Fuel Cell Electric Buses Research Articles

Design of Two Fuel Cell Buses for Public Transport According to Two Different Operating Scenarios: Urban and Motorway

<div>The transport sector is one of the major parties responsible for carbon dioxide (CO<sub>2</sub>) and pollutants emissions in Europe. For this reason, one of the main commitments of the European Commission is its decarbonization by 2035/2040. To achieve this target, during the last decades, different propulsion technologies were developed such as hybrid electric vehicles (HEVs), plug-in electric vehicles (PHEVs), and battery electric vehicles (BEV). The first two proposals can be considered as bridging technology between the internal combustion engine (ICE) and the BEV because they offer at the same time comparable performance as conventional powertrains and improved efficiency. However, both technologies are struggling with the tightening of pollutants and CO<sub>2</sub> limits. On the other hand, the BEV can offer zero emissions at the tailpipe, but it suffers from limited range capabilities and the lack of fast-charging infrastructures. Within this context, the fuel cell vehicle (FCV) appears as an interesting opportunity because it offers zero tailpipe emissions and equivalent refuelling time of the ICE. This article evaluates through mathematical simulations the performance of two fuel cell electric buses (FCEBs), which are supposed to work respectively in urban and highway driving conditions. The urban bus is equipped with a single fuel cell (FC) module of 85 kW-Net and an electric motor (EM) of 225 kW. The intercity bus is equipped with two FC modules with a total power of 170 kW-Net and two EMs of 225 kW each. A sensitivity to the battery capacity from 20 kWh to 40 kWh was performed for both FECBs. The power split between the FC module and the high-voltage battery was optimized with the Equivalent Consumption Minimization Strategy (ECMS). The two FCEBs were tested considering different portfolios of cycles: in the case of the urban bus in Braunschweig and the Standardized On-Road Test Cycles SORT1 and SORT2 were assumed as a reference, while cycles like the Highway Fuel Economy Test (HWFET), European Transient Cycle (ETC), and cruising at 100 km/h were assumed as reference for the intercity. Simulation results highlighted that the increase of battery capacity in the case of the urban bus from 20 kWh to 30 kWh reduces hydrogen (H<sub>2</sub>) consumption by 11% along the Braunschweig cycle. On the other hand, in the case of the intercity bus, the fuel consumption is less affected by the increase of capacity in the same range. In this case a reduction of 4.7% is estimated for the HWFET cycle, and it is less than 1% in the case of cruising conditions.</div>

Different strategies in an integrated thermal management system of a fuel cell electric bus under real driving cycles in winter

Due to the climate crisis and the restriction measures taken in the last decade, electric buses are gaining popularity in the transport sector. However, one of the most significant disadvantages of this type of vehicle is its low autonomy. Many electric buses with proton-exchange membrane fuel cells (PEMFC) systems have been developed to solve this problem in recent years. These have an advantage over battery-electric buses because the autonomy depends on the capacity of the hydrogen tanks. As with batteries, thermal management is crucial for fuel cells to achieve good performance and prolong service life. For this reason, it is necessary to investigate different strategies or configurations of a fuel cell electric bus's integral thermal management system (ITMS). In the present work, a novel global model of a fuel cell electric bus (FCEB) has been developed, which includes the thermal models of the essential components. This model was used to evaluate different strategies in the FCEB integrated thermal management system, simulating driving cycles of the public transport system of Valencia, Spain, under winter weather conditions. The first strategy was to use the heat generated by the fuel cell to heat the vehicle's cabin, achieving savings of up to 7%. The second strategy was to use the waste heat from the fuel cells to preheat the batteries. It was found that under conditions where a high-power demand is placed on the fuel cell, it is advisable to use the residual heat to preheat the battery, resulting in an energy saving of 4%. Finally, a hybrid solution was proposed in which the residual heat from fuel cells is used to heat both the cabin and the battery, resulting in an energy saving of 10%.

