Hydrogen Fuel Cell Electric Vehicles Research Articles

A Comprehensive Design Pipeline for FCEV Powertrain Configuration Considering the Evolutionary Development Process and Extreme Economic Performance

Due to stringent emission regulations, the zero-emission hydrogen fuel cell electric vehicles (FCEVs) are gaining significant attention, but their slow power response requires careful selection of auxiliary energy sources and power systems to optimize energy efficiency. This paper presents a comprehensive design pipeline for the FCEV powertrain, encompassing methods for powertrain configuration design, feasible domain design for component parameters, and parameter matching. Initially, a powertrain configuration design method based on evolutionary game theory is introduced, forecasting trends in energy-efficient powertrain configurations using a dynamic cost function that adjusts based on the proportions of different configurations. Next, a feasible domain design method is developed to establish fixed constraints on component parameters, ensuring a fair balance between performance needs and overall costs, including development and lifecycle expenses associated with the powertrain configuration. Subsequently, dynamic programming (DP) is used for parameter matching, assessing the utmost energy-saving potential. The cost function in this method incorporates the degradation cost of powertrain components, underscoring the economic performance of the target FCEV over its lifespan. Finally, simulation assessments indicate that the proposed design pipeline effectively identifies the optimal powertrain configuration for FCEVs, endowing each possible configuration with exceptional economic efficiency across different component parameters.

A structural mechanics analysis on a Type IV hydrogen storage tank during refueling and discharging

High-pressure hydrogen gas, as a power generation fuel widely used in transportation, has significantly contributed to the development of hydrogen fuel cell electric vehicles. However, obvious temperature rise and drop during fast refueling and discharging cause serious safety risk to the structural stability of on-board hydrogen storage tank. The American Society of Automotive Engineers SAE J2601 and the international standard ISO 15869 strictly stipulate that the operation temperature range of hydrogen storage tank varies from −40 °C to 85 °C. In this study, a finite element mechanics model was constructed using ACP and Static Mechanical software to better understand the deformation, stress, strain, and failure modes experienced by a Type IV tank during charging and discharging. Detailed parameters such as ply angle, ply thickness, mesh generation, and boundary conditions, were extensively elucidated. The results indicate that the high temperature and pressure generated during fast fueling of the storage tanks are less likely to cause yield failure of the inner, outer layers and plug, but the stress concentration caused by low temperature and high pressure may lead to the fracture rupture of internal polyethylene materials. Aluminum alloy plug, serving as sealing devices for the tank, are most susceptible to yielding failure under coupled conditions. The mechanical load reaching the yield stress of the plug is approximately 85 MPa with the nominal working temperature of 85 °C. Additionally, the maximum stress on the outer layer can be reduced by adjusting the circumferential layer direction from 90° to 70° or by optimizing the orientation of the maximum stress layer increasing it by 110°. The present study can offer new insights into the dynamic loading behavior of the Type IV tanks during fast charging and discharging, and may provide technical references for optimization design of the tank structures.

Review and modeling on hydrogen fuel cells electric vehicle (HFCEV), in comparison with battery electrical vehicle (BEV) using MATLAB environment. Case study: Postal car

This research puts forward the modeling of a Hydrogen Fuel Cell Electric Vehicle (HFCEV) and its validation, in comparison with battery electrical vehicle (BEV) based on a postal vehicle and its subsystems. The main investigation parameters are the amount of hydrogen consumed, and the change in the state of charging of the battery. For the profile of the same speed route, an HFCEV model and a BEV model, consisting of multiple subsystems, were developed, and simulated in the MATLAB® Simulink environment. We make use of various sources of drive cycles to obtain our outcomes such as the New European Diving Cycle (NEDC). By running simulations for different stages, we are able to generate simulation results. The discrepancies in the graphs and the visual demonstrations guided us to variable conclusions on how different factors affect an electric vehicle’s performance and efficiency. The simulation result shows that the (BEV) is 30% more effective for NEDC drive cycle comparing with (HFCEV).

