Publications

This paper introduces a novel dual-purpose transmission system that integrates power transmission and energy storage using hydrogen ammonia and compressed air—an area largely unexplored in the literature. Unlike conventional cable transmission which requires separate storage infrastructure the proposed approach leverages the transmission medium itself as an energy storage solution enhancing system efficiency and reducing costs. By incorporating a defined storage allocation factor this study examines the delivery of offshore-generated power to onshore locations calculating the necessary media flow rates and evaluating the required transportation infrastructure including tunnels and pipelines. A comparative cost-effectiveness analysis is conducted to determine optimal conditions under which storage-integrated transmission outperforms conventional cable transmission. Various transmission powers storage fractions pressures and distances are analysed to assess feasibility and economic viability. The findings indicate that for a 75 % storage allocation factor compressed air can transmit up to 450 MW over 300 km more cost-effectively than cables while hydrogen enables 230 MW transmission beyond 310 km. Ammonia proves to be the most efficient facilitating the transmission of over 2000 MW across distances exceeding 140 km at a lower cost than cables all without requiring onshore storage. Moreover for a 500-km transmission line compressed air hydrogen and ammonia can store the equivalent of 62 58 and 152 h of wind farm output respectively significantly reducing the need for additional onshore storage. This study fills a critical research gap by optimizing offshore wind power delivery through an innovative cost-effective and scalable transmission and storage approach.

This study focuses on the power systems of inland waterway vessels in Chinese Yangtze River systematically outlining the low-carbon technology pathways for different power system types. A comparative analysis is conducted on the technical feasibility emission reduction potential and economic viability of LNG methanol ammonia pure electric and hybrid power systems revealing the bottlenecks hindering the large-scale application of each system. Key findings indicate that: (1) LNG and methanol fuels offer significant short-term emission reductions in internal combustion engine power systems yet face constraints from methane slip and insufficient green methanol production capacity respectively; (2) ammonia enables zero-carbon operations but requires breakthroughs in combustion stability and synergistic control of NOX; (3) electric vessels show high decarbonization potential but battery energy density limits their range while PEMFC lifespan constraints and SOFC thermal management deficiencies impede commercialization; (4) hybrid/range-extended power systems with superior energy efficiency and lower retrofitting costs serve as transitional solutions for existing vessels though challenged by inadequate energy management strategies and multi-equipment communication protocol interoperability. A phased transition pathway is proposed: LNG/methanol engines and hybrid systems dominate during 2025–2030; ammonia-powered systems and solid-state batteries scale during 2030–2035; post-2035 operations achieve zero-carbon shipping via green hydrogen/ammonia.

To reduce fossil fuel dependency in shipping adopting alternative fuels and innovative propulsion systems is essential. Solid Oxide Fuel Cells (SOFC) powered by hydrogen carriers represent a promising solution. This study investigates a multi-fuel SOFC system for ocean-going vessels capable of operating with ammonia methanol or hydrogen thus enhancing bunkering flexibility. A thermodynamic model is developed to simulate the performance of a 3 kW small-scale system subsequently scaling up to a 10 MW configuration to meet the power demand of a container ship used as the case study. Results show that methanol is the most efficient fueling option reaching a system efficiency of 58% while ammonia and hydrogen reach slightly lower values of about 55% and 51% respectively due to higher auxiliary power consumption. To assess technical feasibility two installation scenarios are considered for accommodating multiple fuel tanks. The first scenario seeks the optimal fuel share equivalent to the diesel tank’s chemical energy (17.6 GWh) minimizing mass increase. The second scenario optimizes the fuel share within the available tank volume (1646 m3 ) again minimizing mass penalties. In both cases feasibility results have highlighted that changes are needed in terms of cargo reduction equal to 20.3% or alternatively in terms of lower autonomy with an increase in refueling stops. These issues can be mitigated by the benefits of increased bunkering flexibility

Green hydrogen is likely to play a major role in decarbonising the aviation industry. It is crucial to understand the effects of microstructure on hydrogen redistribution which may be implicated in the embrittlement of candidate fuel system metals. We have developed a multiscale finite element modelling framework that integrates micromechanical and hydrogen transport models such that the dominant microstructural effects can be efficiently accounted for at millimetre length scales. Our results show that microstructure has a significant effect on hydrogen localisation in elastically anisotropic materials which exhibit an interesting interplay between microstructure and millimetre-scale hydrogen redistribution at various loading rates. Considering 316L stainless steel and nickel a direct comparison of model predictions against experimental hydrogen embrittlement data reveals that the reported sensitivity to loading rate may be strongly linked with rate-dependent grain scale diffusion. These findings highlight the need to incorporate microstructural characteristics in hydrogen embrittlement models.

