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Carbon fiber paper (CFP) is one of the most widely used gas diffusion layer materials for proton exchange membrane fuel cells (PEMFC) due to its excellent properties such as high conductivity, high strength, high air permeability and corrosion resistance. In this study, CFP was prepared using the phenolic resin (PF) in-pulp addition method. The effect of PF content on the properties of hot-pressed paper (HPP) and CFP was investigated. The results showed that when the dosage of polyethylene oxide (PEO) was 1.5 wt%, the flocculation effect of PEO on PF was basically complete, and the water filterability and retention of carbon fiber pulp were relatively optimal. After HPP was carbonized into CFP, the hydrophobicity, average pore size, porosity, and air permeability increased, while the resistivity and tensile strength decreased. With the increase of PF content, the tensile strength of CFP gradually increased, while the average pore size, porosity, air permeability and resistivity decreased. When the PF content was 250 wt%, the average pore size of CFP was 36.5 μm, the water contact angle was 127°, the porosity was 69.7%, the air permeability was 7.81 × 103 mL mm/(cm2·h·mmHg), the resistivity was 21.1 mΩ cm, and the tensile strength was 15.7 MPa. In addition, the CFP prepared using PF in-pulp addition method had a relativity uniform pore size distribution and high air permeability. Therefore, this work shows that the CFP prepared using this technique exhibits excellent comprehensive performance, and enables the manufacturing of CFP to be more efficient, low-cost, and environmentally friendly. [Display omitted] • Carbon fiber paper was prepared efficiently using the phenolic resin in-pulp addition method. • Polyethylene oxide exhibits strong adsorption ability on phenolic resin in carbon fiber pulp. • The melting temperature of phenolic resin is a critical point in the preparation process of carbon fiber paper. • Carbon fiber paper possesses a relatively uniform pore size distribution and high air permeability. [ABSTRACT FROM AUTHOR]

A facile method is proposed in this work to prepare a carbon paper (CP) with outstanding properties by doping boron to catalyze graphitization at lower temperature. Boron was introduced into CP by impregnating carbon fiber preform into a boron/phenolic resin/ethanol solution, and then CP was obtained after the consecutive procedures of hot pressing, carbonization, and graphitization. Morphology, microstructure, composition, and physical properties of the doped and undoped CPs were thoroughly investigated via various techniques to exam the effects of boron concentration and graphitization temperature. Furthermore, the boron doped CP was fabricated into fuel cell gas diffusion layer (GDL) and membrane electrode assembly (MEA) to evaluate its performance through the single cell performance. The findings indicated CP doping with 2 wt% boron could lower the graphitization temperature by at least 200 °C. The B-doped GDL had a higher power density in comparison with the undoped GDLs made in our lab or from the commercial brands. • The innovative preparation method for carbon paper with high conductivity. • The effect of boron concentration and graphitization temperature on carbon paper. • The single cell performance of B-doped gas diffusion layer. [ABSTRACT FROM AUTHOR]

Paper-type gas diffusion layer (GDL) plays the role of structural support, mass transport, electron and heat transfer in the fuel cell. The deformation and fracture behavior of paper-type GDL directly determines its physical characteristics. In this paper, we obtained the distribution function of fiber length among intersections using statistical analysis. Based on the bending theory and fracture analysis, the deformation model and the maximum allowable pressure criterion of paper-type GDL are established. The deformation modulus is related to the modulus and the initial volume fraction of carbon fiber, with an ideal value of 1.4 MPa. The tensile fracture is the main form of fiber fracture. The maximum allowable pressure is related to the expected fracture probability, the strength and the initial volume fraction of carbon fiber. The residual strain increases and the deformation modulus decreases with load range, which means that the strength of the paper-type GDL is weakened when residual strain occurs. [Display omitted] • The fiber length between intersections obeys exponential distribution function. • The compression deformation model of paper-type GDL is established. • The maximum allowable pressure criterion for the paper-type GDL is obtained. [ABSTRACT FROM AUTHOR]

In this work, a paper-based hydrogen fuel cell is developed without the need for hydrogen storage. Instead, an embedded aluminum foil inside the paper is utilized for in-situ hydrogen generation. The electrodes and current collectors are also deposited on the paper, leading to a lightweight, compact and flexible hydrogen fuel cell with an OCV reaching 0.93 V and a peak power density of 4 mW cm−2. Benefited from the impeded hydroxyl ion diffusion, the hydrogen generation rate is well controlled, leading to a high faradaic efficiency of 72%. In addition, the cell can be operated under different bending angles with negligible power loss. Furthermore, it can be conveniently stacked in the same piece of paper for higher voltage and power outputs. Such a novel fuel cell design is especially suitable for powering various flexible devices with small rated power. • A paper-based hydrogen fuel cell is developed with an OCV of 0.93 V. • The peak power density is 4 mW cm−2 and the maximum current density is 8 mA cm−2. • Faradaic efficiency and energy efficiency are as high as 72% and 18%, respectively. • 75–87.5% of the cell performance remains when bended by angles from 45° to 135°. • A 4-cell stack is developed with an OCV of 3.8 V and a stacking efficiency of 90.6%. [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]

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]

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]

Online fault diagnostics is a crucial consideration for fuel cell systems, particularly in mobile applications, to limit downtime and degradation, and to increase lifetime. Guided by a critical literature review, in this paper an overview of Health management systems classified in a scheme is presented, introducing commonly utilised methods to diagnose FCs in various applications. In this novel scheme, various Health management system methods are summarised and structured to provide an overview of existing systems including their associated tools. These systems are classified into four categories mainly focused on model-based and non-model-based systems. The individual methods are critically discussed when used individually or combined aimed at further understanding their functionality and suitability in different applications. Additionally, a tool is introduced to evaluate methods from each category based on the scheme presented. This tool applies the technique of matrix evaluation utilising several key parameters to identify the most appropriate methods for a given application. Based on this evaluation, the most suitable methods for each specific application are combined to build an integrated Health management system. • HMS methods for FC diagnosis are introduced and classified into three main categories. • New scheme is introduced categorising HMS methods by approach and characteristics. • Matrix evaluation is introduced rating HMS methods for individual FC application. • Method properties affect classification results requiring evaluation for each use case. • For FCs, feature extraction, reduction and fault classification methods are chosen. [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]

Renewable energy systems (RESs) have played a vital role in meeting the continuously fast-rising energy demand. While RESs provide limitless and ecologically good possibilities, putting RESs in place has proven to be a challenging task due to their intermittent energy supply. Battery energy storage systems have widely been used in microgrids to manage the issue of intermittent energy supply caused by the RESs. The disadvantages of batteries include, large size, limited lifespan, and high cost. For this reasons, energy planners are looking into hydrogen-based storage systems as a potential solution. This paper aims to provide the recent advancements in the sizing and energy management of hybrid RES (HRES), as well as conventional methods. To achieve this, the authors have employed a review strategy that involves several specific tasks, such as preparing a database of articles related to Hybrid RESs with hydrogen storage, designing inclusion/exclusion criteria to filter out relevant articles, and analyzing each article from critical viewpoints. Thus, this paper elaborates on the general formulation framework for optimization, the classification and review of different optimization methods, and the literature on the application and research of Energy Management Systems (EMS). Additionally, the review presents an analysis and comparison of various system optimization methods and EMS through a study of several cases from the literature. It is hoped that the review will act as a basic framework for researchers looking to investigate HRES incorporated with hydrogen storage. • An efficient energy storage system is essential for managing intermittent energy supply. • A fuel cell generates electricity by combining hydrogen and oxygen to form water. • Soft computing techniques use both single and hybrid algorithms. • Deterministic rule-based controllers operate based on pre-defined rules. • Energy Management System coordinate the flow of power between different components. [ABSTRACT FROM AUTHOR]

