Inside FrHyGe: Expert voices on hydrogen storage and hydrogen systems #3

“Connecting hydrogen systems across Europe: the role of infrastructure and storage”

As hydrogen projects scale up across Europe, connecting production, transport and storage infrastructures is becoming a key challenge.

In this third edition, Enagás (José A. Lana, R&D Coordinator) and NaTran (Pierre Roy, Head of Laboratory & Claudia Paijens, Head of Gas Quality R&D) share their perspectives on how infrastructure development and cross-border cooperation will shape the future hydrogen ecosystem — and the role projects like FrHyGe can play in this transformation.

  1. What is your respective rôle within the FrHyGe project, and how does your background as transmission system operators prepare you to contribute to a project focused on underground hydrogen storage?

J A.Lana: Enagás involvement in the project focusses on studies for the replication of the FrHyGe concept at the European level, as well as support for dissemination and communication activities.

With more than 50 years of experience managing the natural gas system in Spain, including 3 underground storage facilities, Enagás contributes to the project as an expert in storage operation and as a promoter of the technological development required for underground hydrogen storage (UHS).

As designated provisional Hydrogen Transmission Network Operator (HTNO) in Spain, Enagás is designing the future Spanish hydrogen network. This network includes not only pipeline but also underground storage facilities. In fact, the initial design of the Spanish hydrogen network includes two underground hydrogen storage facilities based on salt caverns (both UHS are EU Project of Common Interest, PCI, P.24.1 & P.24.2). In addition, Enagás has extensive experience in the operation of natural gas underground storages.

P. Roy & C.Paijens: At NaTran, we bring a transmission system operator’s perspective to FrHyGe. Our role is to ensure that underground hydrogen storage can be safely monitored, qualified and integrated into future transmission networks.

Through our R&I activities, notably led by Claudia Paijens, Head of Gas Quality R&D at NaTran, we focus on hydrogen quality, measurement and operational interfaces, which are key to bridging storage and network operation. In parallel, our R&I Safety team contributes its expertise on risk assessment and operational safety, helping ensure that future hydrogen storage and transport infrastructures meet the highest safety standards.

  1. FrHyGe brings together partners from several European countries. How do NaTran and Enagás complement each other within the project, particularly in terms of experience, regulatory context, or infrastructure planning?

J A.Lana: This is not the only collaboration between our companies in place, as an example, Enagás and NaTran are working together in several EU funded R&D projects related to hydrogen development and innovation, such as H2Flowtrace, Opthycs, PillgrHym and THOTH2, along with other partners. Also, on the H2med – BarMar offshore pipeline connecting Barcelona (Spain) and Marseille (France). This project aims to enable the export of renewable hydrogen to France and further to Germany and Central Europe.

The development of these projects requires close coordination across multiple dimensions, including technical experience and specifications as network developers and operators, regulatory frameworks in France and Spain, and each company’s national hydrogen development plans to supply hydrogen (on the Spanish side) and to deliver hydrogen (on the French side). In particular, regulatory frameworks at both national and European levels are still under development. Therefore, close coordination between Enagás and NaTran in regulatory matters is essential for the successful future implementation of hydrogen infrastructure, including underground hydrogen storage solutions such as those demonstrated in the FrHyGe project. All these points taken into account in our collaboration in WP4.

P. Roy & C.Paijens: NaTran and Enagás are highly complementary: Spain brings strong hydrogen production and export potential, while France plays a key role in transmission and integration within Europe.

This cooperation already materializes in projects such as H2Med, including the BarMar and HyFen infrastructures, where Enagás and NaTran contribute to the development of cross-border hydrogen networks. Beyond individual projects, this collaboration reflects the need for European infrastructure operators to work together in support of common interests and the coordinated development of gas and hydrogen infrastructures at continental scale.

  1. FrHyGe’s success relies on strong coordination between work packages. Could you explain how your activities interface with other technical and scientific WPs to ensure consistency between storage design, network integration, and operational constraints?

J A.Lana: Enagás is actively involved in WP4, which focuses on the regional implementation of UHS business in Manosque region and also the replication of this model first to Germany and subsequently at the European level. Within this WP, Enagás contributes its perspective on the development of hydrogen market and export capacity in Spain, which has a direct impact on the Manosque/Marseille area. In addition, we share our knowledge and experience regarding the hydrogen regulatory framework across Europe.

Furthermore, Enagás is actively participating in the project’s dissemination activities, such as in the recent involvement in European Hydrogen Energy Conference   in Spain.

P. Roy & C.Paijens: FrHyGe is structured to connect science, engineering and system integration.

NaTran mainly operates at the interface between technical WPs (storage design and demonstration) and system WPs (market integration, safety and regulations). Our role is to ensure that outputs from the demonstrator are directly usable for future network operations, particularly through the harmonization of practices between storage and transmission operators.

  1. Europe is accelerating hydrogen deployment. What are the key infrastructure challenges today? And how important is cross-border cooperation for building a viable hydrogen ecosystem?

J A.Lana: We see the following key challenges:

  • “Chicken-and-Egg” Dilemma: producers are hesitant to commit investment without guaranteed transport, while infrastructure developers struggle to justify investments without steady, large-scale hydrogen flows.
  • Storage Shortage: large-scale storage solutions, such as salt caverns, are essential to balance intermittent renewable production but are currently lacking, existing projects under development (e.g., in France, Germany, Netherlands) are below what is needed.
  • Regulatory Fragmentation: Member States are progressing at different speeds, with varying national legislation that hinders the development of a uniform, cross-border hydrogen infrastructure.

