Explore the vast range of titles available.

This study explores the safety problems of hydrogen leakage and explosion in hydrogen fuel cell buses through Computational Fluid Dynamics simulations. The research investigates the diffusion behavior of hydrogen in the passenger cabin depending on the leakage position and flow rates, identifying a stratified, constant-concentration layer formed at the top of the cabin. Leakage near the rear wall of the vehicle provided the highest hydrogen concentration, while at higher flow rates, the diffusive process accelerated the spreading of flammable hydrogen concentrations. Hydrogen ignition simulations showed a fast internal pressure increase and secondary explosions outside the vehicle. Thermal hazards in the cases were higher than overpressure. The research’s additional analysis of ignition timing and source location shows that overpressure peaked initially with delayed ignition but declined afterward, while rear-ignited flames exhibited the farthest high-temperature hazard range at 10.88 m. These findings are fundamental for giving insight into hydrogen behavior in confined spaces and thus guiding risk assessment and emergency response planning for the development of safety protocols in hydrogen fuel cell buses, contributing to the safer implementation of hydrogen energy in public transportation.

Growing concerns over greenhouse gas (GHG) emissions have positioned hydrogen fuel cell buses (HFCBs) as a promising alternative for sustainable urban mobility. By eliminating tailpipe emissions and enabling significant reductions in well-to-wheel GHG intensities when hydrogen is sourced from renewables, HFCBs can contribute to improved urban air quality, energy diversification, and alignment with climate goals. Despite these benefits, large-scale adoption faces challenges related to production costs, hydrogen infrastructure, and efficiency improvements across the supply chain. Life cycle assessment (LCA) provides a valuable framework to assess these trade-offs holistically, capturing environmental, economic, and social dimensions of HFCB deployment. However, inconsistencies in system boundaries, functional units, and impact categories highlight the need for more standardized and comprehensive methodologies. This paper examines the potential of hydrogen buses by synthesizing evidence from peer-reviewed studies and identifying opportunities for integration into urban fleets. Findings suggest that when combined with robust LCA approaches, hydrogen buses offer a pathway toward decarbonized, cleaner, and more resilient public transport systems. Strategic adoption could not only enhance environmental performance but also foster innovation, infrastructure development, and long-term economic viability, positioning HFCBs as a cornerstone of sustainable urban transportation transitions.

Conventional transportation systems are facing many challenges related to reducing fuel consumption, noise, and pollutants to satisfy rising environmental and economic criteria. These requirements have prompted many researchers and manufacturers in the transportation sector to look for cleaner, more efficient, and more sustainable alternatives. Powertrains based on fuel cell systems could partially or completely replace their conventional counterparts used in all modes of transport, starting from small ones, such as scooters, to large mechanisms such as commercial airplanes. Since hydrogen fuel cells (HFCs) emit only water and heat as byproducts and have higher energy conversion efficiency in comparison with other conventional systems, it has become tempting for many scholars to explore their potential for resolving the environmental and economic concerns associated with the transportation sector. This paper thoroughly reviews the principles and applications of fuel cell systems for the main transportation schemes, including scooters, bicycles, motorcycles, cars, buses, trains, and aerial vehicles. The review showed that fuel cells would soon become the powertrain of choice for most modes of transportation. For commercial long-rage airplanes, however, employing fuel cells will be limited due to the replacement of the axillary power unit (APU) in the foreseeable future. Using fuel cells to propel such large airplanes would necessitate redesigning the airplane structure to accommodate the required hydrogen tanks, which could take a bit more time.

This paper presents a comprehensive review of scientific papers and market reports analyzing the economic competitiveness of fuel cell electric buses (FCEBs) with respect to their conventional alternatives via the total cost of ownership (TCO) methodology. We discussed the variables and data taken into account and compared the resulting outcomes by year and geographical areas. It emerged that FCBs are not currently cost competitive. The decreasing trend in acquisition and fuel costs, however, indicates potential for future competitiveness. We find that the current TCO literature on FCEBs presents several areas of uncertainty and weakness. Potential improvements can be achieved by: (i) extending the geographic coverage to Asian and African developing countries; (ii) making use of real-world data instead of simulated data, in particular, concerning acquisition costs, hydrogen costs under different pathways, fuel efficiency, and maintenance costs; (iii) clarifying the role of infrastructural costs; (iv) exploring the existence of economies of scale at fleet level; (v) distinguishing among different bus sizes.

