Off-grid solar powered charging station for electric and hydrogen vehicles including fuel cell and hydrogen storage

This paper designs an off-grid charging station for electric and hydrogen vehicles. Both the electric and hydrogen vehicles are charged at the same time. They appear as two electrical and hydrogen load demand on the charging station and the charging station is powered by solar panels. The output power of solar system is separated into two parts. On part of solar power is used to supply the electrical load demand (to charge the electric vehicles) and rest runs water electrolyzer and it will be converted to the hydrogen. The hydrogen is stored and it supplies the hydrogen load demand (to charge the hydrogen-burning vehicles). The uncertainty of parameters (solar energy, consumed power by electrical vehicles, and consumed power by hydrogen vehicles) is included and modeled. The fuel cell is added to the charging station to deal with such uncertainty. The fuel cell runs on hydrogen and produces electrical energy to supply electrical loading under uncertainties. The diesel generator is also added to the charging station as a supplementary generation. The problem is modeled as stochastic optimization programming and minimizes the investment and operational costs of solar and diesel systems. The introduced planning finds optimal rated powers of solar system and diesel generator, operation pattern for diesel generator and fuel cell, and the stored hydrogen. The results confirm that the cost of changing station is covered by investment cost of solar system (95%), operational cost of diesel generator (4.5%), and investment cost of diesel generator (0.5%). The fuel cell and diesel generator supply the load demand when the solar energy is zero. About 97% of solar energy will be converted to hydrogen and stored. The optimal operation of diesel generator reduces the cost approximately 15%.     

A hierarchical energy management strategy for fuel cell/battery/supercapacitor hybrid electric vehicles

In this paper, a hierarchical energy management strategy (EMS) based on low-pass filter and equivalent consumption minimization strategy (ECMS) is proposed in order to lift energy sources lifespan, power performance and fuel economy for hybrid electrical vehicles equipped with fuel cell, battery and supercapacitor. As for the considered powertrain configuration, fuel cell serves as main energy source, and battery and supercapacitor are regarded as energy support and storage system. Supercapacitor with high power density and dynamic response acts during great power fluctuations, which relives stress on fuel cell and battery. Meanwhile, battery is used to lift the economy of hydrogen fuel. In higher layer strategy of the proposed EMS, supercapacitor is employed to supply peak power and recycle braking energy by using the adaptive low-pass filter method. Meantime, an ECMS is designed to allocate power of fuel cell and battery such that fuel cell can work in a high efficient range to minimize hydrogen consumption in lower layer. The proposed EMS for hybrid electrical vehicles is modeled and verified by advisor-simulink and experiment bench. Simulation and experiment results are given to confirm effectiveness of the proposed EMS of this paper.     

Technological-economic assessment and optimization of hydrogen-based transportation systems in China: A life cycle perspective

Hydrogen energy is increasingly incorporated into long-distance transportation systems. Whether the coupled hydrogen-based transportation system can achieve a sustainable business operation mode requires quantification of environmental and economic performance by a comprehensive cost-benefit analysis. This study proposes a cost-based life cycle assessment method to evaluate the environmental and economic benefits of hydrogen-based long-distance transportation systems. The innovative cost assessment method introduces internal and external economic costs to conduct a multi-scenario assessment. According to the key factors of mileage, government subsidies and hydrogen fuel prices, this research identifies the key cost component of the hydrogen-based transportation system in China by using a multilevel comparison with cell-driven and oil-fueled vehicles. The results show that hydrogen fuel cell electric vehicles are competitive in terms of both fuel costs and environmental costs. As hydrogen costs are expected to be gradually reduced by 43% in the future, hydrogen logistics vehicles and heavy trucks are expected to have better life-cycle economics than other energy vehicles by approximately 2030. Hydrogen buses will outperform other vehicles by approximately 2033, while hydrogen passenger cars will have a reduced life-cycle cost per kilometre within 0.1 CHY/km compared to other vehicles by approximately 2035. Ultimately, fuel consumption, average annual mileage, and hydrogen fuel cell electric vehicle policy are three factors that have greater impacts. Policy implications are put forward to implement optimal investment plan for hydrogen transportation systems.     

