Renewable Gases

Energy solutions

Renewable Gases

The Portuguese National Strategy for Hydrogen sets a target for incorporation of H2 in gas networks by volume of 5% by 2025 and 10 to 15% by 2030. 

Aligned with European Union policies, the decarbonisation of gas infrastructures is one of the strategic objectives of the Portuguese energy policy, along with the promotion of types of energy from renewable origin.  

Public policy and the legislative context acknowledge the need to decarbonise the gas sector as a key factor to ensure the achievement of the economy’s decarbonisation objectives, especially in the industry and mobility sectors (heavy, maritime, and aviation), and gas networks are a vehicle for this purpose. 

Decree Law 62/2020

Despachos n.º 806-B

Despachos n.º 806-C/2022

Energy transition
REN is committed to the energy transition, as a key player in the decarbonisation of electricity and gas energy systems.


Renewable Gas Projects 

REN’s strategy for renewable gases is based on two pillars: the adaptation of existing infrastructures to accommodate these gases and the development of local hydrogen infrastructures, having thus set up three major projects for this purpose. 

Asset Compliance Plan

Prepare, on a national scale, the infrastructures of the Portuguese National Gas Transmission Network, of Portgás’s Distribution Network and of the Underground Storage in order to meet the objectives of the Portuguese National Strategy for Hydrogen regarding the incorporation of gases of renewable origin in the Portuguese National Gas System. 

The main objective is, in a first phase, to certify the REN transmission and storage infrastructures to receive up to 10% in volume of hydrogen mixed with Natural Gas and certify the distribution infrastructures up to 20%. This is so that it will be possible to guarantee the first injections of hydrogen into the Portuguese National Gas System by the end of 2023. Subsequently, and by the end of 2024, the goal is to assess and identify the roadmap of adaptations and investments, in order to ensure the adequacy of these infrastructures to accommodate up to 100% hydrogen. 

Electricity regulated
Gas regulated

Hydrogen Valleys

REN is developing infrastructure solutions to integrate multi-production and multi-consumption in the 100% renewable Hydrogen value chain in local and/or regional poles/ecosystems. These solutions are leveraged on existing expertise from the operation of current gas concessions. 

REN Gás leads Agenda H2 Green Valley, a candidate for funding from the Recovery and Resilience Plan and selected for a negotiation process with the Agency for Competitiveness and Innovation.

The consortium also includes REN Gasodutos, Dianagás (Floene), Bosch Termotecnologia, Hylab, Instituto Superior Técnico, and Laboratório Ibérico Internacional de Nanotecnologia.

The project brings together a set of complementary projects in the green hydrogen value chain that aim to develop infrastructures for transmission, storage, and distribution, with the goal of creating the first green hydrogen hub, in Sines, by 31 December 2025. 

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Celza Project

“Celza” is a renewable hydrogen pipeline project interconnecting Portugal and Spain. This project is part of the recent commitment made by the governments of Portugal, Spain, and France for the development of the Green Hydrogen Corridor in the framework of REpowerEU, called H2MED.

Its goal is to create technical conditions for the export of H2 from the Iberian Peninsula to central Europe. This project involves the construction of two new hydrogen-only gas pipeline sections – Figueira da Foz-Cantanhede and Celorico da Beira-Zamora – as well as the conversion to hydrogen-only of the sections that make up the existing gas network between Cantanhede-Celorico da Beira-Monforte.

This way, the results of the work in progress in the Asset Compliance Programme are leveraged, and capacity is created to receive hydrogen in a region with high potential.

Presently, REN, with the Spanish and French Transmission System Operators – Enagás, GRT Gas, and Terega – is developing the technical studies to support the application for a European Union Project of Common Interest, with a view to enabling access to financial support.

This project includes the necessary coordination with the Distribution Network Operators of the gas networks along Celza Project’s gas pipelines and the evaluation of the user supply options along the project’s route.

Learn about REN’s activity as the Portuguese national gas system operator. 


We have the answer to frequently asked questions

REN, in its various gas transmission, storage, and distribution concessions, ensures the passage of any gas as long as it is compatible with its assets and within the legal framework in force. Currently, and as a result of developments in European and national policy, there is a clear need to include renewable gases in the energy mix, such as hydrogen, biomethane, and synthetic methane.

The proper mixing of hydrogen with natural gas is ensured by a Mixing and Injection Station. The volume of hydrogen to be mixed with natural gas is limited to a certain percentage, given existing technical constraints, both at infrastructure and legal capacity level. In Portugal, legislation provides for a maximum limit of 5% for the transmission network until 2025 and 10% until 2030, while for the distribution network it is 20%. REN is carrying out studies and developing the necessary projects to accommodate these limits. 