Optimal Design and Operation of Electrolytic Hydrogen Production and Storage System for Solar Photovoltaic Power Smoothing

Even though the increasing penetration of solar photovoltaic (PV) energy into the electric grid can reduce the carbon emission of power generation, the intermittency and variability of renewable solar energy lead to frequent and steep ramping operations of conventional fossil fuel power plants. Hydrogen production via water electrolysis using solar power can serve as a controllable load and provide a short/long duration energy storage to mitigate the grid fluctuations (i.e., PV smoothing) and improve the resiliency of power grid. The generated green hydrogen will be further stored under high pressure for subsequent utilizations (e.g., hydrogen fuel cell electric vehicle refueling).Polymer electrolyte membrane (PEM) electrolyzer with high efficiency and quick dynamic response is used to generate hydrogen [1,2]. The capacity factors of PV field and PEM electrolyzer can affect the performance of PV smoothing on the cloudy day. Even though PEM electrolyzers directly producing high pressure hydrogen are more energy efficient than ambient pressure electrolyzers followed by mechanical compression, higher pressure leads to more undesired hydrogen back diffusion to the oxygen side, which causes lower hydrogen production efficiency, cell degradation, and safety risk of hydrogen explosion limit [3,4]. Optimal design and operation of electrolyzer under fluctuating solar power are formulated based on an integrated hydrogen-based energy storage system (renewable solar coupled with green hydrogen production and storage). Different PV smoothing scenarios as well as optimal size and operation conditions of the PEM electrolyzer are investigated.The high-fidelity dynamic model of a PEM electrolyzer cell/stack is established with consideration of two-dimensional (“through-plane” and “in-plane”) mass/heat transfer coupled with electrochemical kinetics. The electrochemical reactions are considered using Butler-Volmer kinetics with varying surface molar concentrations of components. Maxwell-Stefan diffusion equation is adopted to calculate the gas-phase species molar concentration in the backing and catalyst layers. Hydrogen permeation back through membrane is included with consideration of both diffusion and convective transports as a function of operational pressure.To evaluate the transient response of the PEM electrolyzer stack, real-time PV data based on an Orlando Utilities Commission (OUC) solar farm is smoothed using the developed power signal control algorithm. The optimal PV smoothing control algorithm and the electrochemical dynamic stack model show the effectiveness of hydrogen-based energy storage system in smoothing the PV signal to improve the grid stability and flexibility.[1] Kumar, S.S. and Himabindu, V., 2019. Hydrogen production by PEM water electrolysis–A review. Materials Science for Energy Technologies, 2(3), pp.442-454.[2] Götz, M., Lefebvre, J., Mörs, F., Koch, A.M., Graf, F., Bajohr, S., Reimert, R. and Kolb, T., 2016. Renewable Power-to-Gas: A technological and economic review. Renewable energy, 85, pp.1371-1390.[3] Trinke, P., Bensmann, B., Reichstein, S., Hanke-Rauschenbach, R. and Sundmacher, K., 2016. Hydrogen permeation in PEM electrolyzer cells operated at asymmetric pressure conditions. Journal of The Electrochemical Society, 163(11), p.F3164.[4] Scheepers, F., Stähler, M., Stähler, A., Rauls, E., Müller, M., Carmo, M. and Lehnert, W., 2020. Improving the efficiency of PEM electrolyzers through membrane-specific pressure optimization. Energies, 13(3), p.612.

(Invited) Hydrogen Detection Strategies to Support H2@Scale--the NREL Sensor Laboratory

