ACER (an EU Agency) is a valued partner to the EU Institutions providing data, insights and advice on the regulatory aspects of the Green Deal:

1. ​Regulating hydrogen and power-to-gas in the context of the Commission's Hydrogen Strategy for a Climate-Neutral Europe and the Strategy for Energy System Integration.
2. ​​Revising TEN-E Regulation (a legislative Initiative on energy infrastructure).
3. ​Offshore Renewable Energy Strategy.

Hydrogen and Power to Gas​​

ACER and CEER have developed a series of European Green Deal Regulatory White Papers to increase public understanding on key regulatory aspects and to assist the European Institutions as part of the preparations for legislation.​

TEN-E Regulation

The Trans European Network-Energy (TEN-E) Regulation is the EU framework for planning and supporting cross-border energy infrastructure.

The European Commission proposal (December 2020) on the TEN-E Regulation revisions seek to modernising the TEN-E framework, reflecting the Green Deal objectives and making it fit for the infrastructure needs of the sustainable energy system of the future. 

As input to the European Commission's review of the TEN-E Regulation, in July 2019, regulators set out 18 recommendations on how to improve the TEN-E Regulation and energy infrastructure governance in the ACER-CEER Position Paper on Revision of the Trans-European Energy Networks Regulation (TEN-E) and Infrastructure Governance.

ACER and CEER see scope​ to further improve the Commission's proposals (December 2020)​.
 

Off-shore wind

The European Commission in its Offshore Renewable Energy Strategy has set a massive goal of increasing offshore wind capacity from 12 GW to 300WG in 2050.

It is important to facilitate the deployment of hybrid projects - combining power, storage and/or electrolysis - such as cross-border offshore windfarm projects (that also function as interconnectors) to enable the massive four-fold increase in offshore wind to 60 GW in 2030 and to 300GW by 2050.

A coordinated offshore strategy builds mutual reliance across EU Member States with cooperation needed on multiple aspects e.g. planning, governance, optimisation, plus potentially also proving an ill-fit over time with national energy or renewable strategies (risk of accounting or methodological rigour becoming aims 'in their own right').

Successfully scaling offshore is inextricably linked to Europe's infrastructure challenge and hence touches upon many elements of ACER's core work such as bidding zones, European infrastructure Projects of Common Interest (PCIs) and how to allocate costs (Cross-border cost allocation (CBCA).

This level of ramp up requires the right legal regulatory framework.  ACER notes that the European Commission's TEN-E proposal excludes ACER from off-shore network development process. Furthermore, it detaches off-shore network development from on-shore (through separate network development plans, run in different cycle lengths). 

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​​Energy System Integration

The decarbonisation of the energy system requires an increasing level of integration between its various components.

Energy system integration refers to the planning and operation of the energy system as a whole - across multiple energy carriers (e.g. electricity, gas, heat), infrastructures, and consumption sectors (industry, buildings, transport) - by more strongly linking them with the objectives of decarbonisation, energy efficiency, affordability and reliability of the energy system.

The European Green Deal is Europe's growth strategy to make its economy more sustainable.

This ambitious Green Deal strategy aims to make Europe “climate neutral" by 2050. This means “net-zero" emissions.

Energy accounts for more than 75% of the EU's greenhouse gas (GHG) emissions. Decarbonising the energy sector forms the backbone of the Green De​al and ACER's work is highly relevant.​

The Green​ Deal sees as key parts of the decarbonisation solution:​

• A massive increase in renewables (i.e. sustainable electricity)

• Increased electrification (i.e. using sustainable electricity to then decarbonise other sectors such as transport and heating)

• Sustainable or low-carbon hydrogen (for “hard to decarbonise" sectors) ​​

The Green Deal introduces concepts which until recently were not part of most policymakers' vocabulary: e.g. Climate Neutrality, Power-to-Gas, Energy System Integration, Sustainable Taxonomy. ​

Check out ACER's Green Deal Glossary.​ 

ACER, as an EU Agency, significantly contributes in two main ways to Europe's Green Deal objective and the broader energy and decarbonisation objectives set at political level​:

1. ​delivering on our core regulatory mandate which are rooted to Europe's (2019) Clean Energy laws. 

