New regulation key to the development of renewable and low-carbon gases in the gas sector

Following a process that began in June 2024, the National Commission for Markets and Competition ("CNMC") approved on 9 April 2025 Circular 2/2025, establishing the methodology and conditions for access and capacity allocation in the natural gas system (the "Circular 2/2025"). Initially conceived as a modification of CNMC Circular 8/2019, of 12 December (the "Circular 8/2019") which until now regulated access and connection to the gas grid, finally, as proposed by the Ministry for Ecological Transition and the Demographic Challenge during the public information process, it has been decided to approve this new Circular 2/2025, which repeals and replaces the aforementioned Circular 8/2019.

This new Circular 2/2025 stands out for establishing, for the first time, the regulation of access and connection to the gas system specifically for renewable and low-carbon gases, thus adapting the regulation of the sector to the new needs and objectives derived from the decarbonisation of the economy. The approval of this new regulation brings to an end a period in which the existing regulation had proved to be insufficient in view of the reality of the gas sector in Spain. It is foreseeable that this regulation will serve to put an end to a period that has been particularly conflictive, as evidenced by the large number of disputes regarding connection to the gas system that have been brought before the CNMC in recent years, mainly in relation to the connection to the natural gas grid of projects that provide for the injection of renewable or low-carbon gases, such as green hydrogen.

For this reason, and although there are many modifications introduced by Circular 2/2025, we will focus on listing the main novelties regarding access and connection to the natural gas grid of renewable or low-carbon gases.

New subjects with the right of connection and access to the grid: operators of "other gases" production plants

Circular 2/2025 recognises as new subjects with the right to access and connect to the gas grid the owners of "other gases" productions plants. The term "other gases" includes those gases that meet the requirements established current regulations for injection into the natural gas grid and which are different from natural gas of fossil, differentiating between those that need to be mixed with natural gas and those that do not.

As subjects with access rights, they are recognised as having a series of rights: (i) to request connection from the transmission or distribution facilities operator, (ii) to inject the gas produced into the natural gas grid, (iii) to demand that the grid operators comply with the established technical safety and control requirements, and (iv) to receive from the grid operators the information necessary for the correct and safe injection of the gas produced.

In return, a series of obligations are imposed on them: (i) to comply with the regulatory obligations regarding quality and measurement, (ii) to report any maintenance and incidents that may affect the injection of the gas produced into the natural gas grid and (iii) to follow the instructions of the owner of the grid to which they are connected and of the technical system operator regarding the use of the connection.

Procedure for access and connection to the grid for "other gases"

The procedure for connecting 'other gases' production plants to the natural gas grid is detailed in Articles 14 and following of Circular 2/2025, establishing two procedures through telematic application and contracting platforms, depending on the need to mix these gases with natural gas:

• Gases not needing to be mixed with natural gas: the acceptance of connection shall be subject to the agreement of the technical system operator and the grid operator shall determine whether the conditional capacity available in its grid is sufficient to meet the request.
• Gases that need to be mixed with natural gas: the acceptance of connection will be decided annually and will be regulated by a three-phase mechanism: (i) phase of submission of information to the technical system operator and its evaluation, (ii) phase of request for connection to the transmission or distribution system operator, (iii) phase of acceptance or rejection of the connection request.

For these facilities the capacity is considered "conditional", which means that the contracted capacity is variable and can be limited under certain circumstances related to the supply and demand of gas in the grid and the connection capacity of other plants producing "other gases".

Circular 2/2025 sets out the minimum content of connection contracts for plants producing "other gases" that inject into the transmission grid and the possibility to create framework access contracts. 

Anti-capacity hoarding measures and guarantees

Circular 2/2025 introduces anti-capacity hoarding measures to alleviate congestion in the connection and access of production plants of "other gases" to the natural gas grid. These measures are as follows: (i) the possibility for "other gases" production plants to waive their contracted conditional connection capacity, subject to payment of the costs incurred or firmly committed, (ii) the loss of the right to use the allocated conditional connection capacity due to non-use during the period determined by the CNMC and (iii) the release of the contracted conditional connection capacity, subject to a resolution by the CNMC, in the event of unjustified under-utilisation of the conditional connection capacity.

A special feature of the guarantees for "other gases" production plants is the possibility of agreeing with the grid operators on the terms and conditions of connection payments and the guarantees relating to them in the connection contract. If no agreement is reached between the parties, it is established that the applicant must provide the guarantees corresponding to the outstanding amount of the connection cost agreed and not paid upon signature within a maximum period of 30 working days from the date of notification by the grid owner of the administrative authorisation to build the connection. The guarantees will be released progressively in accordance with compliance with the payment schedule of the connection contract.

Other modifications

The circular also provides:

• Transparency and publicity requirements to be met in relation to the connection of "other gases" production plants.
• The competence of the CNMC to monitor and resolve disputes related to the connection procedures of "other gases" production plants and congestion management mechanisms.
• The obligation of transmission and distribution grid operators to enable and manage telematic platforms for requesting and contracting the connection of "other gases" production plants to the natural gas grid, with the CNMC being able to establish specific requirements for such platforms.

Entry into force

Circular 2/2025 will enter into force on 1 July 2025, repealing Circular 8/2019, except for Articles 36 (Capacity reservation for short- and long-term contracts) and 38 (Flexibility of use of contracted slots) which will enter into force on 1 August 2025 and 1 November 2025, respectively.

Should you wish to know more about the new Circular 2/2025 or any other energy and energy transition issues, please do not hesitate to contact one of our experts listed below or your usual contact at Osborne Clarke.