Hydrogen represents a major pathway to decarbonize and stabilize the national and international energy industry and select manufacturing markets. To facilitate the development of hydrogen markets, the US Department of Energy initiated H2@Scale to bring together stakeholders to advance affordable hydrogen production, transport, storage, and utilization to increase revenue opportunities in multiple energy sectors. One major impediment to hydrogen implementation is cost. To expedite the use of hydrogen in energy and other markets, the United States announced in 2021 the Hydrogen Shot, which seeks to reduce the cost of clean hydrogen by 80% to $1 per 1 kilogram in 1 decade ("1 1 1"). As the cost of hydrogen drops, new applications will emerge that will require unique configurations of existing equipment and infrastructure, and eventually lead to advances in the generation and utilization of hydrogen. As the hydrogen economy expands, sensors and detection methods will need to adapt to changing infrastructure demands to address the primary targets of health & safety, emissions monitoring, and process control. The NREL Sensor Laboratory is playing a pivotal role in advancing the use of hydrogen sensors and detection methodologies in each of these categories to support DOE’s mission for safe and efficient utilization in emerging markets. Health & safety monitors are required to ensure that operators and facilities can react to unintended hydrogen releases, either as GH2, LH2, or as a constituent of blends (e.g., natural gas or ammonia). Current detection methodologies focus on safety applications to detect near its lower flammable limit (4 vol %), and typically include point sensors in applications such as fixed or mobile detectors (e.g., personal gas monitors). Methodologies amenable for area detection include acoustic, emerging optical imaging methods, and flame detectors.Comparable detection strategies can be utilized for emissions monitoring and quantization, however few methods can simultaneously cover both low (emissions) and high (health & safety) levels. Deployment of emission level detectors will be required to 1) reduce product loss through small but potentially significant leaks from an environmental or cost perspective, 2) reduce downtime of high demand systems by early identification of eminent system failures (leaks through pump or compressor seals indicative of impending failure), and 3) address potential emission monitoring requirements that may be set by regulating bodies. The first two points should be adopted by industry to reduce the cost-of-goods-sold.The third main category for hydrogen detection relates to process control and may be advantageous for many existing applications. Two main applications are emerging. For example, the purity requirements for hydrogen that is dispensed from refueling systems for hydrogen fuel cell electric vehicles (FCEV) is rigorously regulated by the Standard SAE J2719, which prescribes maximum allowable levels of multiple impurities in the hydrogen fuel and must be verified by a regulatory body. Hydrogen contaminant detectors (HCD) integrated to the fueling station can assure this compliance. HCDs must be able operate in 100% H2 backgrounds and be able to distinguish between multiple contaminants at low ppm to low ppb levels.Secondly, as a strategy to decarbonize the natural gas grid, there are proposals to blend hydrogen with natural gas. This blending will affect transport applications (pipeline infrastructure), stationary combustion systems (turbines), and consumer and commercial appliances. In the short-term, hydrogen levels up to 20% are proposed. Variations in the hydrogen level can have dramatic impact on the combustion process and on the potential response of safety sensors. These mixtures may be regulated so that the concentration at a delivery point must be monitored with high precision. However, routine maintenance may introduce background gases such as ambient air (with water) or maintenance gases (introduced with welding processes or adhesive outgassing.) Therefore, the detection methodology must be robust enough to recover or respond to various contaminants.Several reviews can be found in literature addressing sensing and detection technologies, including their limitations and applications. However, for most applications, limitations can be alleviated by combining various detection techniques either through system integration or implementation of machine learning methods (artificial intelligence). Many detection methods already implement some sort of senor fusion, i.e., integrated temperature and humidity sensors allow for compensation methods of point sensors to increase the accuracy and precision of detectors through a wide range of environmental conditions. Similarly, sensing arrays (electronic noses) may implement intelligent algorithms to quantify multiple gasses present in a sample, or simply to identify a single gas in a mixture.In this presentation, we will discuss several applications, highlight their current approach for hydrogen detection, and suggest detection strategies to supplement their limitations.

Effects of structure parameter and material property on thermal performance of on-board hydrogen storage tanks during fast refueling

As a power generation fuel, high-pressure hydrogen gas is widely used in transportation, and significantly contributed to development of hydrogen fuel cell electric vehicles. However, obvious temperature rise generated during fast refueling causes serious safety risk to reliable operation of fuel cell stacks. Therefore, it is necessary to conduct in-depth research on fast filling process. Based on safety reasons, the SAE J2601/ISO 15869 strictly regulates the maximum temperature limit of 85 °C in specifications for refueling hydrogen gas tanks. In this study, a 70 MPa, Type IV on-board hydrogen storage tank is adopted as the research object, and a 2-dimensional axisymmetric numerical model is established to study the temperature rise of the vapor within storage tanks during fast refueling. The Realizable k-ε turbulence model is employed to simulate high intensity turbulent fluctuation during fast filling. Considering the compressibility of vapor, the state of equation for real hydrogen gas is used by obtaining fluid thermodynamic properties from the National Institute of Standards and Technology database. Three groups of fast filling experiments are selected to validate the developed numerical model. The comparison result shows that the numerical model has good prediction ability on hydrogen fast refueling. The final mass average temperature differences between numerical results and experimental data are 2.6 K, 4.3 K, and 0.03 K, respectively. Based on the developed numerical model, the influences of structure parameters and material properties on the temperature rise of hydrogen storage tanks are investigated. The results indicate that the inlet diameter and wall thickness of the inner and outer layers of the storage tank have weaken impacts on the temperature rise during rapid charging, with the maximum temperature differences of 1.8 K, 0.74 K, and 0.54 K, respectively. Due to the influence of heat capacity, the material properties of different layers exhibit a similar variation trend. This work can deepen researchers' understanding of the temperature rise of on-board hydrogen storage tanks during fast filling, and provide technical references for the structural optimal design of tanks and rapid refueling at hydrogen stations.

