The storage of hydrogen onboard maritime vessels represents a big challenge for the decarbonisation of the long-haul transport sector since the discussion around the best suited alternatives to replace fossil fuels is still undecided. It is not even sure that a single fuel will replace oil derivatives since different applications show different critical issues with logistics, storage volume and overall efficiency of the supply chain, thus making the decision on fuel choice a complex one for end users operating both at local and global levels.

It is difficult to categorise heavy duty maritime transport modes, ranging for instance from point-to-point routes travelled by sea ferries up to long distance maritime logistics which induces quite different requirements for fuel storage volume, distribution logistics, and bunkering/refuelling networks.

Bunkering and refuelling strategies affect the selection of fuels and the type of on-board storage. Novel solutions to onboard storage need to be studied without limitations concerning the type of fuels or its physical state. Issues to also address are the safety characteristics, including fire and explosion hazard, measures to cope with toxicity, as well as environmental impact and supply chain energy efficiency.

This topic centres around maritime transport, with a view on a spill-over to rail and road applications of similar energy storage needs (resulting from power by trajectory length). The candidate technology and fuel(s) for supplying pure hydrogen (5.0 fuel cell grade) on board of maritime vessels are expected to contribute to all of the following expected outcomes:

• Contribute to the selection of most appropriate fuels for maritime transport across the widely differing operation requirements from short to deep sea shipping, thereby consolidating Europe's leading role in decarbonising maritime transport;
• Ease the end-users' challenge of selecting the most suitable fuel for their new and retrofitted ships so that they can take well-informed decisions in the green energy (and fuel) transition.
• Define optimal fields of application of the proposed storage technology considering the logistics and the mission of each category of maritime transport by the end of the project; additionally, the pathways to spill-over to heavy-duty rail and road transport systems should be elaborated;
• Improve the operational capacity of storage systems to achieve performance according to the KPIs listed below;
• Deployment of cost-effective hydrogen or hydrogen carrier fuel storage system for maritime, and if applicable, also other heavy-duty applications by 2030.

Project results are expected to contribute to the following objectives and KPIs of the Clean Hydrogen JU SRIA (on a basis of the amount of hydrogen delivered to the energy conversion technology):

• Hydrogen bunkering rate: 20 tonH2/h in 2030;
• Tank volumetric Capacity system: 45 gH2/L (system) in 2030;
• Tank CAPEX lower than 245 €/kgH2 in 2030.

The scope of the topic is to provide a full conceptual study of the proposed solution to storing hydrogen or a hydrogen carrier below deck of a vessel with high power propulsion needs (>500 kW) and high frequency operation. The scope further entails building a reference prototype for validating the concept, or several concepts in comparison, under real-world operating conditions.

Proposals should propose a storage technology which will be able to go beyond the state of art for on-board hydrogen storage with respect to the amount of energy stored, the space occupied per MWh of stored chemical energy, and the reduced shipping space (passengers/vehicles/containers), moving closer to current fuels properties and bunkering rates.

Proposals are expected to focus on below-deck innovative inland and sea waterborne transport hydrogen storage systems beyond the State-of-the-Art in any of the well-established physical states and chemical compositions (CH2, LH2, NH3, LOHC, solid state carriers) as well as potential novel hydrogen carriers or combinations of technologies with the following characteristics:

• Supply of pure hydrogen (5 point) to the propulsion system;
• Vessel propulsion and auxiliary power systems requiring a hydrogen supply flow of minimum 30 kgH2/h with a modular approach capable of achieving MW scale capacities;
• Bunkering/refuelling expected during adequate and suitable timeslots within daily operation or at the beginning or end of daily service;
• Below-deck, integrated onboard tanks to be filled directly (excluding exchangeable mobile tank systems (i.e., tank swapping)). The whole bunkering system needs to be addressed which means that the system boundary is on one side the feeding pipe for refuelling and on the other one the pure hydrogen output to the conversion unit. Thus, everything in between is part of the system to be designed and trialled (i.e., LOHC+ and LOHC- tanks).

A complete fuel infrastructure should be described, including solutions to refuelling logistics, but not including the supply of hydrogen itself, nor taking into account whether the hydrogen supplied is used in fuel cells of different types, internal combustion engines, or gas turbines.

Proposals should also:

• Provide a realistic design study for storage tank integration into a marine or inland waterway vessel;
• Provide the design of a potential hydrogen supply chain for at least one real operational case of fossil fuel replacement, such as one or more daily ferry routes (mainland to islands or mainland to mainland), or one point to point transport line, or one multi point ferry or transport route (serviced daily or weekly);
• Provide cost estimates of the levelised cost of fuel supply, including cost of fuel storage;
• Provide cost estimates of the fuel infrastructure and storage CAPEX, and the operations OPEX (excluding the cost of hydrogen purchase);
• Provide an energy balance and LCA of the total fuel system (excluding hydrogen production), including potential uses of hydrogen in different propulsion systems;
• Address any safety measures and mitigation strategies;
• Provide an Approval in Principle by a certification body;
• Describe the scale-up to larger marine vessels, as well as the spill-over to road, off-road and rail applications (including scale-down, if applicable).

Energy performance results and/or LCA of the full supply chain well to tank and tank to motion should be clearly presented and include all aspects from fuel storage at the refuelling system, fuel distribution, to refuelling.

The mechanical design should be compatible with all requirements typical of the vessel/vehicle industry in terms of durability, exposure to harsh environments, vibrations, accelerations, safety, and exceptional loads e.g., fire. The validation of concepts shall occur through an experimental programme backed up by simulation activities, that will allow to validate the concept under a wider range of constraints.

Proposals should elaborate on potential technology spillovers to other heavy duty means of transportation (road, trains, special vehicles, etc.), through scaling and/or adapting the proposed solutions or using parts (modules) of the larger system.

Projects should provide supporting evidence concerning:

• Measures to deal with fuel spills and safety (fire, explosion, toxicity);
• Energy efficiency and fossil carbon footprint from total fuel supply concept (well to hydrogen supply) based on the chosen hydrogen carrier and on-board storage solution;
• The HAZID analysis as input to an Approval in Principle.

The following activities are out of scope for this topic:

• Technology and design developments concerning tank swap and mobile tank concepts;
• compression and liquefaction technologies;
• technologies which produce the hydrogen, such as electrolysers or ammonia synthesis;
• technologies that use the hydrogen, such as fuel cells, gas turbines, or internal combustion engines;
• technologies only aimed at terrestrial heavy-duty utilisation.

Proposals are encouraged to explore synergies with the activities and projects supported under the Zero Emission Waterborne Transport (ZEWT) Partnership, in view of the provision of storage solutions for hydrogen fuelled vessels.

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

Activities are expected to start at TRL 4 and achieve TRL 6 by the end of the project - see General Annex B.

The JU estimates that an EU contribution of maximum EUR 5.00 million would allow these outcomes to be addressed appropriately.

The conditions related to this topic are provided in the chapter 2.2.3.2 of the Clean Hydrogen JU 2024 Annual Work Plan and in the General Annexes to the Horizon Europe Work Programme 2023–2024 which apply mutatis mutandis.