Intelligent energy management strategy based on hierarchical approximate global optimization for plug-in fuel cell hybrid electric vehicles

The energy management strategy (EMS) is a key to reduce the equivalent hydrogen consumption and slow down fuel cell performance degradation of the plug-in fuel cell hybrid electric vehicles. Global optimal EMS based on the whole trip information can achieve the minimum hydrogen consumption, but it is difficult to apply in real driving. This paper tries to solve this problem with a novel hierarchical EMS proposed to realize the real-time application and approximate global optimization. The long-term average speed in each future trip segment is predicted by KNN, and the short-term speed series is predicted by a new model averaging method. The approximate global optimization is realized by introducing hierarchical reinforcement learning (HRL), and the strategy within the speed forecast window is optimized by introducing upper confidence tree search (UCTS). The vehicle speed prediction and the proposed EMS have been verified using the collected real driving cycles. The results show that the proposed strategy can adapt to driving style changes through self-learning. Compared with the widely used rule-based strategy, it can evidently reduce hydrogen consumption by 6.14% and fuel cell start-stop times by 21.7% on average to suppress the aging of fuel cell. Moreover, its computation time is less than 0.447 s at each step, and combined with rolling optimization, it can be used for real-time application.     

Energy management strategies for a zero-emission hybrid domestic ferry

The paper presents three approaches for the sizing and control of a maritime hybrid power-plant equipped with proton exchange membrane fuel cells and batteries. The study focuses on three different power-plant configurations, including the energy management strategy and the power-plant component sizing. The components sizing is performed following the definition of the energy management strategy using the sequential optimization approach. These configurations are tested using a dynamic model developed in Simulink. The simulations are carried out to validate the technical feasibility of each configuration for maritime use. Each energy management strategy is developed to allow for the optimization of a chosen set of parameters, such as hydrogen consumption and fuel cell degradation. It is observed that in the hybrid power-plant optimization there are always trade-offs, and the optimization should be carried out by prioritizing primary factors the ship owner considers most important for day-to-day operations.     

Impact of urban development on residents’ public transportation travel energy consumption in China: An analysis of hydrogen fuel cell vehicles alternatives

Urban development has an important influence on the energy consumption of transportation. To develop public transportation is one of the important ways to decrease the energy consumption of urban transportation. It is very urgent to upgrade technology to reduce the energy consumption and emissions of the vehicles constantly. The popularization of hydrogen fuel cell vehicles is the trend of the future automobile industry, which can effectively reduce traffic energy consumption and alleviate urban pollution. This article analyzes the impact of urban development on public transport and private transportation energy consumption from 2013 to 2015; and uses hydrogen fuel cell vehicles alternatives in urban public transport as a scenario. It shows that urban economic development can effectively reduce public transport. Population growth will increase greatly energy consumption of public transport, while larger cities with reasonable spatial density can reduce traffic energy consumption. Moreover, hydrogen fuel cell vehicles can effectively reduce the energy consumption and pollution emissions of urban transportation during operating. Based on the above conclusions, this article will eventually provide targeted recommendations for the development of Chinese cities, public transport, and hydrogen fuel cell vehicles.     

Analytical method to evaluate fuel consumption of hybrid electric vehicles at balanced energy content of the electric storage devices

Innovative analytically based method to calculate corrected fuel consumption of parallel and series hybrid electric vehicles (HEVs) at balanced energy content of the electric storage devices is proposed and validated in the paper. The proposed analytical method is generally applicable and features highly accurate corrected fuel consumption results. It enables calculation of the corrected fuel consumption out of a single fuel consumption test run in a single analytic post-processing step. An additional fuel consumption test run might be needed to obtain highly accurate results if ratio of the energy content deviation of the electric storage devices to the energy used for vehicle propulsion over the test cycle is high. Proposed method enables consideration of non-linear energy flow changes and non-linear HEV component efficiency changes caused by the energy management strategy or by the component characteristics. The method therefore features highly accurate results out of the minimum number of fuel consumption test runs and thus optimizes workload for development or optimization of HEVs. The input data of the method are characteristic energy flows and efficiencies that are derived from the energy flows on selected energy paths of HEVs.     