Composite predictive trajectory control of HS-PMSM with LCL filter for hydrogen electric vehicle at low fuel condition

Limitations in current fuel cell technology lead to instability in output voltage for hydrogen fuel cells, particularly under the influence of temperature variations and fuel flow fluctuations, thereby affecting the normal operation of hydrogen-powered vehicles. Improving the motor drive control system and optimizing energy management are crucial for enhancing overall vehicle performance. To improve dynamic response speed while suppressing harmonics, this paper proposes a predictive control strategy for high-speed permanent magnet synchronous motors with LCL filter in hydrogen fuel cell electric vehicles. The proposed control strategy suppresses high-frequency current harmonics by sampling only the current on the motor side, enabling fast predictive control of the high-order system motor-side current. Additionally, to mitigate the issue of unstable torque output of the electric motor at low fuel levels, this paper proposes a new composite predictive torque trajectory control strategy based on the previous control strategy. This strategy ensures rapid and accurate tracking of motor output torque, particularly during decreases in fuel cell output voltage. Experimental results validate the feasibility and effectiveness of the proposed control strategies in this paper.

Effects of hydrogen permeation on the mechanical characteristics of electroless nickel-plated free-cutting steel for application to the hydrogen valves of hydrogen fuel cell electric vehicles

Electroless nickel plating is a suitable technology for the hydrogen industry because electroless nickel can be mass-produced at a low cost. Investigating in a complex environment where hydrogen permeation and friction/wear work simultaneously is necessary to apply it to hydrogen valves for hydrogen fuel cell vehicles. In this research, the effects of hydrogen permeation on the mechanical characteristics of electroless nickel-plated free-cutting steel (SUM 24L) were investigated. Due to the inherent characteristics of electroless nickel plating, the damage (cracks and delamination of grain) and micro-particles by hydrogen permeation were clearly observed at the grain boundaries and triple junctions. In particular, the cracks grew from grain boundary toward the intergranualr. This is because the grain boundaries and triple junctions are hydrogen permeation pathways and increasing area of the hydrogen partial pressure. As a result, its surface roughness increased by a maximum of two times, and its hardness and adhesion strength decreased by hydrogen permeation. In particular, hydrogen permeation increased the friction coefficient of the electroless nickel-plated layer, and the damage caused by adhesive wear was significantly greater, increasing the wear depth by up to 5.7 times. This is believed to be due to the decreasing in wear resistance of the electroless nickel plating layer damaged by hydrogen permeation. Nevertheless, the Vickers hardness and the friction coefficient of the electroless nickel plating layer were improved by about 3 and 5.6 times, respectively, compared with those of the free-cutting steel. In particular, the electroless nickel-plated specimens with hydrogen embrittlement exhibited significantly better mechanical characteristics and wear resistance than the free-cutting steel.

Contribution of regenerative suspension module to charge efficiency and range in hydrogen fuel cell electric vehicles

Energy and transport are the two largest contributors to carbon emissions. In recent years, the transport sector has made strides in reducing its carbon footprint by producing electric vehicles that emit zero carbon. This paper investigates the use of Fuel Cell Electric Vehicles (FCEVs) with a newly developed regenerative suspension module (RSM). The RSM uses an electromechanical mechanism to obtain regenerative electrical energy from the engine and is mounted to the passive suspension system. To determine the potential energy savings of the RSM module, a hydrogen fuel cell electric vehicle simulated under specific road geometries, speeds, and acceleration conditions. The simulation results indicate that the Regenerative Suspension Modules (RSM) mounted on each wheel of the FCEV generate 2.5 times more energy than the regenerative braking system. This result is evaluated as an increase in efficiency and range in electric vehicles.