Mixing green hydrogen with natural gas makes it possible to take advantage of current infrastructure and existing gas consumption, creating scale and providing a vehicle for decarbonisation, as well as boosting the development of the hydrogen market.

For each end consumer it will be necessary to validate the relevant gas quality and safety characteristics, in order to be able to account for the volume of gas consumed and the gross calorific value. Only then will it be possible to bill energy consumption fairly and ensure that it is delivered with quality and safety. 

Currently, the monitoring of new gas mixtures is done by: 

  • Assigning gas quality parameters to all outlets.  
  • Creating local quality areas.  
  • Installing devices to determine the calorific value at critical points in the network.  
  • Computational simulation of gas quality.  
  • Combining the calorific value of different types of gas by conditioning.   

The characteristics of the installation will determine the technical and economic feasibility of each solution.  

For questions regarding connections to the Gas Transmission Network, please contact REN at

There are different processes and technologies for producing hydrogen: 

Grey Hydrogen: grey hydrogen uses fossil fuels as an energy source, with CO2 emissions into the atmosphere. It can be produced by steam reforming coal or natural gas. 

Blue Hydrogen: blue hydrogen uses natural gas as its energy source. The CO2 released is captured, stored, and used in various industrial processes or buried in the ground. It is produced through the steam reforming of natural gas. 

Green Hydrogen: green hydrogen uses renewable energy sources. It is produced through the electrolysis of water, photo-electrochemical processes, the gasification of organic matter at high temperatures, and the anaerobic digestion of biomass. 

The Portuguese National Strategy for Hydrogen sets out to produce green hydrogen in Portugal in two ways:  


  • Centralised for large-scale production. 
  • Decentralised for small-scale production close to consumption sites, such as near domestic and industrial wastewater collection and treatment sites, in order to take advantage of this resource. 

Portugal needs to reduce greenhouse gas emissions by 85–90% by 2050, using land and forest to offset the remaining emissions. In other words, it is necessary to reduce emissions between 45% and 55% by 2030, and between 65% and 75% by 2040, compared with 2005.  

Decree-Law 62/2020 created the conditions for the incorporation of gas of renewable origin and low-carbon gases in the assets of the Portuguese National Gas System. This injection of new gases will significantly reduce CO2 emissions and increase the consumption of energy from renewable sources, thus enabling the defined climate goals to be met.

In accordance with the Legal Separation articles of Decree-Law 62/2020 of 28 August, REN cannot hold any shareholding in a production or marketing company.

The advantages of introducing gases of renewable origin into the Portuguese National Gas Sector include: 

  • As a complement to the electrification strategy, reducing decarbonisation costs.  
  • Strengthening the security of supply, as hydrogen can store energy from renewable electricity for long periods of time.  
  • Reducing the national energy dependence by using endogenous sources in production.  
  • Producing clean fuels.  
  • Promoting efficiency in energy generation and consumption.   
  • Stimulating economic growth and job creation through the development of new industries and related services. 
  • Greater sustainability of investments in the gas network, allowing revitalisation of the rural economy, with lower population density but greater predominance of primary sectors. 
  • Compressed gas storage at high pressures (200–700 bar) is the preferred method in places where the hydrogen demand is variable and not too high, notably in fuel cell stack units, in buses, cars, homes, and commercial and industrial establishments. 
  • The transition from hydrogen to the liquid state occurs at temperatures below -235ºC, so it can be stored in cryogenic tanks. 
  • Metal hydrides, carbon nanotubes and nanofibres, glass microspheres, and polymers enable the storage of hydrogen at low pressures (< 10 bar).

Underground salt caverns are suitable for storing hydrogen and are already in use in England and in the United States. These infrastructures are also feasible for storing hydrogen mixtures of up to 10%, and tests and tests revealing no safety problems have already been carried out. However, for injection and mixing in storage infrastructures, an assessment of the facility’s integrity is required, which REN is currently carrying out at Carriço.

An hydrogen valley is the bringing together of different production, consumption, transmission, as well as storage and compression projects, with the goal of creating a local hydrogen market. A valley can be developed in a closed logic, in which the production is dimensioned to satisfy self-consumption, or in a free access logic enabling the connection of different producers and local consumers. This is the case of Agenda H2 Green Valley, led by REN Gás and a candidate for funding from the RRP for the establishment of the first hydrogen valley in Portugal, in the Industrial and Logistics Zone of Sines. 


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