Access ACE​R Q​​&As and explore the different sections:

• Background information on REMIT
• ACER's role
• REMIT Definitions
• Obligations and prohibitions for market participants
• Timeline of the implementation​

The Regulation on guidelines for trans-European energy infrastructure (TEN-E Regulation) introduced the cross-border cost allocation (CBCA) as a regulatory tool to facilitate the implementation of projects of common interest (PCIs).

European PCIs and Projects of Mutual Interests (PMIs) are key cross-border infrastructure projects that further link the energy systems of EU countries. Such infrastructure projects are a strategic priority for achieving Europe’s ambitious clean energy goals.

CBCA decisions establish the sharing of the efficient investment costs of a PCI between the countries which are significantly impacted by the projects. NRAs jointly scrutinise the investment requests and determine which countries will contribute to financing them, and in which proportion. Cost sharing agreements may facilitate the implementation of PCIs if the territorial distribution of benefits and costs is not well aligned.

Promoters of PCIs and PMIs can submit their investment requests, including for CBCA, to the relevant national regulatory authority (NRA).​ In case the NRAs cannot reach an agreement after 6 months, or upon NRAs’ joint request, ACER serves as a last-resort decision maker in CBCA cases.

CBCA Guidelines

In June 2023, ACER adopted a recommendation for identifying good practices for the treatment of investment requests for PCIs. It builds upon past decisions and stakeholders’ feedback collected through a workshop and public consultation.

The recommendation provides guidance to project promoters on submitting investment requests, as well as to NRAs on their assessment and the allocation of costs among Member States. Additionally, it outlines reporting requirements of project promoters towards NRAs and transmission system operators (TSOs) of the relevant Member States.

What are the main elements of ACER’s CBCA recommendation?

• Pragmatism and flexibility, as there is no one-fits-all solution;
• Basic guiding principles for all projects;
• CBCA also for clusters of projects;
• Choice and evaluation of scenarios;
• A stable framework for the identification of contributing countries;
• Treatment of uncertainty and adjustment mechanisms.

This CBCA recommendation shall be regularly updated as necessary, in particular to ensure consistency with the principles on the offshore grids for renewable energy cross-border cost sharing. ACER shall consult all relevant stakeholders when modifying the recommendation.

CBCA monitoring

ACER’s 2025 monitoring shows:

• 65% fewer CBCA decisions issued in the second half of the monitoring period (2019-2024), reflecting a drop in eligible cross-border projects due to completed infrastructure, the phase-out of natural gas and Brexit.
• Costs stay national in most cases, as Member States usually agree to cover their own share.
• Access to EU grants via the Connecting Europe Facility (CEF) is the main reason project promoters submit investment requests. 
• No CBCA decisions yet for hydrogen, as the sector is still in early stage of development.

​For NRAs:

NRAs should inform ACER about investment requests and CBCA decisions without delay and share the relevant documents.

For promoters:

​The guidance on the submission of an investment request for project promoters is accompanied by a template (Annex IV) summarising all relevant information to be provided.​

The Regulation on guidelines for trans-European energy infrastructure (TEN-E Regulation) was first introduced in 2013 to facilitate the development of European energy networks.

The Regulation was revised in 2022 to align with the goals of the European Green Deal and introduced the concept of projects of mutual interest (PMIs) alongside the existing projects of common interest (PCIs). These are key cross-border infrastructure projects designed to improve network connections between EU Member States (PCIs) or with non-EU countries (PMIs). These projects benefit from accelerated permitting procedures and funding, as they are key to achieving the EU’s energy and climate objectives.

The European Commission is responsible for selecting and publishing a list of these projects every two years (known as the Union list). In 2024, the Commission published the first Union list including both PCIs and PMIs.

ACER monitors and evaluates the implementation progress of PCIs and PMIs based on reports submitted by project promoters and national competent authorities.

In May 2025, ACER published its first interactive dashboard presenting the monitoring findings for both PCIs and PMIs.

Pursuant to Article 59(1) of EB Regulation, ENTSO-E shall publish a European report focusing on monitoring, describing and analysing the implementation of EB Regulation, as well as reporting on the progress made concerning the integration of balancing markets in Europe.

The format of the report shall vary as follow:

(a) two years after entry into force of this Regulation and subsequently every second year a detailed report shall be published;

(b) three years after entry into force of this Regulation and subsequently every second year a shorter version of the report shall be published to review the progress made and update the performance indicators.

No actions have been completed yet with regard to this topic.​

Pursuant to Article 60 of EB Regulation, at least once every two years, each TSO shall publish a report on balancing covering the previous two calendar years, which shall either be in English or at least contain an executive summary in English. The Agency plans to gather and publish these reports.

No actions have been completed yet with regard to this topic.​