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The global pursuit of sustainable energy solutions has led to an increased interest in green hydrogen as a significant contributor to the transition towards a low-carbon economy. This comprehensive analysis delves into the progress made in green hydrogen production using alkaline water electrolysis, shedding light on the fundamental principles, materials, design, operational conditions, and integration with renewable energy sources. The paper critically evaluates the economic and environmental aspects, providing valuable insights into the challenges, future prospects, and real-world applications. The importance of green hydrogen as a clean energy carrier is emphasized in the context of mitigating climate change and achieving energy independence. The paper outlines various methods for hydrogen production, with a focus on alkaline water electrolysis, highlighting its role in sustainable hydrogen generation. The structure of the review paper is well-detailed, guiding the reader through a systematic exploration of key aspects related to green hydrogen production. The fundamentals of alkaline water electrolysis are explained in detail, covering the basic principles, reactions at electrodes, components, working mechanisms, efficiency calculations, and existing challenges. An in-depth examination of materials and electrodes is presented, showcasing recent innovations that enhance performance. Electrolysers design and system configurations are discussed, incorporating recent developments aimed at improving efficiency and scalability. The paper explores operating conditions and optimization strategies, emphasizing the impact of temperature, pressure, and current density on electrolysis efficiency. The integration of renewable energy sources, such as wind and solar power, with alkaline water electrolysis is analyzed, addressing both the benefits and challenges. The economic feasibility of green hydrogen production and its environmental impacts, including life cycle assessments and carbon footprint, are meticulously examined. The paper concludes with an overview of current challenges and limitations, ongoing research insights, and future prospects for alkaline water electrolysis technology. Real-world case studies are presented to showcase the practical applications of this technology in industries, transportation, and energy storage. In summary, this review highlights the pivotal role of alkaline water electrolysis in advancing green hydrogen production, offering a promising pathway towards a sustainable and decarbonized energy future. [ABSTRACT FROM AUTHOR]

Currently, hydrogen generation is considered a crucial aspect of sustainable energy production. This paper disscusses the hypothesis that hydrogen generation occurs during the operation of the membrane electrode assembly and is an acceptable and eco-friendly method for producing hydrogen without carbon dioxide. This paper considers the hypothesis by simulating hydrogen generation in fuel cells that rely on fossil fuels using proton fuel cells. The O ptimized H ydrogen G eneration-based R egression (OHGR) model is based on a deep learning architecture. The architecture is based on stacking multiple neural networks with crossover connections that feed information through a pool of activation functions. The OHGR predicts the amount of hydrogen generated in 1 mA cm−2 and can exceed 10–20 mA cm−2 after long-term operation. For given temperatures, pressures, and humidity, which are considered fundamental factors in the hydrogen crossing phenomenon.The OHGR uses a stochastic gradient as an optimization engine that informs the most-recommended values for temperature, pressure, and humidity to generate the optimal amount of hydrogen. In addition, the OHGR model is interoperated to accept the same number of most significant features obtained from the principal component analysis. The OHGR was evaluated using empirical regression evaluation metrics, including the root mean square error, R2, Mean Square Error, and Mean Absolute Error. The optimization process was designed to include the hypothesis and hyperparameters to determine the most significant values for the OGHR and its outcomes. The introduced OHGR model is sufficiently efficient to predict the generated hydrogen with RMSE = 0.220 and R2 = 0.564, indicating an enhancement of the OHGR model compared to recently reported models. Since the sustainability of hydrogen generation is important for energy availability and reducing climate change, the OHGR model is justified using the SHapley Additive exPlanations (SHAP) method to ensure that the model is transparent, reliable, and trustworthy. [Display omitted] • Optimized Hydrogen Generation-based Regression (OHGR) model using a custom architecture. • OHGR predicts generated hydrogen PEM by optimizing temp, pressure & humidity of CNN structure. • OHGR uses an optimization engine to detect most recommended to generate hydrogen. • OHGR accepts same number of significant features by principal component analysis. • XAI is used to ensure transparent, reliable, and trusted of OHGR using SHAP. [ABSTRACT FROM AUTHOR]

Hydrogen is emerging as a critical player in transitioning to sustainable and renewable energy systems, serving roles in energy storage, grid balancing, and decarbonization. This paper explores various aspects of hydrogen, including its production through renewable-electricity-driven electrolysis, advanced storage techniques, and incorporation into current energy systems. It highlights primary electrolysis methods like PEM and alkaline, noting their improved efficiency and cost-effectiveness. Various hydrogen storage methods, such as physical, chemical, and advanced porous materials, are examined for their benefits and limitations. The review further explores hydrogen's integration into grid storage systems and microgrids to enhance energy reliability. It discusses hydrogen's application in fuel cells for electricity generation, focusing on technological advancements that improve efficiency and reduce costs. Additionally, the paper underscores hydrogen's crucial role in reducing CO 2 emissions in industrial processes like steel production and its use in residential and commercial energy supply through combined heat and power systems. Economic aspects and supportive policies from regions are analyzed, highlighting the global efforts and policies supporting the potential hydrogen in renewable energy systems. This analysis emphasizes hydrogen's comprehensive role in enhancing renewable energy systems and achieving global sustainability objectives, providing a thorough review of recent progress and challenges. • Identifies PEM and alkaline as efficient electrolysis methods. • Analyzes varied H 2 storage options for mobility and stationarity. • Highlights advancements in H 2 fuel cells for vehicles. • Discusses global policies supporting H 2 integration. • Reviews economic impacts of scaling H 2 infrastructure. [ABSTRACT FROM AUTHOR]

Green hydrogen is typically produced by water electrolysis. In this process, water is split into hydrogen and oxygen by an electric current. Different technologies exist to produce hydrogen by electrolysis, including the four best recognized: Anion Exchange Membrane (AEM), Solid Oxide Electrolysis Cell (SOEC), Polymer Electrolyte Membrane (PEM) and Alkaline Water Electrolysis (AWE). While the latter two are commercially available, SOEC shows promise for efficient hydrogen production, and AEM combines advantages from both AWE and PEM systems. However, the most mature technology remains the most mature and cost-effective technology for industrial and large-scale hydrogen production. This review provides a comprehensive overview of recent advances in alkaline water electrolysis (A-WE) for hydrogen production, including a comparative assessment of the four commonly used electrolysis technologies. The paper covers the current status, recent research advances, and commercialization challenges of A-WE technology, offering insight into its potential and outlining future research directions. • The paper comprehensively assesses A-WE, PEM, SOEC, and AEM technologies for green hydrogen production. • Alkaline Water Electrolysis (A-WE) is the most cost-effective and mature technology for large-scale hydrogen production. • A-WE's limitations include low current density, corrosivity, gas permeation, slow response, and sensitivity to impurities. • Advanced materials, optimized electrolytes, membranes, and innovative electrode designs enhance A-WE performance. • A-WE market saw 6.5% CAGR growth, driven by sustainable energy demand despite supply chain and geopolitical challenges. [ABSTRACT FROM AUTHOR]

The transition to sustainable energy sources is a global imperative in the face of climate change and dwindling fossil fuel reserves. Hydrogen, as a clean and versatile energy carrier, has garnered significant attention as a potential solution. This paper provides a comprehensive overview of various electrolyzer types, their features, advantages, disadvantages, and future expectations in the context of sustainable energy generation. The article begins by outlining the fundamental principles of electrolysis, highlighting its potential to harness surplus renewable energy. Four main types of electrolyzers are discussed: alkaline electrolyzers, proton exchange membrane electrolyzers, anion exchange membrane electrolyzers, and solid oxide electrolyzers. Each type is explored in depth, with a focus on their unique operating principles, efficiency, scalability, and suitability for different applications. The paper further delves into recent advancements in electrolyzer technology, discussing emerging trends, improved catalysts, and innovative system designs aimed at enhancing efficiency and reducing costs. It also explores the role of policy support and research initiatives in accelerating the adoption of electrolysis for sustainable hydrogen production. • Water electrolyzer systems are one of the most promising technologies for green hydrogen production. • This review provides insights into the current state and future potential of water electrolysis technologies. • Challenges, advantages, and future directions of electrolyzer types are discussed. • Green hydrogen plays a crucial role in decarbonization efforts and offers a sustainable solution for future energy needs. [ABSTRACT FROM AUTHOR]

