The following components and sub-system are of high relevance:

• Air humidifiers are considered a component that contributes to improving the gravimetric power index, if the component becomes more integrated and more light weight.
• Anode gas recirculation components enable high utilisation of hydrogen and are therefore to be developed and optimised for the aforementioned requirements. The possibilities of fuel cell reconditioning measures are to be considered.
• To reliably operate fuel cell drivetrains gas sensors need to measure mass flow, humidity, temperature, pressure and gas compositions accurately. These sensors need to be operational under changing environmental conditions and need to be robust against gas impurities and water phase.

Increasing the fuel cell system gravimetric power index above 2.5 kW/kg requires the development of light weight and compact BoP components as well as novel and innovative system architectures. In particular, proposals should address the following:

• Re-design of BoP component(s) and enhanced system architectures for a minimum of 250 kW PEM fuel cell platform compatible with reaching the multi-MW scale and with end-user requirements (system power output, voltage level, weight, volume …);
• Investigations to simplify architectures by e.g., removing components such as gas sensors, the anode gas recirculation machine, water separators, the humidifier bypass and/or the humidifier itself;
• Analyses of the trade-offs between system efficiency, operational bandwidth and system complexity for waste heat recovery from fuel cell system components e.g., stack(s), power electronics and motors;
• Design and validation of the electric power supply architecture for BoP components used for heavy duty fuel cell systems containing one single fuel cell stack or multiples of stacks;
• Design and validation of the thermal integration of the waste heat management of the BoP components into the overall thermal system of the heavy-duty fuel cell system;
• Evaluation of auxiliary functions performed by the up-scaled BoP components e.g., for cold start and fuel cell stack reconditioning operations;
• Assessments to ensure a scalable, modular and multi modal product family that allows the usage in a wide range of HD applications (aviation, maritime, rail and road transport);
• Development, testing and validation of selected, up-scaled BoP components (PEMFC stack may be emulated);
• Implementation and testing of control strategies to validate the improved system performance, efficiency and reliability.

Original equipment manufacturers (OEMs), end users and research institutes should indicate how product relevant R&D activities lead to improved components and achieve the required system level functionality.