Thermal energy storage (TES) technologies are emerging as key enablers of sustainable energy systems by providing flexibility and efficiency in managing thermal resources across diverse applications. This review comprehensively examines the latest advancements in TES mechanisms materials and structural designs including sensible heat latent heat and thermochemical storage systems. Recent innovations in nano-enhanced phase change materials (PCMs) hybrid TES configurations and intelligent system integration are highlighted. The role of advanced computational methods such as digital twins and AI-based optimization in enhancing TES performance is also explored. Applications in renewable energy systems industrial processes district heating networks and green hydrogen production are discussed along with associated challenges and future research directions. This review aims to synthesize current knowledge while identifying pathways for accelerating the development and practical deployment of next-generation TES technologies.

With the increasing adoption of renewable energy sources such as solar and wind power it is essential to achieve carbon neutrality. However several shortcomings including their intermittence pose significant challenges to the stability of the electrical grid. This study explores hydrogen-based technologies such as fuel cells and water electrolysis systems as an effective solution to improve frequency stability and address the problems of power grid reliability. Using power system analysis programs modeling and simulations performed on IEEE-25 Bus and Jeju Island systems demonstrate the potential of these technologies to mitigate reductions reduce transmission constraints and stabilize frequencies. The results show that hydrogen-based systems are important factors enabling sustainable energy transition.

Hydrogen energy one of the renewable energy sources plays a crucial role in combating climate change since its usage aims to reduce carbon emissions and enhance energy security. As the global energy trend moves toward cleaner alternatives countries start to adapt their energy strategies. In this transition hydrogen is one of the energy sources with the potential to increase long-term energy security. Developing countries face challenges such as high energy import dependency rising industrial demand and the need for infrastructure modernization making hydrogen valleys one of the viable solutions since they integrate hydrogen production storage distribution and utilization at one facility. However establishing small-scale hydrogen valleys requires a comprehensive decision-making strategy consisting of technical financial environmental social and political factors while addressing uncertainties in the system. To systematically manage the process this study proposes a Z-numberbased fuzzy cognitive mapping approach which models the interdependencies among success factors supported by Z-number Decision-Making Trial and Evaluation Laboratory for structured prioritization with a multi-expert perspective. The results indicate that Financial Factors emerged as the most critical category with Government Incentives Infrastructure Investment Cost and Land Acquisition Cost ranking as the top three sub-success factors. Availability of Skilled Workforce and Regional Energy Supply followed in importance which demonstrates the importance of social and technical dimensions in the hydrogen valley development. These findings demonstrate the critical role of policy support infrastructure readiness and workforce availability in the design process. Sensitivity analyses are also conducted to present robustness of the given decisions for the analysis of the results. Based on the results and analyses possible implications based on the policy and practical dimensions are also discussed. By integrating fuzzy logic and Z-numbers the study aims to minimize loss of information enhances the analytical background for decision-making and provides a strategic roadmap for hydrogen valley development.

Against the backdrop of the global transition towards clean energy deep-sea wind-power hydrogen production integrates offshore wind with green hydrogen technology. Addressing the technical coupling complexity and the impact of uncertain hydrogen prices this paper develops a capacity optimization model. The model incorporates floating wind turbine output the technical distinctions between alkaline (ALK) electrolyzers and proton exchange membrane (PEM) electrolyzers and the synergy with energy storage. Under three hydrogen price scenarios the results demonstrate that as the price increases from 26 CNY/kg to 30 CNY/kg the optimal ALK capacity decreases from 2.92 MW to 0.29 MW while the PEM capacity increases from 3.51 MW to 5.51 MW. Correspondingly the system’s Net Present Value (NPV) exhibits an upward trend. To address the limitations of traditional methods in handling multi-dimensional benefit correlations and information ambiguity a comprehensive benefit evaluation framework encompassing economic technical environmental and social synergies was constructed. Sensitivity analysis indicates that the comprehensive benefit level falls within a relatively high-efficiency interval. The numerical characteristics an entropy value of 3.29 and a hyper-entropy of 0.85 demonstrate compact result distribution and robust stability validating the applicability and stability of the proposed offshore wind–hydrogen benefit assessment model.

Under the dual pressures of global climate change and energy structure transition the offshore wind–solar–current energy coupling hydrogen production (OCWPHP) system has emerged as a promising integrated energy solution. However its complex multi-energy structure and harsh marine environment introduce systemic risks that are challenging to assess comprehensively using traditional methods. To address this we develop a novel risk assessment framework based on hesitant fuzzy sets (HFS) establishing a multidimensional risk criteria system covering economic technical social political and environmental aspects. A hybrid weighting method integrating AHP entropy weighting and consensus adjustment is proposed to determine expert weights while minimizing risk information loss. Two aggregation operators—AHFOWA and AHFOWG—are applied to enhance uncertainty modeling. A case study of an OCWPHP project in the East China Sea is conducted with the overall risk level assessed as “Medium.” Comparative analysis with the classical Cumulative Prospect Theory (CPT) method shows that our approach yields a risk value of 0.4764 closely aligning with the CPT result of 0.4745 thereby confirming the feasibility and credibility of the proposed framework. This study provides both theoretical support and practical guidance for early-stage risk assessment of OCWPHP projects.

