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[Display omitted] • A two-phase mass transfer model of paper-based microfluidic fuel cell is proposed. • The coupling characteristics of capillary action and two-phase flow are revealed. • The fluctuation mechanism of cell performance and gas distribution is explored. • Gas removal strategies are summarized, with a maximum gas removal rate of 42.30%. Paper-based microfluidic fuel cell powered by capillary force has the advantages of compactness, low cost, and high sensitivity, presenting broad application prospects in portable electronic devices. However, the gas-liquid mass transfer mechanism within the porous medium remains unclear, with a lack of two-phase flow theories adapted to the unique paper-based system. In this study, a two-dimensional two-phase numerical model of a Y-shaped paper-based microfluidic fuel cell is developed to reveal the two-phase flow characteristics under capillary action and explore gas removal strategies. The reliability of the model is validated by real experimental data. By coupling multiple physical fields, the study elucidates the working principle and gas-liquid flow phenomena within the cell. Then, the effects of contact angle, inlet fuel concentration, and paper type on output performance, gas distribution, parasitic effect, and fuel utilization are discussed. The results indicate that increasing the contact angle and using paper with a larger average pore size and porosity as the channel substrate are ideal for promoting gas discharge. The optimal gas removal rate reached 42.30 %, with a favorable power density of 33.92 mW/cm2. This study provides a theoretical basis for a deeper understanding of the two-phase mass transfer process in paper-based microfluidic fuel cell. [ABSTRACT FROM AUTHOR]

Paper-based self-pumping microfluidic fuel cells (PMFCs) typically exploit the wicking effects in porous papers to enable passive reactant delivery and co-laminar flow, eliminating micro pumps and physical membranes. PMFCs have been regarded as promising micro-power sources for next-generation paper-based electrochemical microfluidic assays for biomedical applications. However, the PMFC performance is fundamentally limited by the low capillary flow velocity and ineffective diffusive fuel transport. In this study, a novel PMFC with an anodic wedge-shaped channel is developed. The anodic wedge-shaped channel enables reactant convection at improved fuel flow velocity. Visualization experiments suggest that the fuel flow velocity can be improved by about 23 times in this anodic wedge-shaped channel configuration as compared to that in conventional single-layer paper-based flow channel. In addition, favorable features like localized enhancement of fuel transport and reduced fuel crossover are also observed in this novel configuration. Due to enhanced convective-diffusive fuel transport, the cell performance can be improved 245.8 % as compared to the single-layer case. The peak power density reaches 59.9 mW cm−2 and the limiting current density achieves 305.9 mA cm−2, outperforming most of the previous PMFCs. This anodic wedge-shaped channel configuration can also be potentially used in paper-based assays to enhance reactant delivery. • Wedge-shaped channel is formed by inserting anode between two-layer flow channel. • The anodic wedge-shaped channel can significantly increase fuel flow velocity. • The anodic wedge-shaped channel also helps to reduce fuel crossover. • Anodic fuel transport is enhanced by convection and diffusion. • The peak power density is increased 245.8 % by using wedge-shaped channel. [ABSTRACT FROM AUTHOR]

• Efforts to enhance PMFC performance are reviewed. • Both exciting advancements and current limitations are discussed. • An innovative strategy of multi-scale simultaneous optimization is proposed. Paper-based microfluidic fuel cell (PMFC) has attracted great attention in the microfluidic fuel cell field in recent years. It utilizes the spontaneous capillary flow of reactant solutions in paper-based porous substrate to achieve passive transportations of fuel and oxidant, solving the fluid driving issue encountered in traditional microfluidic fuel cells and thus having broad application prospects in medical detection, wearable devices, micro sensors, environmental monitoring, and many other fields. However, the commercialization of this technology is impeded by the low output performance caused by the limited mass and energy transfer in PMFCs. To enhance the mass and energy transfer in PMFCs, numerous research studies have been conducted via experimental optimization of the cell materials and structures. Numerical analyses focusing on the structure–activity relationship of PMFCs were also performed recently. To provide a comprehensive and thorough review about the efforts devoted to improving performance of PMFC, research papers relevant to PMFC since its invention in 2014 have been extracted in this work and significant works were filtered to highlight the exciting advancements. The experimental studies were classified and discussed based on the key components involved in the PMFC system, followed by a critical review of the limited computational models. Potential directions for future research were also provided, aimed at overcoming the current technological challenges in PMFCs. Importantly, an innovative strategy of multi-scale simultaneous optimization of the cell properties is proposed considering the typical multi-scale feature of the PMFC system, which could inspire the designing of advanced cell materials with optimal multi-scale structures for applications of PMFCs. [ABSTRACT FROM AUTHOR]

Hydrogen Economy and Cyclic Economy are advocated, together with the use of perennial (solar, wind, hydro, geo-power, SWHG) and renewable (biomass) energy sources, for defossilizing anthropic activities and mitigating climate change. Each option has intrinsic limits that prevent a stand-alone success in reaching the target. Humans have recycled goods (metals, water, paper, and now plastics) to a different extent since very long time. Recycling carbon (which is already performed at the industrial level in the form of CO 2 utilization and with recycling paper and plastics) is a key point for the future. The conversion of CO 2 into chemicals and materials is carried out since the late 1800s (Solvay process) and is today performed at scale of 230 Mt/y. It is time to implement on a scale of several Gt/y the conversion of CO 2 into energy products, possibly mimicking Nature which does not use hydrogen. In the short term, a few conditions must be met to make operative on a large scale the production of fuels from recycled-C, namely the availability of low-cost: i. abundant, pure concentrated streams of CO 2 , ii. non-fossil primary energy sources, and iii. non-fossil-hydrogen. The large-scale production of hydrogen by Methane Steam Reforming with CO 2 capture (Blue-H 2) seems to be a realistic and sustainable solution. Green-H 2 could in principle be produced on a large scale through the electrolysis of water powered by perennial primary sources, but hurdles such as the availability of materials for the construction of long-living, robust electrochemical cells (membranes, electrodes) must be abated for a substantial scale-up with respect to existing capacity. The actual political situation makes difficult to rely on external supplies. Supposed that cheap hydrogen will be available, its direct use in energy production can be confronted with the indirect use that implies the hydrogenation of CO 2 into fuels (E-fuels), an almost ready technology. The two strategies have both pros and cons and can be integrated. E-Fuels can also represent an option for storing the energy of intermittent sources. In the medium-long term, the direct co-processing of CO 2 and water via co-electrolysis may avoid the production/transport/ use of hydrogen. In the long term, coprocessing of CO 2 and H 2 O to fuels via photochemical or photoelectrochemical processes can become a strategic technology. • Hydrogen Economy and Cyclic Economy are discussed as an option for defossilizing anthropic activities and mitigating climate change. • In the short term, a few conditions must be met to make operative on a large scale the production of fuels from recycled-C. • In the medium-long term, the direct co-processing of CO 2 and water via co-electrolysis may avoid the production/transport/ use of hydrogen. • In the long term, coprocessing of CO 2 and H 2 O to fuels via photochemical or photoelectrochemical processes can become a strategic technology. [ABSTRACT FROM AUTHOR]

The application of hydrogen energy is affected by the safety of hydrogen storage system. To grasp the current status of research and application in the research field of hydrogen storage safety and explore its research development trend, data analysis techniques, such as co-occurrence, co-citation, and burst detection, were adopted to conduct bibliometric analysis of the relevant literature. The study results show that the research hotspots of hydrogen storage safety mainly concentrate on six aspects: the stability of metal hydride hydrogen storage materials, the study of thermal management and stress relief in metal hydride reactors, the safety analysis of hydrogen fuel cells and hydrogen leakage monitoring, the analysis of leakage and explosion risks in hydrogen refueling stations, the study of filling pressure and temperature distribution in hydrogen storage tanks, and the study of safety issues in underground hydrogen storage. Mg-based hydride stability and underground hydrogen storage risk analyses are current research frontiers in hydrogen storage safety. • This paper presents the development of hydrogen storage in safety research. • 1552 papers are visualized and analyzed using bibliometrics. • Identifying research frontiers by combining timeline view with burst detection. • Knowledge bases, research hotspots, and frontiers are discussed. • The current challenges and perspectives for the future are proposed. [ABSTRACT FROM AUTHOR]

The durability is a key factor of fuel cell in large-scale application of automobiles. It is great important to real the lifetime and health status of fuel cells, especially in vehicle driving conditions. Based on the experimental data, this paper used the model-based method and data-driven method to predict the life of fuel cells, respectively. The model-based method established the equivalent circuit model according to the mapping law of electrochemical impedance spectroscopy (EIS) and the parameters of the equivalent circuit model were identified by newly considering the phenomenon of voltage recovery, revealing the strong linear correlation between impedance and voltage. The data-driven method selected a combinatorial optimization PSO-LSSVM algorithm and compared it with the prediction results of MATLAB's time series toolbox. The results show the mean square error (MSE), End of Life (EOL) of the model-based method, the time series toolbox and PSO-LSSVM algorithm are 0.019, 8.2 × 10−3 and 4.42 × 10−5, the 260h, 438h and 427h, respectively. Comparing with the real EOL of 421h, the error of PSO-LSSVM algorithm is only 6 h, which means the remaining useful life can be predicted with high accurately. Thus this study provides a reference for fault identification and life prediction of fuel cell health management. • The equivalent circuit model is established to realize the segmented voltage prediction and analysis of fuel cells. • The MSE of combinatorial optimized algorithms PSO-LSSVM to predict voltage is only 4.42 × 10−5. • The method in paper provides a reference for fault identification and life prediction of PEMFC's health management. [ABSTRACT FROM AUTHOR]