Evaluation of Different Scenarios to Switch the Whole Regional Bus Fleet of an Italian Alpine Region to Zero-Emission Buses

Public bus decarbonization is increasingly important to address the global issue of climate change. There are several challenges associated with large-scale introduction of zero-emission technologies in public fleets. This is especially the case in an extra-urban context, of mountain regions with challenging weather conditions. In this work the analysis of the state-of-the-art ZEBs, local bus lines, and timetables was performed to understand the best fit of technology—battery electric buses (BEBs) or fuel cell electric buses (FCEBs)—for each line in such a region. Further, a simulation tool was developed to calculate the compatibility of zero-emission technologies with the current needs of the public transportation considering distance, altitude difference, and climate conditions. The results show that a complete switch of the fleet is possible with a slight increase in the number of buses and that there is no clear difference in the distance covered in mountainous areas by BEBs versus FCEBs, but that both technologies can cover similar distances. The tool developed is not limited to bus fleets but can be applied to all kinds of fleets that cover clearly defined daily routes.

Pathways to the hydrogen mobility futures in German public transportation: A scenario analysis

The present study elaborates on the perspectives of fuel cell electric buses in German public transportation from a purely economic point of view and formulates recommendations for policies in public transportation in Germany. To this end, the study proposes nine valid scenarios and embeds diesel and fuel-cell bus operations into them. The total cost of ownership-based scenario analysis shows that beginning from 2035 fuel cell electric buses will be economically more attractive than diesel buses. The study identifies carbon pricing and subsidization of solar and wind power generation as the central drivers of fuel cell-based public transportation.

Nonlinear Model Predictive Control Based Adaptive Equivalent Consumption Minimization Strategy for Fuel Cell Electric Bus Considering Average Travel Speed

Nonlinear Model Predictive Control Based Adaptive Equivalent Consumption Minimization Strategy for Fuel Cell Electric Bus Considering Average Travel Speed

A life cycle impact analysis of various hydrogen production methods for public transportation sector

Reducing greenhouse gas emissions is an important task to reduce the adverse effects of climate change. A large portion of greenhouse gas emissions apparently originates from the transportation sector. Therefore, adopting cleaner technologies with lower emission footprints has become vital. For this reason, in this study, a life cycle impact analysis of hydrogen production technologies as an alternative to fossil fuels and the utilization of hydrogen in fuel cell electric buses is carried out. According to the results of this study, the operational contributions of internal combustion engines have a significant impact on life cycle impact analysis indicators. The global warming potentials of clean hydrogen production technologies result in much lower results compared to conventional hydrogen production technologies. Also, almost all indicators for biohydrogen production technologiess yield lower results because of the wastewater removal. The global warming potential results of hydrogen production methods are found to be 6.8, 1.9, 2.1, 0.5, 0.2, and 7.9 kg CO2 eq./kg H2 for PV electrolysis, wind electrolysis, high temperature electrolysis, dark fermentation, photo fermentation and conventional hydrogen production, respectively. However, the chemicals used in PV and wind turbine production increased the ecotoxicological indicators. On the other hand, hydrogen utilization in buses is a better option environmentally. The global warming potentials for PV electrolysis, wind electrolysis, high temperature electrolysis, dark fermentation, photo fermentation, conventional hydrogen, compressed natural gas bus, and diesel bus are found to be 0.060, 0.016, 0.018, 0.007, 0.006, 0.053, 0.082, and 0.125 kg CO2 eq./p.km, respectively. The results are especially important in terms of reducing the effects at the source and optimizing the systems.

Review of Energy Challenges and Horizons of Hydrogen City Buses

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.

Taguchi robust design for adaptive energy management of plug-in fuel cell electric bus

This paper presents an adaptive energy management strategy (EMS) based on Pontryagin's Minimum Principle (PMP), considering both historical driving cycles and stochastic vehicle mass. First, an improved battery state of charge (SOC) feedback control method based on Proportion-Integration (PI) controller is proposed for adaptive energy management. Second, a Taguchi robust design (TRD) method is proposed by considering the noises of historical driving cycles and stochastic vehicle mass. The main purpose of the TRD is to find the robust parameters (P and I) that can counter to the above noise disturbance, thereby neglecting the influence of noise disturbance in adaptive energy management control and minimizing the mean hydrogen consumption. The results show that the TRD is reasonable and applicable in the robust design of plug-in fuel cell electric buses (PFCEBs); the fuel economy of the proposed strategy can be averagely improved by 18.36%, compared to the rule-based energy management strategy.