This review provides a comprehensive examination of artificial intelligence methods applied to the design optimization and performance prediction of composite-based hydrogen storage vessels with a focus on composite overwrapped pressure vessels. Targeted at researchers engineers and industrial stakeholders in materials science mechanical engineering and renewable energy sectors the paper aims to bridge traditional mechanical modeling with evolving AI tools while emphasizing alignment with standardization and certification requirements to enhance safety efficiency and lifecycle integration in hydrogen infrastructure. The review begins by introducing HSV types their material compositions and key design challenges including high-pressure durability weight reduction hydrogen embrittlement leakage prevention and environmental sustainability. It then analyzes conventional approaches such as finite element analysis multiscale modeling and experimental testing which effectively address aspects like failure modes fracture strength liner damage dome thickness winding angle effects crash behavior crack propagation charging/discharging dynamics burst pressure durability reliability and fatigue life. On the other hand it has been shown that to optimize and predict the characteristics of hydrogen storage vessels it is necessary to combine the conventional methods with artificial intelligence methods as conventional methods often fall short in multi-objective optimization and rapid predictive analytics due to computational intensity and limitations in handling uncertainty or complex datasets. To overcome these gaps the paper evaluates hybrid frameworks that integrate traditional techniques with AI including machine learning deep learning artificial neural networks evolutionary algorithms and fuzzy logic. Recent studies demonstrate AI’s efficacy in failure prediction design optimization to mitigate structural risks structural health monitoring material property evaluation burst pressure forecasting crack detection composite lay-up arrangement weight minimization material distribution enhancement metal foam ratio optimization and optimal material selection. By synthesizing these advancements this work underscores AI’s potential to accelerate development reduce costs and improve HSV performance while advocating for physics-informed models robust datasets and regulatory alignment to facilitate industrial adoption.

Crude oil distillation is one of the most energy-intensive processes in petroleum refining consuming up to 20% of total refinery energy. Improving the energy efficiency of crude distillation units (CDUs) is essential for reducing costs lowering emissions and achieving sustainable refining. Current studies often examine energy savings operational flexibility or renewable energy integration separately. This review brings these aspects together focusing on heat integration advanced control systems and renewable energy options such as solar-assisted preheating and green hydrogen. Advanced column designs including dividing-wall and hybrid systems can cut energy use by 15–30% while AI-based optimization improves process stability and flexibility. Solar-assisted preheating can reduce fossil fuel demand by up to 20% and green hydrogen offers strong potential for decarbonization. Our findings highlight that integrated strategies including advanced simulation tools and machine learning significantly improve CDU performance. We recommend exploring hybrid algorithms renewable energy integration and sustainable technologies to address these challenges and achieve long-term environmental and economic benefits.

Hydrogen-based direct reduction of iron ore is a promising route to reduce CO2 emissions in steelmaking where uniform particle flow inside shaft furnaces is essential for efficient operation. In this study a full-scale three-dimensional Discrete Element Method (DEM) model of a shaft furnace was developed to investigate the effects of a diverter device on granular flow. By systematically varying the radial width and top/bottom diameters of the diverter particle descent velocity residence time compressive force distribution and collision energy dissipation were analyzed. The results demonstrate that introducing a diverter effectively suppresses funnel flow prolongs residence time and improves radial flow uniformity. Among the tested configurations the smaller central diameter diverter showed the most favorable performance achieving a faster and more uniform descent reduced compressive force concentration and lower collision energy dissipation. These findings highlight the critical role of diverter design in regulating particle dynamics and provide theoretical guidance for optimizing shaft furnace structures to enhance the efficiency of hydrogen-based direct reduction processes.

The present work focused on the comparison between HHO and hydrogen electrolyzers in design gas production and various parameters which affect the performance and efficiency of alkaline electrolyzers. The primary goal is to generate the highest possible hydrogen and HHO gas flow rates. Hydrogen and HHO were produced using 3 mm electrode of stainless steel 316L with 224 cm2 surface area. Hydroxy and hydrogen rates were affected by electrolyte content cell connection electric current operating time electrolyte temperature and voltage. Maximum HHO generation values were 1020 1076 1125 and 1175 mL min−1 n at 5 10 15 and 20 g L−1 of sodium hydroxide (NaOH) with supply currents of 15 15.3 15.6 and 16 A respectively. Once it stabilized after 30 min the temperature increased to 26 30 35 and 38 °C respectively and remained there. With currents of 18 18.45 18.7 19.2 19.5 and 19.8 A hydrogen output peak values after 60 min. stayed constant at 680 734 785 846 897 and 945 mL min-1. at 5 10 15 and 20 g L−1 NaOH catalyst concentrations. At 5 10 15 and 20 g L−1 catalyst ratios the temperatures were elevated to constant values of 28.5 32 37.9 40.5 41.4 and 43 °C respectively. With cell design [4C3A19N] electrolyte concentration of 5 g L−1 NaOH and current of 14 A maximum HHO productivity was 866 mL min−1. and 74.23% efficiency. In a cell design of [4C5A17N] with catalyst content of 10 g L−1 maximum productivity was 680 mL min−1 for hydrogen and highest production efficiency of 72.85% was attained at 18 A.