Comparative life cycle assessment of hydrogen pathways from fossil sources in China

Emissions of multiple hydrogen production pathways from fossil sources were evaluated and compared with that of fossil fuel production pathways in China by using the life cycle assessment method. The considered hydrogen pathways are gasoline reforming, diesel reforming, natural gas reforming, soybean‐derived biodiesel (s‐biodiesel) reforming, and waste cooking oil‐derived biodiesel reforming. Moreover, emissions and energy consumption of fuel cell vehicles utilizing hydrogen from different fossil sources were presented and compared with those of the electric vehicle, the internal combustion engine vehicle, and the compression ignition engine vehicle. The results indicate both fuel cell vehicles and the electric vehicle have less greenhouse gas emissions and energy consumption compared with the traditional vehicle technologies in China. Based on an overall performance comparison of five different fuel cell vehicles and the electric vehicle in China, fuel cell vehicles operating on hydrogen produced from natural gas and waste cooking oil‐derived biodiesel show the best performance, whereas the electric vehicle has the worse performance than all the fuel cell vehicles because of very high share of coal in the electricity mix of China. The emissions of electric vehicle in China will be in the same level with that of natural gas fuel cell vehicle if the share of coal decreases to around 40% and the share of renewable energy increases to around 20% in the electricity mix of China. Copyright © 2016 John Wiley & Sons, Ltd.     

Neural network based optimization for cascade filling process of on-board hydrogen tank

Compressed hydrogen storage is widely used in hydrogen fuel cell vehicles (HFCVs). Cascade filling systems can provide different pressure levels associated with various source tanks allowing for a variable mass flow rate. To meet refueling performance objectives, safe and fast filling processes must be available to HFCVs. The main objective of this paper is to establish an optimization methodology to determine the initial thermodynamic conditions of the filling system that leads to the lowest final temperature of hydrogen in the on-board storage tank with minimal energy consumption. First, a zero-dimensional lumped parameter model is established. This simplified model, implemented in Matlab/Simulink, is then used to simulate the flow of hydrogen from cascade pressure tanks to an on-board hydrogen storage tank. A neural network is then trained with model calculation results and experimental data for multi-objective optimization. It is found to have good prediction, allowing the determination of optimal filling parameters. The study shows that a cascade filling system can well refuel the on-board storage tank with constant average pressure ramp rate (APRR). Furthermore, a strong pre-cooling system can effectively lower the final temperature at a cost of larger energy consumption. By using the proposed neural network, for charging times less than 183s, the optimization procedure predicts that the inlet temperature is 259.99–266.58 K, which can effectively reduce energy consumption by about 2.5%.     

Modeling operating modes,energy consumptions,and infrastructure requirements of fuel cell plug in hybrid electric vehicles using longitudinal geographical transportation data

The fuel cell plug in hybrid electric vehicle (FCPHEV) is a near-term realizable concept to commercialize hydrogen fuel cell vehicles (FCV). Relative to conventional FCVs, FCPHEVs seek to achieve fuel economy benefits through the displacement of hydrogen energy with grid-sourced electrical energy, and they may have less dependence on a sparse hydrogen fueling infrastructure. Through the simulation of almost 690,000 FCPHEV trips using geographic information system (GIS) data surveyed from a fleet of private vehicles in the Puget Sound area of Washington State, USA, this study derives the electrical and hydrogen energy consumption of various design and control variants of FCPHEVs. Results demonstrate that FCPHEVs can realize hydrogen fuel consumption reductions relative to conventional FCV technologies, and that the fuel consumption reductions increase with increased charge depleting range. In addition, this study quantifies the degree to which FCPHEVs are less dependent on hydrogen fueling infrastructure, as FCPHEVs can refuel with hydrogen at a lower rate than FCVs. Reductions in hydrogen refueling infrastructure dependence vary with control strategies and vehicle charge depleting range, but reductions in fleet-level refueling events of 93% can be realized for FCPHEVs with 40 miles (60 km) of charge depleting range. These fueling events occur on or near the network of highways at approximately 4% of the rate (refuelings per year) of that for conventional FCVs. These results demonstrate that FCPHEVs are a type of FCV that can enable an effective and concentrated hydrogen refueling network.     