Highly filled conductive polymer composites (CPCs) are widely used in applications such as bipolar plate materials for polymer electrolyte membrane fuel cells and redox flow batteries, electromagnetic interference shielding and sensors due to their useful electrical properties. A common method for determining through-plane electrical conductivities σ tp of such highly filled CPCs applies a conductive carbon paper between electrodes and sample with application of external pressure to improve electrical contact. We show the pressure-dependence of the measured σ tp can be eliminated by using a liquid metal such as the gallium-indium eutectic alloy (EGaIn) as contact material. Results indicate that EGaIn reduces contact resistance and causes a four times larger σ tp compared to measurements with carbon paper contacts and a pressure of 20 bar. • Eutectic gallium-indium (EGaIn) as liquid metal electrical contacts. • EGaIn contacts for pressure-independent through-plane electrical conductivity. • Compared to carbon paper contacts, EGaIn reduces contact resistance. [ABSTRACT FROM AUTHOR]

Waste heat is one of the major problems associated with the energy system. This paper discusses an energy, exergy, and emissions approach for the hybrid system by utilizing waste heat to the maximum extent. A thermoelectric generator (TEG) is incorporated to utilize the low-temperature waste heat from a hybrid model of a solid oxide fuel cell (SOFC) and a combined heat and power (CHP) system. SOFC is an electrochemical cell that generates power at high temperatures through an electrochemical reaction. The high-temperature, unutilized fuel leaves the SOFC, which is burned in the afterburner. The afterburner temperature controls the operating temperature of SOFC. Here, three recuperators are used to utilize this high-temperature waste heat to improve the performance of SOFC and simultaneously generate heat power from the water or gas recuperator. TEG is an auxiliary power production technology that converts waste heat into energy. A novel integration of TEG with SOFC–CHP hybrid system to utilize the low temperature waste heat, is employed. The main goal of this study is to analyze a novel SOFC–CHP-TEG hybrid system in terms of its thermodynamics and emissions. A Two stage TEG is integrated with the SOFC–CHP hybrid system. The simulation model of high temperature fuel cell (SOFC) is developed on MATLAB and validated with published results. This study analyses the impact of pressure ratio and afterburner temperature on the performance of SOFC–CHP-TEG. To do this, perform energy and exergy assessments using the principles of the first and second laws of thermodynamics. A novel exergy-based sustainability index with emissions analysis for the proposed SOFC–CHP is presented. The achieved overall energy efficiency is 62.54% at a pressure ratio of 12 and an afterburner temperature of 1000 K. With an increase in pressure ratio and temperature, the level of CO emissions reduces significantly. [Display omitted] • A novel energy exergy for SOFC–CHP-TEG system is presented. • Exergy based performance is compared and achieve 56.62. • Utilization of waste heat via TEG. • Energy efficiency of SOFC–CHP-TEG is 62.54% at rp = 12 and afterburner temperature of 900 K. [ABSTRACT FROM AUTHOR]

Among the global carbon emissions in different fields, the carbon emissions in the transportation sector account for more than 1/4. Only the development of passenger car technology makes it difficult to achieve the climate goals. E-bike is considered to be one of the effective solutions. Hydrogen energy, as one of the representatives of new energy, has the advantages of cleanliness, high efficiency, and high energy density. Therefore, in this paper, a long-range hydrogen-electric hybrid bike and its energy management strategy are designed to achieve optimal performance. Herein, two energy management strategies, including the threshold-based and fuzzy logic optimized threshold-based strategy, are designed and compared by evaluating the parameters of equivalent hydrogen consumption, state of charge fluctuation, and the final state of the control system. The results show that with an initial SOC of 50% for Li-ion battery, the fuzzy logic optimized threshold-based strategy reduces equivalent hydrogen consumption by up to 16% compared to the threshold-based strategy. Besides, the fluctuation of the Li-ion battery's state of charge could be reduced by up to 54.7%, indicating that the fuzzy logic optimized threshold-based strategy is a promising energy management strategy for fuel cell hybrid E-bike. [Display omitted] • A long-range hydrogen-electric hybrid E-bike with metal hydride hydrogen storage is designed. • A fuzzy logic optimized threshold-based energy management strategy (EMS) is proposed. • Li-ion battery SOC fluctuations could be reduced by up to 54.7% via fuzzy logic optimized EMS. • Fuzzy logic optimized EMS shows self-adaptability and economic H 2 consumption for hybrid E-bike. [ABSTRACT FROM AUTHOR]

In the contemporary global discourse on environmental and developmental issues, the dual challenges of sustainable green energy and water supply stand paramount. These elements are vitally intertwined with the socio-economic vitality of the world. Notably, regions plagued by freshwater scarcity are increasingly turning to desalination which consists of a reliable and unconventional water source. The intersection of renewable energy with desalination and water purification processes presents a compelling synergy. This approach is particularly pertinent in areas where freshwater shortages coexist with abundant solar energy availability. Additionally, these technologies boast the advantage of low operational and maintenance costs. This paper delves into the design, optimization and financial analysis of a novel, standalone hybrid energy system, integrating photovoltaic and fuel cell technologies, for an agriculture farm situated in Kairouan, Tunisia. Unlike conventional systems, this model foregoes battery storage in favour of hydrogen storage, generated through water electrolysis powered by solar energy. This system harnesses solar energy for direct electrical power generation and hydrogen gas production. A segment of the generated electricity is allocated to electrolysis for green hydrogen production. In times of solar unavailability, the stored hydrogen is reconverted to electricity via a fuel cell. An intriguing aspect of this system is the utilization of saline well water, which, due to its high salt content, necessitates purification through desalination to prevent damage to the electrolysis unit and to render it suitable for agricultural irrigation. [Display omitted] • The production of green hydrogen, water and electricity for agriculture farm in Tunisia is analyzed. • The Levelized cost of green hydrogen produced in the PV farm is 2.25 €/kg. • A PV hydrogen Farm station with a capacity of 140 kW produces 1991 kg of green hydrogen and 235 MW h of electricity yearly. [ABSTRACT FROM AUTHOR]

Increasing greenhouse gas emissions and the increase in renewable energy sources in electricity generation have led to an increasing interest in hydrogen in recent years. As an energy storage solution for renewable energy, hydrogen can contribute to decarbonizing industries and transportation sectors as well as balancing energy systems. In this paper, the primary objective is to examine different methods for producing hydrogen depending on the primary energy source. In addition, it evaluates the economic and environmental performance of three types of hydrogen, known as hydrogen colors, and the significant obstacles to widespread fuel cell adoption. The key finding is that hydrogen's environmental benefits depend heavily on how hydrogen is produced and what fuel is used to produce it. Green hydrogen can only be produced using wind, solar photovoltaic (PV), and hydroelectric power. The emissions from other sources, such as blue hydrogen that uses carbon capture, utilization, and storage (CCUS) or electrolysis using electricity from the grid, are significantly higher than those from grey hydrogen. Furthermore, establishing an international hydrogen market will reduce costs and allow hydrogen to be produced in optimal locations. Lastly, a key unresolved question is whether hydrogen, whatever its color, is economically competitive in any sector of the energy system, despite all external costs associated with it. A policy framework that supports technological advancements, cost reductions, and future priorities will determine hydrogen's success in the future. The transition from grey hydrogen to green hydrogen should be facilitated by this framework. [ABSTRACT FROM AUTHOR]