This article takes the perspective of Hydrogen Load Aggregator (HLA) to optimize the declaration strategy of peak shaving market improve the flexible regulation capability of power system and HLA economy as the research objectives and proposes an optimization strategy method for HLA to participate in peak shaving market. Firstly an improved Convolutional Neural Networks–Long Short-Term Memory (CNN-LSTM) time series prediction model is developed to address peak shaving demand uncertainty. Secondly a bidding strategy model incorporating dynamic pricing is constructed by comprehensively considering electrolyzer regulation costs market supply–demand relationships and system constraints. Thirdly a market clearing model for peak shaving markets with HLA participation is designed through analysis of capacity contribution and marginal costs among different regulation resources. Finally the capacity allocation model is designed with the goal of minimizing the total cost of peak shaving among various stakeholders within HLA and the capacity won by HLA in the peak shaving market is reasonably allocated. Simulations conducted on a Python3.12-based experimental platform demonstrate the following: the improved CNN-LSTM model exhibits strong adaptability and robustness the bidding model effectively enhances HLA market competitiveness and the clearing model reduces system operator costs by 5.64%.

The transition to a sustainable energy future hinges on the development of reliable large-scale hydrogen storage solutions to balance the intermittency of renewable energy and decarbonize hard-to-abate industries. Underground hydrogen storage (UHS) in salt caverns emerged as a technically and economically viable strategy leveraging the unique geomechanical properties of salt formations—including low permeability self-healing capabilities and chemical inertness—to ensure safe and high-purity hydrogen storage under cyclic loading conditions. This review provides a comprehensive analysis of the advantages of salt cavern hydrogen storage such as rapid injection and extraction capabilities cost-effectiveness compared to other storage methods (e.g. hydrogen storage in depleted oil and gas reservoirs aquifers and aboveground tanks) and minimal environmental impact. It also addresses critical challenges including hydrogen embrittlement microbial activity and regulatory fragmentation. Through global case studies best operational practices for risk mitigation in real-world applications are highlighted such as adaptive solution mining techniques and microbial monitoring. Focusing on China’s regional potential this study evaluates the hydrogen storage feasibility of stratified salt areas such as Jiangsu Jintan Hubei Yunying and Henan Pingdingshan. By integrating technological innovation policy coordination and cross-sector collaboration salt cavern hydrogen storage is poised to play a pivotal role in realizing a resilient hydrogen economy bridging the gap between renewable energy production and industrial decarbonization.

Due to the environmental impact of fossil fuels renewable energy such as wind and solar energy is rapidly developed. In energy systems energy storage units are important which can regulate the safe and stable operation of the power system. However different energy storage methods have different environmental and economic impacts in renewable energy systems. This paper proposed three different energy storage methods for hybrid energy systems containing different renewable energy including wind solar bioenergy and hydropower meanwhile. Based on Homer Pro software this paper compared and analyzed the economic and environmental results of different methods in the energy system through the case of a residential community in Baotou City. The result showed that (1) the use of batteries as energy storage in communities posed the lowest energy costs whose NPC was $197396 and LCOE was $0.159 consisting of 20 batteries 19.3 kW PV 6 wind turbines a 12.6 kW converter. (2) Lower fuel cell prices mean lower NPC and the increase in the Electric Load Scaled Average implied a decrease in LCOE and the increase of the NPC. (3) The use of fuel cells also had impacts on the environment such as resulting CO2 and SO2.

This study develops a photovoltaic (PV)-based hydrogen production system specifically designed for university campuses which is expected to lead in sustainability efforts. The proposed system aims to meet the electricity demand of a Hydrogen Research Center while supplying energy to an electric charging station and a hydrogen refueling station for battery-electric and fuel-cell electric vehicles operating within the campus. In this integrated system the electricity generation capacity of PV panels installed on the research center’s roof is determined and the surplus electricity after meeting the energy demand is allocated to cover the varying proportions needed for both electric charging station and hydrogen production system. The green hydrogen produced by the system is compressed to 100 350 and 700 bar with intermediate cooling stages where the heat generated at the compressor outlet is absorbed by a cooling fluid and repurposed in a condenser for domestic hot water production. A full thermodynamic analysis of this entirely renewable energy-powered system is conducted by considering a 9-hour daily operational period from 8:00 AM to 5:00 PM. The average incoming solar radiation is determined to be 484.63 W/m2 resulting in an annual electricity generation capacity of 494.86 MWh. Based on the assumptions and data considered the energy and exergy efficiencies of the proposed system are calculated as 17.71 % and 17.01 % respectively with an annual hydrogen production capacity of 3.642 tons. Various parametric studies are performed for varying solar intensity values and PV surface areas to investigate how the overall system capacities and efficiencies are affected. The results show that an integration of hydrogen production systems with solar energy offers significant advantages including mitigating intermittency issues found in standalone renewable systems reducing carbon emissions compared to fossil-based alternatives and enhancing the flexibility of energy systems.

