Transportation is one of the largest sources of CO₂ emissions, accounting for more than 20% of worldwide emissions. However, it is one of the areas where decarbonization presents the greatest hurdles, owing to its capillarity and the benefits that are associated with the use of fossil fuels in terms of energy density, storage, and transportation. In order to accomplish comprehensive decarbonization in the transport sector, it will be required to encourage a genuine transition to low-carbon fuels and the widespread deployment of the necessary infrastructures to allow for a large-scale innovation. Renewable hydrogen shows potential for sustainable transportation applications, whether in fuel cell electric vehicles (FCEVs), such as automobiles, trucks, and trains, or as a raw material for ship and airplane synthetic fuels. The present paper aims to present how hydrogen-fuel cell hybrid powertrains for road vehicles work in terms of conceptual layouts and operating strategies. A comprehensive overview of real and current applications is presented, concerning existing prototypes and commercially available vehicles, with a focus on the main key performance indicators, such as efficiency, mileage, and energy consumption.

Solid oxide fuel cell (SOFC) systems are spreading worldwide and, for limited applications, also in the transport sector where high power rates are required. In this context, this paper investigates the performance of a six-cell SOFC stack by means of experimental tests at different power levels. The experimental campaign is based on two different stages: the heating phase, useful for leading the system temperature to approximately 750 °C, and the test stage, in which the experimental activities are properly carried out with varying input parameters, such as the DC current load. In addition, a detailed post-processing activity is conducted to investigate the main performance that could be used in the scale-up processes to design and size a SOFC-based system for transportation. The experimental results concern the electrical power, which reaches 165 W, roughly 27 W for each cell and with 52% electrical efficiency, as well as the theoretical thermal power and efficiency, useful for cogeneration processes, with maximum values of 80 W and 25%, respectively, achieved at maximum load. This discussion then shifts to an in-depth analysis of the possible applications of SOFCs in sustainable mobility, particularly in the maritime and aviation industries. The complexities of the issues presented underscore the field’s multidisciplinary nature, ranging from materials science to system integration, and environmental science to regulatory standards. The findings presented could be useful to scientists, engineers, policymakers, and industry stakeholders working on the development and commercialization of SOFC systems in the sustainable transportation sectors.

An Intermediate Temperature Solid Oxide Fuel Cells (IT‐SOFC) system fed by not conventional fuels such as biogas can produce electric energy with high conversion efficiency and thermal energy. Inside the energy system, the methane in the biogas is mixed with steam, and then it is converted into carbon monoxide, hydrogen and carbon dioxide through steam reforming and water gas shift chemical reactions in an indirect internal reformer (IIR) mostly and in the SOFC anode minimally. The chemical energy of the electro‐oxidation of hydrogen and carbon monoxide produced is directly converted into electric energy in the fuel cell anode. A part of the anode exhaust gas can be recirculated at the IIR inlet and the percentage of this recirculated anode exhaust gas together to the fuel utilization factor influence the performances (electric and thermal powers and efficiencies, primary energy saving and first law efficiency) of the SOFC system in a cogenerative arrangement. Through the simulation model of an IT‐SOFC system fed by biogas in cogenerative arrangement, which was formulated ad hoc and implemented in a Matlab environment, the influence of the above‐mentioned variables on the IT‐SOFC system performances was evaluated. The verification of carbon formation at the anode was made.

An energy storage system based on a Proton Exchange Membrane (PEM) electrolyzer system, which could be managed by a nanoGrid for Home Applications (nGfHA), is able to convert the surplus of electric energy produced by renewable sources into hydrogen, which can be stored in pressurized tanks. The PEM electrolyzer system must be able to operate at variable feeding power for converting all the surplus of renewable electric energy into hydrogen in reasonable time. In this article, the dynamic electric simulation model of a PEM electrolyzer system with its pressurized hydrogen tanks is developed in a proper calculation environment. Through the calculation code, the stack voltage and current peaks to a supply power variation from the minimum value (about 56 W) to the maximum value (about 440 W) are controlled and zeroed to preserve the stack, the best range of the operating stack current is evaluated, and hydrogen production is monitored.

This paper describes the implementation of a hydrogen-based system for an autonomous surface vehicle in an effort to reduce environmental impact and increase driving range. In a suitable computational environment, the dynamic electrical model of the entire hybrid powertrain, consisting of a proton exchange membrane fuel cell, a hydrogen metal hydride storage system, a lithium battery, two brushless DC motors, and two control subsystems, is implemented. The developed calculation tool is used to perform the dynamic analysis of the hybrid propulsion system during four different operating journeys, investigating the performance achieved to examine the obtained performance, determine the feasibility of the work runs and highlight the critical points. During the trips, the engine shows fluctuating performance trends while the energy consumption reaches 1087 Wh for the fuel cell (corresponding to 71 g of hydrogen) and 370 Wh for the battery, consuming almost all the energy stored on board.