Life cycle assessment of waste-to-hydrogen systems for fuel cell electric buses in Glasgow, Scotland

Waste-to-hydrogen (WtH) technologies are proposed as a dual-purpose method for simultaneous non-fossil-fuel based hydrogen production and sustainable waste management. This work applied the life cycle assessment approach to evaluate the carbon saving potential of two main WtH technologies (gasification and fermentation) in comparison to the conventional hydrogen production method of steam methane reforming (SMR) powering fuel cell electric buses in Glasgow. It was shown that WtH technologies could reduce CO2-eq emissions per kg H2 by 50–69% as compared to SMR. Gasification treating municipal solid waste and waste wood had global warming potentials of 4.99 and 4.11 kg CO2-eq/kg H2 respectively, which were lower than dark fermentation treating wet waste at 6.6 kg CO2-eq/kg H2 and combined dark and photo fermentation at 6.4 kg CO2-eq/kg H2. The distance emissions of WtH-based fuel cell electric bus scenarios were 0.33–0.44 kg CO2-eq/km as compared to 0.89 kg CO2-eq/km for the SMR-based scenario.

Development and analysis of new pneumatic based powering options for transit buses: A comparative assessment

Carbon dioxide reduction has been the central focus of current climate change public policy and largely determines procurement of next generation ‘clean’ transit buses. Development of alternative nature-friendly systems for clean transportation is critical in the transition of the sector from conventional fossil fuel-based powertrains. The current study undertakes the design and analysis of a newly-developed hybrid pneumatic powertrain concept for fourty-foot public transit buses using liquid nitrogen and compressed natural gas as a secondary fuel. Various fuel types for system hybridization are investigated comparatively in terms of fuel economy and well-to-wheel carbon dioxide emission ratios. A pure pneumatic configuration is also considered as a base case and discussed accordingly. The performance of the proposed system is evaluated through parametric studies by considering primary design and operational parameters. In similar operational conditions, the performance of a conventional diesel bus, a plug-in hybrid electric bus, a battery-electric bus and a hydrogen fuel cell electric bus is considered in the further comparative assessment of the proposed system. From a well-to-wheel point of view, the emission ratio of the developed hybrid pneumatic system is evaluated at 0.1452 kg carbon dioxide equivalent per kilometer of city driving, which corresponds to a 95% emission reduction compared to conventional diesel buses. The present study results indicate that a hybrid pneumatic configuration carries significant potential for a green transition in the public transit sector. Furthermore, eliminating the need for charging infrastructure, grid upgrading and additional infrastructure capacity, the system can be assembled with readily available off-the-shelf components.

An assessment study on various clean hydrogen production methods

In this study, an assessment study using the life cycle impact analysis of renewable and nuclear-based hydrogen production methods is conducted for possible implementation of hydrogen energy projects. The processes starting from the energy production, energy required for the hydrogen production, hydrogen transportation, and utilizing hydrogen at the refueling station are evaluated. The three methods, namely alkaline electrolysis, proton exchange membrane electrolysis, and the Cu–Cl cycle are selected as clean hydrogen production methods. Also, the potential environmental effects of using hydrogen to utilize fuel cell electric buses are investigated by comparing them with diesel buses. Accordingly, the Cu–Cl cycle itself provides the most environmentally friendly result with 0.86 kg CO2 eq./kg H2 when both energy and heat are considered as primary commodities from renewable energy sources. However, the electrolysis methods also provide better results than conventional hydrogen production. By comparison, conventional hydrogen production resulted in 7.95 kg CO2 eq./kg H2. The emissions of FCEBs utilizing the hydrogen from clean energy sources vary between 0.016 and 0.025 kg CO2 eq./p⋅km. However, even though upstream emissions are low in diesel buses, they have a GWP value of approximately 0.09 kg CO2 eq./p⋅km during operation.