Nowadays, hydrogen is gaining attention as one of the green energy alternatives within transition to a zero-emission economy. Increasing demand for hydrogen and its production has prompted the development of low-carbon strategies and technologies for hydrogen generation from hydrocarbons. This paper provides a thorough analysis of traditional and innovative methods for hydrogen production from fossil feedstock, reviewing the critical aspects and recent advancements in the field. The paper emphasizes the potential of in situ hydrogen generation as the most promising method, taking into account CO2 emission concerns. Additionally, this study explores the use of software packages for modeling hydrogen production, outlining their advantages and disadvantages and proposing the most favorable software for in situ hydrogen generation from hydrocarbons. Subsequent analysis sheds light on the effectiveness, economic viability, environmental impact, and future perspectives of various hydrogen production technologies. • Overview of hydrogen production technologies: conventional and innovative methods. • Key issues and best practices of the latest experimental and numerical studies. • Comparative analysis of various hydrogen production technologies and approaches. • Subsurface hydrogen generation has a great development potential. • There are methods for clean hydrogen production from hydrocarbon feedstock. [ABSTRACT FROM AUTHOR]

This paper examines the potential of solar and hydrogen (H 2) energy-based hybrid energy systems for residential applications. The growing need for energy and the demand for sustainable energy sources have led to the development of integrated energy systems that combine renewable energy resources to meet energy needs. This paper overviews recent studies on hybrid energy systems for on-grid and off-grid residential utilizations. It discusses the system configuration and components of hybrid energy systems, including solar panels, electrolyzers, fuel cells (FC), and batteries. It also covers the technical optimization of integrated energy systems, including sizing, control strategies, and economic analysis. The key findings of this review paper indicate that hybrid energy systems can offer dependable and sustainable energy for residential applications. Through numerical analyses, the optimal dimensioning of the system elements and control strategies can significantly enhance the system's performance and lower the cost of energy. This study also highlights the challenges and opportunities for integrating hybrid energy systems within residential applications. Overall, it provides in-depth perspectives on the possibilities inherent in solar and hydrogen energy-based hybrid energy systems for residential applications. The findings can guide future research and the advancement of hybrid energy systems for sustainable energy solutions. • Comprehensive review on solar and hydrogen-based residential applications. • Holistic approach to system configuration, optimization, and economics. • Detailed analysis of interconnected components enhancing system efficiency. • Unique focus on real-world residential applications and scenarios. • Broad applicability across diverse geographical regions. [ABSTRACT FROM AUTHOR]

Transitioning to a sustainable energy future necessitates innovative storage solutions for renewable energies, where hydrogen (H₂) emerges as a pivotal energy carrier for its low emission potential. This paper explores unlined rock caverns (URCs) as a promising alternative for underground hydrogen storage (UHS), overcoming the geographical and technical limitations of UHS methods like salt rock caverns and porous media. Drawing from the experiences of natural gas (NG) and compressed air energy storage (CAES) in URCs, we explore the viability of URCs for storing hydrogen at gigawatt-hour scales (>100 GWh). Despite challenges such as potential uplift failures (at a depth of approximately less than 1000 m) and hydrogen reactivity with storage materials at typical conditions (below temperatures of 100°C and pressures of 15 MPa), URCs present a flexible, scalable option closely allied with green hydrogen production from renewable sources. Our comprehensive review identifies critical design considerations, including hydraulic containment and the integrity of fracture sealing materials under UHS conditions. Addressing identified knowledge gaps, particularly around the design of hydraulic containment systems and the interaction of hydrogen with cavern materials, will be crucial for advancing URC technology. The paper underscores the need for further experimental and numerical studies to refine URC suitability for hydrogen storage, highlighting the role of URCs in enhancing the compatibility of renewable energy sources with the grid. • Detailed exploration of unlined rock cavern (URC) technology. • Analysis of URCs' potential for large-scale hydrogen storage. • Insights from historical use of URCs in compressed gas storage. • Examination of the opportunities and challenges in using URCs for hydrogen storage. [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]

This review paper explores into the extensive realm of alkaline water electrolysis (AWE), a transformative technology for hydrogen production, offering profound insights and future prospects for sustainable growth. It embarks on this journey by explaining the fundamental principles, the application of Faraday's laws, electrolyzer design, and the intricate electrochemical processes transpiring at the cathode and anode. Subsequently, it investigates electrode materials, catalysts, membrane material and their recent developments, unveiling essential aspects of material selection and performance enhancement. The exploration extends to the domain of alkaline electrolyte solutions, where it provides a comprehensive overview of common electrolytes, the impact of concentration on system performance, and pioneering research on alternative electrolytes. Shifting focus towards large-scale systems and industrial applications, the paper unravels the economic feasibility, considerations regarding costs, and the transformative influence of alkaline water electrolysis on diverse industries. The final segment is dedicated to emerging trends and future directions. It casts light on recent breakthroughs and the potential for commercialization, presenting a vivid image of the evolving role of this technology in the sustainable energy landscape. The conclusive segment, this review offers a recapitulation of the key discoveries and insights presented throughout the paper, while delivering a critical evaluation of the present state of alkaline water electrolysis. It emphasizes the potential of the technology while recognizing critical research areas such as electrode materials, safety standards, scaling efficiency, flexible operation, and surface modification techniques. In the rapidly changing energy scenario, this paper stands as a testament to the dynamic nature of alkaline water electrolysis and its pivotal role in a sustainable energy future. • Identifying different alkaline water electrolysis (AWE) cell efficiencies and transport resistances. • Insights into recent development in electrodes, catalysts, and separator membranes materials. • Recognizing recently examined alkaline electrolytes. • Recent and emerging trends in AWE including the use of electromagnetic field and pulsating potential. • Perspectives of scaling up AWE and its industrial commercial applications. [ABSTRACT FROM AUTHOR]

Hydrogen is a kind of clean renewable energy with great development potential. However, traditional electrocatalytic water splitting methods often require high energy consumption and expensive catalysts, which limits their practical application. Transition metal selenides (TMSes), as a new type of hydrogen production materials from electrolytic water, have been the focus of research in recent years. The basic principle of electrochemical water cracking and the preparation of TMSes are reviewed in this paper. The electrocatalysts for hydrogen evolution, oxygen evolution and integral water cracking based on TMSes, including single metal selenides, binary metal selenides, and multinary mixed metal selenides, are discussed. Finally, the future research direction and the development prospect of TMSes electrocatalysts are prospected. • Eley-Rideal and Langmuir-Hinshelwood mechanisms were used to analyze the OER reaction mechanism. • The production and properties of transition metal selenides in recent years are introduced in detail. • In this paper, transition metal selenides are introduced from single TMSes, binary TMSes and multinary mixed TMSes. • The physical properties and electronic structures of transition metal selenides are described in detail. [ABSTRACT FROM AUTHOR]

This paper explores green hydrogen-based carbon dioxide (CO 2) hydrogenation for the production of oxygenates, presenting it as a pivotal strategy for mitigating carbon emissions and advancing sustainable energy solutions. The conversion of CO 2 into oxygenates through hydrogenation emerges as a promising avenue, particularly in the context of transportation applications where the storage of hydrogen poses challenges. The substitution of fossil diesel and gasoline fuels with green hydrogen-derived dimethyl ether, or methanol/ethanol, is advantageous from a life cycle analysis (LCA) CO 2 emission perspective even without the capture of the CO 2. However, the greatest sustainability appeal is contingent on the crucial aspect of capturing CO 2 when utilizing these fuels, which is an aspect currently absent in the literature. This narrative review comprehensively explores catalytic processes, mechanisms, sustainability perspectives, and the current state of research in this evolving area. It encompasses both the production of oxygenates through CO 2 hydrogenation and the subsequent utilization of these oxygenates in fuel cells or combustion systems, emphasizing the integration of CO 2 capture technologies. The paper contributes to the discourse surrounding the environmental and technological dimensions of energy storage ecosystems, providing a holistic view of their potential to foster sustainable energy solutions. [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]