The role of hydrogen cars in the economy of California

Hydrogen has been proposed as an alternative transportation fuel that could reduce energy consumption and eliminate tailpipe emissions when used in fuel cell vehicles (FCVs). To investigate the potential effects of hydrogen vehicles on California’s economy over the next two decades, we employed the modified Costs for Advanced Vehicles and Energy (CAVE) model and a California-specific computable general equilibrium model. Results indicate that, even in the aggressive scenario, hydrogen cars can only account for a minor fraction of the on-road fleet through 2030. Although new sales could drop sharply, conventional gasoline cars and carryover pre-2010 vehicles are still expected to dominate the on-road vehicle stock and consume the majority of transportation energy through 2030. Transportation energy consumption could decline dramatically, mainly because of the fuel economy advantage of FCVs over conventional cars. Both moderate and aggressive hydrogen scenarios are estimated to have a slightly negative influence on California’s economy. However, the negative economic impacts could be lessened as the market for hydrogen and FCVs builds up. Based on the economic optimization model, both hydrogen scenarios would have a negative economic impact on California’s oil refining sector and, as expected, a positive impact on the other directly related sectors that contribute to either hydrogen production or FCV manufacturing.     

Metaheuristic-based energy management strategies for fuel cell emergency power unit in electrical aircraft

This paper aims at presenting a comparative analysis of different metaheuristic algorithms in the application of energy management for fuel cell-based hybrid emergency power unit within electrical aircraft. Two energy management conventional strategies are employed while optimizing the operating temperature. Both the external energy maximization and the equivalent consumption minimization strategies are dealt with. The most efficient up-to-date metaheuristic techniques such as the artificial bee colony, the grey wolf optimization, the cuckoo search, the mine blast algorithm, the whale optimization algorithm, the moth swarm algorithm, the harmony search, the modified flower pollination algorithm and the electromagnetic field optimization are considered. The overall index of optimization performance is considered as a function of hydrogen consumption, overall system efficiency, variations of states of charge and stresses in different energy sources. The numerical simulations, through Matlab™/Simulink, highlights the capability of the different metaheuristic optimization techniques towards reducing the amount of consumed hydrogen in fuel cell-based emergency power unit in electrical aircrafts. The electromagnetic field optimization method results in significant hydrogen consumption reduction in comparison with the other proposed techniques.     

Cost-optimal design and energy management of fuel cell electric trucks

Road freight transport on hilly routes represents a significant challenge for the advancement of fuel cell electric trucks because of the high-performance requirements for fuel consumption, vehicle lifetime, and battery charge control. Therefore, it is essential to optimize the vehicle design and energy management, which greatly influence the driving performance and total cost of ownership. This paper focuses on the cost-optimal design and energy management of fuel cell electric trucks, considering five key influencing factors: powertrain component sizing, driving cycle, vehicle weight, component degradation, and market prices. The cost optimization relies on a novel predictive energy management scheme based on dynamic programming and the systematic calibration of control parameters. The paper analyzes the simulation results to highlight three main findings for fuel cell electric trucks: 1) cost-optimal energy management is essential to define the best trade-off between fuel consumption and component degradation; 2) the total cost of ownership is significantly influenced by component sizing, driving cycles, vehicle weight, and market prices; 3) predictive energy management is highly beneficial in challenging road topographies for substantial cost-saving and lower component size requirements.     

Solar-powered hydrogen refuelling station for unmanned aerial vehicles: Design and initial AC test results

Fuel cell technology can offer environmental benefits (low noise and emissions) and also a competitive advantage over conventional power sources (better performance, low thermal signature, less vibration issues, etc) in small manned and unmanned electric air vehicles (UAVs). To develop an environmentally acceptable solution, the hydrogen fuel source must be produced on-site from renewable energy sources. This paper describes the development and testing of a fully operational small-scale demonstrator to generate and supply hydrogen for 2 to 3 daily fuel cell-powered UAV operations. The purity of the hydrogen delivered to the air platforms is ≥99.99%.     

