Expected Outcome:

Clean hydrogen plays a pivotal role in decarbonising Europe’s energy system by enabling fossil-free energy supply in hard-to-abate sectors. In this context, safe, affordable, and scalable hydrogen storage systems are critical for ensuring energy system flexibility, grid resilience, and continuous integration of variable renewable energy (VRE) sources. Aboveground hydrogen storage solutions, such as compressed gas, are essential for decentralised hydrogen hubs requiring large feedstocks such as refuelling stations, industrial clusters, and Hydrogen Valleys. They offer a medium to long-term storage and servicing solution, high-frequency storage capabilities (in 5 to 20t H₂) near production and demand centres, particularly where underground options are not viable.

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

• Improved materials knowledge through validated data on the mechanical and chemical degradation behaviour of advanced low-cost materials (e.g., hydrogen-compatible steels, nanoparticle-reinforced aluminium alloys, metal matrix composite liners, and multi-layer coatings) for compressed gas storage.
• Development and application of mechanistic-based design and assessment methodologies that capture actual degradation mechanisms under hydrogen service (short, medium and long term i.e., 20-30 years), supporting more reliable and cost-effective storage solutions configuration and design.
• Integration of circular economy principles into compressed gas hydrogen storage through the use of recyclable and low-carbon materials, modular storage solution designs enabling complete reuse of liners and structural components, and energy-efficient manufacturing processes.
• Deliver compressed gas hydrogen storage systems that are affordable, safe, modular, deployable, easily serviceable and long term operable in decentralised hydrogen hubs to support H₂ refuelling stations, large H₂ feedstocks and industrial clusters.
• Demonstrate measurable improvements over state-of-the-art (e.g., reduced material cost, improved safety, extended fatigue life, lower hydrogen permeability)
• Contribute to harmonised EU safety and performance standards for compressed gas storage, including validated operational envelopes for medium to large tank capacities (5-20 tonnes per module).
• Incorporation of breakthrough fire safety features through novel tank designs that enable self-venting behaviour, reducing the risk of catastrophic failure, including under extreme conditions.
• Provide digital design tools and modular frameworks enabling adaptation of compressed gas storage solutions across regional, climatic, and industrial contexts in Europe, while also delivering recommendations for future design standards to ensure safety, interoperability, and harmonisation across the EU market.

Project results are expected to contribute to the following objectives of the Clean Hydrogen JU SRIA:

• Increase fatigue life by ≥30% compared to current SoA (typically <5,000 cycles at 700 bar).
• Reduction of safety design margins by ≥20% compared to SoA, while maintaining equivalent or higher safety levels.
• Increase recyclability of fully metal system, metal with liner systems, composite matrix-particulate/fibre systems from current SoA <30% to ≥70% by 2030. Reduce embodied CO₂ footprint of above-ground GH₂ storage tanks by ≥25% compared to conventional designs (baseline: ~15–18 kg CO₂/kg H₂ stored).
• Reduce CAPEX from current SoA ~600 €/kg H₂ stored to ≤450 €/kg H₂ stored by 2030.

Scope:

This topic targets the development and validation of low-cost advanced hydrogen-compatible materials and tank architectures for aboveground compressed hydrogen storage, with modular or containerised units sized 5 - 20 tonnes. Proposed solutions should demonstrate improved material resilience against hydrogen-induced degradation, ≥30% increase in fatigue life (from <5,000 cycles to ≥6,500 cycles at 700 bar), and enhanced performance across varying environmental conditions (temperature range: –40 °C to +60 °C). Materials may include high-strength steels, fibre/nanoparticle-reinforced composites, metal-matrix composites, and multi-layer coatings with low hydrogen permeability.