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]

A solid oxide electrolyzer cell (SOEC) is a promising clean energy technology due to with high conversion efficiency and the ability to directly produce syngas. This paper summarizes technical challenges of SOEC in terms of dynamic response, co-electrolysis and material degradation, and recent developments on the manufacturing technology, materials for each component, mathematical models, flow channel designs and reversible solid oxide fuel cells (RSOFCs). The model development and related research on SOECs are explored in this paper, encompassing sensitivity analyses, dynamic responses, structural degradation and practical applications. This paper aims to promote the future development of SOECs, including the improvement of electrolysis efficiency, lifetime and economic performance. • Technological limitations and recent developments for SOEC are reviewed. • The dynamic response, co-electrolysis and material degradation are discussed. • Component materials and their manufacturing techniques are summarized. • Multi-physics coupling models at different scales are highlighted. • Future research direction in materials and modeling are proposed. [ABSTRACT FROM AUTHOR]

In the quest for sustainable and efficient energy solutions, hydrogen fuel cells emerge as a beacon of hope, offering a promising pathway towards a greener future. Accurate Identification of the ungiven parameters of proton exchange membrane fuel cell (PEMFC) mathematical models is indispensable for designing, managing, and simulating the practical PEMFC. In order to identify the parameters of PEMFC punctually, this paper presents a modified version of the slime mould algorithm (MSMA). In order to increase capability of the MSMA in the exploitation phase, both locally and globally, the sine-cosine technique has been utilized to boost the search capabilities. To assess the performance of MSMA, MSMA is first utilized to address ten well-known benchmark functions. The obtained results confirm that MSMA outperforms SMA on all benchmark functions. Then, MSMA is employed to solve the optimization problem of different mechanical design problems and also the MSMA provides superior performance over the standard SMA. Finally, the MSMA is used to identify the unknown parameters of four typical PEMFCs: 250W PEMFC, BCS 500W PEMFC, AVISTA SR-12 model, and the Temasek 1 kW PEMFC model. Experimental results boost the supremacy of MSMA in the PEMFC parameters extraction by comparing it with the original SMA and well-known potent optimization techniques. Furthermore, MATLAB/Simulink is employed for advanced dynamic PEMFC modeling, facilitating a comprehensive assessment of fuel cell parameters. The validation of this dynamic PEMFC model, using MSMA-optimized parameters, establishes its practical utility in system analysis and real-world fuel cell operation, marking a significant advancement in PEMFC technology management and simulation. [ABSTRACT FROM AUTHOR]

Fossil fuels are deemed to diminish because of their limited availability, no renewability, and emissions of greenhouse gases and other poisonous materials to the atmosphere and the ecosystem. Renewable energy based on sustainable biomass has occupied an increasing share of the energy system over the past decade. Among several massively cultivated crops worldwide, corn, sugarcane bagasse, and soybean straws are some of the leading agricultural by-products that can generate substantial energy (e.g., biofuels, hydrogen) as vital sustainable energy to substitute non-renewable fossil fuels. This paper aims to review recent progress in renewable energy generation from biomass based on thermochemical techniques-i.e., gasification, pyrolysis, and liquefaction-detailed technical features and their application for extraction energy from biomass. The quality, composition, and productivity of renewable energy extracted from biomass based on existing thermochemical techniques are compared, and their technical dependencies upon the thermochemical processes are discussed. Furthermore, analysis of technical deficiencies of existing methods, and exploration of innovative emerging technologies for high-efficiency and high-quality renewable energy generation from biomass straws. In general, biomass gasification stands out as the most efficient technique for hydrogen production (HP) from biomass due to mature technology, high hydrogen yield, and potential for integration with other presented techniques. [Display omitted] • A detailed review of HP from biomass using thermochemical techniques. • Discussion about gasification, pyrolysis, and liquefication working principles. • Comparison between all types of presented thermal techniques. • Advantages and disadvantages of gasification, pyrolysis, and liquefication. • Overall performance of all thermal techniques presented in this review. [ABSTRACT FROM AUTHOR]

Hydrogen locomotives offer a promising cleaner alternative to conventional diesel locomotives. However, hydrogen production methods and energy sources may introduce additional emissions. This paper evaluates the environmental and potential social impacts of hydrogen locomotives in Canada from a life cycle perspective, encompassing the locomotive's retrofitting components and the fuel life cycle. Results show varying emissions across different hydrogen production pathways and regions. Electrolysis has the highest emission reduction potential in provinces with cleaner electricity sources, such as Manitoba, Quebec and British Columbia, resulting in up to 47% reduction in life cycle emissions. Conversely, in Alberta and Saskatchewan, emissions are approximately three times higher than diesel due to reliance on fossil fuel-derived electricity. The social assessment underscores the imperative of considering emissions, costs, and technical implications to address potential social impacts. This positions hydrogen locomotives with significant challenges that necessitate resolution before they can be considered a superior alternative to diesel. • A social and environmental life cycle analysis of hydrogen locomotives is provided. • Various hydrogen production methods and different regions are analyzed. • Emissions from fuel production are the primary drivers of the lifecycle emissions. • The region's electricity source highly impacts hydrogen locomotive evaluation. • Hydrogen locomotives pose potential social challenges that need to be addressed. [ABSTRACT FROM AUTHOR]

α-Fe 2 O 3 attracted great attention as a promising photoanode candidate for photoelectrochemical (PEC) H 2 O spitting. In this paper, one dimensional (1D) α-Fe 2 O 3 nanorods coupled 2D porous In 2 O 3 nanosheet assemblies were designed to construct a S-scheme α-Fe 2 O 3 /In 2 O 3 heterojunction photoanode. The unique porous In 2 O 3 nanosheet assemblies are conductive to improve light-harvesting efficiency and provide more active sites. An internal electric field induced at the α-Fe 2 O 3 /In 2 O 3 heterojunction interface could promote interfacial charge separation and transfer, enhancing redox kinetics. The as-obtained 2D/1D In 2 O 3 /α-Fe 2 O 3 photoanode achieved a stable photocurrent density of 2.2 mA cm−2 at 1.23 V (vs. RHE). It is 6.3 times higher than that of the α-Fe 2 O 3 component, and got a max applied bias photo-to-current efficiency (ABPE) of 0.28%, which is about 5.8 times that of bare α-Fe 2 O 3 at 1.01 V. The work provides a promising strategy to construct high-performance S-scheme heterostructure photoanodes, featuring the role of surface and interface science in sustainable energy. [Display omitted] • 1D α-Fe 2 O 3 nanorods coupled 3D porous In 2 O 3 nanosheet assemblies were constructed. • In 2 O 3 nanosheets modified on α-Fe 2 O 3 nanorods could promote interfacial charge separation and transfer. • α-Fe 2 O 3 /In 2 O 3 photoanode achieved 2.2 mA cm−2 at 1.23 V (vs. RHE) and ABPE of 0.28% at 1.01 V. • The photoanode follows a S-scheme mechanism for enhanced photoelectrochemical activity. [ABSTRACT FROM AUTHOR]