This paper shows the results of an in-depth techno-economic analysis of the public transport sector in a small to midsize city and its surrounding area. Public battery-electric and hydrogen fuel cell buses are comparatively evaluated by means of a total cost of ownership (TCO) model building on historical data and a projection of market prices. Additionally, a structural analysis of the public transport system of a specific city is performed, assessing best fitting bus lines for the use of electric or hydrogen busses, which is supported by a brief acceptance evaluation of the local citizens. The TCO results for electric buses show a strong cost decrease until the year 2030, reaching 23.5% lower TCOs compared to the conventional diesel bus. The optimal electric bus charging system will be the opportunity (pantograph) charging infrastructure. However, the opportunity charging method is applicable under the assumption that several buses share the same station and there is a “hotspot” where as many as possible bus lines converge. In the case of electric buses for the year 2020, the parameter which influenced the most on the TCO was the battery cost, opposite to the year 2030 in where the bus body cost and fuel cost parameters are the ones that dominate the TCO, due to the learning rate of the batteries. For H2 buses, finding a hotspot is not crucial because they have a similar range to the diesel ones as well as a similar refueling time. H2 buses until 2030 still have 15.4% higher TCO than the diesel bus system. Considering the benefits of a hypothetical scaling-up effect of hydrogen infrastructures in the region, the hydrogen cost could drop to 5 €/kg. In this case, the overall TCO of the hydrogen solution would drop to a slightly lower TCO than the diesel solution in 2030. Therefore, hydrogen buses can be competitive in small to midsize cities, even with limited routes. For hydrogen buses, the bus body and fuel cost make up a large part of the TCO. Reducing the fuel cost will be an important aspect to reduce the total TCO of the hydrogen bus.

The heavy reliance on petroleum-based fuels in the road transport industry, especially public transportation, results in substantial emissions of greenhouse gases. A significant obstacle on the path to a more sustainable public transportation sector is the employment of alternative fuels with lower environmental implications. Although there are several in-depth well-to-wheel studies for developed countries, extrapolating those results to gasoline markets in developing countries presents challenges because of significant differences in local fuel conditions and vehicle engine technologies. Notably, this study provides a national-level environmental life cycle assessment of alternative buses in Morocco and compares current diesel buses to potential hybrid diesel-electric buses, battery-electric buses, and fuel-cell buses from a well-to-wheel perspective. The model and approach used in this study applies to other countries with developing economies. Total energy consumption broken out by fuel type, greenhouse gas emissions, and criterion air pollutants is the primary outcome of this investigation. Findings highlight an energy cut of 44.7% from battery-electric buses, 36.3% from fuel-cell buses, and 31.7% from hybrid buses with regard to the current diesel buses. Additionally, alternative fuel buses proved to be less polluting in terms of greenhouse gas emissions with 50.8% less from battery-electric buses, 46.7% less from fuel-cell buses, and 26.8% less from hybrid buses; consequently, this would lead to reduced climate change, air pollution, acidification, and eutrophication, given the Egalitarian Environmental Impact Assessment. Ultimately, Morocco will have to tackle technological, financial, and institutional barriers to fully implement the change by 2030.

This comprehensive review explores recent developments in Proton Exchange Membrane Fuel Cells (PEMFCs) and evaluates their alignment with the ambitious targets established by the U.S. Department of Energy (DOE). Notable advancements have been made in developing catalysts, membrane technology advancements, gas diffusion layers (GDLs), and enhancements in bipolar plates. Notable findings include using carbon nanotubes and graphene oxide in membranes, leading to substantial performance enhancements. Innovative coatings and materials for bipolar plates have demonstrated improved corrosion resistance and reduced interfacial contact resistance, approaching DOE targets. Nevertheless, the persistent trade-off between durability and cost remains a formidable challenge. Extending fuel cell lifetimes to DOE standards often necessitates higher catalyst loadings, conflicting with cost reduction objectives. Despite substantial advancements, the ultimate DOE goals of USD 30/kW for fuel cell electric vehicles (FCEVs) and USD 600,000 for fuel cell electric buses (FCEBs) remain elusive. This review underscores the necessity for continuous research and innovation, emphasizing the importance of collaborative efforts among academia, industry, and government agencies to overcome the remaining technical barriers.