Hydrogen-powered aviation is becoming a promising and competitive aviation power selection for developing zero-emission aerial vehicles. The current options for hydrogen aviation power include hydrogen gas turbines, hydrogen fuel cells, and hydrogen hybrid power. Among them, hybrid power offers a greater competitive advantage as it possesses the advantages of both gas turbines and fuel cells and exhibits higher efficiency levels. Nonetheless, there is still a lack of research on thermal management strategies to improve hydrogen-powered hybrid system efficiency. In this paper, a method that integrates thermal management and topology optimization is proposed to realize the energy-efficient system topology design of the hydrogen-powered hybrid system. Initially, based on the existing topology of the hydrocarbon fuel hybrid system, the overall design of the thermal management architecture of the hydrogen fuel hybrid system is improved, and an integrated calculation method for coupling subsystems such as fuel cells, gas turbines, and component cooling is established. Afterward, a method for optimizing the topology is put forward to improve the flow of mass and energy among components in the hybrid system, and the topology with higher energy efficiency is determined through exergy analysis. Ultimately, through parametric analysis of the optimized hybrid system performance, it is obtained that when the fuel cell fuel utilization rate is 80 %, an energy conversion efficiency of 69 % can be achieved during the cruise phase. • A thermal management system for hydrogen-powered hybrid systems is proposed. • Topology optimization of the hybrid system structure is performed for the first time. • Detailed exergy analysis is performed to determine system performance. • The optimized system can achieve an efficiency of 69 %. [ABSTRACT FROM AUTHOR]

Sustainable aviation is a key part of achieving Net Zero by 2050, and is arguably one of the most challenging sectors to decarbonise. Hydrogen has gained unprecedented attention as a future fuel for aviation, for use within fuel cell or hydrogen gas turbine propulsion systems. This paper presents a survey of the literature and industrial projects on hydrogen aircraft and associated enabling technologies. The current and predicted technology capabilities are analysed to identify important trends and to assess the feasibility of hydrogen propulsion. Several key enabling technologies are discussed in detail and gaps in knowledge are identified. It is evident that hydrogen propelled aircraft are technologically viable by 2050. However, convergence of a number of critical factors is required, namely: the extent of industrial collaboration, the understanding of environmental science and contrails, green hydrogen production and its availability at the point of use, and the safety and certification of the aircraft and supporting infrastructure. [Display omitted] • Brief insights of previous research (Lockheed 1970s, Tupolev-155, Cryoplane 2000s). • Findings of recent projects (FlyZero, ENABLE-H2, CHEETA, AIA, NAPKIN) discussed. • State of the Art status and future projections of enabling technologies presented. • Fuel cell propulsion system could enable regional electric aircraft by 2035. • Hydrogen-burning turbines crucial for mid to long-haul aircraft. [ABSTRACT FROM AUTHOR]

Recent advances in renewable energy research have suggested the fuel cell as a promising future energy source. Compared to the conventional power generation process, which has multiple-step conversion, a fuel cell is a single-step conversion process and produces power and sometimes heat. The efficiency of the individual existing conventional system is increased by integrating with fuel cells. The purpose of hybridization is to fulfill the demand and supply of power and heat. This paper starts with the historical development of fuel cell proceed with different categorize of hybrid systems. Discuss the possibilities of integration of existing fuel cell with other existing technologies such as SOFC-PEMFC, FC-CHP, FC-GT-ST, FC-Hybrid Vehicle, FC-PV/Battery. Numerical modeling can be done for each hybrid system considering mass balance, energy-exergy balance. At the end of the paper a discussion on the technical, economical, and commercial challenges and their solutions with future possibilities is presented. [Display omitted] • Study the integration potential of fuel cell with other power generating systems. • Fuel-cell hybrid configurations are analyzed. • Modelling aspect of various fuel cell hybrid configurations were summarized. • Fuel cell behavior with power and heat generation is presented. [ABSTRACT FROM AUTHOR]

Abstract: Electrocatalysts were fabricated for a polymer electrolyte membrane fuel cell using a sputter deposition technique. A pure Ni target was deposited onto a carbon nanotube impregnated on carbon paper. The sample was then heat treated in ammonia based environment. In examining the ORR polarization curve and cyclic voltammetry, as the heat treatment temperature changed, the sample showed the highest mass activity at 850 °C. This level of mass activity was 3 times higher than that of samples treated at other temperatures at the same voltage (0.9 V). The optimal heat treatment temperature for maximum mass activity was dependent on the formation of ligands between Ni and CNT which were linked by nitrogen. Even though the catalytic activity is not comparable to that of Pt/C catalysts yet, sputtered Ni based electrocatalysts may potentially serve as the non-precious metal electrocatalysts. [Copyright &y& Elsevier]

Fuel Cell Hybrid Electric Vehicles (FCHEV) use batteries and Photo Voltaic (PV) arrays to overcome Fuel Cell (FC) limitations like slow reaction times and low power densities. In a traditional power conversion system, three converters link FC, PV array, and battery to the output load. Despite using the FC, PV array, and battery, it has three inductors and several switches. Each switch also endures high voltage stress, possibly lowering power density and efficiency. This paper proposes a single-inductor multi-input converter (SI-MIC) that achieves 550 V as output where the input is variable. The fuzzy logic controller enables the integration of multiple power sources by selectively turning the ON and OFF switches in various operating modes. Fewer active switches during the powering process make it possible to employ semiconductors with a lower voltage. Thus, the converter generates high power with low conduction and switching losses. The state space model verifies the validity and stability of the converter under various operating modes. • Battery and PV array are integrated with the fuel cell using the single inductor multi-input converter (SI-MIC). • Fuzzy logic controller is used for switching the semiconductor devices for operating in various modes. • Battery can be charged and discharged in standby and normal operating modes. • Even if the input voltage fluctuates, the output voltage is always maintained at 550 V. [ABSTRACT FROM AUTHOR]

In the modern world, zero-carbon society has become a new buzzword of the era. Many projects have been initiated to develop alternatives not only to the environmental crisis but also to the shortage of fossil fuels. With successful projects in automobile technology, hydrogen fuel is now being tested and utilized as a sustainable green fuel in the aviation sector which will lead to zero carbon emission in the future. From the mid-20th century to the early 21st numerous countries and companies have funded multimillion projects to develop hydrogen-fueled aircraft. Empirical data show positive results for various projects. Consequently, large companies are investing in various innovations undertaken by researchers under their supervision. Over time, the efficiency of hydrogen-fueled aircraft has improved but the lack of refueling stations, large production cost, and consolidated carbon market share have impeded the path of hydrogen fuel being commercialized. In addition, the Unmanned Aerial Vehicle (UAV) is another important element of the Aviation industry, Hydrogen started to be commonly used as an alternative fuel for heavy-duty drones using fuel cell technology. The purpose of this paper is to provide an overview of the chronological development of hydrogen-powered aircraft technology and potential aviation applications for hydrogen and fuel cell technology. Furthermore, the major barriers to widespread adoption of hydrogen technology in aviation are identified, as are future research opportunities. [Display omitted] • Hydrogen is extensively researched and acknowledged as a viable mainstream fuel option. • Hydrogen fuel is now being tested and utilized as a sustainable green fuel in the aviation sector. • Numerous countries and companies have funded multimillion projects to develop hydrogen-fueled aircraft. • Empirical data show positive results for various projects. • New engine modules have been designed to accommodate hydrogen fuel cells economically. [ABSTRACT FROM AUTHOR]