This study presents a techno-economic and environmental optimization of hydrogen-based hybrid energy systems (HESs) for Broken Hill City Council in New South Wales Australia. Two configurations are evaluated: Configuration 1 includes solar PV battery fuel cell electrolyzer and hydrogen storage while Configuration 2 includes solar PV fuel cell electrolyzer and hydrogen storage but excludes the battery. The system is optimized using advanced metaheuristic algorithms such as Harris Hawks Algorithm (HHA) Red-Tailed Hawk Algorithm and Non-Dominated Sorting Genetic Algorithm-II while ensuring real-time supply–demand balance and system stability through a robust energy management strategy. This integrated approach simultaneously determines the optimal sizes of PV arrays battery storage (where applicable) fuel cells electrolyzers and hydrogen storage units and maintains reliable energy supply. Results show that HHA Configuration 1 achieves the lowest net present cost of $338111 a levelized cost of electricity of $0.185/kWh and a levelized cost of hydrogen of $4.60/kg. Sensitivity analysis reveals that PV module and hydrogen storage costs significantly impact system economics while improving fuel cell efficiency from 40% to 60% can reduce costs by up to 40%. Beyond cost-effectiveness life cycle analysis demonstrates annual CO2 emission reductions exceeding 500000 kg compared to an equivalent diesel generator system meeting the same load demand. Socio-economic assessments further indicate that the HES can support improvements in the Human Development Index by enhancing access to healthcare education and economic opportunities while also creating local jobs in PV installation battery maintenance and hydrogen infrastructure. These findings establish hydrogen-based HES as a scalable cost-effective and environmentally sustainable solution for energy access in remote areas.

Enhancing the economics of microgrid systems and achieving a balance between energy supply and demand are critical challenges in capacity allocation research. Existing studies often neglect the optimization of electrolyzer efficiency and multi-stack operation leading to inaccurate assessments of system benefits. This paper proposes a capacity allocation model for wind-PV-hydrogen integrated microgrid systems that incorporates hydrogen production efficiency optimization. This paper analyzes the relationship between the operating efficiency of the electrolyzer and the output power regulates power generation-load mismatches through a renewable energy optimization model and establishes a double-layer optimal configuration framework. The inner layer optimizes electrolyzer power allocation across periods to maximize operational efficiency while the outer layer determines configuration to maximize daily system revenue. Based on the data from a demonstration project in Jiangsu Province China a case study is conducted to verify that the proposed method can improve system benefits and reduce hydrogen production costs.

Fuel cell vehicles (FCVs) represent an intriguing alternative to battery electric vehicles (BEVs). While the acceptance of BEVs has been widely discussed acceptance-based recommendations for promoting adoption of FCVs remain ambiguous. This paper aims to improve our understanding by reporting results from a pioneer study based on the standardized Unified Theory of Acceptance and Use of Technology 2 (UTAUT2). The sample consists of n1 = 258 registered customers of H2mobility in Germany. For effect control another n2 = 294 participant sample was drawn from the baseline population. Data were analyzed using SmartPLS 4 and importance-performance mapping (IPMA). Results demonstrate that FCV acceptance primarily relies on Perceived Usefulness Perceived Conditions and Normative Influence while surprisingly hypotheses involving Perceived Risk and Green Attitude are rejected. Finally a discussion reveals ways to increase the level of public acceptance. Three practical strategies emerge. For future acceptance analyses the authors suggest incorporating the young concept of ‘societal readiness’.

Vietnam recognizes hydrogen as a key fuel for decarbonization under its National Hydrogen Strategy. Here we quantified the environmental and economic performance of Vietnam’s optimal hydrogen-production pathways by evaluating combinations of green and blue hydrogen under varying demand scenarios using life-cycle assessment and optimization modeling techniques. The environmental performance of hydrogen production proved highly sensitive to the electricity source with water electrolysis powered by renewable energy offering the most favorable outcomes. Although green hydrogen production reduced carbon emissions it shifted environmental burdens toward increased resource extraction. Producing 20 Mt of hydrogen by 2050 would require 741.56 TWh of electricity 178 Mt of water and USD 294 billion in investment and it would emit 50.48 Mt CO2. These findings highlight the importance of strategic hydrogen planning and resource strategy aligned with national priorities for energy transition to navigate trade-offs among technology selection emissions costs and resource consumption.