Assessing the Performance of Fuel Cell Electric Vehicles Using Synthetic Hydrogen Fuel

The deployment of hydrogen fuel cell electric vehicles (FCEVs) is critical to achieve zero emissions. A key parameter influencing FCEV performance and durability is hydrogen fuel quality. The real impact of contaminants on FCEV performance is not well understood and requires reliable measurements from real-life events (e.g., hydrogen fuel in poor-performing FCEVs) and controlled studies on the impact of synthetic hydrogen fuel on FCEV performance. This paper presents a novel methodology to flow traceable hydrogen synthetic fuel directly into the FCEV tank. Four different synthetic fuels containing N2 (90–200 µmol/mol), CO (0.14–5 µmol/mol), and H2S (4–11 nmol/mol) were supplied to an FCEV and subsequently sampled and analyzed. The synthetic fuels containing known contaminants powered the FCEV and provided real-life performance testing of the fuel cell system. The results showed, for the first time, that synthetic hydrogen fuel can be used in FCEVs without the requirement of a large infrastructure. In addition, this study carried out a traceable H2 contamination impact study with an FCEV. The impact of CO and H2S at ISO 14687:2019 threshold levels on FCEV performance showed that small exceedances of the threshold levels had a significant impact, even for short exposures. The methodology proposed can be deployed to evaluate the composition of any hydrogen fuel.

Assessing total cost of driving competitiveness of zero-emission trucks

Medium- and heavy-duty vehicles are 21% of US transportation greenhouse gas (GHG) emissions and a major source of air pollution. We explore how the total cost of driving (TCD) of zero-emission vehicles (ZEVs), including battery electric vehicles and hydrogen fuel cell electric vehicles (EVs and FCEVs), could evolve under alternative scenarios. With continued improvements in vehicles and fuels, ZEVs can rapidly become viable, potentially reaching TCD parity or better compared to diesel vehicles by 2035 for all market segments. For heavy long-haul trucks, EVs become competitive on a TCD basis at charging costs below $0.18/kWh, while FCEVs become competitive on a TCD basis at hydrogen costs below $5/kg. A full transition to ZEV sales by 2035 results in 65% emissions reductions by 2050 compared to 2019 without supportive policies. Incentives such as the Inflation Reduction Act vehicle purchase credits further accelerate ZEV TCD competitiveness with major adoption opportunities over the next five years.

A comparative study of the machine learning-based energy management system for hydrogen fuel cell electric vehicles

The demand for better energy technologies has sparked research and development of electric and hybrid vehicles. Due to their clean, sustainable, and high energy density, fuel cell vehicles have begun to stand out above the rest. Therefore, fuel cell hybrid vehicles can compete with internal combustion engine-powered vehicles in the future. However, fuel cells face obstacles, including slow dynamics that necessitate managing their operation together favorably. To reduce an HEV's operational costs, this study analyzes the HEV energy management issue utilizing machine learning approaches, particularly reinforcement learning. This paper aims to comprehensively review the existing work on a couple of machine-learning-based energy management systems for an electric vehicle run by hydrogen fuel cell, it can be concluded that progress was evident when the Q-learning-based algorithm was utilized towards lowering the SOC battery variation of about 0.7 per unit which was the primary task, while a Deep Deterministic Policy Gradient (DDPG) based energy management system (EMS) starts operating the fuel cell at a higher efficiency rate comparatively while using the battery.

Comparative Assessment of the Prospects for Hydrogen Fuel Cell Electric Vehicles

Today, road transport is one of the main environmental pollutants. It accounts for more than half of all emissions. In this regard, the issue of developing measures to reduce the impact of cars on the environment is gaining relevance. There are various approaches to solve this issue, but the most promising direction is the use of electric vehicles. It should be noted that we cannot talk about their absolute environmental friendliness, since there is still an indirect impact on the environment.The paper examines the prospects for the use and disadvantages of two types of electric vehicles powered, respectively, by battery or hydrogen fuel cells. Currently, production of battery electric vehicles is a more popular direction, which is largely due to development of technologies in the field of battery production. At the same time, one should not completely exclude other areas, such as hydrogenfuelled vehicles. Such vehicles are distinguished by good environmental friendliness, which is determined by the nature of the combustion product and the possibility of obtaining this type of resource. However, the use of hydrogen as a fuel for internal combustion engines is not relevant. Development of a car with an electrochemical generator is more promising. Today, a fairly large number of the world’s leading car manufacturing companies are advancing in this direction.The electric vehicles considered in the work have similar emissions of harmful substances, which, under equal conditions, approach zero. However, both types of vehicles leave a carbon footprint, the bulk of which comes from electricity generation and hydrogen production. The study carried out a comparative assessment of the quality characteristics, carbon footprint and operating costs of electric vehicles with various types of power plants under Russian operating conditions. Based on the comparison, the main advantages, and disadvantages of those types of electric vehicles have been identified. Actions are proposed to increase the environmental friendliness of electric vehicles and solve problems that complicate their operation.