Hydrogen transfer leaks are one of the most important life-limiting faults in polymer electrolyte membrane fuel cells (PEMFCs). Hydrogen transfer leaks result in a reduction in the amount of oxygen available in the cathode (air) channel, with large leaks resulting in oxygen starvation and hydrogen emission. This paper aims to develop an adaptive extended Kalman filter (EKF) to estimate the unknown oxygen concentration, which is then used to infer hydrogen leaks. To this end, the paper first develops the lumped model of the fuel cell from a pseudo-2D model of a fuel cell. Next, a (non-adaptive) EKF is developed to estimate the fuel cell states under both normal and oxygen-starved conditions. The adaptive EKF is then implemented by adding the unknown hydrogen leak to the list of estimated states. Finally, the paper demonstrates the efficacy of the proposed adaptive EKF by using it to accurately estimate unknown hydrogen leaks in a high-fidelity virtual fuel cell under excessively noisy conditions. • Adaptive extended Kalman filter under normal and starved conditions. • Detects leaks under the presence of excessive noise. • Uses transient model of starved fuel-cell capturing voltage. • Based on previously validated pseudo-2D model. • Transient response agrees with simulated experiments. [ABSTRACT FROM AUTHOR]

Fuel cell electric buses (FCBs) have proven to be a technically viable solution for transportation, owing to various advantages, such as reliability, simplicity, better energy efficiency, and quietness of operation. However, large-scale adoption of FCBs is hindered by the lack of extensive and structured infrastructure and the high cost of clean hydrogen. Many studies agree that one of the significant contributors to the lack of competitiveness of green hydrogen is the cost of electricity for its production, followed by transportation costs. On the one hand, to reduce the investment cost of the electrolyzer, high operating hours should be achieved; on the other, as the number of operating hours decreases, the impact of the electricity costs declines. This paper presents an innovative algorithm for a scalable hydrogen refuelling station (HRS) capable of successfully matching and identifying the most cost-efficient levelized cost of hydrogen (LCOH) produced via electrolysis and connected to the grid, based on the HRS components' cost curves and the hourly average electricity price profile. The objective is to identify the least-cost range of LCOH by considering both the electric energy and the investment costs associated with a hydrogen demand given by different FCB sizes and electrolyzer rated powers. In addition, sensitivity analyses have been conducted to quantify the technology cost margins, and a cost comparison between the refuelling of an FCB fleet and the recharging infrastructure required for an equivalent fleet of Battery Electric Buse (BEB) has been performed. An LCOH of around 10.5 €/kg varying from 12 €/kg (2 FCB) to 10.2 €/kg (30 FCB) has been found for the best-optimized configurations. The final major conclusion of this paper is that FCB technology is currently not economically competitive. Still, a cost contraction of the electric energy price and the electrolyzer capital investment would lead to a 50% decrease in the LCOH. Furthermore, increasing renewable energies into the grid may shift the electricity cost curve, resulting in higher prices when the BEB recharging demand is more significant. This impact, in addition to the peak power load and longer recharging times, might contribute to bridging the gap with FCBs. • Techno-economic model for the sizing of an HRS with grid-connected electrolyzer. • The widespread diffusion of H2 technology in mobility needs both reliability and cost-effectiveness. • Investigation of various electrolysers rated powers and fuel cell buses fleet size. • An action on both CAPEX and OPEX would lead to potential cost margins improvement. • It is found that the best configuration that balances the CAPEX and OPEX coincides with an LCOH ranging from 12 to 10 €/kg. [ABSTRACT FROM AUTHOR]

This paper provides an in-depth examination of critical and strategic raw materials (CRMs) and their crucial role in the development of electrolyzer and fuel cell technologies within the hydrogen economy. It methodically analyses a range of electrolyzer technologies, including alkaline, proton-exchange membrane, solid-oxide, anion-exchange membrane, and proton-conducting ceramic systems. Each technology is examined for its specific CRM dependencies, operational characteristics, and the challenges associated with CRM availability and sustainability. The study further extends to hydrogen storage and separation technologies, focusing on the materials employed in high-pressure cylinders, metal hydrides, and hydrogen separation processes, and their CRM implications. A key aspect of this paper is its exploration of the supply and demand dynamics of CRMs, offering a comprehensive view that encompasses both the present sttate and future projections. The aim is to uncover potential supply risks, understand strategies, and identify potential bottlenecks for materials involved in electrolyzer and fuel cell technologies, addressing both current needs and future demands as well as supply. This approach is essential for the strategic planning and sustainable development of the hydrogen sector, emphasizing the importance of CRMs in achieving expanded electrolyzer capacity leading up to 2050. • Analyzes CRMs in hydrogen tech, focusing on electrolyzers and fuel cells. • Explores CRM implications in hydrogen storage and separation. • Investigates CRM supply and demand, identifying risks and strategies. • Highlights the role of CRMs in sustainable hydrogen sector development. [ABSTRACT FROM AUTHOR]

The power system using hydrogen fuel cells (FCs) as the primary energy source holds significant potential for applications in emergency fields such as post-disaster relief and outdoor power supply. The operational environment of the FC emergency power supply system (FCEPSS) is challenging, with long continuous operation time, difficulties in hydrogen supply, high maintenance costs, and, accordingly, requirements for hydrogen consumption and useful life of FCs are heightened. Hence, this paper proposes a multi-objective energy management strategy (EMS) for FCEPSS. First, the structure of FCEPSS is designed based on the demand analysis in emergency scenarios. Then, the hydrogen consumption and life degradation models of FCEPSS are established. Aiming at the multi-objective optimization problem of minimizing hydrogen consumption and life degradation value in the FCEPSS, an improved multi-objective optimization algorithm is proposed. This paper converts complex constraints into the penalty term and incorporates it as one of the objectives, constructing a three-objective optimization model. To enhance the solution of multi-objective optimization problems, an improved strategy based on relaxation-tightening and three-objective sorting is proposed. Combining the fast non-dominated sorting genetic algorithm-II and the above improved strategy, an improved multi-objective optimization algorithm (IMOOA) is constructed. In the simulation, the advantages of the proposed IMOOA algorithm are verified. In the experimental part, compared with the logical threshold strategy, the proposed strategy saves 0.60% of hydrogen consumption and reduces 5.65% of life degradation within 24 h, respectively. Finally, the superiority of the multi-objective EMS utilizing the IMOOA is demonstrated. [Display omitted] • The demand analysis and scheme design of fuel cell emergency power supply system are carried out. • A multi-objective energy management strategy for low hydrogen consumption and long useful life is designed. • An algorithm based on the relaxation-tightening and three-sorting principle is constructed. [ABSTRACT FROM AUTHOR]

Promoting green hydrogen has emerged as a pivotal discourse in the contemporary energy landscape, driven by pressing environmental concerns and the quest for sustainable energy solutions. This paper delves into the multifaceted domain of C -Suite issues about green hydrogen, encompassing both technological advancements and policy considerations. The question of whether green hydrogen is poised to become the focal point of the upcoming energy race is explored through an extensive analysis of its potential as a clean and versatile energy carrier. The transition from conventional fossil fuels to green hydrogen is considered a fundamental shift in energy paradigms, with far-reaching implications for global energy markets. The paper provides a comprehensive overview of state-of-the-art green hydrogen technologies, including fuel cells, photocatalysts, photo electrocatalysts, and hydrogen panels. In tandem with technological advancements, the role of policy and strategy in fostering the development of green hydrogen energy assumes paramount significance. The paper elucidates the critical interplay between government policies, market dynamics, and corporate strategies in shaping the green hydrogen landscape. It delves into policy mechanisms such as subsidies, carbon pricing, and renewable energy mandates, shedding light on their potential to incentivize the production and adoption of green hydrogen. This paper offers a nuanced exploration of C -Suite issues surrounding green hydrogen, painting a comprehensive picture of the technological and policy considerations that underpin its emergence as a transformative energy source. As the global community grapples with the imperatives of climate change mitigation and the pursuit of sustainable energy solutions, understanding these issues becomes imperative for executives, policymakers, and stakeholders alike. [Display omitted] • The latest advancements in photo electrocatalysts and fuel cell technologies are reviewed. • The storage and transportation within the realm of green hydrogen energy were discussed. • Policy and strategy for fostering the development of green energy are proposed. [ABSTRACT FROM AUTHOR]

