ACER published its Opinion on Portugal’s National Resource Adequacy Assessment (NRAA).

The NRAA is part of the country’s electricity security of supply monitoring report, the RMSA-E 2025 (Relatório de Monitorização da Segurança de Abastecimento), and complements the European Resource Adequacy Assessment (ERAA) 2025.

What is a resource adequacy assessment?

The ERAA assesses whether the EU has enough electricity resources to meet demand and ensure security of supply. It is carried out annually by the European Network of Transmission System Operators for Electricity (ENTSO-E) and reviewed by ACER.

Member States can complement this European analysis with national assessments (NRAAs) that reflect local conditions. When a national assessment differs from the European one, ACER issues an opinion.

What did the Portuguese NRAA find?

Unlike the ERAA 2025, which found no adequacy concerns for Portugal, the national assessment identified adequacy risks in all target years from 2028 to 2035.

The NRAA projects that Portugal’s loss of load expectation (i.e. the number of hours per year when demand is expected to overcome supply) will exceed the country’s 1.46-hour reliability standard. This is expected to increase over the years:

• slightly in 2028;
• by about five times in 2030; and
• by nearly fifty times in 2035.

The projected increase assumes electricity demand growing much faster than the resources needed to meet it. Compared with the reference ERAA, the NRAA assumes:

• higher demand from new energy-intensive consumers, particularly data centres;
• slower deployment of renewables;
• lower availability of pumped-hydro storage, based on historical data;
• conservative assumptions on long-term battery deployment; and 
• the shift of the Tapada do Outeiro gas-fired power plant into an out-of-market reserve, taking offline about a quarter of Portugal’s thermal capacity, normally highly available during scarcity times.

Figure: Portugal’s projected installed electricity capacity, 2028-2035

The Portuguese NRAA assumes considerably slower growth in installed electricity capacity than the ERAA 2025, with a gap of around 15 GW by 2030 and 12 GW by 2035. This is largely due to assumptions of slower wind and solar deployment in the national assessment.

Source: ACER based on the NRAA and ERAA 2025.

What are ACER’s key findings? 

ACER finds that the projected resource adequacy risks are mainly driven by assumptions of strong demand growth, while new capacity, including demand-side response, is assumed to lag behind.

At the same time, the NRAA does not adequately assess how the market could respond to increasing electricity supply scarcity. Its economic viability analysis shows that existing gas-fired generation capacity would remain highly profitable, especially long-term, as tighter supply could push prices up. However, the NRAA does not examine whether these price signals could attract investments in new resources, including batteries and demand response, and offers only a limited projection of their potential contribution to security of supply.

The national assessment also overlooks cross-border factors, such as Spain’s recently approved capacity remuneration mechanism, that could affect how much electricity Portugal can import during scarcity periods.

As a result, the NRAA may overestimate Portugal’s adequacy gap by not fully accounting for resources that could realistically enter the market or be available cross‑border.

What does ACER recommend?

To strengthen Portugal’s assessment, ACER recommends:

• Applying the economic viability assessment in line with the ERAA methodology.
• Assessing the potential for new market-based investments, particularly batteries and demand response.
• Reflecting the contribution of currently ‘out-of-market' resources, such as the Tapada do Outeiro gas-fired power plant.
• Using more realistic demand response projections.

Overall, ACER considers that a robust adequacy assessment should capture new investments that could be delivered in response to market conditions, in addition to current resource development trends.

What are the next steps? 

ACER encourages the Portuguese authorities to consider its feedback to improve the assessment.

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.

ACER’s REMIT Quarterlies provide updates on REMIT-related activities, helping stakeholders stay informed. Due to strong interest from readers, the latest issue continues the series on algorithmic trading in energy markets.

What’s new?

Following the overview of algorithmic trading and its implications under REMIT in the 44^th edition, the 45th REMIT Quarterly explains how ACER is adapting its market surveillance to the growing use of this practice in wholesale energy markets.