This paper examines the potential role of hydrogen and ammonia in the European energy transition to reach net-zero greenhouse gas targets. We analyse trade of green hydrogen and ammonia between Europe and the Middle East and North Africa (MENA), since the latter possesses a high potential for solar power, making it a possible low-cost supplier of these two clean energy carriers. The economic attractiveness of such trade depends on the additional infrastructure and transportation costs required for the roll-out of these clean energy carriers. Using a global integrated assessment model, TIAM-ECN, we evaluate the trade-off between costs and benefits of establishing import-export links between Europe and MENA for hydrogen and ammonia. Our study assumes the availability of hydrogen pipelines from North Africa to Europe, and of liquefied hydrogen and ammonia shipping from the Middle East to Europe. We find that MENA could realize cost savings of over 6% by 2050 through hydrogen and ammonia trade. Furthermore, despite the availability of gaseous green hydrogen from North Africa (via pipelines), for Europe the import of liquefied green hydrogen and ammonia from MENA (through shipping) can also be economically viable. Although this trade could generate cost savings of 40 billion dollars per year by 2050, we conclude that for Europe import diversity, rather than cost savings, could become the main factor driving hydrogen and ammonia imports. • H 2 and NH 3 play an increasingly important role in the European energy transition. • Liquified hydrogen and ammonia import from Middle East to EU can be economically viable. • H 2 and NH 3 trade with MENA could save Europe 40 G$/yr by 2050. • MENA could realize cost savings of over 6% by 2050 thanks to H 2 and NH 3 trade. • Import diversity rather than cost savings could drive H 2 and NH 3 imports to EU. [ABSTRACT FROM AUTHOR]

It is of great significance for cleaner production to partially replace traditional coke with biomass fuel in iron ore sintering processes. However, the higher reactivity of biomass leads to an unacceptable deterioration in sintering performance, which limits its high proportion application. This paper presents the numerical simulation of the technology of combining gaseous fuels and biomass for iron ore sintering. The improvement effect and mechanism of the methane injection method on the heat pattern and performance of the coke/biochar co-sintering bed were discussed. To more accurately quantify the coupling phenomena involved, the proposed model especially considers sub-processes of biomass combustion and gaseous reactions including volatile release/char formation, burning of the volatiles, and the oxidation and gasification of char particles. The results indicated that the equivalent methane heat injection method reached its limit of improvement at a concentration of about 0.6%, and failed to obtain qualified products. The thermal indicators and yield kept increasing within the concentration simulation range of 0∼0.8% under the extra methane method. At a concentration of 0.8%, peak temperature (PT), duration time (DTMZ), and enclosed area (MQI) in the high-temperature zone are 1442.094 K, 165.6 s, and 15923.72 K s, respectively, reaching the level of all coke method. The use of local concentration segregation can significantly optimize heat distribution and increase the yield of the coke/biochar co-sintering process. • A numerical model for combining gaseous fuel and biomass in sintering is proposed. • Extra methane injection has no improvement limit within concentrations 0.1%–0.8%. • Gaseous fuel combustion zone makes the melting zone enlarge. • Coke/biochar co-combustion is helpful in attaching the secondary combustion zone. • Methane injection makes 60% biochar sintering reach the level of all coke method. [ABSTRACT FROM AUTHOR]

This paper proposes stochastic programming to optimal economic scheduling problems of a sustainable integrated energy system with renewable resources including power, natural gas, and hydrogen carriers. Hydrogen is considered a byproduct of electrical power and natural gas carriers using water electrolysis and steam methane reform process technologies. The main objective is to minimize the operation and emission costs while addressing uncertainties of electric/heating/cooling demands, electricity price, and renewable generation using scenario-based stochastic programming. To achieve a risk-hedging strategy, downside risk constraints are involved to minimize the risky scenarios portfolio. The whole problem is modeled as mixed-integer linear programming in GAMS optimization software. The analysis revealed that the expected operation cost without DRC is $ 577.52 and the expected risk-in-cost value for risky scenarios is $ 470.7. However, a conservative decision for reaching zero risk is costly and increases the expected cost up to $ 2901.1, which is not economically viable. A modest decision-making strategy compromises the cost and risk values where for decreasing the risk-in-cost to $ 288.7 (36.8%), the expected cost increased by to $1010.39 (75.95%). Moreover, the risk-averse decision-maker lowers the power sold to the grid, increases the use of water electrolyzing instead of the SMR process to reduce the environmental charges, and tries to increase flexibility with the help of hydrogen and battery storage. • The operation of a multi-carrier energy system is evaluated by stochastic programming. • The risk of different uncertainties is involved using downside risk constraints. • The risk-neutral and risk-averse strategies are developed by adjusting a risk level. • The hydrogen carrier considered as an intermediate to serve multi-energy demands. • The water electrolyze and steam methane reform technologies produce hydrogen gas. [ABSTRACT FROM AUTHOR]

Hydrogen, as a clean energy carrier, presents a significant step toward sustainable energy solutions but faces challenges in storage due to its low energy density and high volatility. This study addresses the optimization of Type V hydrogen storage tanks by investigating the burst pressure performance of spherical, cylindrical, and toroidal shapes. Using finite element analysis (FEA) and first-order shear deformation theory, we examined how these geometries impact burst pressure outcomes across a range of composite materials and layup configurations. The materials tested included carbon T700/epoxy, Kevlar/epoxy, E-glass fiber/epoxy, and basalt/epoxy. Results demonstrate that the toroidal shape significantly outperforms spherical and cylindrical designs in stress distribution and burst pressure, with basalt/epoxy composites exhibiting superior burst pressure performance (12.7 MPa) compared to Kevlar/epoxy (10.8 MPa), E-glass fiber/epoxy (11.4 MPa), and carbon T700/epoxy (8.9 MPa). Kevlar/epoxy toroidal tanks outperform other materials in weight performance, having a structural performance index of 0.0305 Mpa.m3/kg and hydrogen density per unit mass of 0.0251 kg H 2 /kg. The stacking sequence [-45/45]s optimized stress distribution for the toroidal shape across all materials. The findings highlight that toroidal designs offer significant advantages for high-pressure hydrogen storage, providing efficient stress management and improved safety. This paper underlines the potential of toroidal vessels for enhancing hydrogen storage efficiency and emphasizes the importance of material selection and stacking sequences in achieving optimal burst pressure performance for international organization for standardization (ISO) certification. • Toroidal tanks show superior burst pressure over spherical and cylindrical designs. • The [-45/45]s stacking sequence optimizes stress distribution for toroidal tanks. • Basalt/epoxy composites outperform other materials in burst pressure performance. • Kevlar/epoxy toroidal tank outperforms others in weight performance. • Toroidal tanks offer efficient stress management and enhanced safety for hydrogen storage. [ABSTRACT FROM AUTHOR]

Green hydrogen production from renewable energy sources has emerged as a promising solution towards achieving the global target of net-zero emissions by 2050. The sultanate of Oman is among the countries that have a significant green hydrogen potential, as evident by the national target of producing one million tons of green hydrogen by 2030. This paper aims to study the techno-economic viability of integrating a floating solar photovoltaic (FPV) system with hydrogen energy storage for electricity generation in Oman. The integration of this system is modelled and simulated using HOMER Pro software to determine the optimum component sizes with the minimum cost of energy (COE). While the FPV system is designed and simulated using PVsyst software. The simulated system incorporates a 26.57 MWp FPV system, 22 MW PEM electrolyser, 13 MW PEM fuel cell, 60,000 kg hydrogen tank and 12.4 MW converter and generates 65.5 GWh of clean electricity annually. The system produces 826,624 kg of green hydrogen annually, significantly contributing to Oman's green hydrogen economy. The simulation results reveal a levelized cost of energy (LCOE) of $0.97/kWh and a levelized cost of hydrogen (LCOH) of $29.7/kg. The relatively high LCOH is attributed to the utilisation of large-scale hydrogen energy storage components, which results in a higher initial cost of the system. However, the system demonstrated its ability to meet the electrical demands of 422 households near Wadi Dayqah dam area in Qurayat with minimal capacity shortage, emphasising its technical viability. The economic viability may be improved in the future with advancements in hydrogen energy storage technology and rising fossil fuel prices. • Techno-economic analysis of large-scale hydrogen storage with FPV application. • LCOE is determined to be at $0.970/kWh. • The system is capable of fulfilling 100% of the electrical demands of 422 households. [ABSTRACT FROM AUTHOR]