As the global shipping industry experiences rapid expansion, the imperative to address greenhouse gas emissions and environmental impact becomes increasingly paramount. Hydrogen has emerged as a pivotal and eco-friendly energy source, offering a pathway towards carbon neutrality and a complete zero-carbon transition in maritime operations. However, the widespread adoption of hydrogen-powered ships hinges on the establishment of robust regulations and technical standards. This paper conducts a comprehensive examination of hydrogen fuel cell (FC) technology in ships, scrutinizing the role of international classification societies and exploring existing standards and regulations within the maritime industry, specifically centered around hydrogen energy. The study outlines a strategic developmental roadmap for a green shipping hydrogen energy system tailored for hydrogen FC-powered ships in China. Emphasizing the differences in hydrogen application between fuel cell vehicles and ships, the paper elucidates technical challenges unique to hydrogen FC-powered ships. Furthermore, it proposes a visionary framework for future technical standards, advocating for the creation of a ship-based hydrogen energy standard system, the development of core technical standards, and a heightened focus on safety regulations. Through comprehensive analysis and compelling argumentation on hydrogen fuel cell ship technology and standards, this paper underscores the indispensable role that technical standards play in propelling the advancement of environmentally friendly shipping. Beyond serving as an informative resource, the paper aims to provide valuable guidance and direction for the future demonstration, application, and promotion of hydrogen fuel cell ship technology. Ultimately, it underscores the pivotal role of technical standards in advancing sustainable maritime transportation. • Analyze hydrogen energy technical standards from the production, storage, safety. • Comparison of hydrogen energy technical differences between vehicles and ships. • Outline the unique challenges of applying hydrogen technology to ship operations. • Constructed a technical standard framework for future hydrogen energy ships. [ABSTRACT FROM AUTHOR]

Locomotive engines serve as the powering heart of rail transportation which is widely used for massive cargo over long distances. The traditional locomotive engines have depended on the internal combustion engine for decades, operated using fossil fuels that negatively impact the environment. Since more and more commodities are transported by trains, the prime engines need to be improved where the fuels are expected to enhance the engine's performance and alleviate the environmental impact. This paper presents a comparison of three developed locomotive engines with different configurations, such as an internal combustion engine combined with a gas turbine and molten carbonate fuel cell (ICE-GT-MCFC), a gas turbine combined with a solid oxide fuel cell and onboard hydrogen production using aluminum electrolysis cell (GT-SOFC), and a GT combined with sold oxide and proton exchange membrane fuel cells (GT–SOFC–PEMFC). The paper then identifies one hybridized engine, which is GT–SOFC–PEMFC, according to its low weight and better performance to conduct an optimization study to enhance its efficiency, reduce the cost, and lower the environmental impact. The present optimization study is undertaken through a multi-objective particle swarm optimization, involving thermodynamic, exergoeconomic, and exergoenvironmental analyses. The optimized GT–SOFC–PEMFC locomotive engine is improved in power from 5.9 MW to 7.3 MW and improved in performance to 49.1% energetic efficiency and 47.0% exergetic efficiency. Additionally, the optimized GT–SOFC–PEMFC engine has less specific fuel and product cost of 24.9 $/GJ and 34.7 $/GJ, respectively, and less specific exergetic environmental impact of fuel and product of 13.2 Pt/GJ and 16.2 Pt/GJ, respectively. Also, the relative cost difference and relative environmental impact difference are significantly reduced by more than 20% to 39.4% and 22.8%, respectively. The operational conditions of the optimized GT–SOFC–PEMFC engine are improved to achieve better efficiency and better cost effectiveness in a more environmentally-benign manner. • Comparison between three hybridized combined locomotive engines is established. • Optimized GT–SOFC–PEMFC engine has 7.3 MW power and 49% energetic efficiency. • Specific exergetic product cost declined to 51 $/GJ for fuel and 35 $/GJ. • Specific exergetic environmental impact for fuel and product becomes 13 and 16 Pt/GJ. • The relative environmental impact difference becomes 22.8% instead of 44.3%. [ABSTRACT FROM AUTHOR]

Clean energy devices have a great ability to change the world because they strengthen the economy and preserve society. The continuous improvement and progress in nanomaterials and nanotechnology have a great role in human life. The increasing prevalence of PEM fuel cells makes them one of the most viable sustainable energy sources. Nanostructured materials synthesis methodologies have introduced a breakthrough and found to overcome the obstacles for PEMFC commercialization. Amongst them, wet chemical approaches are rapidly expanding and beneficial for the fabrication of nanoparticles since they contribute toward the attainment of a range of essential nanoparticle characteristics like sizes, morphologies, structures, and phases. Wet chemical manufacturing enables fine-tuning of reaction parameters to generate the desired nanomaterials. This review article focuses on the latest improvements in wet chemical methods to better regulate the quality of nanomaterials. This paper examines how wet chemical approaches (hydrothermal synthesis, spray pyrolysis, sol-gel processing, and co-precipitate synthesis, among others) can contribute to the scalable manufacturing of nanoparticles to uphold rising industrial requirements. And how wet chemical methods have a significant influence on power generation systems (Fuel cells) along with their pros and cons. This review carefully analyzes and summarizes synthetic methods and optimized factors in order to prepare nanoparticles and carefully analyzes the reported data. In this paper, the electrochemical analysis, morphological evaluation, compositional analysis, and performance testing of materials produced using wet chemical techniques have been investigated. Recent signs of progress and innovative techniques used to overcome the complexities of synthetic nanoparticle processing. This article is a holistic approach including social, economic, and ecological aspects in the wet chemical process and will certainly help in the fabrication, and application of nanoparticles for PEM Fuel cells. [Display omitted] • Introduction to the status of materials synthesis in energy generating devices. • Overview of wet chemistry Approaches for PEMFC. • Impact of synthesis parameters on properties of materials. • Pros and Cons of wet chemistry techniques for material synthesis. [ABSTRACT FROM AUTHOR]

Unitized regenerative proton exchange membrane fuel cell (URPEMFC) as a self-sufficient hydrogen energy system offers a unique proposition for achieving a net zero emissions future. The system combines the operation of water. Due to the design parameters and operating conditions of URPEMFC, the potential cycling from the mode switching, high temperature, humidified environment and the long exposure of metallic components to hydrogen are the primary factors causing degradation to the system. Consequently, the conventional graphite bipolar plate (BP) suffers heavily under such an environment while giving rise to alternative metallic base materials, such as titanium, stainless steel, and aluminum. Various surface treatment and coating methods are currently under investigation to provide the required corrosion resistance while maintaining feasible manufacturing process and cost. This paper presents an overview into the degradation phenomena of URPEMFC that contributes to the corrosion of BP that is affecting the performance and future commercialization of the system. The operating condition of the system is summarized in terms of fuel cells and water electrolyzers respectively, along with the integration of both operations as a system. Next, the paper outlines the degradation phenomena observed on BP and the behavior of various materials under such conditions. The performances of various base and coating materials have been compiled as have characterization methods that are useful in measuring corrosion resistance. This paper aims to provide a better understanding on the overall degradation of BP in URPEMFC and overview of various material choices to identify the optimal corrosion mitigation solution. [Display omitted] • Breakdown of the URPEMFC operating parameters from the respective operation modes. • System design approaches allowing integration of fuel cell and electrolyzer modes. • Identification of the main degradation mechanism on the BP. • Tabulated data of various base materials and coatings performance. • Discussion of current experimental and modeling methods for corrosion resistance characterization. [ABSTRACT FROM AUTHOR]

This paper proposes a novel energy management strategy satisfying real-time and highly efficient energy management strategies for fuel cell hybrid electric vehicles (FCHEVs). The strategy is based on model predictive control (MPC), which integrates long short-term memory (LSTM) and dynamic programming (DP). A high-precision powertrain model of the investigated FCHEV is established for subsequent simulations. After training under several typical working conditions, LSTM is designed to forecast future power demands of the entire vehicle. Using the prediction results, the DP algorithm calculates the control scheme based on model predictive control. Considering the economy and durability of power sources, the results of four different control strategies are compared: thermostat, power following, traditional DP, and MPC. The MPC proposed in this paper reduces the total usage cost per 100 km on the test set by 9%, 33.5%, and −4.6%. • The economy and durability of vehicular fuel cell system are both considered. • The LSTM neural network is imported into MPC theory for vehicular power prediction. • The key parameters of MPC and LSTM are determined by referring to the greedy algorithm. • The computational load in MPC optimisation is reduced by simplifying DP algorithm. • The real-time performance of the supposed EMS on-board is validated. [ABSTRACT FROM AUTHOR]

The fuel cells need the high step-up DC/DC converter with low current ripples to interface to the high voltage DC grid. A novel zero voltage switching high step-up multiphase interleaved boost converter (ZVS HSMIBC) is proposed in this paper. This new converter employs advantages of low input current ripples, high voltage step-up ratio, soft-switching operation, and low switching harmonics and noise. In this paper, the two-phase interleaved structure of the proposed ZVS HSMIBC is analyzed and researched in detail as a representative topology. The relevant conclusions also can apply to multiphase (3 and above) interleaved structure of the HSMIBC. Finally, an experimental prototype is built and test, the experimental results show that the proposed converter can operated under ZVS conditions with low input current ripples and low switching noise and harmonics. In addition, this converter can obtain high voltage step-up ratio up to 45 (mn = 8, d = 0.8) with high efficiency, and proportion of the experimental ratios to theoretical ratios is also high (not less than 0.8). • A high step-up multiphase interleaved boost converter is proposed for the fuel cell power system. • The converter includes soft-switching circuit, high voltage ratio circuit, and interleaved structure. • The converter employs advantages of low input current ripples, high voltage gain, and low switching harmonics. • The operating principle and performance of the converter is verified by an experimental prototype. [ABSTRACT FROM AUTHOR]

