination and volume risk. 
• However, it does not comply with the requirements on cost-reflectivity, cross-subsidisation and cross-border trade.

What does ACER recommend? 

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

• Follow ACER’s previous guidance (2023) on the FinEstLat market merger, monitoring how changes in gas flows could affect cross-subsidisation between networks.
• Switch to a capacity-based tariff system, allowing for a transitional period (if needed).
• Improve transparency by publishing the capacity-weighted distance components used in the cost allocation assessment.
• Compare capacity forecasts with those of neighbouring regulators and explain any differences found at the interconnection point with Lithuania.

Next steps

The Latvian regulator needs to adopt its final decision in time to publish the gas transmission tariffs by 6 June 2026.

See all ACER reports on national tariff consultation documents.