MARENSIN exploration license

Marensin in brief

Bibliographical research and initial field studies were carried out in 2021 and 2022. This research, carried out as part of a research project called H2NA in which 45-8 ENERGY and Storengy was involved, revealed a potential for native hydrogen in the French Nouvelle-Aquitaine region.

In this context, Storengy and 45-8 ENERGY have jointly applied for an exploration license covering an area of 691km² in the Landes Département (40) for a period of 5 years. Storengy is the operator on this license.

The purpose of this application is to gain a deeper understanding of the geology of the area and to confirm the potential for native hydrogen.

A totally carbon-free resource, native hydrogen - also known as geological, natural or white hydrogen - could make a major contribution to the low-carbon hydrogen mix, particularly in the current context of the search for energy independence and decarbonisation of industries.

The Marensin exploration license, which is currently being examined by the relevant authorities, represents an opportunity for the production and use of native hydrogen in south-west France.



Marensin exploration license

Bibliographic research and preliminary field studies have been carried out in 2021 and 2022, as part of the H2NA research project. Partly financed by the Nouvelle-Aquitaine Region, and in partnership with the French National Geological Survey (BRGM), UPPA (Université de Pau et des Pays de l’Adour), ENGIE, Storengy and CVA Group, the H2NA project studied the area’s potential for native hydrogen and defined the contours of an exploration license in a high-potential zone.

Storengy and 45-8 ENERGY have jointly filed a license application for a 691km² area in the Landes Département (40) with the French Ministry of Ecological Transition, which is currently being examined by the relevant authorities. The purpose of this application is to gain a deeper understanding of the geology of the area and confirm the potential for native hydrogen.

The granting of this exploration permit, and the subsequent validation of our hypotheses, would enable us to extract value from the native hydrogen and any associated gases. This potential production would encourage the use of hydrogen as a low-carbon energy carrier and contribute to the energy transition in south-western France.

The PER application has been submitted for a period of 5 years, in order to progressively acquire the necessary data to validate the hypotheses.

In addition to this exploration license, 45-8 ENERGY and Storengy are also working together on the Grand Rieu exploration license, in which 45-8 ENERGY, via its subsidiary 45-8 Grand Rieu, is the operator. Located in south-west France, in the Pyrénées-Atlantiques département (64), this Native Hydrogen exploration license also aims to deepen geological knowledge of the area and confirm the potential for native hydrogen.


A solid partnership between 45-8 ENERGY and Storengy

The license application is being submitted jointly with Storengy, a subsidiary of the ENGIE Group, as part of a partnership that will make it possible to draw on the respective expertise and resources of both parties.

Storengy is the project operator. The company is coordinating all the activities to be carried out on the exploration license and will carry out the studies and works.


Storengy, an ENGIE subsidiary, is one of the world leaders in subsurface natural gas storage. The company has 21 natural gas storage sites in Germany and the UK. Storengy is also a key player in renewable gases. With 70 years' experience in subsurface exploration and exploitation, and in response to the current energy challenges of decarbonization and sovereignty, Storengy is today mobilizing its skills in the development of hydrogen storage infrastructures and the exploration of natural hydrogen with research and development projects initiated in 2016.

45-8 ENERGY is a partner in the project. It is contributing its technical expertise to the studies and work that will be carried out.

Exploration area size

0 km²

691 km²

Exploration area size




Valid period of the license
0 years

5 years

Valid period of the license


The license goals

Identify the location of hydrogen-generating rocks and understand the migration path of hydrogen to the surface or to geological structures where it may have accumulated.

Precise characterization of the area’s geology and the zones most conducive to hydrogen accumulation.
Quantify the volumes of hydrogen that could be stored in the subsurface, and assess the technical and economic potential, all with the utmost respect for the environment.


The exploration area

The license area covers 691km² and involves 13 municipalities in the French Landes Département (40) :

  • Bias
  • Castets
  • Léon
  • Lesperon
  • Lévignacq
  • Linxe
  • Lit-et-Mixe
  • Mézos
  • Saint-Julien-en-Born
  • Saint-Michel-Escalus
  • Taller
  • Uza
  • Vielle-Saint-Girons.


Native Hydrogen

The license application is exclusively for native hydrogen.

Is native hydrogen natural?

Native hydrogen is produced naturally in the subsurface. As such, its formation requires no critical materials, no anthropogenic energy and no impact on available fresh water resources.

How is hydrogen formed?

Native hydrogen is formed by the transformation of a rock from the earth’s mantle, reacting with water as it seeps through faults. This process, known as serpentinization, generates a rock called serpentine, as well as native hydrogen.

Is native hydrogen a carbon-free resource?

Yes, because it is produced naturally in the subsurface, native hydrogen is a totally carbon-free resource. Its production would therefore make it possible to envisage low-cost, low-carbon production to serve the energy transition of the south-west and of France as a whole.

Why produce native hydrogen?

Native hydrogen has a role to play in the decarbonization of industry and mobility. This type of hydrogen could easily be integrated into the existing low-carbon hydrogen mix as a natural, decarbonized and competitive resource.

Is it possible to find other gases?

Indeed, other resources could potentially be associated with native hydrogen. Helium, for example, could be associated! In the event that other resources are found, 45-8 ENERGY’s ambition is to exploit all subsurface resources.


The work program


The license key steps

Application for an exploration license
Competitive bidding
Semester 1*
Public consultation
Semester 2*
Potential results of the instruction
2025 - 2029
If license obtained*
Geological synthesis and data acquisition

Theoretical dates. The steps to follow will depend on how long it takes to process the application with the authorities.

Find out more about 45-8 ENERGY