Development of a framework to assess the greenhouse gas mitigation potential from the adoption of low-carbon road vehicles in a hydrocarbon-rich region

This study developed a novel assessment framework to analyze long-term energy transition in the road transport sector in which various technology options, market shares, policy measures, costs, and greenhouse gas emissions are considered in a single framework analysis. A data-intensive model was developed with the Low Emissions Analysis Platform (LEAP) and used to analyze policy scenarios up to 2050 for Alberta, Canada, a hydrocarbon-rich province with an emission-intensive energy sector. Three key policy measures – carbon pricing, zero-emission vehicle sales mandate, and incentivization – were analyzed in nine individual and combined policy scenarios. The transition to both hydrogen fuel cell electric vehicles and battery electric vehicles was assessed for all vehicle categories. Each fuel's full energy supply chain was modelled, including resource extraction, conversion, transmission and distribution, and fuelling, allowing for final and primary energy analysis. The findings show that carbon price and zero-emission vehicle incentives do not effectively lower greenhouse gas emissions on their own; zero-emission vehicle mandates are needed to transition the sector to a low-carbon energy system. The system-wide greenhouse gas emission footprints of hydrogen and battery electric vehicles are significantly below conventional vehicles in all cases. Scenarios biased towards battery electric vehicles had the most favorable results. The greenhouse gas emission footprint of hydrogen vehicles supplied by auto-thermal reforming with 91% carbon capture was lower than for battery electric vehicles powered by a primarily natural gas-based power grid. The findings on the effectiveness of carbon prices, incentives, and vehicle mandates should be considered by government policymakers aiming to reduce greenhouse gas emissions, infrastructure planners, and other energy stakeholders.

Mathematical modelling of hydrogen transportation from reservoir tank to hydrogen fuel cell electric vehicle (FCEV) tank

Mathematical modeling of Hydrogen transfer from reservoir tank to fuel tank of vehicle can help to transfer hydrogen fuel in safe and efficient way. Hydrogen refueling model using MATLAB version 22 has developed in this work. This simulated model can accurately estimate the cooling power required to ensure target hydrogen temperature at destination tank. This model tested for both perfect hydrogen and semi perfect hydrogen for cooling power estimation. The outcomes such as cooling power (KW), pressure (bar), gas density (kg/cm3) and temperature (K) measured using this model at different cooling temperatures −5 °C, −25 °C, −45 °C, −65 °C and the outcomes were compared. From the simulation results it is found that minimum cooling power of 5.431 KW required for hydrogen transfer from reservoir tank to vehicle tank when cooling temperature maintained at −5 °C. The proposed model also provides optimum pressure of 580 bar, temperature of 270 K and gas density of 45.12 kg/cm3.Thus, this model can provide insight into hydrogen transfer in safe and efficient manner.

Hydrogen volumetric fraction effects on HCNG refuelling station CAPEX

Greening the transport sector is crucial for the achievement of the ambitious decarbonisation goals set by the Conference of the Parties (COP21) Paris agreement to keep global warming “well below 2 degrees Celsius above preindustrial levels, and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius”. Battery electric vehicles and hydrogen fuel cell electric vehicles will play a key role in the reduction of greenhouse gas emissions in the road mobility. Nonetheless, those technologies still need to face some technological challenges. Hence, hydrogen enriched natural gas (HCNG) can play an important role as bridging technology. This study envisages the upgrade of an existing compressed natural gas (CNG) refuelling station (RS) in HCNG-RS. Particularly, an analysis regarding the impact of different hydrogen volumetric fractions in the blend on the total CAPEX of the HCNG refuelling station is carried out, by evaluating the HCNG fill-up demands for a proper refuelling station sizing. The proposed HCNG refuelling station layout foresee the on-site hydrogen production by means of an electrolyser fed by PV energy. Each component of the station has been adequately sized based on the resulting peak HCNG refuelling demand. The highest CAPEX value is recorded for the 30%vol. HCNG, amounting up to 3.52 M€.