Environmental working conditions have a great impact on the power demand and fuel consumption of vehicles, and the rational use of road terrain information plays an important role in the improvement of vehicle economy and energy sources durability. In this paper, a fuel cell hybrid electric bus (FCHEB) energy management strategy (EMS) based on deep deterministic policy gradient (DDPG) algorithm taking into account future terrain information is proposed based on cyber-physical system (CPS) to reduce the economic cost of FCHEB. First, this paper implements the information exchange between the vehicle system and the network layer through CPS to obtain the environmental working conditions of the vehicle operation. Second, future terrain information is introduced into the framework for the first time with hydrogen consumption, battery degradation and fuel cell durability constraints to rationally allocate the power of the FCHEB. The results show that the proposed strategy improves the power battery durability by 7.39% and reduces the total operating cost by 5.76% compared to the EMS that ignores the future terrain information. • An energy management strategy that considers future terrain information is proposed. • The proposed strategy achieves an effective combination with cyber physical system. • A trade-off between hydrogen consumption and energy sources durability is achieved. • The proposed strategy reduces the total cost by 7.81% compared to NTI EMS. [ABSTRACT FROM AUTHOR]

Hydrogen is considered as a promising fuel in the 21st century due to zero tailpipe CO 2 emissions from hydrogen-powered vehicles. The use of hydrogen as fuel in vehicles can play an important role in decarbonising the transport sector and achieving net-zero emissions targets. However, there exist several issues related to hydrogen production, efficient hydrogen storage system and transport and refuelling infrastructure, where the current research is focussing on. This study critically reviews and analyses the recent technological advancements of hydrogen production, storage and distribution technologies along with their cost and associated greenhouse gas emissions. This paper also comprehensively discusses the hydrogen refuelling methods, identifies issues associated with fast refuelling and explores the control strategies. Additionally, it explains various standard protocols in relation to safe and efficient refuelling, analyses economic aspects and presents the recent technological advancements related to refuelling infrastructure. This study suggests that the production cost of hydrogen significantly varies from one technology to others. The current hydrogen production cost from fossil sources using the most established technologies were estimated at about $0.8–$3.5/kg H 2 , depending on the country of production. The underground storage technology exhibited the lowest storage cost, followed by compressed hydrogen and liquid hydrogen storage. The levelised cost of the refuelling station was reported to be about $1.5–$8/kg H 2 , depending on the station's capacity and country. Using portable refuelling stations were identified as a promising option in many countries for small fleet size low-to-medium duty vehicles. Following the current research progresses, this paper in the end identifies knowledge gaps and thereby presents future research directions. • Technological advancements of hydrogen production, storage and transport are reviewed. • Emissions and economic aspects of production, storage, transport and fuelling are analysed. • Refuelling protocols, temperature rise issue and its control strategies are discussed. • Recent progress of mobile hydrogen refueller is explored. • Challenges of hydrogen production to fuelling and future research directions are presented. [ABSTRACT FROM AUTHOR]

With the rapidly evolving geo-political landscape and unceasing advancements in technology, sustainable energy security is a very important topic. Research indicates that electrochemical energy systems are quite promising to solve many of energy conversion, storage, and conservation challenges while offering high efficiencies and low pollution. The paper provides an overview of electrochemical energy devices and the various optimization techniques used to evaluate them. The optimization techniques include linear regression, factorial design, the Taguchi method, artificial neural networks, filters, and a combination of such methods to improve these systems. To support the growing interest in research, the bulk of this study focuses on a review of the most promising and highly researched electrochemical energy devices, such as fuel cells, batteries, and supercapacitors. The paper also provides modest commentary on hydrogen production technologies, electrochemical reactors, and membrane separation technologies, amongst other technologies. Building on a previous paper by the authors of this paper on artificial intelligence in hybrid renewable energy systems with fuel cells, this work provides a comparative review of optimization techniques for supercapacitors by highlighting key findings based on model accuracy. A summary of the advantages and disadvantages of the different major optimization techniques is presented. The paper concludes that a combination of optimization techniques is used to overcome the drawbacks of individual techniques, with adaptive filters being the most widely studied. This paper presents studies on the Design of Experiments (DoE) with the goal of building a better understanding of the relationships that exist between different operating variables in various electrochemical devices. • The electrochemical systems can be optimized for better performance with high accuracy. • The optimization techniques used are either model-based or data-driven. • Linear regression and artificial neural networks are the most common techniques studied. • Hybrid models could be applied to enhance systems' accuracy and minimize errors. [ABSTRACT FROM AUTHOR]

This paper provides a cost-effective energy management method for the microgrid's standalone and on-grid operational modes. The considered microgrid based on Green-to-Green systems such as a photovoltaic array (PV), wind turbine (WT) as renewable generators, hydrogen fuel cell (FC) system, microturbine (MT), and battery storage system. The suggested technique is based on the marine predator algorithm (MPA) that and created for a scheduling horizon of one day. The main objective of this paper is to reduce operating costs while satisfying the demand power. To approve the performance of the suggested management strategy, the simulation results are compared with other recent optimization algorithms. These algorithms include particle swarm optimization (PSO), salp swarm algorithm (SSA), and coot optimization algorithm (COOT). To approve the performance of the proposed EMS, the system will be evaluated for three cases: free renewable generation, restricted generation mode, and unlimited main grid power mode. For the first case, the proposed EMS reduces the operating costs by 0.8732%. For case 2, the economic benefits have been raised by 1.0815% and by 0% for the last case because of the reduced problem complexity. • A cost-effective energy management strategy for the microgrid based PEM fuel cells is proposed. • Implementation of marine predator algorithm to minimize the operating costs. • The performance has been investigated under various operating conditions. [ABSTRACT FROM AUTHOR]

With the growing demand for green technologies, hydrogen energy devices, such as Proton Exchange Membrane (PEM) fuel cells and water electrolysers, have received accelerated developments. However, the materials and manufacturing cost of these technologies are still relatively expensive which impedes their widespread commercialization. Additive Manufacturing (AM), commonly termed 3D Printing (3DP), with its advanced capabilities, could be a potential pathway to solve the fabrication challenges of PEM parts. Herein, in this paper, the research studies on the novel AM fabrication methods of PEM components are thoroughly reviewed and analysed. The key performance properties, such as corrosion and hydrogen embrittlement resistance, of the additively manufactured materials in the PEM working environment are discussed to emphasise their reliability for the PEM systems. Additionally, the major challenges and required future developments of AM technologies to unlock their full potential for PEM fabrication are identified. This paper provides insights from the latest research developments on the significance of advanced manufacturing technologies in developing sustainable energy systems to address the global energy challenges and climate change effects. • The AM technologies relevant to PEM fabrication are reviewed. • Corrosion performance of AM materials in the PEM working environment is presented. • The challenges and prospects of AM for PEM fabrication are discussed. • AM has the potential to revolutionize the fabrication of PEM systems. [ABSTRACT FROM AUTHOR]

The hydrogen supply system (HSS) is an important part to ensure the efficient and reliable operation of fuel cells. As one of the key equipment of hydrogen supply system, the hydrogen circulation pump (HCP) has a significant impact on improving the utilization rate of hydrogen and the output characteristics of fuel cell stacks. Considering the function and operating conditions, this paper proposes the design requirements for HCPs. The principles and characteristics of several mechanical pumps that can be used for hydrogen circulation are introduced, including root pump, claw pump, vortex pump, and centrifugal pump. And the research progress and technical innovation of these four types of HCPs are summarized. Then, the control methods and purge strategies of the hydrogen supply system with an HCP are also summarized. And the performance parameter of HCP products in the current market is compared. Finally, the possible solutions are given to address some challenges faced by the actual operation of HCPs, including hydrogen safety issues, cold start at low temperature, leakage, vibration, and noise. This paper is helpful for researchers to understand the overall research progress of HCP and provide a reference for optimizing the performance and achieving more efficient hydrogen circulation. • Proposing design requirements for hydrogen circulation pumps. • Summarizing the research progress in structural design and performance analysis. • Providing feasible solutions to the challenges faced in actual operation. • Control of hydrogen supply system with a hydrogen circulation pump is complicated. • Water and heat management in hydrogen circulation pumps needs to be studied. [ABSTRACT FROM AUTHOR]