Lifecycle performance assessment of fuel cell/battery electric vehicles

This paper has performed an assessment of lifecycle (as known as well-to-wheels, WTW) greenhouse gas (GHG) emissions and energy consumption of a fuel cell vehicle (FCV). The simulation tool MATLAB/Simulink is employed to examine the real-time behaviors of an FCV, which are used to determine the energy efficiency and the fuel economy of the FCV. Then, the GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model is used to analyze the fuel-cycle energy consumption and GHG emissions for hydrogen fuels. Three potential pathways of hydrogen production for FCV application are examined, namely, steam reforming of natural gas, water electrolysis using grid electricity, and water electrolysis using photovoltaic (PV) electricity, respectively. Results show that the FCV has the maximum system efficiency of 60%, which occurs at about 25% of the maximum net system power. In addition, the FCVs fueled with PV electrolysis hydrogen could reduce about 99.2% energy consumption and 46.6% GHG emissions as compared to the conventional gasoline vehicles (GVs). However, the lifecycle energy consumption and GHG emissions of the FCVs fueled with grid-electrolysis hydrogen are 35% and 52.8% respectively higher than those of the conventional GVs. As compared to the grid-based battery electric vehicles (BEVs), the FCVs fueled with reforming hydrogen from natural gas are about 79.0% and 66.4% in the lifecycle energy consumption and GHG emissions, respectively.     

The potential role of hydrogen as a sustainable transportation fuel to combat global warming

Hydrogen is recognized as a key source of the sustainable energy solutions. The transportation sector is known as one of the largest fuel consumers of the global energy market. Hydrogen can become a promising fuel for sustainable transportation by providing clean, reliable, safe, convenient, customer friendly, and affordable energy. In this study, the possibility of hydrogen as the major fuel for transportation systems is investigated comprehensively based on the recent data published in the literature. Due to its several characteristic advantages, such as energy density, abundance, ease of transportation, a wide variety of production methods from clean and renewable fuels with zero or minimal emissions; hydrogen appears to be a great chemical fuel which can potentially replace fossil fuel use in internal combustion engines. In order to take advantage of hydrogen as an internal combustion engine fuel, existing engines should be redesigned to avoid abnormal combustion. Hydrogen use in internal combustion engines could enhance system efficiencies, offer higher power outputs per vehicle, and emit lower amounts of greenhouse gases. Even though hydrogen-powered fuel cells have lower emissions than internal combustion engines, they require additional space and weight and they are generally more expensive. Therefore, the scope of this study is hydrogen-fueled internal combustion engines. It is also highlighted that in order to become a truly sustainable and clean fuel, hydrogen should be produced from renewable energy and material resources with zero or minimal emissions at high efficiencies. In addition, in this study, conventional, hybrid, electric, biofuel, fuel cell, and hydrogen fueled ICE vehicles are comparatively assessed based on their CO₂ and SO₂ emissions, social cost of carbon, energy and exergy efficiencies, fuel consumption, fuel price, and driving range. The results show that when all of these criteria are taken into account, fuel cell vehicles have the highest average performance ranking (4.97/10), followed by hydrogen fueled ICEs (4.81/10) and biofuel vehicles (4.71/10). On the other hand, conventional vehicles have the lowest average performance ranking (1.21/10), followed by electric vehicles (4.24/10) and hybrid vehicles (4.53/10).     

An experimental and analytical comparison study of power management methodologies of fuel cell-battery hybrid vehicles

The implementation of fuel cell vehicles requires a supervisory control strategy that manages the power distribution between the fuel cell and the energy storage device. Some of the current problems with power management strategies are: fuel efficiency optimization methods require prior knowledge of the driving cycle before they can be implemented, the impact on the fuel cell and battery life cycle are not considered and finally, there are no standardized measures to evaluate the performance of different control methods. In addition to that, the performances of different control methods for power management have not been directly compared using the same mathematical models. The proposed work will present a different optimization approach that uses fuel mass flow rate instead of fuel mass consumption as the cost function and thus, it can be done instantaneously and does not require knowledge of the driving cycle ahead of time. Also this study presents an experimental approach to validate the mathematical simulation results.     

