Hydrogen produced via water electrolysis powered by renewable electricity or green H2 offers new decarbonization pathways. Proton exchange membrane water electrolysis (PEMWE) is a promising technology although the current density, temperature, and H2 pressure of the PEMWE will have to be increased substantially to curtail the cost of green H2. Here, a porous transport layer for PEMWE is reported, that enables operation at up to 6 A cm−2, 90 °C, and 90 bar H2 output pressure. It consists of a Ti porous sintered layer (PSL) on a low‐cost Ti mesh (PSL/mesh‐PTL) by diffusion bonding. This novel approach does not require a flow field in the bipolar plate. When using the mesh‐PTL without PSL, the cell potential increases significantly due to mass transport losses reaching ca. 2.5 V at 2 A cm−2 and 90 °C. On the other hand, the PEMWE with the PSL/mesh‐PTL has the same cell potential but at 6 A cm−2, thus increasing substantially the operation range of the electrolyzer. Extensive physical characterization and pore network simulation demonstrate that the PSL/mesh‐PTL leads to efficient gas/water management in the PEMWE. Finally, the PSL/mesh‐PTL is validated in an industrial size PEMWE in a container operating at 90 bar H2 output pressure.

PEM Electrolysis In article number 2100630, Aldo Sau Gago and co‐workers develop novel porous transport layers for proton exchange membrane water electrolyzers, allowing operation under extreme conditions of current density, temperature, and pressure. By optimizing the water/gas transport properties of this component, a flow field in the bipolar plate becomes unnecessary. Thus, high production rates of hydrogen can be achieved efficiently, making it more economically attractive.

This paper presents an investigation of a storage option of green hydrogen (H 2 ) in the form of ammonia (NH 3 ) based on system simulations considering detailed technical properties. Experimental data from a 1 MW PEM electrolyzer is used to develop an electrolyzer model and downstream a kinetic reactor for NH 3 synthesis. Exemplarily, the electricity is supposed to be supplied by a hydropower plant in Norway. An economical evaluation of the plant is performed for optimized process parameters. The costs of H 2 and NH 3 are calculated based on electrolyzer investment costs published for deployment between 2020 and 2030 and several electricity cost scenarios. From the results, a broad economic optimum of the operating range of the electrolyzer in the entire plant is obtained. This work provides a basis for the future evaluation of complex plants with electrolyzers for the production of green ammonia as well as strategies for the reduction of costs of green NH 3 in the future.

In this work a methanol steam reforming (MSR) reactor has been operated thermally coupled to a high temperature polymer electrolyte fuel cell stack (HT-PEMFC) utilizing its waste heat. The operating temperature of the coupled system was 180 °C which is significantly lower than the conventional operating temperature of the MSR process which is around 250 °C. A newly designed heat exchanger reformer has been developed by VTT (Technical Research Center of Finland LTD) and was equipped with commercially available CuO/ZnO/Al 2 O 3 (BASF RP-60) catalyst. The liquid cooled, 165 cm², 12-cell stack used for the measurements was supplied by Serenergy A/S. The off-heat from the electrochemical fuel cell reaction was transferred to the reforming reactor using triethylene glycol (TEG) as heat transfer fluid. The system was operated up to 0.4 A cm-2 generating an electrical power output of 427 W el. A total stack waste heat utilization of 86.4 % was achieved. It has been shown that it is possible to transfer sufficient heat from the fuel cell stack to the liquid circuit in order to provide the needed amount for vaporizing and reforming of the methanol-water-mixture. Furthermore a set of recommendations is given for future system design considerations.

Fuel cell systems provide a zero-emission and low noise solution for on-board power generation in aircraft. To assure safe and reliable fuel cell operation in aircraft, system testing has to be conducted under realistic operating conditions. On the one hand these conditions can hardly be simulated in laboratory; on the other hand evaluation of the systems with a wide-body aircraft like an Airbus A320 is inflexible, time and cost consuming. Therefore the aerodyne Antares DLR-H2 has been developed as a flying test bed to provide a system carrier for time and cost effective airborne fuel cell system testing.In this presentation the test platform Antares DLR-H2 will be described with the new fuel cell system generation and latest results, comprising laboratory measurements (fuel consumption, power output) and insights on the system design, especially focusing on the concept of direct hybridization, allowing a simple and therefore reliable possibility of coupling fuel cells and batteries.