Hydrogen stations are an important component of urban clean energy development. In the event of an accident, they can have a serious impact on the safety and stability of the urban system. This paper identifies and analyzes the main influencing factors of hydrogen station safety resilience based on an improved HFACS model. It establishes a safety resilience evaluation index system from four dimensions: spatial resilience, engineering resilience, management resilience, and social resilience. Subjective index weights are determined through fuzzy analytic hierarchy process, objective index weights are determined through entropy method, and combined index weights are determined based on game theory. A system dynamics model of hydrogen station safety resilience is constructed, and model verification and comparative analysis are conducted. The influence of different dimensions on system safety resilience is analyzed, and quantitative evaluation and prediction research on hydrogen station safety resilience is carried out. Targeted safety resilience improvement suggestions are also proposed. The research results can provide a reference for the safety management of hydrogen stations. • Constructing a resilience evaluation index system using the modified HFACS model. • Modeling the safety resilience evaluation of hydrogen stations from four dimensions. • Simulation and prediction of safety resilience levels for hydrogen stations. [ABSTRACT FROM AUTHOR]

This paper presents a detailed techno-economic review and assessment of a hydrogen refueling station (HRS) powered by a grid-connected photovoltaic (PV) system to address the issues of carbon emissions and energy sustainability in transportation. In the study, the HRS system with 1, 3 and 5 MW PV installed capacity for Ankara, the capital city of Türkiye, is considered for different system lifetimes. In the proposed HRS, on-site hydrogen production is achieved through anion exchange membrane water electrolysis (AEMWE) using a grid-connected PV system, and the produced hydrogen is stored in a cascaded storage system and is utilized at the HRS station. In order to evaluate the cost competitiveness and economic viability of the designed HRS system, the levelized cost of hydrogen (LCOH) is determined by considering the initial investment costs, operating expenses and potential revenue streams. The results show that the HRS capacity, PV installed capacity and system lifetime significantly impact the LCOH. The technoeconomic analysis results show that the best system configuration was determined as 8.54 €/kg H 2 in the 20-year long term refueling scenario for a 5 MW installed PV capacity with a daily refueling capacity of 170 kg H 2. This study contributes to the development of sustainable energy infrastructure by providing a comprehensive framework for the design, calculation and economic evaluation of PV-integrated hydrogen refueling stations. The results provide valuable information for policymakers, industry stakeholders, and researchers to help achieve a carbon-neutral transportation sector and promote energy sustainability. • PV integrated onsite hydrogen refueling station is proposed. • Techno-economic evaluation of the HRS was conducted. • The lowest levelized cost of hydrogen (LCOH) was obtained as 8.54 €/kg H 2. • HRS infrastructure required to support hydrogen vehicles through the carbon zero transition. [ABSTRACT FROM AUTHOR]

As a promising green energy technology, low-temperature proton exchange membrane (PEM) electrolysis exhibits different reaction efficiencies and flow performances under various flow channel structures, but the specific impacts of these different layouts on performance are not well understood. To reveal the influence of the channel layouts, a two-phase PEM electrolysis model is established based on the experiment in this paper. Combing with flow characteristics, current density, and product distribution in the porous transport layers (PTLs) and catalyst layers (CLs), the results indicate that the flows from different directions have a significant impact on the electrolyzer. The vertical flow, perpendicular to the CLs, can greatly alleviate the product accumulation; meanwhile the transverse flow, parallel to the CLs, has a weaker but noticeable effect in gas ventilation. Partial gas will continue to accumulate in the region of weak vertical flow, especially at the end of the transverse flow. Except for the pin-type layout, other structures have a neat and orderly transverse flow within the porous medium, in the direction perpendicular to the flow channel's orientation. This flow pattern leads to product accumulation increasing along the exit direction, as well as product stagnation in the region of weak flow intensity. To facilitate the product discharge, a new flow channel layout, the pyramidal flow layout is proposed, which navigates the flow trend and enhances the convection near the exit. This new layout greatly evens out the current density and product concentration distribution. • Based on two-phase flow PEM electrolysis model of different flow channel layouts. • Finding a universal flow pattern within the porous medium among different layouts. • Proposed a new flow layout with better product distribution and discharge efficiency. [ABSTRACT FROM AUTHOR]

In this paper, the structure, hydrogen storage capacity, mechanical, electronic, optical and thermodynamic properties of hydride perovskites KCuH 3 and RbCuH 3 are systematically studied via using density functional theory (DFT) for the first time. The formation energies and mechanical properties of XCuH 3 (X = K, Rb) hydrides indicate that KCuH 3 and RbCuH 3 are both thermodynamically and mechanically stable. The values of Pugh's index and Cauchy pressure for KCuH 3 and RbCuH 3 indicate that they are both brittle materials. In addition, their bonding types are mainly ionic bonds. Electronic properties show that these compounds are metallic. The hydrogen storage capacities of KCuH 3 and RbCuH 3 are calculated to be 2.78 wt% and 1.95 wt%, respectively. The optical properties indicate that KCuH 3 and RbCuH 3 both have high dielectric functions in the visible range and their absorption coefficient peak in the ultraviolet range. Additionally, the thermodynamic properties, including free energy, Debye temperature, melting temperature, entropy and heat capacity are calculated. The analyzed physical properties of KCuH 3 and RbCuH 3 perovskite hydrides suggest that they have great prospect in hydrogen applications. All the above parameters are calculated for the first time, which could contribute significantly to the development of sustainable energy technologies. • XCuH 3 (X = K, Rb) perovskite have been investigated using the first principles. • XCuH 3 perovskite exhibit thermodynamic and mechanical stability. • The gravimetric hydrogen storage capacity is found to be 2.78 wt% for KCuH 3. [ABSTRACT FROM AUTHOR]

In pursuit of environmentally friendly and effective photocatalytic materials for water splitting, this research paper presents a thorough evaluation of WSi 2 N 4 , WGe 2 N 4 , and their Janus counterpart WSiGeN 4 monolayers through the application of Density Functional Theory. The study elucidates the optical, electronic, and structural characteristics of these monolayers, thereby demonstrating their potential as highly favorable contenders for applications involving photocatalytic water splitting. By means of comprehensive optimization and analysis, it is shown that these monolayers possess advantageous characteristics, such as favorable band gaps, stable work functions, and stability over a broad pH range. These attributes are of utmost importance in ensuring the effectiveness of hydrogen evolution reaction (HER). The inclusion of Janus WSiGeN 4 , which possesses an intrinsic mirror asymmetry, significantly improves the photocatalytic efficacy of the material. This is achieved by meeting the demands of optimal redox reaction levels in both the conduction and valence bands. In conjunction with machine learning force fields, ab initio molecular dynamics (AIMD) simulations validate the thermal stability of these monolayers at 300 K. In addition, our analysis of the optical properties reveals substantial absorption in the visible spectrum - vital for photocatalytic applications powered by solar energy. In summary, the research highlights the potential of Janus WSiGeN 4 , WGe 2 N 4 , and WSi 2 N 4 monolayers as multifunctional and effective substances for forthcoming photocatalytic water-splitting systems. This advancement indicates of a significant stride in the direction of sustainable energy solution development. • Analyzed WSi 2 N 4 , WGe 2 N 4 , and WSiGeN 4 for effective hydrogen production. • Proved thermal stability at 300 K, enabling real-world use. • Highlighted Janus WSiGeN 4 's superior efficiency for photocatalysis. • Confirmed stability via machine learning, promising for sustainable technology. • Noted significant visible light absorption for solar-driven applications. [ABSTRACT FROM AUTHOR]

