Cost-efficient and reliable designs towards gigawatt-scale electrolytic hydrogen production plants

Expected Outcome

As Europe strives towards its objective of climate neutrality, renewable hydrogen at industrial scale is pivotal for decarbonising energy-intensive sectors. Large-scale water electrolysis is central to this transition, yet Europe faces significant challenges in building gigawatt-scale hydrogen production plants that are reliable enough to ensure consistent operation and financially sustainable to attract unsubsidised investment. Current projects struggle with costly and fragmented system integration, limited scalability from electrolyser providers and unoptimised Balance-of-Plant (BoP) systems, resulting in high electrolytic hydrogen costs. In particular:

• Expectations on CAPEX reduction have not been met, recent reports from BNEF[1], IEA[2] and TNO[3] indicate actual hydrogen plant cost of 2160-3050 \$/kW, far from SRIA objectives.
• The way to develop large scale projects (>400MW) or a small scale 20 MW projects is very similar and based on the same identical electrolyser bricks thus limiting economies of scale.
• Restricted freedom to adapt or optimise OEM designs depending on the project.
• If the standardised approach has been chosen on most of small-scale projects, there is no or few alternatives available for large scale projects.
• What is optimum for OEMs limit of scope is not always the optimum at the hydrogen plant level.

Aside from these hurdles, the BoP of a hydrogen plant can be built with components (pumps, exchangers, separators, piping, instruments, compression, purification, storage etc.) that already have a high level of maturity inherited from similar industries (oil & gas, water, etc.), apart from stacks for which iterative improvements are still expected.

Thus, it is possible to overcome some of the current limitations by relying on mature components while exploring innovative new plant architectures (electrical, process), new construction philosophies, new integrations between parts of the plant, etc., pushing the mature components to their current capacity limits.

The main challenge is to achieve a unified vision of different stakeholders (OEM, integrator, EPC contractors, operators, developers, etc.) in the design of a hydrogen plant, with a common objective of making it as cost-effective and reliable as possible. Moving away from the pre-existing model to create a new one is challenging even if based on mature components as it requires opening/exploring/closing multiple ways in parallel by engaging all stakeholders in the discussion.

By building robust and efficient system designs, the projects outcomes should identify best fit evolutions to expect in future steps for components becoming bottlenecks to improve and optimise factories, and by such paving the way to future works at European level.

The results are expected to position Europe as a global leader in designing and implementing gigawatt-scale hydrogen plants, stimulate industrial investment, and foster a sustainable hydrogen economy through innovation, integration, and cost-efficiency.

Project results are expected to contribute to the following expected outcomes:

• Acceleration of investment decisions for commercial hydrogen facilities at 400 MW scale and beyond, supported by validated FEED-level designs and Class 3 cost estimates.
• Reduced Levelised Cost of Hydrogen (LCOH) through optimised plant integration, economies of scale, and valorisation of by-products such as heat, oxygen, and grid services.
• Enhanced energy system flexibility, supporting grid balancing and sector coupling through integration with renewable power sources and industrial processes.
• Improved environmental performance, reducing lifecycle greenhouse gas emissions, water consumption, and overall energy intensity of hydrogen production.
• Increased investor and policy confidence through evidence-based technical, economic, and regulatory feasibility aligned with EU sustainability and certification criteria.
• Strengthened European industrial leadership in renewable hydrogen technologies, supporting a competitive and resilient supply chain for gigawatt-scale deployment.

Project results are expected to contribute to the following objectives at the full plant scope:

• Reduction in CAPEX and OPEX per installed MW;
• Reduction in water and energy consumption per kg of hydrogen produced;
• Increased system availability, maintainability, safety and reliability;
• Reduction in LCOH (€/kg H₂) compared to existing large-scale systems;
• Reduction in physical and environmental footprint;

More specifically for the electrolysis part of the plant, the project results should contribute to the relevant KPIs of the SRIA[4], with an objective to reach 2030 targets in priority. As an example for alkaline technology : Electrical Consumption at 48kWh/kg, CAPEX at 400 €/kW, O&M cost at 35 €/kg/day/year, Turn-Down Ratio (Cold start 300s).

Scope

This topic aims to drive innovation in integrated hydrogen production plants by reimagining plant design, architecture, and deployment models. The focus should be on developing novel concepts for highly efficient, cost-competitive, and reliable electrolytic hydrogen production plants at very large scales (≥400 MW), leveraging commercially available electrolyser stacks, advanced system engineering, and innovative BoP and plant components (e.g., purification, compression, thermal integration, power electronics). As relevant, the design specifications and components innovation roadmaps (e.g to optimise performances and durability when operating dynamically or improve end of life recycling), is also encouraged.