This paper presents a method for gas turbine performance calculations with alternative fuels with a particular focus on their use in aircraft engines. The effects of various alternative aviation fuels on fuel consumption CO2 emissions and contrail formation are examined in a comparative study. We use the GasTurb performance software and calculate heat release and hot section gas properties using a chemical equilibrium solver. Fuels with complex compositions are included in the calculation via surrogates of a limited number of known species that mimic the relevant properties of the real fuel. An automated method is used for the fuel surrogate formulation. We compare the results of this rigorous approach with the simplified approach of calculating the heat release using an alternative fuel’s heating value while still using the gas properties of conventional Jet A-1. The results show that the latter approach systematically overpredicts fuel consumption by up to 0.2% for aromaticsfree synthetic kerosene (e.g. “biofuels”). Overall aircraft engines running on alternative fuels tend to be more fuel efficient due to their often higher hydrogen contents and thus fuel heating values. We find reductions in fuel consumption of up to 2.8% during cruise when using aromatics-free synthetic kerosene. We further assess how alternative fuels affect contrail formation based on the Schmidt-Appleman criterion. Contrails can form 200 m lower under cruise conditions when burning aromatics-free synthetic kerosene instead of Jet A-1 with identical thrust requirements and under the same atmospheric conditions mainly due to their higher hydrogen content. In summary we present a flexible yet easy-to-use method for studying fuel effects in performance calculations that avoids small but systematic errors by rigorously calculating the heat release and hot section gas properties for each fuel.

Solar-driven water electrolysis has emerged as a prominent technology for the production of green hydrogen facilitated by advancements in both water electrolyzers and solar cells. Nevertheless the majority of integrated solar-to-hydrogen systems still struggle to exceed 20% efficiency particularly in large-scale applications. This limitation arises from suboptimal coupling methodologies and system-level inefficiencies that have rarely been analyzed. To address these challenges this study investigates the fundamental principles of solar hydrogen production and examines key energy losses in photovoltaic-electrolyzer systems. Subsequently it systematically discusses optimization strategies across three dimensions: (1) enhancing photovoltaic (PV) system output under variable irradiance (2) tailoring electrocatalysts and electrolyzer architectures for high-performance operation and (3) minimizing coupling losses through voltage-matching technologies and energy storage devices. Finally we review existing large-scale solar hydrogen infrastructure and propose strategies to overcome barriers related to cost durability and scalability. By integrating material innovation with system engineering this work offers insights to advance solar-powered electrolysis toward industrial applications.

China’s dual-carbon goals have positioned hydrogen as a central pillar of its energy transition. This review examines the recent development of China’s hydrogen supply chain with particular focus on manufacturing technologies for alkaline electrolysers high-pressure cylinders and diaphragm compressors. In 2024 China produced 36.5 million tons of hydrogen of which 77 % was grey and only 1 % derived from electrolysis. Storage and transportation account for nearly 30 % of end-use costs while reliance on imported compressors increases refuelling station expenses by approximately 40 %. We identify key bottlenecks including limited electrolyser efficiency the high cost of carbon fibres for Type III/IV cylinders and insufficient domestic capacity for highreliability compressors. To address these challenges targeted advances are proposed: membrane materials with engineered hydrophilicity advanced surface modifications and hydrophilic inhibitors; liner design incorporating grooved-liner braided layers with double-fibre configurations; and a three-layer diaphragm compressor architecture. By consolidating fragmented studies this review provides the integrated manufacturing perspective on China’s hydrogen supply chain offering both scientific insights and practical guidance for accelerating costeffective large-scale low-carbon hydrogen deployment.

Offshore hydrogen production offers a promising solution for harnessing wind energy far from shore by using hydrogen as an energy carrier instead of electrical cables. Flexibility in hydrogen production systems is crucial to maximising the conversion of intermittent wind energy into hydrogen. To improve the performance of lowpressure compressed gas buffer stores hybrid gas-hydride tanks have been identified as a viable solution increasing useable storage density from 1.2 kg m− 3 to 6.3 kg m− 3 with just a 5 vol% addition of hydride. This study evaluates the reduction in tank volume reduction in cost and enhancements in useable storage density achieved by integrating different hydrides under varying temperature conditions. Using hydrogen mass flow rate profiles a storage mass target was determined for optimisation. The results demonstrate that hybrid gas-hydride tanks can reduce tank size by around 80 % lowering costs by 24 % and achieve a 5.1-fold improvement in useable storage density.