The competitiveness of hydrogen as a sustainable energy carrier depends greatly on its transportation and storage costs. Liquefying hydrogen offers advantages such as enhanced purity, versatility, and higher density, yet current industrial liquefaction processes face efficiency and cost challenges. Although various large-scale and efficient liquefaction concepts exist in the literature, they often overlook the economic and technical viability of such plants. Here, we addresses this issue by establishing a framework for modeling a large-scale hydrogen liquefaction concept and conducting both technical and economic assessments, with a specific focus on 125 tonnes per day (TPD) high-pressure hydrogen Claude-cycle concept. The technical analysis involves preliminary designs of key process components, while the economic assessment utilizes Aspen Process Economic Analyzer. Our findings indicate that at an electricity price of €0.1/kWh, the Claude-cycle liquefier concept yields a specific liquefaction cost (SLC) of €1.55/kg LH 2 . A sensitivity analysis was performed, which shows that electricity price has a significant influence on the economics. Further investigation on the compressors design shows that incorporating high-speed centrifugal compressors could reduce the SLC by 5.42% and potentially more. Scaling up to 250 and 500 TPD reveals further cost improvements, while cost projections indicate substantial declines as the technology matures. Ultimately, this paper presents novel cost-scaling and experience curves of hydrogen liquefaction technology, demonstrating the compelling economic viability of integrating large-scale hydrogen liquefaction into sustainable energy infrastructure. [Display omitted] • A process model of a large-scale Claude-cycle hydrogen liquefaction plant has been developed for both technical assessment and economic analysis. • The technical evaluation primarily centers on the preliminary design of key process equipment, such as compressors, turbo-expanders, and heat exchangers. • The techno-economic assessment is performed based on the process simulation and equipment preliminary design. • Capital cost estimation is carried out using the Aspen Process Economics Analyzer. • These cost estimations serve as the basis for predicting cost and experience curves of hydrogen liquefaction technology. [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]

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]

Biorenewable hydrogen is requisite to replace non-renewable hydrogen. Decarbonization is assured. Hydrogen demand is severely rising due to mitigating climate change and reducing fossil fuel dependency. Green Hydrogen from agro waste proposition makes bio-circular economy upcycling. The main objective of this study is to reinforce the hope of renewable, sustainable H 2 production from agro-waste. Initially, this paper shows the demand for green hydrogen, the sustainable availability of agro waste, and their capability to produce H 2. Insights into the gasification of agro waste about cellulose, hemicellulose, and lignin with conventional gasification. The effect of catalyst and supercritical gasification and their challenges is discussed. Most uniquely, other reviews highlight various aspirations behind agro-waste gasification to attain a strong business model, such as co-production, co-gasification, and CO 2 reforming with H2 yield. This review exhibits some main insight into various aspects of agro-waste gasification. H 2 from agrowaste gasification has high energy content (122 kJ/g) and high energy conversion efficiency in the range of 55–58 %, in addition to gaining the economic penalties of 2.2–2.5 net points for decarbonization. Agro waste is composed of lignocellulosic material that is relatively richer in hydrogen than fossil fuel resources. In SCWG, water is one of the natural solvents, which means feedstock effectively dissolves with water solvents. Intermittent density, low viscosity, and surface tension are nearly zero values due to SCW having no specific phase boundary, which enhances the gasification and substantially reduces tar formation during SCWG. Catalyst utilization enhances H 2 production. The present study comprehensively exhibits the role of catalyst and their supporter and promoter. Ni-based catalysts are mostly suggested for H2 production but fall into reusability issues. The main reason behind this is that Ni is inefficient in removing HCl, H 2 S, and total trace elements during gasification. Recently, low-cost and waste-to-wealth transformation aspects of biochar-based catalysts have gained attention. Renewable-assisted gasification significantly improves the energy and exergy of the system and suppresses the important concern of energy consumption during gasification. Renewable assisted and various aspiration incorporation into gasification is solidly recommended for future implementation based on energy, economic, and environmental benefits from them. Plastic and biomass are richer in hydrocarbon and oxygen, respectively; this synergistic effect has the potential to enhance the H 2 yield. From this study, PP plastic is mostly preferred for co-gasification with biomass. Compared to 100 wt% of biomass, the introduction of plastic slightly increased the coke formation, but the H 2 yield was improved. When the plastic mixture of 10 wt% increases coke deposition, however, significant coke deposition is not reported when 20 wt% of plastic concentration is not reported. Carbon capture via CO 2 inert gas supply enhances the H 2 yield, provides a route to carbon trade, and substantially contributes to GHG pollution mitigation. Agro-waste gasification is produced by a product that has the potential to be used in a wide range of applications due to its unique properties, such as large specific surface area, porosity, functional groups, high reliability, and minimum cost. Hopefully, this review will be an optic to the most appropriate green hydrogen production path for sustainable clean energy production and effective agro-waste management. • This review acts as an optic to the most appropriate green hydrogen production path. • Hydrogen separation, purification, and storage need more care. • Carbon dioxide reformation aids a carbon trading system and reduces environmental effect. • These research provide direction for energy nexuses that may be derived from agricultural waste. [ABSTRACT FROM AUTHOR]

The investigation of cost-effective and highly efficient electrocatalysts for alkaline water and simulative seawater oxidation is essential to the conversion and storage of renewable energy. In this paper, the Ce–NiSe 2 /CoP catalyst with multihole and ultrathin nanosheet structure is generated. The unique structural characteristics of Ce–NiSe 2 /CoP heterojunction nanosheets contribute the excellent OER performance under different alkaline 1 M KOH and simulated seawater (1 M KOH + 0.5 M NaCl) electrolytes. Specifically, this catalyst exhucture is generated. The unique structural characteristics of Ce–NiSe 2 /CoP heterojunction nanosheets conibits the low overpotentials of 287 and 304 mV at the current density of 10 mA cm−2, along with the Tafel slopes of 87.1 and 78.8 mV dec−1 in two solutions, respectively. Moreover, the Ce–NiSe 2 /CoP target product also displays good stability. The present study introduces a promising strategy for the advancement of high-performance electrocatalysts in green energy field. [Display omitted] • The Ce-doped NiSe 2 /CoP heterostructure nanosheets are triumphantly generated. • The Ce–NiSe 2 /CoP product possesses multihole and ultrathin lamella architecture. • Each nanosheet with coarse surface is composed of prolifically nanosecondary units. • This catalyst presents fine OER properties in alkaline water and simulative seawater. [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]

There is a great desire to integrate multiple energy systems by forming low-carbon energy hubs. Among various energy platforms, the integration of power and gas networks via Power-to-Gas (PtG) technologies is introduced as a promising solution to enhance the flexibility of power grids and facilitate seamless adoption for high penetration levels of renewable energy resources. In addition, the production of green hydrogen from waste/inexpensive clean electricity has recently been identified as a potential means for large-scale energy storage, deployment of hydrogen mobility, and decarbonization of several processes that utilize hydrogen. As integrated hydrogen-based energy hubs (H 2 Hubs) attract more attention for widespread deployment, the security of such new platforms against various cyberattacks is also becoming a critical topic for investigation. This paper proposes a new data estimation technique, developed and integrated with H 2 Hubs scheduling models, for real-time optimal adaptive collection and organization of the system operating parameters for cybersecurity assessment. A new formulation is presented for the adaptive formation of a newly proposed concept, referred to as the system feasibility area , via real-time acquisition of the system operating information. The created feasibility areas are utilized for real-time post-occurrence detection of the bad scheduling data that is invisible to the existing cybersecurity layers. Numerical studies are conducted to demonstrate the efficacy and feasibility of the proposed model. The results demonstrate that the historical data can be adaptively collected in real time and successfully utilized to create feasibility areas to categorize the system operating points. • An optimal scheduling model is proposed for hydrogen-based energy hubs (H 2 Hubs). • A new data estimation method is developed and integrated with the scheduling model. • A new formulation is given for the adaptive creation of the feasibility area. • Simulation case studies are presented and discussed. [ABSTRACT FROM AUTHOR]