In the recent years Green to Green Energy Systems have gain tremendous interest because they are pollution free systems. In this frame, the present paper aims at investigating a Green to Green system coupling Photovoltaic, Wind and Fuel Cell. Furthermore, an analysis procedure is developed allowing to find the optimal configuration of coupling by assessing the output power in terms of the system parameters. Moreover, a case study on Lebanon is considered where three different regions that are Dahr El-Baidar, Klaiaat Akkar and Rayak Bekaa are studied. Results shows the flexibility and strength of the suggested procedure. Indeed, it has been shown that for Dahr El-Baidar it is suggested to adopt WFC system whereas for Klaiaat Akkar hybrid PVWFC is the optimal solution and PVFC is better for Rayak Bekaa. Furthermore, an economic based optimization is carried out. It was surprisingly found that from an economic standpoint and for a land area larger than 3000 m2 Rayak Bekaa is the optimal location for WFC hybrid system. • The work is performed within the frame of Green to Green (G2G) concept that combines green source to green storage. • Green sources are PV and Wind Turbine whereas the green storage system is fuel cell. • The developed model is applied to three different regions in Lebanon in order to find the best configuration. [ABSTRACT FROM AUTHOR]

This paper discusses the technical and economic feasibility of a renewable energy-based system, aimed to replace the traditional diesel engines implemented on a pushed and pusher bulk carrier barge. This barge has a challenging navigational route in the Nile River from Alexandria to Aswan and vice versa. It is scheduled to complete 30 trips annually while carrying 850 tons/trip. The system is based on photovoltaic panels, and was selected with its excess energy to be stored primarily in the form of H 2 gas through electrolysis, and batteries (i.e. Power to Gas technology) to be later converted back to electrical energy through fuel cells. Hence, an operation algorithm was formulated to optimize the performance of the system by defining operating modes that use solar energy, hydrogen energy, batteries, or hybrid energy coming from multiple sources that result in an internal rate of return (IRR) of 15.1% and overall efficiency of 57.9%. This high efficiency is due to the nature of water current that flows from south to north of Egypt, therefore, causing a significant reduction in power demand in the trip from Aswan to Alexandria that requires 11,980 kW h, compared to the trip from Alexandria to Aswan that requires 21,064 kW h. • Zero emission solution combining solar energy, hydrogen generation and fuel cell propulsion for a barge in Nile River. • Preparation to achieve the 7th goal of sustainable development ensuring green propulsion in Nile River cargo transport. • Efficient use of natural resources, solar energy and water current from south to north of Egypt. • Integrating electrolizer, fuel cell, solar energy pv, batteries, and hydrogen storage to form an autonomous barge. [ABSTRACT FROM AUTHOR]

The use of fuel cell (FC) is considered one of the methods of producing electricity with relatively high efficiency. So, it has attracted many researchers' attention to develop and improve its performance. The present study deals with the technical-economic optimal design of a hybrid power generation system based on a Proton Exchange Membrane (PEM) FC combined with an Organic Rankine Cycle (ORC). ORC is used to recover the generated heat in PEM FC. The decision variables of this study include FC operating pressure and temperature, current density, FC area, the quantity of FC, and operating parameters of the ORC system, including HRVG PPTD, condenser PPTD, and refrigerant mass fraction in zeotropic mixture. In this study, three zeotropic mixtures, including R11-R245fa, R11-R123, and R123-R245fa, are studied as the working fluid of the ORC system. The objective functions considered to be optimized are the system's exergy efficiency and total cost rate (TCR). Finally, it is observed that the highest exergy efficiency is obtained using the zeotropic mixture R11-R245fa with a value of 54.15%, and the lowest TCR is obtained with the mixture R11-R123 with a value of 0.65 $/s. Zeotropic mixture R11-R123 has the exergoenvironmental index, environmental damage effectiveness index, and exergy stability factor of 0.5506, 1.277, and 0.4750, respectively. • A hybrid electricity generation system including PEM FC and ORC is analyzed. • Exergy Efficiency and economic analysis are considered for system evaluation. • Three novel zeotropic mixtures are examined as the working fluid of the ORC system. • A Parametric Study and optimization are conducted in this research paper. [ABSTRACT FROM AUTHOR]

There are complex coupling relationships between flight motion and energy management for hybrid electric fixed wing UAVs with photovoltaic/fuel cell/battery. Aiming at realizing high-energy-efficiency long endurance autonomous flight, this paper proposes a coordinated optimization method of trajectory optimization and energy management for hybrid electric UAVs. Numerical simulation and experiment are carried out. Separated by surplus demand energy except that produced by PV, this method includes an optimal energy flight trajectory optimization layer and an energy management layer. For the former, fuzzy neural network sequential convex optimization (FNNSCP) is proposed to handle the flight trajectory optimization problem for maximizing utilization solar energy. For the latter, an online energy management strategy based on convex quadratic programming MPC (CQPMPC) is proposed to realize the power allocation. Numerical simulation results show that FNNSCP reduced 2% energy requirement compared with Radau pseudo-spectral method (RPM) from flight trajectory optimization level. From energy management level, CQPMPC saves hydrogen consumption by 3.1% and 16.3% compared with nonlinear model predictive control (NMPC) and fuzzy logic state machine (FLSM), respectively. In the experiment, less hydrogen fuel is consumed by proposed method by 5.2% and 15.6% compared with NMPC and FLSM, respectively. Experimental results show that the proposed method has better energy-saving performance and excellent real time performance. It indicates that optimizing flight trajectory and improving energy management efficiency can realize the high-energy-efficiency flight of hybrid electric UAVs. This method is conducive to promoting the application of hydrogen energy in the field of UAVs. [Display omitted] • A coordinated optimization method is proposed for the high-energy-efficiency flight. • Fuzzy neural network adaptive sequential convex optimization method is proposed. • Online energy management strategy with convex quadratic programming MPC is proposed. • The proposed method is verified by simulation and energy management experiment. [ABSTRACT FROM AUTHOR]

The hybrid combination of hydrogen fuel cells (FCs) and batteries has emerged as a promising solution for efficient and eco-friendly power supply in maritime applications. Yet, ensuring high-quality and cost-effective energy supply presents challenges. Addressing these goals requires effective coordination among multiple FC stacks, batteries, and cold-ironing. Although there has been previous work focusing it, the unique maritime load characteristics, variable cruise plans, and diverse fuel cell system architectures introduce additional complexities and therefore worth to be further studied. Motivated by it, a two-layer energy management system (EMS) is presented in this paper to enhance shipping fuel efficiency. The first layer of the EMS, executed offline, optimizes day-ahead power generation plans based on the vessel's next-day cruises. To further enhance the EMS's effectiveness in dynamic real-time situations, the second layer, conducted online, dynamically adjusts power splitting decisions based on the output from the first layer and instantaneous load information. This dual-layer approach optimally exploits the maritime environment and the fuel cell features. The presented method provides valuable utility in the development of control strategies for hybrid powertrains, thereby enabling the optimization of power generation plans and dynamic adjustment of power splitting decisions in response to load variations. Through comprehensive case studies, the effectiveness of the proposed EMS is evaluated, thereby showcasing its ability to improve system performance, enhance fuel efficiency (potential fuel savings of up to 28%), and support sustainable maritime operations. [Display omitted] • Hybrid PEM fuel cell/battery system enables zero-emission shipping. • Two-layer EMS enhances fuel efficiency while satisfying real-time load requirements. • Rotational sequential distribution prevents uneven degradation. • Rotational sequential distribution enhances computational efficiency. [ABSTRACT FROM AUTHOR]