With the transition to a fully renewable energy grid arises the need for a green source of stability and baseload support which classical renewable generation such as wind and solar cannot offer due to their uncertain and highly-variable generation. In this paper we study whether green hydrogen can close this gap as a source of supplemental generation and storage. We design a two-stage mixed-integer stochastic optimization model that accounts for uncertainties in renewable generation. Our model considers the investment in renewable plants and hydrogen storage as well as the operational decisions for running the hydrogen storage systems. For the data considered we observe that a fully renewable network driven by green hydrogen has a greater potential to succeed when wind generation is high. In fact the main investment priorities revealed by the model are in wind generation and in liquid hydrogen storage. This long-term storage is more valuable for taking full advantage of hydrogen than shorter-term intraday hydrogen gas storage. In addition we note that the main driver for the potential and profitability of green hydrogen lies in the electricity demand and prices as opposed to those for gas. Our model and the investment solutions proposed are robust with respect to changes in the investment costs. All in all our results show that there is potential for green hydrogen as a source of baseload support in the transition to a fully renewable-powered energy grid.

Green hydrogen offers a promising yet underexplored pathway for agricultural decarbonisation requiring technological readiness and coordinated action from policymakers industry and farmers. This paper integrates techno-economic modelling with stakeholder engagement (semi-structured interviews and an expert workshop) to assess its potential. Analyses were conducted for farms of 123 hectares and clusters of 10 farms complemented by seven interviews and a workshop with nine sector experts. Findings show both opportunities and barriers. While on-farm hydrogen production is technically feasible it remains economically uncompetitive due to high levelised costs shaped by seasonal demand variability and low utilisation of electrolysers and storage. Pooling demand across multiple users is essential to improve cost-effectiveness. Stakeholders identified three potential business models: fertiliser production via ammonia synthesis cooperative-based models and local refuelling stations. Of these cooperative hydrogen hubs emerged as the most promising enabling clusters of farms to jointly invest in renewable-powered electrolysers storage and refuelling facilities thereby reducing costs extending participation to smaller farms and mitigating risks through collective investment. By linking techno-economic feasibility with stakeholder perspectives and business model considerations the results contribute to socio-technical transition theory by showing how technological institutional and social factors interact in shaping hydrogen adoption in agriculture. With appropriate policy support cooperative hubs could lower costs ease concerns over affordability and complexity and position hydrogen as a practical driver of agricultural decarbonisation and rural resilience. Keywords: green

The search for alternatives to fossil fuels has led to hydrogen becoming an important factor in the powering means of transportation. Its most effective application is in fuel cells. A single fuel cell is not a sufficient source of power which is why a stack of fuel cells is the more common solution. Fuel cells are tested using single units as this allows all cell parameters (the current density flow rates and efficiency) to be evaluated. Therefore the scalability of fuel cells is an essential factor. This paper analyses the scalability of fuel cells with a power of approximately 100 kW and 1.2 kW. Road tests of the fuel cells were compared with stationary tests which allowed the load to be reproduced and scaled. This provided a representation of the scaled current and the scalable power of the fuel cell. The research provided voltage–current characteristics of fuel cell stacks and their individual equivalents. It was concluded that regardless of the power scaling or current values the characteristics obtain similar patterns. A very important element of the research is the awareness of the properties of these cells (the number of cells and active charge exchange area) in order to compare the unit characteristics of fuel cells.

This study employs computational thermodynamics to evaluate the feasibility of replacing methane with hydrogen as both burner fuel and reductant during blister copper deoxidation aiming to enhance deoxidation efficiency and reduce CO2 emissions. A comprehensive thermodynamic model was developed using FactSage 8.3 for dilute Cu–O and Cu–S–O melts containing trace impurities (Fe Ni Pb Zn) incorporating methane thermal decomposition and temperature-dependent variations in liquid copper density with oxygen and sulfur content. Model parameters were optimized against over 105 deoxidation simulation data points yielding temperature- and composition-dependent expressions for rapid density estimates. Benchmarking against existing literature models demonstrated improved accuracy. Key findings include: (1) increasing impurities contents from electronics waste recycling (Fe Ni Pb Zn) reduces oxygen activity deteriorating the deoxidation efficiency; (2) under global equilibrium methane provides greater reducing power per mole than hydrogen due to full thermal cracking but real-world mass transfer limitations render hydrogen more consistently effective up to 1200 C with methane gas needing to achieve at least 472 C to match hydrogen’s performance; (3) adiabatic flame equilibrium studies show that O2/H2 ratios of 0.5 to 1 yield liquid copper oxygen activities comparable to industrial O2/CH4 ratios of 2 to 3 supporting the direct substitution of methane with hydrogen in oxy-fuel anode furnace burners without compromising metal quality.