With the future of green energy relying on increases in green-energy production scale to support demand, placing importance on location selection for new energy production methods is going to be vital to secure a zero-carbon future. In this paper, a method called H2Locate is introduced to conduct a down selection sequence for identifying hydrogen production plant location within a defined region. Following the method, resource availability, energy availability, and social impact metrics are analyzed to understand which variables are most vital and what data must be obtained to achieve confidence in the selection of an implementation location. An illustrative example using Oklahoma as the region is produced to demonstrate the proposed method. The counties within Oklahoma are analyzed to identify potential subregions for implementing a hydrogen production plant. Excel-based software, The Probability of Hydrogen Implementation (PHI), using publicly available data regarding energy, resources, and social variables is utilized to carry out the proposed method. Considering the illustrative example with a 290 MW alkaline electrolysis facility, we find that Kay County, Johnston County, Caddo County, and the counties directly surrounding them are the most suitable locations in Oklahoma for the implementation given variables related to the desired energy, resource, and social metrics. • The H2Locate down selection method guides hydrogen production plant location selection. • Analyzes 7 hydrogen hub reports to identify key hydrogen industry variables. • Categorizes energy, feedstock, and social factor variables utilized in the H2Locate method. • An illustrative 290 MW alkaline electrolysis example in Oklahoma identified Kay, Johnston, and Caddo counties as prime locations. [ABSTRACT FROM AUTHOR]

This paper addresses the urgent need for efficient hydrogen storage methods in the context of combating climate change and transitioning to sustainable energy sources. Among various storage options, LiBH 4 is highlighted for its high volumetric and gravimetric energy densities, critical factors in determining its suitability for energy applications. However, challenges arise due to its high thermolysis temperature, which poses difficulties, especially in applications like automotive use where high temperatures are required. The commercial viability of LiBH 4 remains a significant obstacle due to the nascent stage of chemical hydride technology and the absence of large-scale production facilities. Environmental concerns also loom large, as the production of LiBH 4 relies on extensive mining of lithium and boron, known for their environmental impact. Furthermore, the economic feasibility of LiBH 4 as a hydrogen storage medium is questioned, given the substantial portion of total expenses attributed to hydrogen costs, affecting all methods except those based on fossil fuels or electricity. Nevertheless, there is optimism that with technological advancements and improved infrastructure, the costs associated with LiBH 4 and hydrogen storage overall may decrease over time. In conclusion, while LiBH 4 presents promising energy density characteristics, its practical implementation faces challenges such as high production costs, environmental concerns, and technological limitations. Overcoming these obstacles is crucial for realizing a sustainable and carbon-free energy landscape driven by hydrogen. • LiBH 4 shows promise for high energy density storage but faces obstacles high production costs and environmental concerns. • A comprehensive decision matrix analysis showcases the strengths and weaknesses of various hydrogen storage options. • LiBH 4 may find applications in small-scale personal storage due to its safety and energy density. [ABSTRACT FROM AUTHOR]

This paper explores the skills landscape of the emerging green hydrogen industry in Australia drawing on data collected from a study that gathered insights on training gaps from a range of hydrogen industry participants. A total of 41 industry participants completed a survey and 14 of those survey respondents participated in industry consultations. The findings revealed widespread perceptions of training and skilling as being very important to the industry, but under-provisioned across the sector. Data were analysed to consider the problem of skilling the green hydrogen industry and the barriers and enablers as perceived by industry stakeholders. In this paper we argue that urgent cross-sector attention needs to be paid to hydrogen industry training and skill development systems in Australia if the promise of green hydrogen as a clean energy source is to be realised. • Cross-sector collaboration is needed to support education and training on hydrogen energy. • Insufficient training is available to support skill development in hydrogen energy. • Training on electrolysers, fuel cells, hydrogen storage and refuelling stations is most needed. [ABSTRACT FROM AUTHOR]

Clean energy resources will be used more for sustainability improvement and durable development. Efficient technologies of energy production, storage, and usage results in reduction of gas emissions and improvement of the world economy. Despite 30% of electricity being produced from wind energy, the connection of wind farms to medium and large-scale grid power systems is still leading to instability and intermittency problems. Therefore, the conversion of electrical energy generated from wind parks into green hydrogen consists of an exciting solution for advancing the development of green hydrogen production, and the clean transportation sector. This paper presents a techno-economic optimization of hydrogen production for refueling fuel cell vehicles, using wind energy resources. The paper analyses three configurations, standalone Wind-Park Hydrogen Refueling Station (WP-HRS) with backup batteries, WP-HRS with backup fuel cells, and grid-connected WP-HRS. The analysis of different configurations is based on the wind potential at the site, costs of different equipment, and hydrogen load. Therefore, the study aims to find the optimized capacity of wind turbines, electrolyzers, power converters, and storage tanks. The optimization results show that the WP-HRS connected to the grid has the lowest Present Worth Cost (PWC) of 6,500,000 €. Moreover, the Levelized Hydrogen Cost (LHC) of this solution was found to be 6.24 €/kg. This renewable energy system produces 80,000 kg of green hydrogen yearly. • Wind to green hydrogen represents an interesting solution for greenhouse gas reduction. • Three configurations of wind-park stations designed for green hydrogen production are analyzed. • Grid-connected wind park consists of an optimal solution for the wind park hydrogen station. • The Levelized cost of hydrogen production using a 5 MW grid-connected wind park is 6.24 €/kg. [ABSTRACT FROM AUTHOR]

Hydrogen energy, characterized by its high calorific value and sustainability, represents a secondary clean energy source. It is predominantly stored, transported, and utilized through pipeline networks. However, a comprehensive optimization approach for the design for the ground pipeline network of hydrogen storage is currently lacking. This paper embarks on a systematic exploration of the layout, station type and parameter design for the ground pipeline network of hydrogen storage. Addressing various application perspectives, the study constructs two distinct pipeline network structures: the Star-Star Global Optimization Model (SSGO-Model) and the Star-Tree Global Optimization Model (STGO-Model). Three cases are discussed under six different constraint scenarios. These scenarios focus on layout optimization, variable capacity layout optimization, and the overall optimization of layout and parameters. An overall optimization strategy is proposed to solve the models. A detailed analysis of the iteration process, layout schemes, station and pipeline constraints, investment, and flow parameters of the pipeline network in the optimization results is presented. Through systematic analysis, the correctness and effectiveness of the model are verified, demonstrating the variability of optimization results under different topological structures and constraint conditions. Moreover, when conducting integrated optimization, the total investment is minimized, proving its superiority. The findings demonstrate the applicability of these models in guiding the construction for the ground pipeline network of hydrogen storage, thereby fostering the advancement of hydrogen storage technology. Concurrently, this research contributes significantly to the development of hydrogen energy, offering strategic insights and practical solutions for its efficient deployment. • Integrated optimization model for hydrogen storage ground pipeline network. • The model considers layout, station type and parameter design. • Overall optimization strategy is proposed. • Three cases verify optimization model. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carriers (LOHC) can be used as a lossless form of hydrogen storage at ambient conditions. The storage cycle consists of the exothermic hydrogenation of a hydrogen-lean molecule at the start of the transport, usually the hydrogen production site, becoming a hydrogen-rich molecule. This loaded molecule can be transported long distances or be used as long-term storage due to its ability to not lose hydrogen over long periods of time. At the site or time of required hydrogen production, the hydrogen can be released through an endothermic dehydrogenation reaction. LOHCs show similar properties to crude oils, such as petroleum and diesel, allowing easy handling and possibilities of integration with current infrastructure. Using this background, this paper reviews a variety of aspects of the LOHC life cycle, with a focus on currently studied materials. Important factors such as the hydrogenation and dehydrogenation requirements for each material are analysed to determine their ability to be used in current scenarios. Toluene and dibenzyltoluene are attractive options with promising storage attributes, however their dehydrogenation enthalpies remain a problem. The economic feasibility of LOHCs being used as a delivery device were briefly analysed. LOHCs have been shown to be the cheapest option for long distance transport (>200 km), and are cheaper than most at shorter distances in terms of specifically transport costs. The major capital cost of an LOHC delivery chain remains the initial investment for the raw materials and the cost of equipment for performing hydrogenation and dehydrogenation. Finally, some studies in developing the LOHC field were discussed, such as microwave enhancing parts of the process and mixing LOHCs to acquire more advantageous properties. • Efficient hydrogen storage solution for sustainable energy transportation and storage. • Enables safe and cost-effective hydrogen transportation and distribution networks. • Promotes renewable energy integration through versatile and scalable storage capabilities. • Facilitates decarbonization efforts by enabling long-term, stable hydrogen supply chains. [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]