Energy distribution analyses of an additional traction battery on hydrogen fuel cell hybrid electric vehicle

Hydrogen is the most abundant element in the world and produces only water vapor as a result of chemical reaction that occurred in fuel cells. Therefore, fuel cell electric vehicles, which use hydrogen as fuel, continue its growing trend in the sector. In this study, an energy distribution comparison is carried out between fuel cell electric vehicle and fuel cell hybrid electric vehicle. Hybridization of fuel cell electric vehicle is designed by equipped a traction battery (15 kW). Modeled vehicles were prepared under AVL Cruise program with similar chassis and same fuel cell stacks for regular determining process. Numerical analyses were presented and graphed with instantaneous results in terms of sankey diagrams with a comparison task. WLTP driving cycle is selected for both vehicles and energy input/output values given with detailed analyses. The average consumption results of electric and hydrogen usage is found out as 4.07 kWh and 1.125 kg/100 km respectively for fuel cell electric vehicle. On the other hand, fuel cell hybrid electric vehicle’s average consumption results figured out as 3.701 kWh for electric and 0.701 kg/100 km for hydrogen consumption. As a result of this study, fuel cell hybrid electric vehicle was obtained better results rather than fuel cell electric vehicle according to energy and hydrogen consumption with 8% and 32%, respectively.     

70 MPa加氢站动态模拟与能耗分析

目的  加氢站是氢燃料电池车推广应用的关键基础设施。70 MPa加氢可以显著提升氢燃料电池车的续航能力和经济性。为准确分析70 MPa加氢站的能耗,降低运营成本。 方法  建立了70 MPa加氢站加氢过程动态热力学模型,基于SAE J2601加注协议研究了单次加氢过程中压力和温度的动态变化规律,分析了单次加氢的能耗组成和多次加氢的能耗变化。 结果  结果表明：单次加氢过程中165 s加满车载储氢瓶,295 s完成高压储氢瓶补氢,5 min内完成一次加氢循环。加氢能耗由压缩机、冷水机组和冷冻机组能耗组成,其中压缩机能耗超过64%,冷水机组能耗约为压缩机能耗三分之一。随着加氢次数增多,单次加氢能耗升高,第一次和第二十次加氢的比能耗分别为0.98 kWh/kg和1.24 kWh/kg。 结论  缩短单次加氢时间可以从提升压缩机流量入手。降低压缩机能耗是加氢过程节能的关键环节。三级高压储氢瓶的压力配置影响加氢能耗中的多个环节,如何对三级压力进行合理配置,值得进一步研究。     

A robust online energy management strategy for fuel cell/battery hybrid electric vehicles

Traditional optimization-based energy management strategies (EMSs) do not consider the uncertainty of driving cycle induced by the change of traffic conditions, this paper proposes a robust online EMS (ROEMS) for fuel cell hybrid electric vehicles (FCHEV) to handle the uncertain driving cycles. The energy consumption model of the FCHEV is built by considering the power loss of fuel cell, battery, electric motor, and brake. An offline linear programming-based method is proposed to produce the benchmark solution. The ROEMS instantaneously minimizes the equivalent power of fuel cell and battery, where an equivalent efficiency of battery is defined as the efficiency of hydrogen energy transforming to battery energy. To control the state of charge of battery, two control coefficients are introduced to adjust the power of battery in objective function. Another penalty coefficient is used to amend the power of fuel cell, which reduces the load change of fuel cell so as to slow the degradation of fuel cell. The simulation results indicate that ROEMS has good performance in both fuel economy and load change control of fuel cell. The most important advantage of ROEMS is its robustness and adaptivity, because it almost produces the optimal solution without changing the control parameters when driving cycles are changed.