The All-electric ship (AES) concept has revolutionized the maritime sector. Indeed, AES is a promising solution for modern vessels where decreasing emission pollution, suppressing fossil fuel consumption, and making economical operation are its brilliant merits. Fuel cell (FC) technology based on clean hydrogen energy sources can play a significant role in meeting these requirements in the AES platform. Because of the slow transient response of the FC, an energy storage system (ESS) is required to improve AES performance in different operation scenarios. Therefore, optimal sizing of the FC and the ESS and proper design of energy management strategy is a challenging problem. This paper proposes a systematic approach for the optimal design of hybrid FC-ESS of AES power systems. The proposed method is based on an optimization technique to determine the optimal sizing of the FCs and the ESS. Capital investment, fuel consumption, personnel electrical safety, and occupied volume of the AES power system are the main objectives. The FC size, the battery size, the scheduled output power of the FC, and the battery are the decision variables. Genetic Algorithm (GA) is used to solve the optimization problem. To validate the numerical results, the optimization problem is also solved by Mayfly Algorithm (MA) separately. To assess the feasibility of the proposed strategy, the optimal design of hybrid FC-ESS for a vessel is implemented based on the proposed method. The simulation results validate the proposed approach's sufficiency to investigate and optimize the economic, safety, and dimensional aspects of designing the FC ship's IPS. Numerical results are reported for each design aspect. Considering the minor differences of the numerical results obtained by GA and MA, the optimum points are validated by the two techniques. Using the obtained results, various perceptions can be derived from the FC ship's IPS design. For example, the IPS cost in the cases with optimum volume, weight, and safety, has 2.3%, 2.6%, and 7.3% penalties, respectively compared to the case with the minimum cost. • Fuel cell-based electrification of a fishing ship based on practical information. • Systematic approach for optimal power system design of hydrogen-powered ship. • Proposing safety objective function for integrated power system of fuel cell ship. • Fuel cell hybrid IPS optimization based on volume, mass, cost and safety. • Estimation of propulsion power demand based on ship's resistance and speed profile. [ABSTRACT FROM AUTHOR]

This paper presents a framework for the efficient design and evaluation of a standalone hybrid renewable energy system (HRES) to meet the energy requirements of a rural community in the north-eastern region of Nigeria. The proposed microgrid system incorporates solar photovoltaic, wind turbines, biomass gasifier, fuel cell, and Battery storage. The sizing of each component is determined through the utilization of real local meteorological data and the load demand over a year, employing the Levy flight-salp swarm algorithms (LF-SSA). The optimization objective is to minimize the annualized system cost (ASC) of the HRES, while also considering the reliability constraint of Loss of power supply probability (LPSP). The comparative outcomes demonstrate that the LF-SSA surpasses other examined algorithms, namely the salp swarm, genetic algorithm, and HOMER software by achieving substantial cost savings of $29033, $50796, $191771 respectively in relation to the proposed HRES. The result further shows that, the LF-SSA provides the lowest LCOE of $0.933162/kWh, in contrast to SSA at $0.947737/kWh, GA at $0.958660/kWh, and HOMER at $1.075351/kWh. Additionally, the results indicate that the implemented Energy Management System (EMS) has successfully facilitated the establishment of an environmentally friendly and cost-effective energy system. • An efficient energy storage system is essential for managing intermittent energy supply. • The fuel cell can generate DC power by combining hydrogen with oxygen. • The amount of power generated by a PV panel depends on temperature and solar radiation intensity. • Deterministic rule-based controllers operate based on pre-defined rules. • Energy Management System coordinate the flow of power between different components. [ABSTRACT FROM AUTHOR]

This article presents an overview of existing fuel cell technologies with a focus on their microgrid applications with and without heat and power coupled cycles. The cogeneration aspects of FCs in microgrid environment are also highlighted in this article. The paper also focuses on providing a detailed idea about the pros and cons of different types of FCs. A brief idea about the working process and construction of the PEMFC is also included in this article. This article mostly emphasizes the control and management issues which are encountered during the operation of a PEMFC. Different control strategies as well as robust control techniques used for the efficient management of PEMFC are also included in this article. The article articulates different type of control strategies to tackle deficiency of fuel (hydrogen and oxygen) in proton exchange membrane fuel cell (PEMFC) systems. [Display omitted] • Comparative studies of all FCs are presented and their properties are discussed briefly. • It also reviews the FCs which can operate in hybrid cycles with their respective efficiency. • The FCs implementation in microgrid topology, their faults and classifications are studied. • A brief study on Control techniques to prevent hydrogen and oxygen deficiency in PEMFCs is presented. [ABSTRACT FROM AUTHOR]

The problems of energy shortage, severe pollution, and global warming are becoming increasingly severe. Renewable energy systems with hydrogen have been widely used. In recent years, much literature has described the energy management of renewable energy systems with hydrogen in a comprehensive way. However, most of them are proposed and discussed from an academic point of view. There are likewise several different approaches and ideas in the patents that address the energy management of hydrogen renewable energy systems. Moreover, most patents are oriented toward industrial applications and still need to be reviewed and analyzed. To fill this gap, this paper reviews relevant US patents to find potential and industrial hydrogen applications and energy management strategies in renewable energy systems. The work presented in this paper will provide solutions and guidance in solving energy management problems in renewable energy systems. • Review of U.S. patents for hydrogen-containing renewable energy systems management methods. • Review of U.S. patents for application of hydrogen-containing. • Energy management strategy based on object classification. • The industry mainly adopts rules-based energy management strategies. [ABSTRACT FROM AUTHOR]

Short-term performance degradation prediction is significant for fuel cell system control and health management. This paper presents a hybrid deep learning method by combining the convolutional neural network (CNN) and long short-term memory (LSTM) network to predict the short-term degradation of a 110 kW fuel cell system used for the commercial vehicle. First, the complete ensemble empirical mode decomposition (CEEMD) is applied to decompose the nonlinear and non-stationary voltage sequence extracted by the sliding window into modality sequences with different characteristic time scales. Then, these modality sequences are input into the corresponding CNN-LSTM for voltage prediction. Experimental results show that the proposed CNN-LSTM can reduce the root mean square error (RMSE) by 13.55% and 34.40%, respectively, compared to the single CNN and LSTM because it combines the spatial feature extraction ability of CNN and the powerful prediction ability of LSTM. Furthermore, the CEEMD–CNN–LSTM can reduce RMSE by 36.92% compared to CNN-LSTM since the impact of exogenous factors on the recoverable decay and intrinsic decay of the fuel cell can be separated easily for better model learning. The CEEMD–CNN–LSTM is also compared with other recently published deep learning models based on the same data set, and the results show that the prediction framework in this paper has higher accuracy. • Aging data of a 110 kW fuel cell system is used for model training and validation. • Complete ensemble empirical mode decomposition is applied to decompose voltage time. • Convolutional neural network and long short-term memory network are combined. • The prediction result under the delay condition of 5 h–6 h is still referential. [ABSTRACT FROM AUTHOR]