A dedicated grid-tied offshore hybrid energy system for hydrogen production is a promising solution to unlock the full benefit of offshore wind and solar energy and realize decarbonization and sustainable energy security targets in electricity and other sectors. Current knowledge of these offshore hybrid systems is limited, particularly in the integration, component control, and allocation aspects. Therefore, a grid-integrated analytical model with a power dispatch allocation strategy between the grid and electrolyzer for the co-production of hydrogen from the offshore hybrid energy system is developed in this paper. While producing hydrogen, the proposed offshore hybrid energy system supplies a percentage of its capacity to the onshore grid facility, and the amount of the electricity is quantified based on the electricity market price and available total offshore generation. The detailed controls of each component are discussed. A case study considers a hypothetical hybrid offshore energy system of 10 MW situated in a potential offshore off the NSW of Australia based on realistic metrological data. A grid-scale proton-exchange membrane electrolyzer stack is used and a model predictive power controller is implemented on the distributed hydrogen generation scheme. The model is helpful for the assessment or optimization of both the economics and feasibility of the dedicated offshore hybrid energy farm for hydrogen production systems. • Modeling of a grid-integrated analytical model of an OHES for hydrogen co-production. • Development of a power dispatch allocation strategy for the proposed OHES. • Development of detailed controls of each component used in the proposed OHES. • Demonstrations of a case study considering 10 MW OHES situated in offshore off the NSW of Australia. [ABSTRACT FROM AUTHOR]

To address the pressing need for sustainable energy solutions, hydrogen has emerged as a "zero-emission" energy source with vast potential in diverse sectors like manufacturing, transportation, and electricity generation. However, the realization of a hydrogen economy hinges on the development of safe and stable technologies and materials for hydrogen storage and transport. This paper presents a comprehensive review of the latest advancements in hydrogen storage systems, with a particular focus on porous materials. Notably, porous carbon materials derived from biomass waste have garnered attention due to their exceptional qualities. These include abundant and easily accessible raw materials, simplified production processes, adjustable characteristics, cost-effectiveness, low mass density, high specific surface area and porosity, structural diversity, and sustainable regeneration. These attributes position them as promising candidates for further exploration in hydrogen storage devices, particularly for achieving high H2 uptake capacities. The feasibility of utilizing both plant- and animal-based biomass porous carbons is examined, encompassing activated porous carbons, heteroatom doped porous carbons, and their composites, as pivotal components for the development of porous carbon storage devices. The synthesis and characterization of each form, along with their respective hydrogen storage capacities, are highlighted. While each material exhibits promise, it is important to note that they do present certain technological drawbacks. Addressing these limitations through further research and development is crucial to unlocking their full potential for future applications in the burgeoning hydrogen economy. [Display omitted] • Unique features of Biomass-derived carbon materials for hydrogen storage capacity. • Critical overview and key lessons from non-biomass derived materials. • Carbon materials from organic waste bridge hydrogen storage to the future economy. • Biomass-based carbon materials are signalling a need for further investigation. [ABSTRACT FROM AUTHOR]

In this paper, certain issues envisaged in the framework of development of design methodology for intelligent autonomous distributed hybrid power complexes (ADHPC) with green hydrogen and energy storage, functioning in grid mode and in the mode of interaction with the global (national) grid (GN) have been solved. Depending on their energy deficit or surplus, relative to the global grid, ADHPCs can operate as a load or as an energy source, respectively, as follows: based on the analysis of the energy balance management process in the ADHPC, a reasonable choice of the structure of the system of accumulation and distribution of power flows (SADCF) was made from the point of view of increasing the reliability of its functioning and ensuring the physical feasibility of the energy balance management process in this structure, i.e. keeping the actual power consumption of the consumers close to the required rated power at each given time t. This is achieved by including a condenser connected to the SADCF system on its assembly and distribution bus and a storage system BS with double-level ((BS1, BS2), double-circuit ((BS1(1), BS1(2)), (BS2(1), BS2(2))) structure, whereby: BS1of the level 1 - to manage the capacity balance in the SADCF under normal ADHPC regime and the variation of green hydrogen and consumption capacities within their confidence intervals assessed at the design stage; BS2 of the level 2 - to coordinate ADHPC and GN modes of operation and to control, together with BS1 of the level 1, GN, diesel generator (DG), the power balance in the SADCF when the ADHPC fails and when RES and consumption power are outside their confidence intervals; alternating charge/discharge operation of the parallel circuits will extend the life of the BS system; – a comprehensive definition of optimal ADHPC system situational energy balance management task is formulated. [ABSTRACT FROM AUTHOR]

This paper proposes a novel solar-based polygeneration system for simultaneous power generation, desalination, hydrogen-production, and refrigeration. The system integrates parabolic trough solar collectors, multi-effect distillation, polymer electrolyte membrane electrolyzer, Kalina cycle, organic Rankine cycle, Brayton cycle, and ejector cooling. Solar energy and waste heat from the Brayton cycle provide energy input. Power generation is achieved via the Brayton, Kalina, and organic Rankine cycles. The multi-effect distillation unit produces freshwater while the electrolyzer generates hydrogen. The ejector system supplies cooling. A comprehensive steady-state energy and exergy analysis evaluates the thermodynamic performance. The system attains 32.269 MW net power output and ejector COP of 0.3193. The overall energy and exergy efficiencies are 38.45% and 35.64%, respectively. The combustion chamber exhibits maximum exergy destruction. Exergoeconomic analysis determines associated costs and investment feasibility. Integrating multiple technologies into a system with solar input enhances efficiency, sustainability, and environmental benefits. • Presents novel solar multi-generation system integrating power, hydrogen, water and cooling generation • Validated methodology analyzes thermodynamic performance providing insights on efficiencies • Exergy destruction analysis identifies optimization opportunities in integrated solar systems • Showcases potential of intricate integration of solar, desalination, hydrogen and power for sustainable energy • Modular and scalable system design enables flexibility for different applications and demands [ABSTRACT FROM AUTHOR]

Applying clean energy is one of the feasible paths to achieve the "dual carbon target". Hydrogen energy, as an efficient and clean energy, is a new growth point for creating industrial transformation and upgrading. Ammonia is recognized as a zero-carbon hydrogen energy carrier, and utilizing hydrogen through hydrogen production from ammonia decomposition is one of the effective ways to safely store, transport and utilize hydrogen energy. In addition, there are many methods to realize the hydrogen production from ammonia, among which the method based on the combination of non-thermal plasma (NTP) and catalyst can reduce the reaction temperature, significantly improve ammonia (NH 3) conversion efficiency and hydrogen energy yield. As one of the methods with good application prospects, the interaction between NTP and catalyst in this method is complicated, and the efficiency of hydrogen production from ammonia is also affected by various factors, which restricts application of the method. In order to provide new ideas for the development and commercial application of NTP-catalytic technology for ammonia decomposition, this paper reviews the progress of NTP-catalytic hydrogen production from ammonia based on a systematic and integrated literature review methodology, analyses the effects of process parameters, temperature, catalyst, and other factors on the efficiency of plasma-catalytic ammonia decomposition, and discusses the plasma source and the mechanism of plasma-catalytic ammonia decomposition reaction. Finally, the opportunities and challenges of this plasma catalysis method are described. • The progress of low-temperature plasma-catalytic NH 3 decomposition was summarized. • Three factors affecting plasma-catalytic NH 3 decomposition reaction were analyzed. • The mechanism of plasma-catalytic NH 3 decomposition were presented. • Opportunities and challenges for plasma-catalytic NH 3 decomposition were outlined. • Low-temperature plasma catalysis can significantly improve the NH 3 conversion. [ABSTRACT FROM AUTHOR]