Comparative assessment of zero emission electric and hydrogen buses in Australia

The pace of direct electrification vs indirect electrification for public transit bus fleets is accelerating internationally. Clear targets have been established by transport policymakers to achieve a zero-emission bus target as early as 2030 in some jurisdictions. Two prominent choices are battery-driven electric buses and fuel-cell electric buses. We draw on evidence on these current and future developments to provide an assessment of the two types of technology on emission reduction, capital, maintenance and energy costs, and other aspects. We apply a decision support system to compare a number of scenarios for different electrification plans of bus fleets using Australian data. Comparing scenarios such as slow versus fast take up and different mixtures of energy technologies in future zero emission fleets provides evidence on the reductions in carbon dioxide emissions and costs in converting a diesel bus fleet to a fully green, at tailpipe, fleet.

Energy Management Control of Fuel Cell Electric Bus Basing on Fuzzy Rule

A hybrid fuel cell bus was taken as the research object. Firstly, the structure and characteristics of fuel cell bus power system were introduced, and the power system parameter design was completed according to the vehicle parameters and performance design goals; Secondly, in order to improve the durability of fuel cell and the economy of power system, a three input single output fuzzy energy management control strategy was designed, with the fuel cell power increment selected as the control variable to coordinate control fuel cell power output and change; Finally, the effectiveness of the fuzzy control strategy was verified basing on MATLAB/Simulink platform, the results showed that the fuzzy control strategy can control the SOC of battery reasonably and effectively, while is better than the power-following energy management strategy in terms of power system economy and fuel cell durability.

Development of Oshawa hydrogen hub in Canada: A case study

Consumption of fossil fuels, which makes an immense contribution to greenhouse gas emissions, must be reduced. Hydrogen emerges as a unique solution to serve as fuel, energy carrier and feedstock because it is a clean, abundant, environmentally friendly and energy intensive gas. This study aims to investigate the development of a potential hydrogen hub located in Oshawa, Canada, which is aimed to provide a hydrogen infrastructure for future hydrogen economy. Numerous life cycle assessment and cost assessment studies are conducted to investigate what benefits such a hydrogen will bring to the city. The results show that fuel cell electric buses emit 89% fewer pollutants. Also, 60% of overall CO2 reduction is possible with a gradual transition to fuel cell technology within 20 years. However, in order for hydrogen infrastructure and costs to compete with fossil fuels, high-scale projects need to be developed with governmental incentives.

Polymer electrolyte membrane fuel cell and hydrogen station networks for automobiles: Status, technology, and perspectives

The U.S. transportation sector accounts for 37% of total energy consumption. Automobiles are a primary application of polymer electrolyte membrane (PEM) fuel cells, which operate under low temperature and high efficiency, to reduce fossil fuel consumption and CO2 emissions. Using hydrogen fuel, PEM fuel cells can reach a practical efficiency as high as 65% with water as the only byproduct. Almost all the major automakers are involved in fuel cell electric vehicle (FCEV) development. Toyota and Hyundai introduced FCEVs (the Mirai and NEXO, respectively) to consumers in recent years with a driving range between 312 and 402 miles and cold-start capacity from -30 °C. About 50 fuel cell electric buses (FCEB) are operating in California, and most of them have achieved the durability target, i.e., 25,000 h, in real-world driving conditions. As of September 2020, over 8,573 FCEVs have been sold or leased in the U.S. More than 3,521 FCEVs and 22 FCEBs have been sold or leased in Japan as of September 2019. An extensive hydrogen station network is required for the successful deployment of FCEVs and FCEBs. The U.S. currently has over 44 hydrogen fueling stations (HFSs), nearly all located in California. Europe has over 139 HFSs, with ~1500 more stations planned by 2025. This review has three primary objectives: 1) to present the current status of FCEV/FCEB commercialization and HFS development; 2) to describe the PEM fuel cell research/development in automobile applications and the significance of HFS networks; and 3) to outline major challenges and opportunities.