During the project High V.LO-City, which ended in December 2019, 14 hydrogen fuel cell buses were operated in four European cities. This paper aims at presenting total emissions through the lifetime of fuel cell buses with different hydrogen production options, including the refuelling stations. The environmental assessment of such bus system is carried out using the life cycle assessment methodology. Three hydrogen production pathways are investigated: water electrolysis, chlor-alkali electrolysis and steam methane reforming. Fuel economy during bus operation is around 10.25 KgH 2 /100 km, and the refuelling station energy demand ranges between 7 and 9 KWh/KgH 2 . To support the inventory stage, dedicated software tools were developed for collecting and processing a huge amount of bus data and refuelling station performance, for automating data entry and for impacts calculation. The results show that hydrogen-powered buses, compared to a diesel bus, have the potential to reduce emissions during the use phase, if renewables resources are used. On the other hand, impacts from the vehicle production, including battery pack and fuel cell stack, still dominate environmental load. Consequently, improving the emission profile of fuel cell bus system requires to promote clean electricity sources to supply a low-carbon hydrogen and to sharpen policy focus regarding life cycle management and to counter potential setbacks, in particular those related to problem shifting and to grid improvement. For hazardous emissions and resource use, the high energy intensity of mining and refining activities still poses challenges on how to further enhance the environmental advantages of fuel cells and battery packs. Article Highlights This paper aims at presenting a comprehensive LCA case study that uses real-world operations data to investigate the environmental impacts of the High V.LO-City hydrogen fuel cell bus system (i.e. H2FC bus, integrating hydrogen production and delivery options and refuelling stations operation) against a conventional Euro-6 Diesel bus. The High V.LO-City project consisted of the integrated testing of new generation hydrogen buses and their hydrogen production and refuelling infrastructure in some European cities. It differs from other demonstration projects because it intends to evaluate both the operation of the vehicles and the production and supply of hydrogen to use them as substitutes for conventional diesel buses and trolleybuses. Fuel economy during bus operation is around 10.25 KgH 2 /100 km, and the refuelling station energy demand ranges between 7 and 9 KWh/KgH 2 . The results clearly indicate that it is advantageous to promote such mode of transportation in areas where electricity is primarily produced from renewables (i.e. wind power as an alternative to fossil fuels). However, potential setbacks, in particular those related to problem shifting and to grid improvement, should be addressed accordingly.

This paper discusses fuel cell electric vehicles and, more specifically, the challenges and development of hydrogen-fueled buses for people accessing this transportation in cities and urban environments. The study reveals the main innovations and challenges in the field of hydrogen bus deployment, and identifies the most common approaches and errors in this area by extracting and critically appraising data from sources important to the energy perspective. Three aspects of the development and horizons of fuel cell electric buses are reviewed, namely energy consumption, energy efficiency, and energy production. The first is associated with the need to ensure a useful and sustainable climate-neutral public transport. Herewith, the properties of the hydrogen supply of electric buses and their benefits over gasoline, gas, and battery vehicles are discussed. The efficiency issue is related to the ratio of consumed and produced fuel in view of energy losses. Four types of engines–gasoline, diesel, gas, and electrical–are evaluated in terms of well-to-wheel, tank-to-wheel, delivery, and storage losses. The third problem arises from the production, operating, and disposal constraints of the society at the present juncture. Several future-oriented initiatives of the European Commission, separate countries, and companies are described. The study shows that the effectiveness of the FCEBs depends strongly on the energy generation used to produce hydrogen. In the countries where the renewables are the main energy sources, the FCEBs are effective. In other regions they are not effective enough yet, although the future horizons are quite broad.

In the transition to sustainable public transportation with zero-emission buses, hydrogen fuel cell electric buses have emerged as a promising alternative to traditional diesel buses. However, assessing their economic viability is crucial for widespread adoption. This study carries out a comprehensive examination, encompassing both sensitivity and probabilistic analyses, to assess the total cost of ownership (TCO) for the bus fleet and its corresponding infrastructure. It considers various hydrogen supply options, encompassing on-site electrolysis, on-site steam methane reforming, and off-site hydrogen procurement with both gaseous and liquid delivery methods. The analysis covers critical cost elements, encompassing bus acquisition costs, infrastructure capital expenses, and operational and maintenance costs for both buses and infrastructure. This paper conducted two distinct case studies: one involving a current small bus fleet of five buses and another focusing on a larger fleet set to launch in 2028. For the current small fleet, the off-site gray hydrogen purchase with a gaseous delivery option is the most cost-effective among hydrogen alternatives, but it still incurs a 26.97% higher TCO compared to diesel buses. However, in the case of the expanded 2028 fleet, the steam methane-reforming method without carbon capture emerges as the most likely option to attain the lowest TCO, with a high probability of 99.5%. Additionally, carbon emission costs were incorporated in response to the growing emphasis on environmental sustainability. The findings indicate that although diesel buses currently represent the most economical option in terms of TCO for the existing small fleet, steam methane reforming with carbon capture presents a 69.2% likelihood of being the most cost-effective solution, suggesting it is a strong candidate for cost efficiency for the expanded 2028 fleet. Notably, substantial investments are required to increase renewable energy integration in the power grid and to enhance electrolyzer efficiency. These improvements are essential to make the electrolyzer a more competitive alternative to steam methane reforming. Overall, the findings in this paper underscore the substantial impact of the hydrogen supply chain and carbon emission costs on the TCO of zero-emission buses.