​ACER participates in the identification of projects of common interest (PCIs) and monitors their implementation annually.

In addition, the Agency contributes to:

• Developing cost-benefit analysis methodologies to identify the best projects from a socio-economic perspective
• Providing guidelines to facilitate the allocation of projects' costs across borders (CBCA)
• Creating a cooperation framework for NRAs to establish and publish a set of unit investment cost indicators and corresponding reference values for gas infrastructure
• Sharing best practices on regulatory incentives.

ACER has also proposed legislative changes to improve the planning and implementation of electricity and gas infrastructure and their governance, based on its experience with the implementation of the TEN-E regulation.​

The European Commission is developing legislative proposals (as part of the Grids Package) to improve and simplify the current legal framework. This includes the revision and simplification of the 2022 Trans-European Energy Networks Regulation (TEN-E Regulation), a key framework for the European energy infrastructure development. 

On 19 September 2025, ACER published a position paper on improving and simplifying the legal framework on European grids.

In March 2021, ACER and CEER published a position paper​ to set out recommendations on 6 main issues. The paper calls for neutral and independent technical assessment of infrastructure projects and improved regulatory oversight so that the projects bringing most benefits for the European Green Deal are supported and to avoid any risks of unjustified costs to European consumers.​

When the European Commission's revised TEN-E Regulation proposals were published in December 2020, ACER and CEER flagged up the need for further improvement for energy network development (see the ACER-CEER Press Release).​

Already in July 2020, ACER and CEER set out their recommendation to the European Commission (as it began developing its proposals on revising the Trans-European Energy Networks Regulation) in a​ Position Paper on the Revision of the Trans-European ​​​Energy Networks Regulation (TEN-E) and Infrastructure Governance. The proposals highlight how the legislative changes could improve the planning and implementation of electricity and gas infrastructure. The paper also advises on improving the infrastructure development governance, the principles for PCI scope, and the TEN-E processes.

Previously, ACER issued two other Position Papers (2016) and (2017) about possible improvements of the European framework for energy infrastructure development related to the TEN-E Regulation. 

ACER periodically reviews the national network development plans to assess their consistency with the EU TYNDP. As a result, ACER issues Opinions including recommendations for improving the consistency between future network developments plans.​

​Transmission system operators (TSOs) establish regional cooperation within ENTSOG and publish a Gas Regional Investment Plan (GRIP) every two years. Based on this plan, TSOs can take investment decisions. ACER monitors the level of regional cooperation of TSOs within the GRIPs, and takes account of the outcome when formulating its views.​

​ACER is looking at the issue of methane emissions primarily from the viewpoint of sustainability, as a sine qua non for any undertaking in gas infrastructure. Sustainability is one of the criteria that must be met by all projects included in the TYNDPs and in the PCI lists. To achieve the 2050 climate goals of the European Union, a balance must be found between:

• The scale of the problem and the tools to address it,

• The costs and benefits of any possible regulatory measures,

• Best industry practices, technical norms and regulation.​

​ACER's main tasks regarding trans-European gas infrastructure are performed in close cooperation with the national regulatory authorities and the ENTSOs for Electricity and  Gas. ACER monitors  the implementation of projects creating new interconnector capacity and the Union-wide network-development plans. If ACER identifies inconsistencies between those plans and their implementation, the Agency investigates and makes recommendations to the transmission system operators, regulatory authorities or other competent bodies concerned. 

Each year, promoters of projects of common interest report to ACER their progress. Based on these inputs,  ACER produces a consolidated annual report which highlights the development, construction and commissioning of the projects, as well as possible delays and difficulties in their implementation across Europe.

ACER fosters a proper assessment of the projects of common interest in terms of contribution to market integration, competition, security of supply and sustainability.

​ACER and ENTSOG are responsible for jointly drafting the Network Codes, which are adopted by the European Commission through comitology procedure as binding regulations. The European Commission is also in charge of developing specific Guidelines, after consultation with ACER and ENTSOG. The Network Codes' and Guidelines' implementation takes place nationally, while the Agency offers guidance and monitors the effectiveness of the implemented rules at European level. ACER occasionally takes individual decisions in case of disagreement between NRAs on a cross-border issue, to ensure a consistent application of the legislation.

One way to decarbonise natural gas is to find ways to produce methane from renewable resources, such as biomass or natural waste. The resulting fuel is typically biogas (a mixture of methane and other gases) or biomethane (resulting from the separation of methane from the other biogas components).

Another way to decarbonise is to replace the natural gas with a sustainably produced non-methane one. Hydrogen produced via water electrolysis with the help of electricity from renewable resources is an example.

A third way is capturing the carbon contained in the natural gas, either before its use (pre-combustion, for example by converting it in a mixture of hydrogen and carbon dioxide destined for storage) or post-combustion, for instance by capturing the carbon dioxide and placing it in long-term geological storage.

There are other possible ways and means to decarbonise gas apart from the examples above. Methane emissions can be eradicated or minimised by applying a host of common sense practices, such as preventing venting during the exploration and production of natural gas, prohibiting flaring (especially when natural gas is produced as “associated gas” along with liquid hydrocarbons), avoiding fugitive emissions from valves and compressor stations, and making sure that burning is not incomplete. 

Many of these “common sense” approaches apply not only to natural gas, but also to methane-containing decarbonised gases.  It is therefore important to develop and deploy the relevant regulatory tools and methods for all methane-containing gases, decarbonised or not.

Decarbonised gases are only produced and used in the European Union on a minor scale, with the bulk being biogas and biomethane. Besides, most of the natural gas is imported (ca. 80%).

The ramping up of gas decarbonisation poses thus numerous challenges, ranging from assuring that the field is level for all available technology options and pathways, to supporting innovation by the right regulation, to monitoring, reporting and verifying greenhouse gas emissions across the entire international gas supply chain, to properly defining “green gases”, to making sure that competition is fair and market integration works.

Across this broad range of issues, ACER is committed to fostering the decarbonisation of the gas sector, by tackling different aspects in its regulatory tasks.