Projects should prioritise recycled or low-carbon footprint materials, energy-efficient processing (e.g., friction stir welding, heat treatment), and designs enabling ≥70% recyclability and ≥25% reduction in embodied CO₂ (baseline: 15–18 kg CO₂/kg H₂ stored). Validated digital design tools, fatigue/fracture models, and AI-enabled tank material design and optimisation should support predictive low-cost manufacturing, maintenance and safety optimisation of the storage system. Storage systems should target CAPEX ≤ 450 €/kg H₂ stored and exhibit long-term structural integrity under ≥6,500 pressure cycles.

Validated multi-physics simulations should account for fracture, permeability, fire safety, and delivery pressure loss, complemented by lab-scale and pilot-scale testing. Outcomes should support the Findable, Accessible, Interoperable, and Reusable (FAIR) sharing of mechanical performance data and demonstrate pathways toward scalable deployment in Hydrogen Valleys and industrial hubs. To overcome the gaps mentioned above, proposals should address the following:

• Generate new knowledge on the mechanical performance of low-cost compressed hydrogen storage solutions (e.g., high-strength steels, fibre- and nanoparticle-reinforced polymers, aluminium alloys and composites, hybrid/nano composites, multi-layer coated materials) under low-cycle fatigue and pressure variations in hydrogen environments using simulation-driven fatigue, fracture, and deformation models, validated by lab testing in hydrogen environments.
• Investigate degradation mechanisms like permeability loss, embrittlement, corrosion, and material cracking. Emphasise hydrogen purity monitoring before and after storage using full metal and composite liners in controlled environments to simulate operational hydrogen cycling without relying on full-scale demonstrators.
• Assess and optimise the structural performance of various tank types using recycled materials, tanks with liners and coatings. Perform integrity assessments (fracture, porosity, pressure) and develop standardised acceptance testing protocols covering fire safety, weld quality, permeability, and insulation.
• Ensure there are safety provisions in place to exclude tank rupture, long jet flames, flammable cloud formation in naturally ventilated confined spaces, mitigation of the pressure peaking phenomenon in any enclosed rooms.
• Novel tank architectures should incorporate fire safety provisions such as self-venting behaviour to enhance resilience during accidental exposure to fire.
• Design high-performance foundation and support structures (e.g., concrete plinths or buffer layers) to ensure even load distribution and minimise stress concentrations around hydrogen storage tanks. These structures should demonstrate excellent pumpability, self-compacting behaviour, and stability under thermal and mechanical loads.
• Projects should generate knowledge on the influence of environmental and operational conditions—such as temperature fluctuations, wind loads, seismic activity, and foundation settlement—on the durability and safety of above-ground compressed hydrogen storage systems using advanced simulations and modelling techniques.
• Develop preliminary guidelines for material and weld design in hydrogen-exposed tanks and propose a standardised design framework covering tank architecture, material integration, safety margins, and resilience to industrial or natural hazards (e.g., fire, earthquakes, extreme temperatures).
• Investigate advanced real-time monitoring technologies integrating embedded sensors, non-destructive testing, and Generative AI analytics to detect strain, leakage, and degradation—supporting predictive maintenance and future harmonisation of hydrogen storage design standards.
• Validate the design through comprehensive simulation and physical testing, using coupled mechanical, thermal, and hydrogen interaction models.
• A physical proof of concept (PoC) will be developed to assess the impact of cyclic hydrogen pressurisation on key components such as the composite inner liner, metallic shell, insulation layer, and support structures. The PoC will be informed by lab-scale testing and full-system simulations, with recommendations for scaling to commercial demonstration at all levels (5-20 tonnes).
• Evaluate how storage materials and configurations affect hydrogen purity per ISO 14687, identifying degradation mechanisms and purification needs to optimise CAPEX/OPEX and lifecycle performance.

Publicly share validated mechanical performance data following FAIR principles, embedding recyclability and circularity for sustainable, cost-effective hydrogen storage system design.

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

Activities are expected to start at TRL 3 and achieve TRL 5 by the end of the project - see General Annex B.

The JU estimates that an EU contribution of maximum EUR 4.00 million would allow these outcomes to be addressed appropriately.

Technology Readiness Level - Technology readiness level expected from completed projects