Algorithmic trading uses computer programs to automatically execute trades based on pre-defined instructions (such as when to buy or sell), often at speeds and volumes beyond human capacity. As energy markets become increasingly automated, REMIT continues to evolve to ensure that potential market abuse can be effectively detected and addressed, regardless of whether trading is manual or automated. 

Also in this Quarterly:

• Takeaways from two joint ACER-European Commission events: the annual REMIT workshop (11 June 2026) and the webinar on new REMIT implementing rules (23 April 2026). 

• A case report on the Hungarian energy regulator’s decision to fine Hungaro Energy for manipulating the gas market.

• Updates on market surveillance, including statistics on the 453 REMIT breach cases under review at the end of Q2 2026.

• Changes to the geographical scope of inside information platforms (IIPs) and how market participants are using them.

• Recent energy market trends, showing a continued increase in trading on organised market places (OMPs), driven by growth in natural gas forward markets.

Today, ACER publishes the first open-access EU-wide dataset on cost of new entry values (EU CONE Dataset).

The dataset provides economic parameters for new electricity resources (including estimated capital and operational costs for different power generation technologies and demand-side flexibility) to support long-term system modelling.

To make the data easier to explore, ACER has also published an interactive dashboard.

Why does it matter?

Until now, only fragmented data was available at EU level. This made cross-country comparisons difficult and increased the risk that adequacy assessments and investment signals would rely on inconsistent cost assumptions. 

By providing more complete and consistent input data, the new dataset helps improve the accuracy and robustness of adequacy modelling. This supports:

• assessing future investment needs (e.g. whether new generation or flexibility resources are likely to be built and whether existing power plants are expected to remain economically viable);

• understanding how investment and retirement decisions shape the future resource mix in Member States, helping identify potential adequacy gaps; and

• estimating the optimal level of system reliability, by balancing the cost of new capacity against the risk and impact of unmet demand.

How was the dataset developed?

The EU CONE Dataset builds on a preliminary version developed by consultants. Following a public consultation (February 2026), ACER refined its data, integrating feedback from stakeholders (including system operators, generators, manufacturing and technology companies) and national regulators (see the evaluation of responses).

Respondents provided constructive feedback and proposed evidence-based refinements to several parameters, including:

• capital expenditure (CAPEX);

• fixed operating and maintenance (FOM) costs;

• weighted average cost of capital (WACC) for different technologies; and

• the categorisation of demand-side response.

Views on gas technologies were broadly aligned with the consultancy study, while input on batteries and demand-side response was more diverse.

What’s next? 

The EU CONE Dataset can be used to support power system modelling, including future editions of the European Resource Adequacy Assessment (ERAA), national adequacy assessments (NRAAs) and other related studies.

It may also help Member States calculate reference reliability standards and meet the criteria for fast-track approval of capacity mechanisms under the new State aid framework.

On 21 July 2026, ACER received a proposal from all nominated electricity market operators (NEMOs) to amend the methodology for the price coupling, continuous trading matching and intraday auction algorithms.

What is the methodology about?

Established under the Capacity Allocation and Congestion Management (CACM) Regulation, the methodology provides a common framework for the algorithms used to simultaneously match electricity market orders and allocate cross-zonal capacities in Europe’s day-ahead and intraday markets. It defines common requirements, timelines and implementation deadlines.

The current methodology was approved by ACER in July 2018 and amended in January 2020 and September 2024.

Why amend the methodology? 

NEMOs propose amendments to the methodology to enable more efficient cross-border electricity exchanges, deliver greater welfare and maintain the secure operation of the power system by:

• enabling the introduction of three intraday auctions using flow-based capacity calculation by updating the timings and delivery of intraday auction results;

• setting a concrete implementation deadline for flow-based allocation in intraday auctions; and

• amending the relevant deadline for publishing the single day-ahead coupling results.

What are the next steps? 

ACER expects to decide on the methodology by 21 January 2027. 

Interested stakeholders are invited to share their views on the topic by 31 August 2026 via ACER-ELE-2026-006@acer.europa.eu.