Cross-Border cooperation is essential for creating a viable hydrogen ecosystem. Connecting supply and demand will enables high-production regions (e.g., Spain’s production) to be linked with major demand centers (e.g., Germany’s industrial hubs). Additionally, this will help to create a liquid market where a unified network fosters competition and prevents regional monopolies, essential for making hydrogen a tradable commodity. Also, cross-border cooperation will contribute to security of supply because regional interconnections allow for balanced flows, mitigating shortages and creating a more resilient energy system, reducing dependency on single sources. Finally, this will contribute to a cost-efficient infrastructure, coordinated, regional projects are generally more cost-effective than multiple, isolated, small-scale local solutions.

P. Roy & C.Paijens: Europe is now moving from hydrogen ambition to infrastructure implementation.

The challenge is no longer limited to producing hydrogen, but to creating a complete ecosystem that connects production, transport and storage assets across national borders. Underground storage will play a critical role in providing flexibility, balancing renewable energy production and enhancing security of supply.

In this context, cross-border cooperation is not optional: it is a prerequisite for building a resilient and integrated European hydrogen system.

  1. What are the main technical or operational challenges you see when integrating hydrogen stored in salt caverns into existing and future transmission networks, and how does FrHyGe help address them?

J A.Lana: The main challenge related to hydrogen storage in salt cavern is to demonstrate that it can follow market demand, meaning the ability to perform fast cycles of injection/extraction of hydrogen, with the agility required.

From the pipeline perspective, this flow pattern does not pose major technical issues. However, this behaviour still needs to be demonstrated at salt cavern level, and this is precisely the main objective of FrHyGe. Within the project, 100 fast cycles will be carried out to demonstrate the technical and operational feasibility of this approach.

A secondary challenge is to ensure that the hydrogen stored can be delivered back into the transmission network while meeting the required quality specifications. FrHyGe is also addressing this aspect by testing a purification unit. Regarding this, it should be noted that there is not yet a harmonised hydrogen quality specification common for all Europe, but standardisation bodies and stakeholders are working on it.

P. Roy & C.Paijens: While storage operators bring deep expertise in storage design and operation, TSOs focus on how stored hydrogen can be integrated into future networks.

Key questions include gas quality management, pressure compatibility, monitoring systems, safety requirements and operational coordination between storage and transport infrastructures.

FrHyGe provides an opportunity to address these questions using real project experience, helping prepare the conditions necessary for future large-scale network integration.

  1. Beyond the demonstrator, how does FrHyGe contribute to building a systemic vision of hydrogen storage and transport at European scale? What lessons could be transferable to future projects?

J A.Lana: As mentioned, the results of the fast-cycling tests that will be performed in FrHyGe will be a key input for defining the future operation profile of underground hydrogen storage (UHS) in Europe. The lessons learned through the project will be, to a large extent, directly transferable to the operation of future salt cavern storages.

In addition, much of the work done in FrHyGe as engineering activities, safety studies, and the interaction with regulatory authorities will be transferable to the construction of future UHSs and will contribute to accelerate their development while ensuring the necessary technical and safety requirements.

P. Roy & C.Paijens: FrHyGe goes far beyond a single demonstration project.

Its ambition is to develop methodologies, standards and operational knowledge that can be replicated in future hydrogen storage projects across Europe. The replication of the storage design in Germany is a good illustration of this approach.

The project therefore contributes not only to technical validation but also to the future industrialization and large-scale deployment of underground hydrogen storage solutions.

7. From a transmission system operator’s point of view, what do you see as the most valuable outcomes of FrHyGe for the future development of hydrogen infrastructure in Europe?

J A.Lana: The main results of interests will be the demonstration of the feasibility of fast cycles of injection/extraction of hydrogen, this will help to operate the pipeline network with lower pressure cycles, very likely due to the production of hydrogen using renewable energy, that by nature are intermittent.

P. Roy & C.Paijens: For transmission system operators, the main benefit of FrHyGe is building operational confidence.

The project provides practical experience, real-world data and valuable feedback on the interaction between storage and transport infrastructures. These insights will help operators design future hydrogen networks that are safe, reliable, interoperable and economically sustainable.

7. What is one key insight you have gained from working together within FrHyGe that you would not have developed independently?

J A.Lana: To participate in FrHyGe is allowing Enagás to save years in accessing the knowledge, technology and practical experience required to build and operate hydrogen salt cavern hydrogen storages, as safety studies, permitting issues, commissioning activities for storage wells, …

Working within a collaborative project gives us access to other companies with the same interests, enabling us to share experiences in the future.

P. Roy & C.Paijens: One of the key lessons emerging from FrHyGe is that hydrogen infrastructure must be designed as an integrated system rather than a collection of individual assets.

Storage, transport, gas quality, safety and regulatory aspects are all interconnected. The project demonstrates the value of bringing together different expertise from the earliest stages to ensure coherent and scalable infrastructure development across Europe.

CONCLUSION

“Hydrogen systems will not work without strong infrastructure — and infrastructure will not work without storage.”

“Hydrogen storage and hydrogen transport should not be developed separately. FrHyGe demonstrates that a truly European hydrogen economy will only be achieved through common standards, shared operational experience and close cooperation between infrastructure operators.” Claudia Paijens & Pierre Roy