Drivers and Barriers to the Adoption of Fuel Cell Passenger Vehicles and Buses in Germany

As policymakers and automotive stakeholders around the world seek to accelerate the electrification of road transport with hydrogen, this study focuses on the experiences of Germany, a world leader in fuel cell technology. Specifically, it identifies and compares the drivers and barriers influencing the production and market penetration of privately-owned fuel cell electric passenger vehicles (FCEVs) and fuel cell electric buses (FCEBs) in public transit fleets. Using original data collected via a survey and 17 interviews, we elicited the opinions of experts to examine opportunities and obstacles in Germany from four perspectives: (i) the supply of vehicles (ii) refuelling infrastructure, (iii) demand for vehicles, and (iv) cross-cutting institutional issues. Findings indicate that despite multiple drivers, there are significant challenges hampering the growth of the hydrogen mobility market. Several are more pronounced in the passenger FCEV market. These include the supply and cost of production, the lack of German automakers producing FCEVs, the profitability and availability of refuelling stations, and low demand for vehicles. In light of these findings, we extract implications for international policymakers and future studies. This study provides a timely update on efforts to spur the deployment of hydrogen mobility in Germany and addresses the underrepresentation of studies examining both buses and passenger vehicles in tandem.

Decarbonising city bus networks in Ireland with renewable hydrogen

This paper presents techno-economic modelling results of a nationwide hydrogen fuel supply chain (HFSC) that includes renewable hydrogen production, transportation, and dispensing systems for fuel cell electric buses (FCEBs) in Ireland. Hydrogen is generated by electrolysers located at each existing Irish wind farm using curtailed or available wind electricity. Additional electricity is supplied by on-site photovoltaic (PV) arrays and stored using lithium-ion batteries. At each wind farm, sizing of the electrolyser, PV array and battery is optimised system design to obtain the minimum levelised cost of hydrogen (LCOH). Results show the average electrolyser capacity factor is 64% after the integration of wind farm-based electrolysers with PV arrays and batteries. A location-allocation algorithm in a geographic information system (GIS) environment optimises the distributed hydrogen supply chain from each wind farm to a hypothetical hydrogen refuelling station in the nearest city. Results show that hydrogen produced, transported, and dispensed using this system can meet the entire current bus fuel demand for all the studied cities, at a potential LCOH of 5–10 €/kg by using available wind electricity. At this LCOH, the future operational cost of FCEBs in Belfast, Cork and Dublin can be competitive with public buses fuelled by diesel, especially under carbon taxes more reflective of the environmental impact of fossil fuels.