2. ​providing advice and expertise to Europe's co-legislators on key Green Deal energy files​. See also the ACER-CEER Green Deal Regulatory White Papers.​

Article 1 of the ACER Regulation in referring to the establishment and objectives of ACER explains that ACER contributes “to the consistent, efficient and effective application of Union law in order to achieve the Union's climate and energy goals".

The Agency (and national energy regulators) play a pivotal role paving the way to decarbonise the economy at least cost to consumers by facilitating:

• the massive increase in renewables that is needed (about 3 times the current renewable capacity base) to decarbonise the power sector

• increased electrification of sectors (e.g. heating and transport) previously powered by fossil fuels (e.g. the regulatory treatment of EV charging stations)

• the growth of a competitive renewable/low-carbon hydrogen market  for energy-intensive or “hard to abate" emissions sectors (like aviation or chemicals)

• more “flexibility" in the energy system (e.g. storage and Electric Vehicles (EV)) to enable a big shift to renewables. Put simply, more wind and solar is not enough. Storage (e.g. batteries, hydrogen storage) and adapting consumption are two examples of flexibility that is needed to plug the gaps when there is too much/little sun and wind.

• empowering consumers (enabled through technology) to actively contribute to the transition (transforming how we use and generate energy, how we move around, and heat our homes) through smart homes, microgeneration and EV charging stations. The Agency's mandate was extended under the Clean Energy legislation to monitor compliance with the new consumer rights as well as monitoring electricity and gas wholesale and retail markets.

Alongside decarbonisation, ACER must also ensure that the European energy market is fully integrated, interconnected and digitalised to maintain security of supply. With energy identified as a critical sector in terms of cyber security, ACER plays a key role in electricity cybersecurity resilience and thus contributes to the wider EU cybersecurity strategy.

Europe's decarbonisation objective cuts across ACER work.

ACER pushes low-carbon solutions through market design and well-regulated markets and networks.

Energy and climate are linked. Energy accounts for > 75% of Europe's Greenhouse Gas (GHG) emissions. The framework in Europe has evolved.  Europe has a 2020 climate and energy framework, a 2030 climate and energy framework, and now a 2050 climate neutrality objective.

Europe's (2019) Clean Energy laws facilitate the “clean energy transition" away from fossils towards a more sustainable energy. A core focus of ACER's work is implementation of the Clean Energy laws.​ ACER, an EU Agency, contributes from a regulatory perspective, to the implementation of the European Union's Green Deal and the broader energy and decarbonisation objectives set at political level.​

ACER drives the decarbonisation of the energy sector by:

• Developing, implementing and monitoring the Network Codes – the binding EU-wide rules governing the electricity and gas sector. Why? Completing a well-functioning “Internal Electricity Market" is key for sustainable, reliable and affordable energy.

• Ensuring the electricity market rules and design (originally not intended for large amounts of renewables) are “fit for purpose" to integrate the massive expansion in renewables. In particular:
  • ACER is reviewing the functioning of the real-time (intraday and balancing) electricity markets, to improve market access to renewables and help improve forecast accuracy and reduces balancing needs.

• ​Ensuring the electricity market design foster all sources of flexibility (e.g. flexible storage, aggregators).
   
• Integrating national energy markets into a single European-wide market. An integrated electricity market allows electricity to move freely across borders and delivers benefits to generators (bigger market), operators (reducing the costs of balancing, reserves and system operation) and citizens (who have access to competitive markets and secure supply).
   
• Monitoring how markets are functioning and how national network tariffs can be structured to better suit the energy transition (e.g. incentivising grid companies to find the cheapest sources of flexibility and consumers to align their energy use with flexibility needs).
   
• Building cost-efficient infrastructure (e.g. to bring cheap offshore wind to consumers) based on robust regulatory scrutiny (and not building at any cost).
   
• Maximising the interconnection capacity made available to the market for trading so consumers can chose from the cheapest and lowest emitting power available across Europe.
   
• Cooperation and dialogue among relevant stakeholders e.g. to deliver on the envisaged level of off-shore wind requires cooperation among Member States, project developers, network operators etc.

The timely implementation of the necessary electricity transmission infrastructure in Europe is crucial for an efficient EU energy market and to facilitate the integration of increased renewable power generation in view of the decarbonisation objectives.