The plateau environmental adaptability of the proton exchange membrane fuel cell (PEMFC) is a key technical challenge for the development of fuel cells (FCs). This paper reviews the current research on the adaptability of FCs in plateau environments, focusing on the application requirements of automotive FCs in high-cold and high-altitude areas. First, the paper investigates how low temperature and low pressure affect the internal structure and output performance of FCs in plateau environments. Second, it analyzes the recent advances in FC technology to cope with plateau environments and evaluates the technical advantages and disadvantages of various approaches based on essential indicators such as FC output performance, efficiency, and response time. Finally, it identifies future research directions in FC plateau environmental adaptability technology, aiming to provide a reference for using FCs in plateau environments. • Reviewed the development status of plateau environmental adaptation technology for fuel cells. • Analyzes the advantages and disadvantages of various cold start solutions. • The advantages and disadvantages of altitude adaptation technology are analyzed. • Suggests the future research focus of fuel cell plateau environmental adaptation technology. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cell (SOFC) is regarded as a promising energy conversion device because of its advantages such as high efficiency and fuel flexibility. With the advent of aviation electrification era, SOFC has been gradually studied as aviation power system. However, the high temperature operation and temperature gradient of SOFC bring challenges to practical application. Nowadays SOFC systems often use excessive air as coolant to reduce the temperature gradient of SOFC, which leads to the increases of the fuel consumption and reduction of the power generation efficiency. In order to maintain a lower temperature gradient with less air, a supercritical fuel cooled SOFC scheme is proposed in this paper. By establishing a one-dimensional model of conventional air-cooled fuel cell and fuel cell with fuel cooling channel. Through calculating the fuel cell temperature gradient under different working conditions, the results show that when the excess air coefficient (EAC) is 3, the temperature gradient of air-cooled SOFC reaches 22.7K/cm, while the temperature gradient of SOFC with fuel channel decreases to 8.35K/cm. Therefore, the SOFC with fuel channel can effectively reduce the use of air, reduce parasitic power consumption and improve the efficiency of the system while maintaining a lower temperature gradient. • A supercritical fuel cooled SOFC scheme is proposed in this paper. • When the excess air coefficient is 3, the temperature gradient of fuel cell with fuel channel decreases to 8.35K/cm. • The fuel cell system with fuel channel can effectively reduce the use of air. • The SOFC scheme of fuel cooling can improve the electrochemical performance of SOFC. [ABSTRACT FROM AUTHOR]

Fuel cell hybrid electric vehicles (FCHEV) are one of the most promising new energy vehicles. The cost and lifetime of its powertrain have limited its commercial development. This paper proposed an energy management strategy based on nonlinear model predictive control (NMPC) technology to solve the economy and durability problem of FCHEVs. Based on Markov Monte Carlo(MCMC) method, a prediction model of multi-scale operating conditions is established, and dynamic programming(DP) is used to realize the optimal control in the predicted time domain. The "constant speed prediction" is innovatively adopted in the transition stage to improve the prediction accuracy and enable the model to be realized online. The ways to reduce calculating amount of NMPC are also discussed in this paper. This simplification leads to suboptimal fuel economy and durability of control system but can have obvious reduction in calculating time. The simulation results show that, compared with the thermostat strategy and the power following strategy, the degradation cost decrease of 11.1% and 23.9% and the total operation cost of NMPC decrease of 11.0% and 23.5% respectively. The NMPC strategy has better economy and durability than the rule-based energy management strategy, is close to the global optimal result obtained by dynamic programming and can meet the requirements of real-time control. • The economy and durability of vehicular fuel cell system are both considered. • Markov Chain Monte Carlo is imported into MPC theory for vehicular power prediction. • Adaptability to changing conditions is strengthened via "constant speed prediction". • The computational load in MPC optimization is reduced by simplifying DP algorithm. [ABSTRACT FROM AUTHOR]

Hydrogen fuel cell vehicles (HFCVs), as an important strategic path for global sustainable development and energy transition, have now become an important support for the global energy and transportation sectors. The United Kingdom, Japan, the United States, China, and other countries are vigorously developing HFCVs and increasing the construction of hydrogen stations. Before HFCVs enter the stage of rapid commercialization and development, it is necessary to investigate the factors that influence consumer HFCV adoption. In this paper, meta-analysis used 24 pieces of literature to include in a systematic evaluation of the existing research on the factors that influence consumer willingness to purchase HFCVs, setting influencing factors as the dependent variable, to clarify the specific roles of different influencing factors and to address the problem of mixed and contradictory findings in the literature. The results of the study show that: (1) The influence of gender and age on consumer willingness to purchase HFCVs cannot be judged. (2) Education, individual income, household income, family car number, driving range, knowledge, fuel availability, hydrogen refueling station density, environmental impact, policy incentives and attitudes all have a positive effect on HFCV adoption. (3) Household size, purchase price, fuel cost, maintenance cost and refueling time have a negative effect on HFCV adoption. (4) The purchase price, knowledge, fueling time, hydrogen refueling station density, and policy incentives significantly influence HFCV adoption. This paper provides new research methods and perspectives for the HFCV field and presents theoretical references for future governmental promotion of HFCV. • Meta-analysis of 24 studies conducted for consumers' intention to purchase HFCVs. • Subgroup analysis provides evidence of heterogeneity among estimates. • Household size and the other 4 influencing factors inhibit HFCV adoption. • Education and the other 9 influencing factors promote HFCV adoption. • The purchase price and other 4 influencing factors significantly influence HFCV adoption. [ABSTRACT FROM AUTHOR]

Explosion and deflagration may occur when a fuel cell truck in driving has hydrogen leakage faults, and the complex and changeable operating conditions of the vehicle are incredibly unfavorable for fault diagnosis. Therefore, to provide real-time diagnosis on the hydrogen supply system of driving truck, a diagnosis method of hydrogen leakage faults classification based on data-driven in this paper. The faults are divided into 3 levels using the K-means algorithm, and 4 features are selected as the hydrogen leakage faults diagnosis indicators. The Principal Component Analysis (PCA) method is used to reduce the dimensions of the data, while Support Vector Machine (SVM) is used for hydrogen leakage faults diagnosis. Meanwhile, the kernel parameter σ and the penalty factor C of SVM are optimized by Sparrow Search Algorithm (SSA) to improve diagnostic accuracy. The results show that the diagnostic accuracy of the SSA-PCA-SVM method proposed in this paper is higher than that of the ordinary SVM and PCA-SVM diagnosis methods when σ = 9.79, C = 7.89, which is over 97 %. • A classification diagnostic method is proposed for hydrogen leakage faults. • The diagnostic method can perform real-time faults diagnosis for driving truck. • The fault diagnosis accuracy of the proposed SSA-PCA-SVM method exceeds 97 %. [ABSTRACT FROM AUTHOR]

A novel photocatalyst is designed by surface modification and cocatalyst loading of graphitic carbon nitride (g-C 3 N 4) with ammonium hydroxide and silver nanocubes (AgNCs), respectively. The synergistic effect of the modification in the intralayer of g-C 3 N 4 and surface plasmon resonance (SPR) bands of AgNCs significantly enhances the migration and separation efficiency of photo-induced charge carriers. A nickel mesh coated with photocatalyst and the carbon paper loaded with pristine g–C 3 N 4 –mixed iron phthalocyanine (FeIIPc) used as the photoanode and cathode, respectively, are constructed for the self-powered photoelectrochemical cell, which exhibits the maximum power density of 0.74 mW cm−2. The AHCN/AgNCs-based cell reveals approximately a 3.1-times enhancement in maximum power density compared with the pristine g–C 3 N 4 –based cell. In addition, the photocatalytically generated H 2 O 2 (chemical energy) can be stored in water, and then used as fuel by the connection of two electrodes in the dark. After the fuel cell is operated for 12 h, the specific capacitance retention rate still maintains as high as 57.2 %, which is the greatest retention rate in comparison with the previously reported H 2 O 2 fuel cell systems. Our work offers a feasible opinion on how to improve the visible light utilization of semiconductors by tuning the intralayer properties and loading plasmonic metal. • A novel composite photocatalyst (AHCN/AgNCs) is applied in the H 2 O 2 fuel cell. • The metal-semiconductor heterojunction facilitate the photocatalytic H 2 O 2 production. • The AHCN/AgNCs produces 0.045 M H 2 O 2 under light irradiation for 2.5 h. • The specific capacitance keeps 57.2 % of initial value after 12 h of cell operation. [ABSTRACT FROM AUTHOR]

Fuel cell electric vehicles (FCEVs) hold great promise for achieving sustainable and environmentally friendly transportation. However, their widespread adoption depends on the efficient development of the hydrogen supply chain (HSC) required for refueling these vehicles. Given the interdependence between the HSC and power distribution networks (PDNs), this paper presents an innovative model to jointly plan the HSC and reinforce PDNs. In this new model, the inherent uncertainties related to wind energy generation, load demand, and FCEV consumption are modeled. Furthermore, coordinating the planning of hydrogen storage and battery energy storage systems is incorporated. The results underscore the critical importance of simultaneous planning for the HSC and PDN reinforcement. Moreover, the findings reveal that hydrogen storage alone can provide sufficient energy arbitrage, leading to a 9.6% reduction in total costs compared to the scenario where storage is disregarded. [Display omitted] • A novel planning model for hydrogen supply chains and power distribution networks. • Both hydrogen storage and battery energy storage are included. • Uncertainties related to wind generation and loads are modeled. • Model results show that simultaneous planning cuts costs by 25.9%. • Hydrogen storage alone reduces costs by 9.6%. [ABSTRACT FROM AUTHOR]