This paper outlines the optimal design of a hybrid system that includes wind turbines, solar panels, and a fuel cell to successfully meet the load's requirements. All cost components of the system, including load loss and expenditure for operation and maintenance, have been taken into consideration. A modified version of Ruddy Turnstone Optimization Algorithm is applied to determine the ideal equipment capacity for the hybrid system. Comparison and analysis are done between the optimization results and the outcomes obtained through evolutionary techniques. Moreover, the proposed technique is tested on a case study from Egypt and a comparison is made with existing Hybrid Firefly/Harmony Search method from literature. According to the results, both modified Ruddy Turnstone Optimization and Hybrid Firefly/Harmony Search methods have produced satisfactory outcomes. While the production cost slightly increased using the Hybrid Firefly/Harmony Search methodology, the system's dependability level has improved significantly, thereby ensuring reliable load supply. The results of a loss of power supply possibility comparison using 0.5%, 1%, and 2% of the modified Turnstone Optimization algorithm versus Hybrid Firefly/Harmony Search method approach yields a minimum cost of energy of 0.0798, 0.0739, and 0.0573 $/kWh, respectively. • Combined WT, PV, and FC system is described to satisfy the load's requirement. • System includes load loss cost as well as original investment cost for O&M. • Modified Ruddy Turnstone Optimizer is used for determining ideal equipment capacity. • The method is performed to a studied case in Egypt. • Comparison is conducted between the outcomes and HFA/HS method. [ABSTRACT FROM AUTHOR]

Hydrogen can manage intermittent Renewable Energy Sources (RES), especially in high-RES share systems. The energy transition calls for mature, low cost, low space solutions bringing the attention to unitized items such as the reversible Solid Oxide Cell (rSOC). This device, made of a single unit, can work as an electrolyzer and as fuel cell with high efficiency, fuel flexibility and producing combined heat. The objective of this review is to identify and classify rSOC applications to the building sector as an effective solution and to show how much this technology is near to its commercialisation. Research & Development projects were analysed and discussed for a comprehensive overview. Conclusions show an increasing interest in the reversible technology, although it is still at pre industrialisation stage with few real applications in the building sector, of which, the majority is reported, commented, and compared in this paper for the first time. • Reversible solid oxide cell application review as energy system in the building sector. • Interest in reversible solid oxide cell technology has been constantly increasing in the last decade. • 17 large research and development projects concerning the technology have been identified, analysed and compared. • Projects are compared in size, objective, budget, technology readiness level and manufacturer. • Terminology must emphasize the ability of this solution to work bi-directionally as electrolyser and fuel cell. [ABSTRACT FROM AUTHOR]

This paper proposes a system modeling and performance analysis of a renewable hydrogen energy hub (RHEH) connected to an ac/dc hybrid microgrid (MG). The proposed RHEH comprises a photovoltaic (PV)-based renewable energy source (RES) as the primary source, a proton exchange membrane fuel cell (PEMFC) as the secondary power source, and a proton exchange membrane electrolyzer (PEMELZ) that can generate and store hydrogen in a hydrogen tank. All these resources are directly connected at the dc bus of the ac/dc microgrids. The PEMFC operates and utilizes the hydrogen from the hydrogen tank when the energy generated by RES cannot meet the load demand. A coordinated power flow control approach has been developed for the RHEH to mitigate the mismatch between generation and demand in the ac/dc microgrid and produce renewable hydrogen when renewable power is in excess. The paper also proposes a modified hybrid Perturb & Observe-Particle Swarm Optimization (Hybrid PO-PSO) algorithm to ensure the maximum power point tracking (MPPT) operation of the PV and the PEMFC. The operation of the proposed RHEH is validated through simulations under various critical conditions. The results show that the proposed RHEH is effective to maintain the system power balance and can provide power-to-hydrogen and hydrogen-to-power when required. • Modeling and performance analysis of a RHEH connected to a hybrid microgrid. • Development of a coordinated power flow control approach for the RHEH. • Development of a modified Hybrid PO-PSO algorithm to ensure the MPPT operation. • Justification of the proposed RHEH under various critical conditions. [ABSTRACT FROM AUTHOR]

A real-time energy management system for an off-grid smart home is presented in this paper. The primary energy sources for the system are wind turbine and photovoltaics, with a fuel cell serving as a supporting energy source. Surplus power is used to generate hydrogen through an electrolyzer. Data on renewable energy and load demand is gathered from a real smart home located in the Yildiz Technical University Smart Home Laboratory. The aim of the study is to reduce hydrogen consumption and effectively utilize surplus renewable energy by managing controllable loads with fuzzy logic controller, all while maintaining the user's comfort level. Load shifting and tuning are used to increase the demand supplied by renewable energy sources by 10.8% and 13.65% from wind turbines and photovoltaics, respectively. As a result, annual hydrogen consumption is reduced by 7.03%, and the average annual efficiency of the fuel cell increases by 4.6% • Off-grid home energy management system using demand side control is proposed. • The system utilizes PV, WT, FC and an electrolyzer for green hydrogen production. • A FLC is used for real-time energy management and improved RES utilization. • Reduced hydrogen consumption and increased fuel cell efficiency is achieved. • Sustainable energy solution in remote areas without sacrificing user comfort. [ABSTRACT FROM AUTHOR]

At present, the production of electric energy consumer remote from agro-based centralized networks is done using diesel-generator technology with limited service life of the engine and the extremely low efficiency in the use of expensive fuel. In this paper, is considered an innovative technology of combined production of electricity and heat using a preliminary conversion of diesel fuel in the synthesis gas and then serving it at high temperature electrochemical generator. Synthetic gas to operate the generator air conversion is made of an electrochemical engine diesel fuels in catalytic reactor-burner. On the basis of heat balances of the torch, battery power and boiler are calculated: battery electric efficiency SOFC, chemical efficiency burner, SOFC anode temperature, EMF Planar element, the proportion of hydrogen, oxidized anode SOFC, unit cost of diesel fuel for the production of electricity and thermal energy. Specific consumption of diesel fuel for the production of electrical energy 114 g/kWh (162 g. w. t./kWh), and thermal 31.7 kg/Gj (45.1 kg/GJ, w. t. 189 kg standard fuel/Gcal). [ABSTRACT FROM AUTHOR]

The islands usually face challenges in their energy supply due to their specific location. On islands that are distant from the land, power is typically provided by diesel generators. Therefore, oil tankers must regularly refuel the island in order to supply the necessary fuel for diesel generators. As a result, if the fueling procedure is not completed for whatever reason, the island will not receive the necessary energy, which will result in an unavoidable loss of load. Due to their strategic location, some of these islands are used as military islands to protect the nations and waterways. Given the vital role that these military islands play for nations, a delay in supplying the island with energy can seriously harm security, the economy, and other factors. Transferring fuel to these islands is typically difficult, and in some cases impossible, under certain circumstances, such as war. Therefore, reducing the island's reliance on fossil fuels as much as feasible is vital to ensure the energy security of these specific islands. Diesel generators provide electricity to Larak Island, which is situated in the Strait of Hormuz. Larak Island serves as a military island due to its geopolitical location, hence it is crucial to consistently provide Larak with electricity. Therefore, in this paper, a combination of distributed generations and system storage is used to supply the Larak island. The photovoltaic, wind and tidal plants are considered the main power plants, and fuel cells with electrolyzers and hydrogen tanks have also been used as storage systems. In addition, the diesel generator is considered the system backup. The considered objective functions to design and manage Larak island's power supply system are reducing diesel generators fuel consumption, reducing electricity cost, and reducing electricity outages and lost power generation of renewable resources. • Larak island because of its strategic location is used as a military island to secure the waterways in Hormuz Strait. • To ensure the energy security of Larak island it is necessary to reduce its dependence on fossil fuels as much as possible. • Along with the diesel generator, a hybrid of renewable sources is used to supply the electrical load of Lark island. • Reducing diesel generator fuel consumption, energy supply cost, and loss of load are considered to manage power supply. • Using proposed energy management strategy, energy costs and fuel consumption can be decreased by 34% and 66%, respectively. [ABSTRACT FROM AUTHOR]