(Invited) Fuel Cells for Heavy Duty Vehicles

The commercialization of fuel cell products for a variety of applications including forklifts, buses, cars and heavy duty trucks is well underway. Particularly in the heavy duty fuel cell market, recent studies suggest that in Europe, fuel cell electric buses (FCEB) total cost of ownership (TCO) will breakeven with battery electric buses (BEB) by 2023, and with internal combustion engine buses (ICEB) by 20241. For applications such as long-distance and heavy-duty transportation, the hydrogen route appears the decarbonisation option of choice, and can become cost competitive with internal combustion engines by 20302.Over the past 30 years, Ballard has developed a wide array of technology “building blocks” for Fuel Cell stacks components. The application requirements (duty cycle, speed, vehicle weight, lifetime and environmental exposure) will determine the key stack features and result in customization of components where economically viable. In contrast with fuel cell stacks developed for passenger cars, Fuel Cells for heavy duty vehicles are particularly challenged by high durability requirements3, with MEA attributes such as catalyst loading and peak efficiency point significantly affecting stack and fuel costs.Building on proven and demonstrated stack durability in the field of more than 35,000 hours in heavy duty vehicles4 Ballard’s MEA development activities draw from extensive field experience to support step changes in durability with each subsequent product iteration. The use of an accelerated testing and modeling approach developed and validated over numerous product iterations enables continuous cost decreases and gains in power density, operational robustness and reliability, with a calculated risk tolerance for new technology introduction.Those MEA durability prediction models along with a good understanding of failure mechanisms are a cornerstone to developing the next generation of Fuel Cells for heavy duty vehicles. Of particular importance is the use of the voltage degradation model to evaluate the time to reach the degradation target for heavy duty applications (USDOE Ultimate target of 10% degradation at 30,000 hours5). Simulation results as a function of the electrode composition show the relationship between cathode catalyst loading and lifetime, and assist in making electrode design and composition choices for a successfully durable product. A sharp increase in voltage loss is observed when local oxygen transport resistance becomes limiting once the cathode reaches low surface area. Maximizing beginning-of-life catalyst electrochemical surface area (ECSA) utilization in the electrode structure, as well as optimizing surface area retention, can have significant benefits for lifetime. A combination of design choices or processing parameters during catalyst layer fabrication can be effective ways to optimize the electrode6.The same voltage degradation model is used to demonstrate the relationship between lifetime and the peak operating current density of the product, which limits the stack design power density within the allocated voltage degradation constraints of heavy-duty vehicles.The simulation results demonstrate that the ideal Fuel Cell stack for heavy duty applications is the result of complex trade-offs between cost, stack design attributes (e.g. catalyst loading), active area sizing (peak efficiency point) and durability, with the ultimate goal to achieve an attractive TCO for wide acceptance of the technology. References Deloitte and Ballard. (2020). Fueling the Future of Mobility: Hydrogen and fuel cell solutions for transportation. Volume 1 [White paper]. Deloitte China. https://www2.deloitte.com/content/dam/Deloitte/cn/Documents/finance/deloitte-cn-fueling-the-future-of-mobility-en-200101.pdf McKinsey & Company and Hydrogen Council. (2020). Path to hydrogen competitiveness: A cost perspective. https://www.hydrogen.energy.gov/pdfs/19006_hydrogen_class8_long_haul_truck_targets.pdfMacauley, N., Lauritzen, M., Knights, S. and Kjeang, E., J. Electrochem. Soc., 165(10), F780 (2018).https://www.ballard.com/about-ballard/newsroom/news-releases/2020/01/27/ballard-powers-fuel-cell-electric-vehicles-for-unprecedented-30-million-kilometers-enough-to-circle-the-globe-750-timesUSDOE Hydrogen Class 8 Long Haul Truck Targets https://www.hydrogen.energy.gov/pdfs/19006_hydrogen_class8_long_haul_truck_targets.pdf M. Dutta, A. Young, V. Colbow, J. Bellerive, S. Knights, Examining Catalyst Layer Design Strategies for Improved Fuel Cell Performance and Durability, ECS PRiME 2020

Elektrikli Otobüslerde Kullanılan Şarj Hızlı Şarj Sistemleri

With the widespread use of electric vehicles in all areas, developments in the charging infrastructure sector, where the industry is directly related, accelerate and various alternative solutions are offered. Undoubtedly, the most important lane in which electric vehicles with rising trends spread across the world is the electric bus industry. Based on the literature within the general definition of the electric bus, it is seen that the vehicle concepts in different categories such as trolleybuses, plug-in hybrid buses and fuel cell electric buses are taken into consideration. An approach to pantograph structures in their systems will be presented

Analysis of maximum braking power for determination of energy storage device characteristics within fuel cell electric bus

The article describes development of hydrogen energetics over the 2014 to 2018 period. There are statistic data about significant influence of hydrogen vehicles on that energy sector. The development of this means of transport is funded by the governments in different countries and that means big prospects for that technology. Modern researches especially are targeted at optimal approach searching to drive the electrochemical generator (fuel cell) as an initial energy source in the united energy plant. The offered approach is based on the movement characteristics data which were obtained from operated on the real city route trolleybus. The preference is given to use the experimental data for further synthesis of the city fuel cell bus model.