Two routes to renewable hydrogen: how ECHO-WAVE and LuxHyVal can learn from each other

Green hydrogen is often discussed as if there were only one path to produce it. In practice, different routes can lead to renewable hydrogen — each with its own technical logic, regulatory setting, land-use implications and business model. For GPSS, this is where the connection between LuxHyVal and ECHO-WAVE becomes especially valuable: one project develops the hydrogen valley approach, while the other offers a local reference case for comparison.

A local reference for the hydrogen valley

LuxHyVal is Luxembourg’s flagship initiative to develop a national hydrogen valley. Its role is to bring together the different parts of a future hydrogen ecosystem: renewable electricity, hydrogen production, certification, transport, storage, industrial use, mobility applications, regulation, safety and public acceptance. Within this framework, hydrogen production is understood as part of a wider value chain.

The production concept in LuxHyVal is closely linked to the logic of a hydrogen valley. Renewable hydrogen is produced in an industrial environment, connected to the electricity system and embedded in a broader network of users and infrastructure. In such a model, renewable electricity can be supplied through the grid and accounted for on a certified, balance-based basis. This approach is particularly relevant for industrial zones, where hydrogen demand, electricity infrastructure and future users can be brought together in a concentrated area.

ECHO-WAVE approaches the same question from another angle. The project, developed by GPSS together with Soler, is planned as a directly connected renewable hydrogen production project in Kehlen. It combines local renewable electricity from wind power and agrivoltaics with PEM electrolysis. Instead of relying primarily on a balance-based grid connection in an industrial area, ECHO-WAVE explores the direct coupling of renewable generation and hydrogen production in a green-zone setting.

This distinction is central to the contribution GPSS can make within LuxHyVal. As a consortium member, GPSS can help compare two different approaches to renewable hydrogen production: the valley model based on grid-connected, certified production in an industrial zone, and the local direct-connection model based on renewable generation close to the electrolyser. Both approaches can contribute to Luxembourg’s hydrogen economy, but they raise different questions and offer different lessons.

ECHO-WAVE therefore serves as a local reference to LuxHyVal. It is not simply another hydrogen project running in parallel. It provides a practical case through which assumptions made in the hydrogen valley can be tested, contrasted and better understood. How does the project logic change when the electrolyser is directly linked to local renewable generation? What does this mean for system design, permitting, land use, operation, certification and future replication? Which advantages and constraints appear in each model?

These are important questions for Luxembourg. The country has limited space, a strong need to decarbonise industry and mobility, and a growing interest in renewable hydrogen. It will likely need more than one production model. A hydrogen valley can create concentration, coordination and demand. Directly connected local projects can demonstrate how renewable resources outside industrial zones may also contribute, provided they are technically, legally and socially well integrated.

Comparing two production logics

The comparison between LuxHyVal and ECHO-WAVE is not about deciding that one model is better than the other. It is about understanding where each model works best, what conditions it needs, and how both can support the development of a credible hydrogen economy.

In the LuxHyVal approach, the hydrogen production site is part of a larger valley architecture. The production is linked to industrial demand and embedded in an organised ecosystem. This has clear advantages. Industrial zones can offer access to infrastructure, potential offtakers and existing energy networks. They can also make it easier to coordinate demand, logistics and future scaling. For policymakers and industry, this model is attractive because it creates a visible centre of activity and can connect several actors around shared infrastructure.

At the same time, a grid-connected and balance-based production model depends on clear certification rules, reliable electricity sourcing and robust accounting. The renewable character of the hydrogen must be demonstrated in a way that is transparent and trusted. This requires not only technical infrastructure, but also administrative clarity, contractual arrangements and compliance with evolving European rules for renewable hydrogen.

ECHO-WAVE offers a different perspective. By directly connecting renewable electricity production with electrolysis, the project brings the production of hydrogen closer to the physical generation of renewable energy. Wind power and agrivoltaics are not treated only as abstract electricity sources, but as local assets that shape the operation of the electrolyser. This makes the project technically concrete and highly visible.

However, this model also brings its own challenges. Wind and solar generation are variable. Their production profiles do not automatically match hydrogen demand. A directly connected project must therefore be designed around real renewable generation patterns, storage needs and operational flexibility. The electrolyser must be operated in a way that reflects the availability of local renewable electricity, while still delivering hydrogen reliably to future users.

This is where GPSS’s work becomes particularly relevant. In ECHO-WAVE, GPSS is involved in the design of an integrated system combining renewable generation, hydrogen production, storage and use. A key element is the development of a Universal Control Unit using predictive control and data-driven methods. The aim is to optimise operation by anticipating renewable electricity production, hydrogen demand and technical constraints.

The comparison with LuxHyVal is valuable because it highlights two different optimisation problems. In a grid-connected industrial hydrogen valley, the focus is on certified renewable supply, system integration, demand aggregation and infrastructure planning. In a directly connected green-zone project, the focus shifts more strongly towards the physical matching of local renewable generation, electrolyser operation, storage and land-use integration.

Both models require digital tools, but for different reasons. In LuxHyVal, digital planning and monitoring can help coordinate actors, track flows, support certification and improve valley-wide decision-making. In ECHO-WAVE, digital control becomes essential for operating a hybrid renewable hydrogen system with variable local generation. The lessons from both approaches can therefore reinforce each other.