In this paper, self-made diformyl-dibenzo-18-crown-6 ether (DDB 18 C 6) is in-situ grafted into the pores of mesoporous molecular sieve (SBA-NH 2), and then the aforementioned modified molecular sieve (SBA-C) is introduced into the polyvinyl alcohol solution, and then the glutaraldehyde as the crosslinking agent to synthesized the anion exchange membrane under for fuel cell application. During the experiment, a series of anion exchange membranes (P-(SBA x% -C), x is the mass fraction of SBA-NH 2) is developed and the pore channels and chemical structures of the aforementioned membrane is verified by FT-IR, SAXD, N 2 adsorption-desorption, 1H NMR and XPS. Moreover, the performance of the membrane synthesized in this paper is also investigated and the results revealed that the unique membrane internal structure can improve the OH− transportation efficiency. Furthermore, the ionic conductivity of P-(SBA 10% -C) membrane is the highest (0.107S·cm−1) and the power density is the highest (354.8 mW cm−2) at 80 °C. By immersing P-(SBA 10% -C) membrane in 6 mol L−1 KOH solution for 168 h, the conductivity at 80 °C only decreased by 2%, proving that P-(SBA 10% -C) has a higher conductivity, good single cell performance and alkali stability. [Display omitted] • A new kind of mesoporous molecular sieve with ordered pores grafted with crown ether was prepared. • A new type of anion exchange membrane with ordered mesoporous channels grafted with crown ether was prepared. • Using crown ether to complex K+ to improve the conductivity of anion exchange membranes. • Prepared membrane showed excellent OH− conductivity and alkaline stability. [ABSTRACT FROM AUTHOR]

Hydrogen is called to play a vital role in the future decarbonization of the electricity industry. Among its multiple applications, this energy carrier may improve the energy storage, replacing or complementing the traditional battery banks thanks to its higher energy density. However, the low efficiency and cost of associated devices as well as the difficulty in transport make unfeasible the implantation of hydrogen storage systems at the residential level. However, emerging paradigms like energy communities may change this concept making viable the installation of hydrogen chains in the domestic sector. This paper focuses on day-ahead scheduling of energy communities with integrated collective hydrogen storage system. To this end, a three-stage methodology is developed in which the first level is focused on individual home energy management, the second level handles with peer-to-peer energy trading among prosumers and the last level determines the energy exchanging profile with the utility grid accounting with the hydrogen chain. To handle with uncertainties from renewable sources, demand and energy price, the Information Gap Decision Theory (IGDT) is employed, by which an uncertainty-aware scheduling program can be obtained minimizing the negative effects of uncertain parameters. A case study is performed on a six-prosumer energy community with electrolysis, hydrogen vessel and fuel-cell, allowing both purchasing and selling energy with the grid. The results serve to prove the effectiveness of the developed methodology as well as demonstrate the possible impact of unknowns in energy community operation, and how the hydrogen chain can help to improve the economy and self-sufficiency of the system. • A three-level operating strategy for ECs is proposed. • A multi-stage methodology for day-ahead scheduling of ECs with collective HSS is developed. • Uncertainties from renewable generation and demand are treated using IGDT. • The impact of uncertainties in the operation of ECs is discussed. • The role of HSS in improving the economy of the community is highlighted. [ABSTRACT FROM AUTHOR]

International trade volumes have grown due to acceleration of marine transportation of goods between continents. However, there is a concomitant increase in fossil fuel consumption and adverse environmental impact. This paper presents a new design of marine engines comprising of gas Brayton cycle, solid oxide fuel cell, and two organic Rankine cycles to replace two-stroke internal combustion engines. Hydrogen, methane, dimethyl ether, ethanol, and methanol are potentially selected as green fuels. In addition, liquified natural gas is used for cooling processes. This integrated hybridized marine engine is thermodynamically analyzed using the Aspen Plus software to assess its performance energetically and exergetically. It is found that the engine's total power is boosted by 33% to an average of 15758 kW with average energetic and exergetic efficiencies of 38% and 46%, respectively. The maximum power is fulfilled using all sustainable fuel blends to reach 16087 kW with a maximum carbon emission reduction of 83% and minimum specific fuel consumption. The proposed engine has better performance and less environmental impact, which is a more convenient choice than traditional engines. [Display omitted] • Five alternative fuels are chosen with different concentrations. • Integrated hybrid marine engine produces a total power of 16087 kW by 33% increase. • Engine runs at a 38% energy efficiency and 46% exergetic efficiency. • Alternative fuels can reduce carbon emissions by more than 80%. • New engine fuel consumption is reduced by more than 55%. [ABSTRACT FROM AUTHOR]

An effective online fault diagnosis system is of great significance to improve the reliability of fuel cell vehicles. In this paper, a fault diagnosis model for proton exchange membrane fuel cells is proposed. Firstly, the tests of electrochemical impedance spectroscopy under different fault types (flooding, drying, air starvation) and fault degrees (minor, moderate, severe) are carried out, and each polarization loss of the fuel cell is denoted by an equivalent circuit model (ECM). Then, the parameters of the ECM are identified by the proposed random mutation differential evolution algorithm. Furthermore, the parameters identified under different fault conditions are used to train and test a probabilistic neural network-based fault diagnosis model. The fault diagnosis model achieves diagnosis accuracies of 100% for the fault type and 96.67% for the fault degree. By setting operating conditions with different fault degrees, the fault diagnosis model proposed in this paper can realize the fault type and fault degree diagnosis, effectively avoiding the misjudgment of fault types, and is effective for improving the reliability of the fuel cell system. [Display omitted] • A RMDE algorithm is proposed to realize the impedance parameter identification. • A fault diagnosis model based on the probabilistic neural network is developed. • The diagnosis accuracies for fault type and fault degree reach 100% and 96.67%. [ABSTRACT FROM AUTHOR]

Abstract: The all-China-made proton exchange membrane fuel cell units were created and one fuel cell stack was assembled, with all domestic material such like Chinese proton exchange membrane, Chinese catalyst, Chinese carbon paper and Chinese graphite plate, on the basis of heat shaping CCM technology and modularized fuel cell stack assembly technology. The fuel cell unit was tested and optimized. The electricity generating test and other related experiments were conducted. It’s showed that the fuel cell unit’s performance was stable and its power density could reach 550 mW/cm2; the fuel cell stack’s operating power had reached 200 mW/cm2 with voltage uniformly distributed. The stack was stable and showed no obvious decrease in performance after 1800 h continuous operation. Discharged water analysis showed the all-China-made fuel cell stack’s materials had good chemical stability. This new type of fuel cell stack is much cheaper in production cost, compared to the same level import fuel cell stack. [Copyright &y& Elsevier]

This paper illustrates the investigation of a higher-scale proton exchange membrane fuel cell (PEMFC) model to realize its performance, simulation analysis and design in terms of reduced order model. The present research aims to visualize the efficacy of the propounded student psychology based optimization (SPBO) approach in terms of different reduced order transfer functions with model order reduction (MOR) studies. The adopted methodology can reduce the obligations encountered by the higher-order model like stability, calculative effort and problem of trapping into local optima. In this paper, the efficacy of the employed approach is established by performing comparative analysis with the existing optimization approaches in terms of various performance indices such as in-depth frequency analysis and time-domain analysis. The MOR study implements the SPBO approach to accomplish its effectiveness for higher dimensional systems with less computational effort to validate the reliability and the robustness of the adopted strategy. The obtained results are related to the outcomes yielded by other optimization approaches reported during recent past. • In PEMFC, significance of MOR based met heuristic approach has been studied. • Investigation of SPBO devoted to PEMFC for higher-order reduction. • Performance of proposed approach at different operating cases has been explored. [ABSTRACT FROM AUTHOR]

