Hydrogen as fuel for the maritime sector could be pivotal to foster global maritime decarbonisation as it has significant advantages compared to pure battery electric propulsion. However, such maritime applications require higher power and much longer lifetimes than those developed and achieved so far by state-of-the-art FC stack/systems. In this sense, projects should still validate in relevant environment and according to real end-users needs and load profiles, high power and long-lasting FC stacks to be in the future building blocks of >10 MW FC systems for maritime applications.

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

• Improvements in design, diagnostics and monitoring procedures of FC stacks (also looking at innovative measuring / sensor devices at this purpose);
• Improvements of testing protocols for the quantification of FC stacks performance and lifetime in maritime environments, including accelerated stress tests;
• Contribute to paving the way towards increased competitiveness of EU FC manufacturing companies in the emerging global market for FC technologies in the maritime sector;
• Improvement of overall system performance of FC stacks in order to improve the availability and durability and meet the needs of naval and maritime end users.

Project results are expected to contribute to the following objectives and KPIs of the Clean Hydrogen JU SRIA for fuel cell technology for maritime sector:

• FC power rating: 3MW for 2024, 10 MW for 2030
• Maritime FCS lifetime: 40.000 h for 2024, 80.000 h for 2030
• PEMFC system CAPEX: <1,500 EUR/kW for 2024, 1,000 EUR/kW for 2030;

Following the validation of “marine ready” and reliable FC stacks (able to operate in multi-modal-modular systems) the proposed project should lay the foundations for future developments of fuel cell system for maritime applications.

Proposals should cover the development of a high-power stack for maritime applications and should address in particular either PEM or Solid Oxide technologies, which are considered the most promising technologies for maritime sector as already proven by the already funded projects MARANDA^[1], HyShip^[2], FLAGSHIPS^[3], and ShipFC.

A large FC stack for maritime applications should be developed by the end of the project according to either one of the following minimum requirements:

• A PEM stack with nominal power in the range of 250-500 kW at beginning of life and with scalability at system level to several tens of MW;

or

• A Solid Oxide (SO) stack with nominal power in the range of 100-250 kW at beginning of life and with scalability at system level to tens of MW.

Above mentioned power capacity levels should be targeted at single stack level (not at subsystem level, overcoming stacks currently validated in the projects HyShip, FLAGSHIPS, MARANDA and ShipFC) with a robust testing campaign to prove stack reliability.

Research should be undertaken based on the newly developed stacks in view of outlining a pathway for a fuel cell system of high power (multi-MW range) that can be adapted to maritime applications (building on the project outcomes and integrating stacks developed in this project), with spill overs towards stationary applications.

Each project should develop one stack technology (PEM or SO) and therefore, at least one FC stack manufacturer should be part of the consortium.

For this purpose, the stack should be developed and validated in relevant environment (at the end of the project, each stack should reach at minimum TRL 6 considering:

• The optimised design of a large active area stack design (PEMFC stack in the range 250-500kW; SOFC stack in the range 100-250 kW) able to operate in multi-modal modular stack systems towards 10 MW scale (also based on the StaSHH project guidelines^[4] defining an open standard for heavy-duty fuel-cell modules);
• At least 2,000 hours of testing of the stack, to be fully characterised in relevant environment, enabling to test modules in moisty and salty conditions and considering different air inlet temperature (to simulate different installation areas on board of vessels);
• The FC stack should be validated to provide power according to sailing profile/load request of a real vessel in a simulation approach;
• High reliability and robustness of FC cell components with high lifetime requirements (> 40,000 hours in maritime application, to be guaranteed via ex-situ and in-situ qualification of components;
• The stack should incorporate features allowing for an on-line diagnostic and prognostics with the goal of reaching a target stack life of 40,000 hours (lifetime of FC stack);
• Demonstration of 40,000 hours stack life should be performed by means of accelerated test procedure, which should also be developed as part of the project;
• The definition of manufacturing and production processes and tolerances for the upscale of the components of the large fuel cell stack;
• Multi-modular connected stack should be able to operate when subject to vibrations and to temporary (for limited duration) tilting of +/- 22.5° in all directions;
• Identification of appropriate air filter specific for marine application should be also part of the project;
• Diagnostic and prognostics of the FC Stack should be developed also targeting features that could advice in advance the best timing for air filter replacement;
• Development of innovative measuring / sensor architecture and devices for proposed diagnostics approaches and testing purposes.

Development of a full FC system is not expected at this stage, the focus should be at stack level where versatility (in terms of responsiveness to load demand of different on-board services and type of vessels) is key. Nevertheless, the proposed solutions should be conceived as multi-modular connected stacks. Development of a proper power electronics/conversion architecture to be developed hand-in-hand with proposed stack and development of single stack to be used into the connected stack system below should be integral part of the project. Therefore, the following specifications should be considered:

• Development should include a multi-modular connection for single stacks into one connected stack system with power from 1 to 5 MW;
• The multi-modular connected stack boundary should be designed in a way that the system integrator uses it as a single fuel cell stack;
• Multi-modular connected stack VI curve and more in general electrical characteristics should be compatible with the commonly used power electronic in the marine application for the 1 to 5 MW range;
• Clear plan for further progress of the technologies towards systems integrated in their powertrain applications should be outlined;
• Clear plan for future capability of the proposed SOFC Stack to operate with fuels different than pure hydrogen should be developed (e.g. ammonia, methanol, natural gas (NG), liquid organic hydrogen carriers (LOHC)… - which could serve as transition fuels for the sector in the near future) should be developed.

Looking at future development and on-board integration, the following activities should be envisaged:

• Scale up activities (targeting specific multi-stack FC systems sizes and cost functions), the setup of a roadmap to TRL9 and the development of potential studies for MW-scale integration on board (and FC stack/system design) are also required. At least one use case , supported by an industrial ship-owner/manager (expected to be part of the consortium or of the Advisory Board), should be developed during the project;
• Engagement of end-users is crucial to collect their feedback about the proposed FC technology, also at regulatory and non-technical level. In this sense, support from ZEWT partnership is of particular importance;
• The possibility to study the applicability of proposed FC stack with batteries and in hybrid systems with traditional on-board propulsion system ,e.g . SOFC gas turbine (GT) system (cycle integrating SOFC and GT) and ICE should be explored at simulation or at experimental level.

Cooperation with FC application in other maritime or similar projects is expected (such as StaSHH, HyShip, FLAGSHIPS, MARANDA, ShipFC, etc.) in order to start from their results on stack design. Proposals are expected to explore synergies with the activities of ZEWT partnership.

While designing the FC stack, applicants should apply a ‘circularity by design’ approach and assess the sustainability of the proposed solutions from a life cycle perspective (also benchmarking it with batteries and other FCs not investigated in design/demonstration). e.g. should estimate the carbon footprint expressed in gr CO2-eq/kWh_el.

Activities developing test protocols and procedures for the performance and durability assessment of electrolysers and fuel cell components proposals should foresee a collaboration mechanism with JRC (see section 2.2.4.3 "Collaboration with JRC"), in order to support EU-wide harmonisation. Test activities should adopt the already published EU harmonised testing protocols^[5] to benchmark performance and quantify progress at programme level.

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 7.50 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 2023 Annual Work Plan and in the General Annexes to the Horizon Europe Work Programme 2023–2024 which apply mutatis mutandis.

[1] https://cordis.europa.eu/project/id/735717/es

[2] https://cordis.europa.eu/project/id/101007205

[3] https://cordis.europa.eu/project/id/826215

[4] https://www.stashh.eu/.

[5] https://www.clean-hydrogen.europa.eu/knowledge-management/collaboration-jrc-0_en