A total cost of ownership analysis of zero emission powertrain solutions for the heavy goods vehicle sector

Transport-related activities represented 34% of the total carbon emissions in the UK in 2022 and heavy-duty vehicles (HGVs) accounted for one-fifth of the road transport greenhouse gas (GHG) emissions. Currently, battery electric vehicles (BEVs) and hydrogen fuel cell electric vehicles (FCEVs) are considered as suitable replacements for diesel fleets. However, these technologies continue to face techno-economic barriers, creating uncertainty for fleet operators wanting to transition away from diesel-powered internal combustion engine vehicles (ICEVs). This paper assesses the performance and cost competitiveness of BEV and FCEV powertrain solutions in the hard-to-abate HGV sector. The study evaluates the impact of battery degradation and a carbon tax on the cost of owning the vehicles. An integrated total cost of ownership (TCO) model, which includes these factors for the first time, is developed to study a large retailer's HGV fleet operating in the UK. The modelling framework compares the capital expenditures (CAPEX) and operating expenses (OPEX) of alternative technologies against ICEVs. The TCO of BEVs and FCEVs are 11% to 33% and 37% to 78% higher than ICEVs; respectively. Despite these differences, by adopting a longer lifetime for the vehicle it can effectively narrow the cost gap. Alternatively, cost parity with ICEVs could be achieved if BEV battery cost reduces by 56% or if FCEV fuel cell cost reduces by 60%. Besides, the pivot point for hydrogen price is determined at £2.5 per kg. The findings suggest that BEV is closer to market as its TCO value is becoming competitive, whereas FCEV provides a more viable solution than BEV for long-haul applications due to shorter refuelling time and lower load capacity penalties. Furthermore, degradation of performance in lithium-ion batteries is found to have a minor impact on TCO if battery replacement is not required. However, critical component replacement and warranty can influence commercial viability. Given the high costs, we propose financial incentives and vehicle tax reforms to reduce costs of critical components that will encourage the roll-out of zero emission HGVs.

Effect of TPRD diameter and direction of release on hydrogen dispersion and jet fires in underground parking

The paper presents safety strategies to support choice of diameter and release direction for thermally activated pressure relief device (TPRD) onboard a hydrogen fuel cell electric vehicle. Analytical and numerical modelling campaigns were performed to study hazards of unignited and ignited hydrogen releases from a vehicle in a real underground parking. TPRD diameter to prevent flammable mixture formation during upward release was determined using similarity law for hydrogen concentration decay along jet centreline. Parametric CFD simulations studied effect of different TPRD diameter, release direction, vehicle distance from obstacles, ceiling height, influence of carpark ventilation on hydrogen hazards. Hazards of unignited releases were associated with the lower flammability limit of hydrogen-air clouds. For ignited releases the temperature threshold 70 °C was used as a no-harm criteria for assessment of thermal hazards to people and threshold 300 °C as a damage criteria for mechanical ventilation system following requirements of BS 7346-7-2013 standard for carpark ventilation. Recommendations on TPRD design were formulated to support safe integration of hydrogen-powered vehicles in the existing underground parking facilities and infrastructure.

Dynamic Modeling and Operation of a Green Hydrogen Fueling Station for Heavy-Duty Fuel Cell Vehicles