The performance of ammonia hydrogen fuel cells (AHFCs) with the same activated area but different aspect ratio is quite different. In this paper, based on the diffusion characteristics of hydrogen nitrogen mixture, five different aspect ratios of AHFCs were designed, and the influence of aspect ratio on the performance of AHFCs was studied by combining experiment and simulation analysis. The results reveal that the power of AHFCs reaches the maximum when the aspect ratio is 1, that is, the shortest hypotenuse of the plate. With the extension of the hypotenuse, the output power decreases, and the output power decreases by 19.3% when the aspect ratio is 4. Due to the strong ability of hydrogen diffusion, when the aspect ratio of AHFCs is 4, the proportion of hydrogen and oxygen starvation area at the interface reaches the maximum and minimum, which are 11.8% and 0.3% respectively, which is contrary to the aspect ratio of 0.25. A larger aspect ratio is conducive to the uniform distribution of gas-water-heat. Although the AHFCs with aspect ratio of 0.64 has advantages in power generation efficiency and fuel utilization, the pressure drop loss increases by 43.7%, and the pressure drop loss with aspect ratio of 0.25 increases by 141.2%. • Experimental data of AHFCs with different aspect ratios are obtained. • Power generation efficiency of AHFCs with different aspect ratios is compared. • AHFC with the shortest hypotenuse has the largest output power. • CV is used to characterize the uniformity of gas-heat-water distribution in AHFC. [ABSTRACT FROM AUTHOR]

Hydrogen fuel cell vehicles (HFCVs) represent an eco-friendly means of transportation, acknowledged for their potential to curtail gasoline consumption, mitigating greenhouse gas emissions and air pollution. The conjoint analysis approach is employed in this paper to comprehend consumers preferences for HFCVs across multiple Chinese cities. Through an online survey questionnaire, car usage and transport policy attributes are identified as crucial factors to establish choice preference models. Results indicate the pivotal role of purchase price and cruising range as the most influential attributes shaping consumer preferences for HFCVs, with rankings varying by geographical location. Market share insights and simulation analysis confirms the significance of attributes and describes the impact of cross-changes on HFCV choice behaviors. These findings offer crucial insights for automakers and policymakers, outlining priorities and optimal policy combination when introducing HFCVs in multiple Chinese cities. • Conjoint analysis was employed to unveil pivotal attributes in Chinese market. • Purchase price and cruising range of HFVCs dominate consumer choices. • HFCV attribute significance varies across Beijing, Shanghai, Guangdong, and others. • Optimal HFCV policies encompass financial subsidies, low fuel cost, and expanded refueling infrastructure. • Provide valuable insights for automakers and policymakers navigating the diverse Chinese market. [ABSTRACT FROM AUTHOR]

The graphite-resin composite bipolar plates prepared by the traditional hybrid pressing process exhibit poor conductivity, processability, and wettability due to the graphite flake layer being covered by resin, hindering the formation of a continuous conductive network, which significantly constrains their promotion and application in the field of proton exchange membrane fuel cells (PEMFC). In this paper, an ultra-thin flexible graphite/epoxy composite bipolar plates (BPs) with a thickness of only 0.775 mm is prepared followed by a process of flexible graphite preforming and impregnation curing. The hydrophilicity-modified BPs surface has a contact angle of 59.01° as well as flexural and compressive strengths of 11 MPa and 4 MPa and possesses a high in-plane conductivity of 380 S/cm and a low in-plane specific resistance of 6 mΩ cm2. The electrostack test results show that the hydrophilic runner channel is more conducive to the diffusion and spreading of H 2 O generated from the cathode-side reduction reaction in the flow channel, so that O 2 smoothly passes through the gas diffusion layer to participate in the reduction reaction of O 2 , and exhibits higher electric power at high current density, while the hydrophobically modified BPs has relatively poor overall performance due to ohmic losses. [Display omitted] • A hydrophilic flexible graphite bipolar plate with a contact angle of 59.01° is prepared. • The bipolar plates with excellent flexural strength of 11 MPa and a high in-plane conductivity of 380 S/cm. • The Electricstack has the best overall monolithic voltage and total power when the current density over 1800 mA/cm2. [ABSTRACT FROM AUTHOR]

This paper aims to apply data-driven maximum power point tracking (MPPT) techniques specifically tailored for fuel cell vehicle (FCV) supported hybrid DC microgrids to enhance the power harvesting capability of fuel cell (FC) stacks. Compared to existing MPPT techniques, the current study focuses on developing and evaluating data-driven approaches for maximum power extraction by dynamically determining the operating point of FC power sources through a Zeta converter. An in-depth analysis is conducted by considering parameters such as efficiency, tracking accuracy, response time, and robustness to variations in load demand and operating conditions. The performance results validate that the developed three-layer neural network (TNN)-based MPPT gives better performance findings than Gaussian process regression (GPR), support vector regression (SVR), decision tree regression (DTR), and bagging ensemble decision tree (BEDT). In the performance evaluation phase, a vehicular FC with a rating of 1.26 kW is designed and operated within the temperature range of 320 K to 343 K for hydrogen pressure values ranging from 1 bar to 1.8 bar. For these operational conditions, the prediction accuracy value of the proposed TNN method is 99.6% while the performance values GPR, SVR, DTR, and BEDT are 99%, 98.6%, 97.2%, and 96%. In addition, system efficiency is increased by 0.98%, 1.25%, 2.51%, and 3.02% compared to GPR, SVR, DTR, and BEDT, respectively. [Display omitted] • Developing data-driven algorithms-based MPPT techniques for vehicular FCs. • Providing advantages regarding high-speed tracking capability and tracking accuracy. • Providing stable DC bus voltage operation. • Improving system performance under dynamic load changes and operating conditions. [ABSTRACT FROM AUTHOR]

As a new type of energy, hydrogen-enriched methane mixed fuel has a high risk of deflagration in the application process. In order to better understand the deflagration and inhibition characteristics of hydrogen-enriched methane fuel, the effect of potassium salt modified dry water material (DW) on the deflagration characteristics of hydrogen-enriched methane fuel was studied by 20 L spherical explosive apparatus, combined with pyrolysis characteristics and kinetic model. The results show that when the addition of different modifier concentrations, it can be divided into three types: small curvature, medium curvature and large curvature according to the change of pressure rising rate. With the increase of the proportion of potassium salt modifiers, the number of areas with small curvature is gradually increasing, the number of large curvature is gradually decreasing, and the number of medium curvature is almost unchanged. When the proportion of potassium salt modifier is 15% and ϕ ≤ 0.7, all enter the area below the medium curvature. When the addition of different modifiers, 15%KCl-DW has the best inhibition effect on P max and (dP/dt) max , while CH 3 COOK-DW and K 2 CO 3 -DW have better inhibition effect on Δ t 2 and Δ t 2. In general, when the hydrogen addition ratio is less than 70%, the addition of inhibitors can significantly reduce the explosion intensity. In terms of inhibition mechanism, we established the decomposition model of potassium salt modified dry water and found that potassium salt modified dry water will produce a large amount of gaseous K and KOH in the explosion system. And gaseous K and KOH will catalyze each other and combine with H and OH to form stable H 2 O, which significantly reduces the mass fraction of H and OH radicals in the chain reaction. The results of this paper provide a theoretical basis for the safe use of hydrogen-enriched methane fuel and the research and development of explosion emergency prevention and control technology. • The explosion suppression of potassium salt modified dry water on H 2 /CH 4 was studied. • The hierarchical inhibition model of H 2 /CH 4 explosion by dry water was defined. • Particle swarm optimization is adopted to optimize the decomposition parameters of DW. • Suppression mechanism of potassium salt modified dry water was analyzed. [ABSTRACT FROM AUTHOR]

Alongside the advancement of navigation, control, and communication technologies, which are fundamental aspects of unmanned underwater vehicles (UUVs), research & development on UUV energy system for long-term mission capabilities has been conducted actively since the 2000s. The hydrogen fuel cell energy system (FCES), which is characterized by low noise, air-independent propulsion, and high energy density, has attracted considerable attention as the energy system for UUVs. In this paper, the key features of the components of a hydrogen FCES meant for use in large-class UUVs are presented. In addition, the current technological development status of FCES-powered large-class UUVs is outlined. Finally, the factors that must be considered when designing large-class UUVs powered by hydrogen FCESs are discussed. • Hydrogen fuel cell systems offer high energy density for long-endurance unmanned underwater vehicles. • Differences between land-based and underwater FCESs include materials and byproduct handling. • Effective design must consider gravimetric and volumetric energy density, heat, and water management. [ABSTRACT FROM AUTHOR]