In this paper 1 1 This paper has been modified from the conference paper "Conceptual Design and Optimization of a General Aviation Aircraft with Fuel Cells and Hydrogen", presented at the Aerospace Europe Conference in Bordeaux, France, February 2020. , an aircraft design from scratch and optimization is carried out to investigate the potentials of using liquid hydrogen and fuel cells in general aviation. The focus is set on finding an efficient aircraft configuration that considers all drive train-related components such as the hydrogen tank, fuel cells, and electric motors as well as passenger seats and cargo hold. The paper starts with the definition of the design requirements and specifications. Following, the baseline design of the aircraft in the Suave tool is presented. This includes making extensions to the Suave tool regarding the compatibility of fuel cells and hydrogen energy networks. Eventually, a multidisciplinary design optimization process of selected design variables together with the design constraints is carried out in Suave. Finally, the design is evaluated in terms of performance and emissions by drawing a comparison with conventional general aviation aircraft. • A clean sheet aircraft design using liquid hydrogen and fuel cells is performed. • A tried and tested fuel cell model is added to the SUAVE aircraft design tool. • Design optimization including both the geometry and propulsion system is carried out. • Performance of small hydrogen aircraft is comparable to conventional aircraft. [ABSTRACT FROM AUTHOR]

Thermal management of metal hydride (MH) hydrogen storage systems is critically important to maintain the hydrogen absorption and release rates at desired levels. Implementing thermal management arrangements introduces challenges at system level mostly related to system's overall mass, volume, energy efficiency, complexity and maintenance, long-term durability, and cost. Low effective thermal conductivity (ETC) of the MH bed (~0.1–0.3 W/mK) is a well-known challenge for effective implementation of different thermal management techniques. This paper comprehensively reviews thermal management solutions for the MH hydrogen storage used in fuel cell systems by also focusing on heat transfer enhancement techniques and assessment of heat sources used for this purpose. The literature recommended that the ETC of the MH bed should be greater than 2 W/mK, and heat transfer coefficient with heating/cooling media should be in the range of 1000–1200 W/m2K to achieve desired MH's performance. Furthermore, alternative heat sources such as fuel cell heat recovery or capturing MH heat during charging and releasing it back during discharging have also been thoroughly reviewed here. Finally, this review paper highlights the gaps and suggests directions accordingly for future research on thermal management for MH systems. • Heat transfer challenges and enhancement techniques of MH are discussed. • Thermal management arrangements of MH hydrogen storage are reviewed. • Research gaps and directions for future studies are provided. [ABSTRACT FROM AUTHOR]

Fuel cells are considered to be a promising system that is utilized in several applications and in various sectors. Particle image velocimetry is extremely practicable for the exploration of the flow field inside fuel cells and channels. This paper reviews fuel cell studies focusing on the particle image velocimetry technique in the open literature. In this regard, state-of-the-art and comparative evaluation have been investigated and are discussed. Additionally, challenges, opportunities and future direction have been studied in terms of fuel cell type, size, voltage value, current value, power output capacity, and CFD applications. It is concluded that the growing demand on fuel cells will increase system design, performance improvement and cost benefit efforts affected by the flow and design parameters and characteristics which are other important issues that could be covered using PIV methods in the future. Moreover, this review paper is expected to be a better guide for researchers, policy makers and technologists working on potential commercial applications of fuel cells in mobile and stationary platforms. • This work reviews fuel cell studies including the particle image velocimetry technique in the open literature. • The state of the art and comparative evaluation of the works done in the literature investigate and discuss in detail. • This paper aims to be a guideline for researchers and policymakers working on fuel cell technologies. [ABSTRACT FROM AUTHOR]

An online impedance calculation method for fuel cells is proposed in this paper. A periodic square wave is selected as the standard excitation current and injected into a fuel cell. Then, the impedance spectrum is obtained by converting the excitation current and response voltage to the frequency domain with the Morlet wavelet. The accuracy of the calculated impedance is firstly tested offline under the stand excitation current condition, and the relative errors of the real part and imaginary part are within 5% and 10%, respectively. To calculate the impedance automatically, a search method is proposed to locate the position of the translation parameters autonomously. Besides, this paper investigates the effects of the stable time and the excitation current form on the calculation results and recommends the excitation current parameters. Finally, an implementation scheme for online impedance measurement is given. • Impedance is calculated by Morlet wavelet combined with a periodic square wave. • An automatic search method for time factors is developed. • The effect of the excitation current form on the calculation result is investigated. • An implementation scheme for the online impedance measurement is given. [ABSTRACT FROM AUTHOR]

PEMFC system is a complex new clean power system. Based on MATLAB/Simulink, this paper develops a system-level dynamic model of PEMFC, including the gas supply system, hydrogen supply system, hydrothermal management system, and electric stack. The neural network fits the electric stack model to the simulation data. The effects of different operating conditions on the PEMFC stack power and system efficiency are analyzed. Combining the power of the reactor and the system efficiency to define the integrated performance index, the particle swarm optimization (PSO) algorithm is introduced to optimize the power density and system efficiency of the PEMFC with multiple objectives. The final optimal operating point increases the power density and system efficiency by 1.33% and 12.8%, respectively, which maximizes the output performance and reduces the parasitic power. [Display omitted] • Build PEMFC system level model in MATLAB/Simulink. • Analyze sensitivity analysis of operating conditions. • Combine stack power and system efficiency to define integrated performance index. • Introduce neural networks and PSO algorithms to optimize system performance. [ABSTRACT FROM AUTHOR]

Proton exchange membranes (PEMs) are widely used in fuel cells, electrolyzers, and electrolytic dehumidifiers. Despite significant improvements in material preparation, operational performance and durability for these applications remain impractical, mainly due to poor multilayer structures and component design. This paper reviews recent ideas on improving the assembly design for three types of PEM applications, focusing on aspects of configuration optimization of the membrane electrode assembly and microstructured anode/cathode materials. Well-designed interfaces in catalyst layers (CLs) and diffusion layers (DLs), and between multilayers, are critical for reducing contact resistance and enhancing water management. Modification of catalyst/ionomer interfaces, such as order-structured CLs and patterned PEM/CLs, can improve catalyst utilization and notably reduce loading. Combining multiple CLs and DLs with different porosity or hydrophobicity, or using metal-based DLs (metal fiber or foam) is also feasible. Another approach receiving much attentions is to improve the common plate-and-frame structure to a plate-less one. Eliminating bipolar plates with ridge grooves or integrating the flow field with DLs can improve the reaction, and reduce mass transfer and interface ohmic resistances. Stack compactness can also be enhanced. From the microstructure of materials to the macrostructure of assembly configurations, this review pointed out systematical guidance for further research to achieve well-designed PEM assemblies. [Display omitted] • We reviewed research on assembly design strategies for various PEM applications. • This review ranges from materials' microstructure to assemblies' macrostructure. • Well-designed interfaces between catalyst and diffusion layers, and between PEMs are critical. • Modification of catalyst/ionomer interfaces can improve utilization and reduce loading. • Elimination of bipolar or flow field plates can reduce mass transfer and ohmic resistances. [ABSTRACT FROM AUTHOR]