The land-use dimension is another important difference. LuxHyVal’s industrial-zone logic places production within an area already intended for economic activity. This can simplify certain aspects of public perception and spatial planning. ECHO-WAVE, by contrast, is located in a green-zone context where renewable energy production, agriculture, landscape and local acceptance must be considered together.

This is why agrivoltaics are so important in the ECHO-WAVE concept. They allow renewable electricity production and continued agricultural activity to coexist on the same land. In Kehlen, this creates a practical example of how renewable hydrogen production can be linked to rural land use, rather than being limited to industrial areas. It also makes the project more understandable for citizens: the connection between land, renewable electricity and hydrogen becomes visible.

For Luxembourg, this comparison matters. If renewable hydrogen is to grow beyond first demonstrations, the country will need a balanced view of where production should happen. Some production may be best located in industrial zones, close to demand and infrastructure. Other production may be suitable near renewable generation, especially when direct coupling and local system optimisation create value. GPSS’s contribution within LuxHyVal is to help make this comparison concrete.

What GPSS brings into LuxHyVal

As a consortium member of LuxHyVal, GPSS can contribute practical experience from both renewable energy development and hydrogen system design. The specific value lies in connecting project-level learning from ECHO-WAVE with the broader hydrogen valley framework.

One area of contribution is the comparison of production architectures. A balance-based, grid-connected model and a directly connected renewable model have different strengths and limitations. They differ in how they use the electricity system, how they manage intermittency, how they interact with land-use planning, and how they demonstrate renewable origin. Understanding these differences is essential for future policy and investment decisions.

Another area is operational learning. ECHO-WAVE can help show what it means to run an electrolyser with variable local renewable generation. This includes questions such as: how much flexibility is needed, how storage should be dimensioned, how predictive control can improve performance, and how hydrogen demand can be matched with renewable availability. These insights can complement LuxHyVal’s work on digital planning, system integration and replication.

A third area is certification and trust. In both approaches, the renewable character of hydrogen must be clear. In a grid-connected model, this requires robust accounting and certification. In a directly connected model, the physical link between renewable generation and hydrogen production may be easier to explain, but still needs to be documented and verified. Comparing the two approaches can help identify what information users, authorities and citizens need in order to trust the final hydrogen product.

A fourth area is replication. Luxembourg is small, but the lessons are relevant beyond national borders. Many European regions will face similar choices. Should hydrogen production be concentrated in industrial zones? Should it be developed close to renewable generation? How can grid-connected and directly connected models coexist? What role can agrivoltaics play? Which model is better suited for which type of demand?

ECHO-WAVE can help answer these questions because it brings the discussion down to the level of a real site. It shows how technical design, permitting, land use, community acceptance and business modelling interact. LuxHyVal provides the broader valley framework; ECHO-WAVE provides a concrete local comparison point. Together, they can help Luxembourg develop a more nuanced hydrogen strategy.

This is also important for policymakers. Support schemes, permitting procedures and certification rules should be able to accommodate different production models without losing clarity. A hydrogen valley may require one set of enabling conditions, while directly connected renewable hydrogen projects may require another. By comparing both, GPSS can help identify where regulation supports innovation and where further clarification may be needed.

For industry, the comparison is equally relevant. Future hydrogen users need reliable, affordable and certifiably renewable supply. Some may benefit from a valley-based supply model connected to shared infrastructure. Others may be interested in local or dedicated renewable hydrogen production. Understanding the trade-offs between these options can help companies make better decarbonisation decisions.

From comparison to confidence

The value of ECHO-WAVE for LuxHyVal lies in its role as a reference case. It offers a second lens through which Luxembourg can look at renewable hydrogen production. LuxHyVal demonstrates the logic of a coordinated hydrogen valley with grid-connected, balance-based production in an industrial setting. ECHO-WAVE explores the logic of directly connected production in a green-zone setting, using local wind and agrivoltaics.

Both approaches are needed to build a serious hydrogen economy. One creates concentration and valley-wide coordination. The other tests how local renewable resources can be converted directly into hydrogen. One is closely linked to industrial infrastructure. The other brings hydrogen production closer to land use, agriculture and local renewable generation. Together, they can help answer not only how Luxembourg can produce renewable hydrogen, but where, under which conditions and for which use cases.

For GPSS, this comparative perspective is the key contribution to LuxHyVal. By developing ECHO-WAVE as a national reference project and participating in LuxHyVal as a consortium member, GPSS can help translate project-level experience into broader learning. The objective is not to promote one model against the other, but to understand how different production pathways can complement each other.

 

As LuxHyVal progresses, the lessons from ECHO-WAVE can feed into the project’s work on hydrogen production, digital planning, certification, business models, public acceptance and replication. They can also support future discussions on how Luxembourg should design a diversified renewable hydrogen portfolio.

Follow our progress through LuxHyVal’s work packages and through the ECHO-WAVE communication channels. The comparison between valley-based and directly connected hydrogen production will provide valuable insights for Luxembourg and for other European regions working to turn green hydrogen from a policy objective into trusted local infrastructure.

Author

Patrick Witte – Managing Director GPSS S.A.

Funding disclaimer

The LuxHyVal project has received funding from the European Union’s Horizon Europe research and innovation programme under Grant Agreement No. 101111984 and is co-funded by the Clean Hydrogen Joint Undertaking. Views and opinions expressed are those of the author only and do not necessarily reflect those of the European Union or the Clean Hydrogen Joint Undertaking.