This paper investigates the feasibility and benefits of integrating hydrogen storage systems into off-grid power systems. As a case study, a stand-alone microgrid located on a small island in southeastern Sardinia (Italy) and already equipped with a photovoltaic (PV) system coupled with batteries is chosen. To evaluate the integration benefits of the two storage systems (hydrogen and batteries) and the optimal sizing of the hydrogen storage section, a parametric analysis with a simulation model implemented in the MATLAB environment has been carried out. Results show that the optimal integration between the two storage systems is found by imposing a share of the batteries (18 kWh, 50% of the overall battery capacity) to exclusively supply the load demand (called battery energy buffer). In these conditions, an almost 100% self-sufficiency of the microgrid can be achieved by a hydrogen generator with the lowest size considered (2.4 kW), a hydrogen storage volume of 10 m3 and a fuel cell, mainly able to completely cover the night loads, of 1.5 kW. This sizing leads to a Levelized Cost of Electricity (LCOE) for the hydrogen section of about 10.5 €/kWh. [Display omitted] • Investigation of a hydrogen storage into off-grid systems characterized by seasonal loads. • Determination of the hydrogen storage sizing through parametric analysis. • Optimal integration with batteries found by imposing an energy buffer equal to 50%. • Through the hydrogen storage, self-sufficiency higher than 99% is achieved. • Significant energy surcharges detected to ensure 100% green electricity. [ABSTRACT FROM AUTHOR]

This paper focuses on the combustion of hydrogen in boilers, as it appears to be a more effective method than using fuel cells for heating purposes due to higher boiler efficiency. One of the main disadvantages of hydrogen combustion in air is NO x formation. Therefore, the authors decided to introduce corona discharge as an innovative technique to clean hydrogen flue gas by effectively reducing NO x levels. The method involves generating positive plasma at atmospheric pressure by applying up to a 23 kV voltage difference between rod and ring-shaped electrodes. Experimental studies have shown that corona discharge can significantly lower the concentrations of NO and NO x in exhaust gases. The maximum DeNO x level was found to be 32.3%, while the plasma generator uses 17.5% of the power contained in burned hydrogen. The findings suggest that this technology holds potential for application in industrial hydrogen combustion systems, offering an environmentally friendly alternative to conventional NO x reduction methods. [Display omitted] • Corona discharge is promising approach for cleaning hydrogen flue gas from NO x. • The level of NO x removal depends on their concentration. • After plasma treatment, the level of NO decreases while NO 2 increases. • The maximum investigated level of DeNO x was 32.3%. [ABSTRACT FROM AUTHOR]

To tackle the carbon emission problem, the exploitation of renewable energy resources (RESs) with zero emissions has gained much importance. In this context, hydrogen has become an important resource to involve itself in distributed energy resources (DERs) to generate electricity, energize vehicles, and heat our living areas. The utilization of hydrogen technologies is indispensable due to their procurement, environmental friendliness, and high efficiency for DERs. A challenging area in the field of hydrogen energy technologies is extracting efficient power and integration to DERs. This paper investigates how to model and operate a proton exchange membrane fuel cell (PEMFC) stack in a DER application to establish a living lab facility for educational and research purposes by covering Power-to-X (P2X). The PEMFC model of the studied system is designed in a MATLAB/Simulink environment and implemented in an experimental testbed. Thus, a fuel cell (FC) unit as a complementary source is preferred to be used near a photovoltaic (PV) array, a small-scale wind turbine (WT), and a lead acid battery energy storage system (BESS) by creating a P2X concept to form a living lab platform. Beyond the model, regarding the experimental part, a PV array, a WT, and a BESS are combined with a PEMFC module that is rated output of 1200 W. Expect for all systems, the FC part is emphasized in this study. Also, a dynamic model of the mentioned PEMFC is proposed and verified. • Importance of hydrogen energy is focused on its advantages, future role, potential, and challenges. • FC unit as a complementary source is evaluated by creating a P2X concept. • This platform is designed to meet the energy needs of research-education, diversify the supply, increase energy independence. • Energy procurement is supplied via green energy during a lesson, which is noteworthy and instructive. • Feasibility of combined PV/WT/BESS/PEMFC system is investigated. [ABSTRACT FROM AUTHOR]

The focus of this study is to investigate the critical matter of voltage sags in power systems, which have a substantial adverse effect on both the functionality of equipment and the quality of power. Central to this investigation is the integration of hydrogen fuel cells and a D-STATCOM system, which is suggested as a substitute approach for mitigating voltage fluctuations. The hydrogen fuel cell serves as the pivotal component, renowned for its ability to significantly improve power quality through the efficient mitigation of voltage sag concerns. The paper provides a comprehensive analysis of the contribution that hydrogen fuel cell integration with D-STATCOM makes to the reliability of power systems. A systematic methodology is employed, supported by simulations and modeling, to emphasize the critical significance of hydrogen fuel cells in surmounting obstacles related to voltage injection and enhancing power quality. By utilizing a Type-3 Fuzzy system, the research evaluates the dependability of the control system and proposed model. The effectiveness of this method, which is focused on hydrogen fuel cells, is verified by means of MATLAB simulations, which demonstrate its superior performance in comparison to conventional PI and ANFIS controllers. • Integrates hydrogen fuel cells with D-STATCOM for improved power quality. • Achieves notable reduction in voltage sags in power systems. • Enhances power system reliability and stability. • Employs Type-3 Fuzzy system for advanced control. • Validated by MATLAB simulations, outperforming traditional controllers. [ABSTRACT FROM AUTHOR]

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. • This study aimed to investigate efficiency gains from adding an RSM to hydrogen fuel cell electric vehicles. • This is the first study in literature to integrate RSM into a Fuel Cell Electric Vehicle. • The charging efficiency of the FCEV is improved by the Regenerative Suspension Modules mounted on each wheel. • The FCEV's Regenerative Suspension Module mounted on each wheel generates 2.5 times more energy than regenerative braking. [ABSTRACT FROM AUTHOR]

Due to the widespread use of multi-generation systems utilizing renewable energy sources and the growing global demand for such systems from both economic and environmental considerations, numerous researchers have focused on the design and evaluation of their performance. To this end, this research presents a biomass-based multi-generation system with an innovative and practical design that can generate electricity, heat, and hydrogen. This system includes a modified gas turbine cycle, a supercritical CO 2 (SCO 2) cycle, a transcritical CO 2 (TCO 2) cycle, a proton exchange membrane (PEM) electrolyzer, and a PEM fuel cell unit. This study aims to evaluate the impact of various biomass sources (paper, wood, paddy husk, and municipal solid waste) on the system performance. The proposed system has been analyzed using the first and second laws of thermodynamics. This system uses the maximum capacity to produce power, heat and hydrogen. A fuel cell unit has been used to consume hydrogen and generate more electricity. In the basic mode, the system has energy and exergy efficiencies of 47.89% and 32.26%, respectively, and can produce 2.74 kg/h of hydrogen. The biomass fuel consumption rate within the system is 0.055 kg/s. The overall exergy destruction of the system amounts to 1240 kW, with the biomass boiler and the condenser being the components that experience the greatest exergy destruction, registering values of 535.5 kW and 432.3 kW, respectively. Notably, employing municipal waste as biomass increases the system's exergy efficiency to 33.16%. • To investigate a biomass-driven system for producing power, hydrogen, and heating. • To evaluate the impact of various biomass sources on the system performance. • To use PEME for hydrogen and PEMFC for power and heat production. [ABSTRACT FROM AUTHOR]

This paper presents a powerful performance optimization approach for load frequency control in the off-grid mode of a delayed fuel cell microgrid with PI controller. The new approach based on stability boundary locus is used. Thanks to this, the search is only carried out in PI control parameter space keeping stable the system in the proposed optimization. The superiority of the proposed approach in terms of iteration history, fitness values, and time responses of the system is presented by comparing the results obtained. According to the results obtained, the proposed approach reaches the global minimum in a very short number of iterations and achieves this by both guaranteeing the stability of the system and providing the desired time response performances compared to the other method. • The stability of a delayed fuel cell microgrid system is a very important issue, especially in off grid mode. • A delayed fuel cell microgrid system should provide the desired quality of energy to the load. • The optimization approach provides the desired quality of energy to the load ensuring the stability of the microgrid. • Proposed optimization approach has great advantages in terms of iteration history and fitness value. [ABSTRACT FROM AUTHOR]

Today, hydrogen fuel cells (HFCs) have become very popular in various applications because of their ability to be a clean energy source. One of the difficulties associated with HFCs is their sluggish response to variations in the load. This paper presents a nested control strategy based on a type-2 neuro-fuzzy controller (T2NFC) to improve the HFC's dynamic response in a hybrid stand-alone power network using HFC and battery. A system model is constructed using Matlab-Simulink. An interleaved converter is used to draw the maximal power from the HFC and reduce the ripple in the HFC's current. Two T2NFCs control DC voltage and battery charge/discharge current. The robustness of the T2NFC is evaluated for input disturbance, output disturbance, and both disturbances. The results show that the proposed control strategy is robust against input and output disturbances. Also, it provides improved dynamic response of the HFC, lower ripple in HFC current, and less overshoot or undershoot in DC voltage both in transient and steady-state. For step reference input, the proposed controller improves settling time of 24.06 % and overshoot of 59.55 % compared to the conventional PI controller. The results verify the effectiveness of the proposed controller under different operating conditions of hybrid stand-alone power network with fuel cell and battery. • The response of HFC is enhanced, leading to faster and more accurate power generation. • The hydrogen fuel cell's current is experienced a significant reduction in ripples. • The hydrogen fuel cell is now being operated at its maximum power point. • A Type-2 Neuro-Fuzzy Controller is developed to provide robust control of the hydrogen fuel cell's output voltage. [ABSTRACT FROM AUTHOR]