The projects' progress may defer from what was previously planned for various reasons. It is important to differentiate between delayed and rescheduled investments:

• A delayed investment means that it is still needed at the expected date, but it cannot be delivered on time because of external factors (e.g. environmental, permit granting or legislative reasons) or

• A rescheduled investment is voluntarily postponed by a project promoter due to changes of its external driver (e.g. lower demand, less urgent need or priority to other transmission solutions).​​

ACER is responsible for monitoring the implementation of investments to create new interconnection capacity as well as the Ten Years Network Development Plans' (TYNDP) progress.

If any inconsistency is found, ACER makes recommendations to the transmission system operators, national regulatory authorities or any other competent bodies concerned. The ACER monitoring of the implementation of investments in electricity transmission networks evaluates the following fundamental aspects: expected benefits, costs, increase of transfer capacity, and the status and time-progress of each investment.

​ACER found that several TYNDP investments encounters delays over time, most frequently due to permit granting reasons and even more have been rescheduled by the promoter. ACER also finds that a number of interconnectors have different investment status across the border, which could point to limited cross-border coordination among the parties.​

Development of the electricity transmission networks is crucial for market integration, security of supply and sustainability in Europe. The EU-wide Network Development Plan (EU TYNDP) developed by ENTSO-E is a major tool for coordinated and efficient network planning. However, given its non-binding nature, the TYNDP implementation strongly depends on National Development Plans (NDP).

This highlights the need for an efficient two-way interaction between the NDPs and the TYNDP.​

ACER assesses the consistency of the NDPs with the EU TYNDP. In case ACER identifies inconsistencies between the two, ACER recommends appropriate amendments. 

As the EU accelerates its transition to renewable energy, electricity networks must keep pace with rising demand, decentralised generation and growing cross-border flows. Strategic grid investments play an important role in supporting this transition and ensuring a reliable and efficient energy system. 

What trends has ACER identified?

In its latest Opinion (July 2025), ACER highlights:

• Improved alignment in electricity network planning: Member States contributed to this progress by strengthening the role of national regulators, expanding public consultations, better synchronising the timing of their national plans with the EU TYNDP, and adopting scenarios similar to those in the EU plan.
• Remaining inconsistencies: Despite these improvements, significant differences remain between national and European planning efforts. These include misaligned planning cycles, TYNDP projects not reflected in corresponding national plans, and limited data transparency, all of which may hinder efficient and coordinated grid development. 

What does ACER recommend?

To further improve consistency, ACER suggests that entities responsible for NDPs: 

• Align national and EU planning cycles on a two-year basis.
• Improve coordination between transmission and distribution system operators.
• Strengthen the role of national regulators by granting them formal approval rights over draft NDPs.
• Consult publicly on early versions of NDPs and conduct more targeted consultations on planning scenarios and cost-benefit analyses.
• Increase transparency around project investment costs.
• Include projects not managed by TSOs in the planning process, while ensuring proper national regulatory oversight.

Every two years, the European Network of Transmission System Operators for Electricity (ENTSO-E) develops a Union-wide ten-year network development​​ plan ​(TYNDP). 

The TYNDP plays a central role in the development of electricity transmission infrastructure across the EU, which is needed for achieving European policy goals such as energy market integration and decarbonisation.

As grid developments require major investments and related costs are expected to make up a growing share of electricity prices, having a robust and fit-for-purpose TYNDP is key to efficient grid development.

The main objectives of the TYNDP are to:

• Identify investment gaps, including cross-border capacities.
• Assess the benefits of proposed infrastructure projects.
• Support adequate cross-border interconnection, non-discrimination, fair competition and a well-functioning electricity market.
• Ensure transparency of the European electricity transmission network.

The plan builds on national and regional investment plans prepared by transmission system operators, also updated every two years.​

Since the 2024 edition, ENTSO-E is required to publish a separate Infrastructure Gaps Identification report as part of the TYNDP framework.

On 9 April 2025, ENTSO-E submitted its 2024 draft TYNDP to ACER, along with the electricity Infrastructure Gaps Identification report.

ACER is responsible for:

• Providing an opinion on the draft TYNDP to ENTSO-E, as well as on the Infrastructure Gaps Identification report to ENTSO-E, the European Parliament, Council and Commission.
• Assessing consistency between the EU-wide TYNDP and national grid plans and suggesting adjustments (either to the TYNDP or the national plans), where needed.