Proposals should deliver a complete fully replicable plant concept: a hydrogen production facility capable of delivering renewable hydrogen ex-works (without transport) at highest consumption quality, using available resources (e.g. water and electricity) and complying with EU regulations (notably RFNBO criteria).

The project should cover the following elements:

• Consider a full system integration of a large-scale (≥400 MW) electrolysis capacity and all necessary BoP subsystems (water treatment, cooling, purification, power electronics, compression, storage, etc) and demonstrate scalability to 1000 MW and beyond with strong replicability potential. When relevant, the project may rely on innovative/breakthrough components developed in previous EU-funded projects on full scope plants and BoPs (e.g. on-going in 2025 DJEWELS[5], ENDURE[6], EPHYRA[7], HERAQCLES[8], HOPE[9], HERMES[10], REMEDHYS[11]);
• Technical and economic optimisation across all parameters affecting hydrogen cost: availability, energy efficiency, DEVEX, CAPEX, OPEX, footprint, water consumption, etc;
• The plant design should valorise as far as possible the by-products from the electrolysis plant (e.g. waste heat, oxygen, water, grid services);
• Scenarios exploring infrastructures and layouts, process simplification, and innovative solutions for cost and footprint optimisation (e.g. pooling, massification, standardisation, …) based on mature solutions. Concrete recommendations are expected to be delivered by the analysis of the scenarios;
• A Reliability, Availability, Maintainability (RAM) analysis or equivalent to quantify system availability, ensuring the plant’s operational reliability. This includes innovations around operations & maintenance solutions particularly to cope with specific challenges of GW-scale plants constraints;
• Investment-grade engineering documentation, including CAPEX Class 3 estimates (AACEI 18R-97) and Front-End Engineering Design (FEED)-level studies, ensuring technical and financial readiness for industrial deployment;
• An energy efficiency and water consumption estimation based on exhaustive analysis (full plant power balance), feedback data from the field and/or supplier guarantees for the major electricity and water consumers of the plant;
• An OPEX estimate based on an explicit methodology, and with verifiable data;
• Modelling, simulation and optimisation tools (development and/or use) to quantify availabilities via RAM studies, achieve techno-economic sensitivity analyses, OPEX and efficiency of the elaborated designs. (FEED-Ready outputs).

Proposals should include RAM analysis, CAPEX Class 3 estimates with FEED-level documentation, and clear OPEX, energy, and water consumption assessments. Designs development will be supported by advanced modelling and optimisation tools to enable robust techno-economic analyses and guide system optimisation. Innovation will focus on system-level integration using existing, proven electrolyser stacks. Proposals should also validate the proposed approach through a representative project case study, demonstrating practical feasibility and scalability. The designed system will target a minimum capacity of 400 MW, with a clear pathway to scale up to 1 GW and beyond.

The following elements are out of scope:

• Activities related to hydrogen pipeline connection or end-use tie-ins;
• Development of new electrolysis cell technologies or fundamental components.

Consortia should include various stakeholders of the hydrogen value chain including, but not limited to, components manufacturers, system manufacturers (at least 2), system integrators, project developers, plant operators, end users, etc. Consortia will gather all technical & economic expertise needed not only for the implementation of the project but also will associate related sectorial clusters and associations helping to ensure the replicability of the project outcomes. To support the replicability of the projects outcomes, project outputs e.g. deliverables, models, etc. are expected to be mainly publicly available.

Projects should build on previous, and find synergies with projects supported under this year Call such as but not only HORIZON-JU-CLEANH2-2026-01-04 ‘Innovative business models advancing renewable electrolysis integration in industry‘ and projects supported by the Process4Planet Partnership and Clean Steel Partnership as well as those projects, activities and initiatives supported by and placed under the Innovation Fund.

For additional elements applicable to all topics please refer to section 2.2.3.2

The JU estimates that an EU contribution of maximum EUR 2.50 million would allow these outcomes to be addressed appropriately.

[1] https://www.hydrogeninsight.com/electrolysers/cost-of-electrolysers-for-green-hydrogen-production-is-rising-instead-of-falling-bnef/2-1-1607220

[2] https://www.iea.org/reports/global-hydrogen-review-2024

[3] https://www.tweedekamer.nl/downloads/document?id=2024D22079

[4] https://www.clean-hydrogen.europa.eu/knowledge-management/strategy-map-and-key-performance-indicators/clean-hydrogen-ju-sria-key-performance-indicators-kpis

[5]

[6] https://cordis.europa.eu/project/id/101137925

[7] https://cordis.europa.eu/project/id/101112220

[8] https://cordis.europa.eu/project/id/101111784

[9] https://cordis.europa.eu/project/id/101111899

[10] https://cordis.europa.eu/project/id/101192352

[11] https://cordis.europa.eu/project/id/101192503