The single-stack fuel cell system is utilized extensively in several industries. Unfortunately, the main problems are its low efficiency and durability, and unsatisfied reliability, especially in the high-power situation. Due to its significant performance, which includes high output power, durability, and reliability, multi-stack fuel cell systems (MFCS) are becoming more and more attractive. In this study, it is aimed to develope a control algorithm in parallel structure in the Matlab/Simulink software for the efficient use of hydrogen fuel consumption of PEM fuel cells – based boost converter using PI controller with PSO method. Models of both single and parallel connected PEM fuel cells were created in Matlab using mathematical equations in this paper. The analysis made in the study were applied for both models. PEMFCs were connected in parallel and only one DC-DC converter was used for the entire system. According to the load change, the required number of cells are activated due to control algorithm to provide the required power. As a result, the proposed method reduces hydrogen consumption by approximately 5 times under the same load, while optimized parameters reduce output voltage oscillation. • A new control algorithm for parallel connected PEM fuel cell has been successfully implemented. • The suggested method reduces hydrogen consumption by approximately 5 times under the same load. • Using small-capacity fuel cells instead of huge ones minimizes hydrogen consumption. • Optimized parameters decrease the voltage oscillation. [ABSTRACT FROM AUTHOR]

Safety issues such as unintentional hydrogen releases in confined spaces limit the widespread promotion of hydrogen terminal applications, especially hydrogen fuel cell vehicles (HFCVs). This paper aims to perform a systematical numerical investigation of hydrogen leakage and dispersion in a full-scale underground garage, and the effects of smoke barriers are also considered. Four sets of smoke barriers with different heights, 0.1–0.7 m with 0.2 m increment, are installed below the ceiling, and three different partition types are set. The results show that smoke barriers can reduce flammable areas but increase local hydrogen concentrations. As the height of the smoke barrier increases, its obstruction to hydrogen dispersion on the ceiling is enhanced, making it easier for hydrogen to accumulate in the area and increasing the hydrogen cloud thickness. The hydrogen concentration in the horizontal direction showed a stair-like stratification phenomenon and decreased with increasing horizontal distance from the leak point. When the height of the smoke barrier is below 0.7 m, a larger partition area is safer. This study can provide new insights into the accidental hydrogen leakage and dispersion issues in confined spaces, in particular the effects of smoke barriers, and lay a theoretical foundation for the safety design of enclosed garages for HFCVs. [Display omitted] • Typical H 2 dispersion in a full-scale underground garage is numerical investigated. • Effects of smoke barriers on hydrogen dispersion is studied. • Smoke barriers can reduce flammable areas but increase local hydrogen concentrations. • Higher smoke barriers result in thicker flammable hydrogen clouds. • Larger partition area is found to be safer for 0.5 m barrier height. [ABSTRACT FROM AUTHOR]

In response to climate change and the imperative for sustainable energy solutions, this study investigates the feasibility of producing green hydrogen and associated e-fuels (methane, methanol, and ammonia) using a renewable energy hybrid system in Dakhla, Morocco. Utilizing the System Advisor Model (SAM) software for simulation-based analysis, the research evaluates a hybrid system combining concentrated solar power (CSP) and photovoltaic (PV) plants against standalone counterparts. Various simulations comparing standalone PV and CSP plants with a novel CSP/PV hybrid concept were carried out. The hybrid system demonstrates significant promise, exhibiting increased annual energy yield and capacity factors up to 90%, leading to enhanced efficiency, performance, and cost savings with a Levelized Cost of Electricity (LCOE) approximating 17 cents/kWh. Furthermore, this paper conducts an in-depth exploration into the feasible production of hydrogen and its derived synthetic fuels utilizing hybrid renewable systems. The study provides a thorough examination of the production processes, yields, and efficiencies of hydrogen and its derivative e-fuels, with a focus on green hydrogen production through water electrolysis, CO2 hydrogenation, the Sabatier process, and the Haber-Bosch process. It sheds light on the potential applications of these fuels in the transportation sector, including in electric and hydrogen vehicles and aviation. The insights garnered are indispensable for crafting future strategies and policies in sustainable energy planning. These findings not only provide valuable direction for forthcoming initiatives in renewable energy but also underscore the pivotal role of hybridization in enhancing the efficient production and utilization of hydrogen within both renewable energy and transportation sectors. • PV and CSP systems to generate electricity for the Dakhla city was investigated. • A Hybrid system optimization has been proposed. • The Electricity surplus was used to produce hydrogen and hydrogen-based products. • Various scenarios for the heavy-duty application of e-fuel were presented and discussed. [ABSTRACT FROM AUTHOR]

With the development of hydrogen fuel cell vehicles, hydrogen refuelling stations are required to operate at a higher pressure. However, the safety issue of high pressure hydrogen is always considered as the barrier of the wide application of such transportation infrastructures. In this paper, the safety evaluation is performed on a 70 MPa hydrogen dispenser, as one of the most vulnerable equipment to safety events in hydrogen refuelling stations. The numerical simulations are conducted for the hydrogen leakage and combustion for the prototype of the dispenser. The results show the high radiation during the combustion, and the environmental wind can reduce it by promoting the diffusion of hydrogen. Accordingly, the lethal ranges in different cases are manifested by radiation heat flux at the concerned height for the safety of humans. Furthermore, an improved design of the hydrogen dispenser is proposed to cancel the lower ventilation holes based on the analysis. As a result, the radiation heat fluxes due to the hydrogen combustion after leakage is significantly reduced and consequently lead to smaller lethal ranges, indicating the enhanced safety performance of the hydrogen dispenser. • A numerical study is conducted for the hydrogen combustion from a 70 MPa hydrogen dispenser. • The safety distance is evaluated for hydrogen leakage and combustion of dispensers under different wind conditions. • An improved design of the hydrogen dispenser is proposed and proved to be effective in enhancing the safety performance. [ABSTRACT FROM AUTHOR]

Hydrogen ejectors effectively utilize excess unreacted hydrogen. However, traditional ejectors have limited operational ranges and are only suitable for specific power ranges. This paper presents a dual-nozzle ejector aimed at broadening its operational range through different working modes. A simulation model, validated by experiments, is employed based on the working principles of ejectors. Spiral blades are installed at drive end to improve the recirculation efficiency. Flow characteristics, including streamwise and spanwise vortices at high power, are also investigated in different modes. Results indicate that optimal operating range for Ring-nozzle(RN) mode is between 31.1 and 124.4A. When output current exceeds 124.4A, it is necessary to switch to Central-nozzle (CN) or Double-nozzles (DNs) mode. Analysis of streamlines and velocity vectors reveals that installing spiral blades can modify directions of primary flow. Blades with appropriate distortion should be selected. In CN mode, when stack reaches 60% of rated power, installing 20° spiral blades has a minimal impact on stability of radial flow. Installing 30° or 40° spiral blades is suitable for full-load condition. In DNs mode, installing 30° spiral blades enhances acceleration of gas flow with lower influence from radial influx. This ejector provides assurance for upgrade of fuel cell stacks by incorporating recirculation technology. • A dual-nozzle ejector with spiral guide blades is designed, verified and evaluated. • Installed spiral blades change direction and gather kinetic energy of primary flow. • Advantageous working conditions of different modes with blades are discussed. • Flow mechanism of different blades under high power in two modes is analyzed. • Flow acceleration and losses should be balanced by changing the twist of blades. [ABSTRACT FROM AUTHOR]

This paper presents a cryogenic turbo-electric hybrid propulsion system (TEHPS) for a 70–80 seat class turboprop regional aircraft, integrating superconducting technology with liquid hydrogen (LH 2) cooling. LH 2 is selected as the cooling medium for the designed cryogenic cooling circuit, and the evaporated hydrogen gas is channeled to a hydrogen fuel cell for electricity generation, making full use of the energy content of the hydrogen. Parametric modeling of critical components is conducted to determine mass, power and heat loss parameters under feasible operating temperature conditions. Four propulsion schemes are conceptualized based on power matching combinations of turbo-engines, hydrogen fuel cell and battery during cruise, descent and landing phases. Performance comparison and analysis of the cryogenic TEHPS for a typical mission profile in 2035 is conducted, considering three projected scenarios – conservative, baseline, and optimistic – derived from existing data. The results show that propulsion Scheme 1, combining turbo-engines, fuel cell and battery for cruise, significantly reduces aviation fuel mass and pollutants emissions, cutting fuel consumption by 34.2%–38.6% at specific power parameters and potentially doubling the cruising range. Propulsion Scheme 3, employing turbo-engines for cruise and a combination of fuel cell and battery for descent and landing, achieves the lowest total mass and highest power-to-weight (PTW). In optimistic scenarios, the PTW ratio reaches 2.40 kW/kg, with baseline and conservative scenarios at 1.81 kW/kg and 1.16 kW/kg respectively, demonstrating significant advancements in propulsion efficiency and sustainability. • Innovative design for a cryogenic turbo-electric hybrid propulsion system. • Developed a cryogenic cooling circuit for efficient hydrogen energy recovery. • Detailed dimensional modeling of critical system components. • Evaluation of performance parameters in different scenarios and propulsion schemes. [ABSTRACT FROM AUTHOR]