• Monitoring the implementation of the TYNDP, once positively evaluated. If inconsistencies arise, ACER investigates the causes and issues recommendations to system operators, national regulators and other competent bodies to support timely investments implementation.

In its latest Opinion (May 2025), ACER welcomed the progress made in the 2024 draft TYNDP and acknowledged ENTSO-E’s continued efforts to introduce improvements in each new edition.

Several previous ACER recommendations remain unaddressed, including the need to improve timeliness and transparency. Other aspects like enhancing the granularity of information also need to be addressed. 

To improve future editions of the TYNDP and Infrastructure Gaps Identification reports, ACER recommends:

• Ensuring timely submission of the documents by addressing the root causes of recurring delays.

• Conducting extensive consultations on assumptions and methodologies used, well before the drafting begins.

• Improving transparency and consistency of the information on existing grids and projects.

• Strengthening the medium-term analyses (over a 10- or 15-year horizon) to better identify future infrastructure gaps and assess projects’ costs and benefits more effectively.

• Basing the modelling of the electricity network on an appropriate starting grid (for the gaps analysis) and reference grids (for the cost-benefit analysis assessment).

• Providing more granular information on infrastructure needs and gaps, including an analysis of capacity constraints within Member States’ networks.

• Improving transparency of the cost-benefit analysis (CBA) results and continue work towards full implementation of the 4th CBA Guideline.

• Ensuring full compliance with ACER’s Scenario Framework Guidelines and its Opinion on ENTSOs’ draft TYNDP 2024 Scenario Report.

​​​​​Network development scenarios represent visions of the future, according to which the assessment of projects’ benefits is made using the CBA. The TEN-E Regulation defines which variables should comprise scenarios for electricity and gas. The European Network of Transmission System Operators (ENTSOs) are responsible for developing common network development scenarios for gas and electricity. 

Under the TEN-E Regulation, ACER is responsible for creating Framework Guidelines for Scenario Development, while ENTSOG and ENTSO-E (the ‘ENTSOs’) are tasked with developing network scenarios based on these guidelines. In January 2023, ACER published its Framework Guidelines, aiming to establish a transparent, inclusive, and robust process.

In its latest Opinion (October 2024), ACER welcomed some improvements in the scenarios’ development process, ACER’s assessment identifies several areas of non-compliance with its Framework Guidelines:

• Diverging scenarios: rather than developing different scenario variants based on economic factors, the ENTSOs created diverging scenarios, leading to less reliable results.
• Delayed process: scenarios’ development was delayed, negatively impacting other processes.
• Slower stakeholder group formation: the process of establishing the Stakeholder Reference Group took longer than expected, which impacted the stakeholder engagement’s overall effectiveness.
• Transparency: despite enhanced transparency and stakeholder consultations, the draft 2024 Scenarios Report still did not fully meet the transparency standards set by the Framework Guidelines.

ACER expects some of these issues to be addressed in the final 2024 Scenarios Report for the TYNDP and anticipates that ENTSOG and ENTSO-E will further tackle the remaining shortcomings in the 2026 scenarios.

When developing new networks, setting up an appropriate and transparent cost estimation is essential. Using reference values of specific costs can facilitate many processes, increase their credibility, and enable reliable comparisons at European level.

Under the TEN-E Regulation (Article 11(9)), ACER is required to establish and publish a set of indicators and corresponding reference values every three years for the comparison of unit investment costs (UICs) for comparable projects of the energy infrastructure categories listed in Annex II.

ACER published the first set of UIC indicators for the categories outlined in points (1), (2), and (3) of Annex II in April 2023. These indicators and their reference values can be used for various planning and evaluation processes, including:

• supporting the European Network of Transmission System Operators for Electricity (ENTSO-E) and Gas (ENTSOG) in the cost-benefit analyses carried out for their Union-wide ten-year network development plans (TYNDPs);
• assessing and selecting projects of common and mutual interest (PCIs/PMIs);
• informing cross-border cost allocation (CBCA) decisions.

UICs indicators were specifically established for the electricity infrastructure category and related assets, based on data provided by project promoters. The indicators provide values for the average, median, first and third quartiles of UICs.

Would you like to know more?

Take a look at our report on European energy infrastructure UICs and watch the recording of our workshop on the topic.