Hydrogen fuel cell electric vehicles (FCEVs) have increased driving ranges and faster refueling times than battery electric vehicles (BEVs). The driving range of FCEVs can be increased by increasing the size, quantity or operating pressure of on-board hydrogen storage tanks at a lower weight and cost than increasing the size or number of Li-ion battery packs in BEVs. Ffast-refueling leads to less waiting time at the fueling station for high-utilization commercial vehicles. As a result, fuel cell system heavy-duty vehicles (HDV) are attracting more attention [1]. Currently, the lack of a hydrogen refueling infrastructure is limiting FCEV adoption. Since the driving routes of HDV trucks are more predictable, a small number of strategically located fueling stations could service pre-planned truck driving routes [2]. While hydrogen refueling protocols and fueling stations for light-duty vehicles (LDV) have been extensively studied [3,4,5], HDV trucks have different refueling protocols and operating conditions (e.g. mass holdup, pressure, refueling rate). To our knowledge, little work has been done on modeling hydrogen fueling stations for HDV trucks applications. With this motivation, a dynamic model of a truck stop coupled with green hydrogen production has been developed for fleet HDV trucks. At the truck stop, green hydrogen is produced from water electrolysis using solar photovoltaics (PV). Electrochemical hydrogen compression (EHC) is implemented for high-pressure hydrogen storage and dispensing. The fluctuations from solar PV and truck hydrogen demand are actively managed by installation of a spherical hydrogen storage vessel. The feasibility and flexibility of a truck stop using 100% renewable electricity and hydrogen will be discussed.A high-fidelity dynamic model of a Proton Exchange Membrane (PEM) electrolyzer is developed for hydrogen production from PV electricity. A PEM electrochemical hydrogen compressor model is developed for gas pressurization with consideration of EHC temperature and water management. The green hydrogen is stored in a large spherical storage vessel to decouple the different PV power loads and HDV trucks hydrogen refueling demands. A modular system for HDV trucks refueling (nominal working pressure of 35 MPa) is designed and modeled with parallel multi-stage hydrogen compression and cascaded storage tanks. It was found that single modular system for FCEV refueling shows a service gap during hydrogen cascaded storage tank refilling, but a multiple modular structure can be easily expanded and provide uninterrupted hydrogen for FCEV refueling.The different hydrogen production and dispensing scenarios are implemented depending on the seasonal solar supply and varied HDV trucks demands. Hydrogen compression using mechanical compressor and electrochemical compressor are compared. The truck stop operation strategies are proposed based on the integrated process systems analysis of solar penetrations, hydrogen production and compression, and HDV trucks demand. The feasibility and flexibility of truck stop fueled by solar energy provide an insight for the transition to Net Zero Emission Transportation.[1] Cullen, D.A., Neyerlin, K.C., Ahluwalia, R.K., Mukundan, R., More, K.L., Borup, R.L., Weber, A.Z., Myers, D.J. and Kusoglu, A. (2021). New roads and challenges for fuel cells in heavy-duty transportation. Nature energy, 6(5), 462-474.[2] Cano, Z. P., Banham, D., Ye, S., Hintennach, A., Lu, J., Fowler, M., & Chen, Z. (2018). Batteries and fuel cells for emerging electric vehicle markets. Nature Energy, 3(4), 279-289.[3] Xiao, L., Chen, J., Wu, Y., Zhang, W., Ye, J., Shao, S., & Xie, J. (2021). Effects of pressure levels in three-cascade storage system on the overall energy consumption in the hydrogen refueling station. International Journal of Hydrogen Energy, 46(61), 31334-31345.[4] Rothuizen, E., Mérida, W., Rokni, M., & Wistoft-Ibsen, M. (2013). Optimization of hydrogen vehicle refueling via dynamic simulation. International journal of hydrogen energy, 38(11), 4221-4231.[5] Rothuizen, E., & Rokni, M. (2014). Optimization of the overall energy consumption in cascade fueling stations for hydrogen vehicles. International journal of hydrogen energy, 39(1), 582-592.

Development of novel composite bipolar plates using surface‐modified conductive carbon filler materials for polymer electrolyte membrane fuel cells

AbstractThe requirement for a lightweight bipolar plate (BP) for Proton Exchange Membrane Fuel Cell (PEMFC) is increasing to make it feasible to power hydrogen fuel cell electric vehicles. Composite BP with carbon materials as conductive fillers and polymer as the binder are preferable over pure graphite and metallic BP. This study investigates the effect of Surface‐enhanced flake graphite (SEFG) as a novel filler material in composite BP. A composite BP is developed with Epoxy Resin (ER) as the binder and Natural Flake Graphite (NFG), Carbon Black (CB) and SEFG as conductive fillers. Composite BP fabricated with 10 vol% SEFG, 10 vol% CB, and 40 vol% NFG exhibited an electrical conductivity of 158 S cm−1, flexural strength of 38 MPa, water contact angle of 90.410 and corrosion current density of 0.261 μA cm−2. The composite BP also achieved a density of 1.55 g cm−3, water absorption of 0.6% and thermal conductivity of 3.6 W m−1 K−1 at 120°C. These results are highly favorable for BPs used in PEMFC. This paper provides an insight into using surface‐modified conductive carbon filler materials to develop composite BP for application in PEMFC.