According to revised TEN-E Regulation, ACER is required to publish the first UIC indicators for energy infrastructure categories related to large electrolyser facilities and carbon dioxide by 24 April 2025. However, since no relevant projects have been commissioned under these categories in recent years, there is currently insufficient data to establish robust indicators by this deadline.

For this reason, ACER has decided to delay data collection until relevant projects are commissioned. In the meantime, ACER will:

• continue to closely monitor developments in these project categories;
• begin the next UIC data collection cycle at the end of 2025. If suitable projects are available by that time, ACER will publish the corresponding indicators and reference values by April 2026.

The Regulation on guidelines for trans-European energy infrastructure ('TEN-E Regulation') foresees the development of a harmonised EU-wide methodology for cost benefit analysis (CBA) of projects included in the future Ten Year Network Development Plans (TYNDP), and for selecting the Projects of Common Interest (PCIs) and Projects of Mutual Interest (PMIs) at European level. 

The Regulation also foresees the use of this methodology for deciding on the cost allocation of cross-border infrastructure projects (CBCA). The CBA methodology is developed and improved over time by ENTSO-E and is approved by the European Commission. ​

Whenever an updated CBA methodology is proposed by ENTSO-E, ACER provides an opinion on it to ENTSO-E. ​

In its latest Opinion, ACER notes improvements, which include:

• the assessment of hybrid offshore projects (i.e. grid projects that serve a dual purpose, to connect offshore generation and interconnect two bidding zones);
• the definition of the reference grid; and
• the assessment of projects’ commissioning dates and the commissioning year of projects involving multiple investments.  

However, important shortcomings are also identified, such as the need to extend the analysis of security of supply by considering future extreme weather events, to simplify the assessment of hybrid offshore projects, to foresee the identification of beneficiaries and cost bearers at national level, and the lack of concrete methodologies for the assessment of ancillary services’ benefits.

ACER urges ENTSO-E to adapt the draft CBA Guideline in line with the considerations included in its Opinion before submitting it to the European Commission for approval. ​​

Developing new networks in Europe in order to facilitate cross-border flows requires a close coordination of several processes and actors.

A common EU-wide Cost-Benefit Analysis methodology was developed by ENTSO-E to be used for infrastructure projects assessment, and it is reviewed when needed. 

Every two years, based on the scenarios on the future state of the electrical system, ENTSO-E assesses the projects included in the EU-wide Ten-Year Network Development Plan (TYNDP). ​

ACER is strongly involved in all network development aspects, assessing not only the methodologies and guidelines developed by ENTSO-E for the various elements of the TYNDP, but also how they are implemented for the project assessments in the TYNDP. The Agency also verifies the consistency of the TYNDP with national development plans and provides an overview of related infrastructure reference costs. ​

Significant enhancement in electricity grid capacity is needed to realise Europe’s decarbonisation objectives and ensure a high level of security of supply. New grid build-out is just one way and proving to be the costliest way to do it. Despite their advantages, innovative solutions are not yet spearheading investment choices.

In the context of the European Commission’s EU Action Plan for Grids, ACER is looking at best practices to promote smart grids and network efficiency technologies through tariff design. 

ACER has thus commissioned the Florence School of Regulation (FSR) to conduct a study on existing regulatory frameworks and how regulators could incentivise a more efficient use of existing and future electricity grids.

Building on the previous research conducted by FSR on behalf of ACER, the report presents a new regulatory scheme which focuses on the value projects bring (i.e. benefit) and not on their costs. By sharing this benefit between the grid user and grid operator, a stronger incentive for technology-neutral solutions is created while mitigating the tariff increase (in comparison to the business as usual, e.g. investing into infrastructure alone).

Maximising cross-zonal trading opportunities is a core element to ensure an efficient internal electricity market. It is also important for meeting a number of future challenges in Europe's energy trajectory, including the decarbonisation targets.

The Clean Energy Package offers a new opportunity to increase the capacity offered for cross-zonal trade. In particular, Transmission System Operators are required to ensure that at least 70% of the transmission capacity is offered for cross-zonal trade, while respecting operational security limits. ​

For more information about the 70% minimum target, read our dedicated Q&A. 

The minimum 70% target has become a key element of market integration, which requires intensive monitoring. To ensure a harmonised approach on how to monitor the achievement of the minimum level of available cross-zonal capacity (MACZT), ACER is monitoring the MACZT in relation to the 70% target.

The results are published yearly in dedicated reports.