To reduce the amount of harmful gases produced by fossil fuels more environmentally friendly and sustainable alternatives are being proposed around the world. As a result technologies for manufacturing hydrogen fuel cells and producing green hydrogen are becoming more widespread with an impact on energy production and environmental protection. In many countries around the world and in Africa in particular leaders scientists and populations are considering switching from fossil fuels to so-called green energies. Hydrogen is therefore an interesting alternative that deserves to be explored especially since both rural and urban populations have shown an interest in using it in the near future which would reduce pollution and the proliferation of greenhouse gases thereby mitigating global warming. The aim of this paper is to determine the hybrid energy system best suited to addressing the energy problem in the study area and then to make successive substitutions of different energy sources starting with the most polluting in order to assess the possibilities for transitioning the energy used in the area to green hydrogen. To this end this study began with a technical and economic analysis which based on climatic parameters led to the proposal of a PV/DG-BATTery system configuration with a Net Present Cost (NPC) of USD 19267 and an average Cost Of Energy (COE) of USD 0.4 and with a high proportion of CO2 emissions compared with the PV/H2GEN-BATT and H2GEN systems. The results of replacing fossil fuel generators with hydrogen generators are beneficial in terms of environmental protection and lead to a reduction in energy-related expenses of around 2.1 times the cost of diesel and a reduction in mass of around 2.7 times the mass of diesel. The integration of H2GEN at high duty percentages increases the Cost Of Energy whether in a hybrid PV/H2GEN system or an H2GEN system. This shows the interest in the study country in using favorable duty proportions to make the use of hydrogen profitable.

For the transition to emission-free or low-emission energy hydrogen is a promising energy carrier and fuel of the future with the possibility of long-term storage. Due to its specific properties it poses certain safety risks; therefore it is necessary to have a comprehensive understanding of hydrogen. This review article contains ten main chapters and provides by synthesizing current findings primarily from standards and scientific studies (predominantly from 2023 to 2024) the theoretical basis for further research directed toward safe hydrogen infrastructure.

From an environmental standpoint carbon-free energy carriers such as ammonia and hydrogen are essential for future energy systems. However their hightemperature chemical behavior remains insufficiently understood posing challenges for the development and optimization of advanced combustion technologies. Ammonia in particular is globally available and cost-effective especially for energy-intensive industries. The addition of ammonia or hydrogen to methane significantly reduces the accuracy of existing predictive models. Therefore validated and detailed data are urgently needed to enable reliable design and performance predictions. This review highlights the compatibility of ammonia with existing combustion infrastructure facilitating a smoother transition to more sustainable heating methods without the need for entirely new systems. Applications in high-temperature heating processes such as metal processing ceramics and glass production and power generation are of particular interest. This review focuses on the systematic assessment of alternative fuel mixtures comprising ammonia and hydrogen as well as natural gas with particular consideration of existing safety-related parameters and combustion characteristics. Fundamental quantities such as the laminar burning velocity are discussed in the context of their relevance for fuel mixtures and their scalability toward turbulent flame propagation which is of critical importance for industrial burner and reactor design. The influence of fuel composition on ignition limits is examined as these are essential parameters for safety margin definitions and operational boundary conditions. Furthermore flame stability in mixed-fuel systems is addressed to evaluate the practical feasibility and robustness of combustion under varying process conditions. A detailed overview of current diagnostic and analysis methods follows encompassing both pollutant measurement techniques and the detection of key radical species. These diagnostics form the experimental basis for reaction kinetics modeling and mechanism validation. Given the importance of emission formation in combustion systems a dedicated subsection summarizes major emission trends even though a comprehensive treatment would exceed the scope of this review. Thermal radiation effects which are highly relevant for heat transfer and system efficiency in large-scale applications are then reviewed. In parallel current developments in numerical simulation approaches for industrial-scale combustion systems are presented including aspects of model accuracy boundary conditions and computational efficiency. The review also incorporates insights from materials engineering particularly regarding high-temperature material performance corrosion resistance and compatibility with combustion products. Based on these interdisciplinary findings operational strategies for high-temperature furnaces are outlined and selected industrial reference systems are briefly presented. This integrated approach aims to support the design optimization and safe operation of next-generation combustion technologies utilizing carbon-free or low-carbon fuels.

As a pivotal clean energy carrier for achieving carbon neutrality green hydrogen technology has attracted growing global attention. This review systematically examines four mainstream water electrolysis technologies—alkaline electrolysis proton exchange membrane electrolysis solid oxide electrolysis and anion exchange membrane electrolysis—analyzing their fundamental principles material challenges and development trends. It further classifies and compares power electronic converter topologies including non-isolated and isolated DC–DC converters as well as AC–DC converter architectures and summarizes advanced control strategies such as dynamic power regulation and fault-tolerant operation aimed at enhancing system efficiency and stability. A holistic “electrolyzer–power converter–control strategy” integration framework is proposed to provide tailored technological solutions for diverse application scenarios. Finally the challenges and future prospects of green hydrogen across the energy transportation and industrial sectors are discussed underscoring its potential to accelerate the global transition toward a sustainable low-carbon energy system.

The cost reduction of electrolysers is critical for scaling up green hydrogen production and achieving decarbonization targets. This study presents a novel and comprehensive dataset of electrolyser projects in Europe. It includes full cost and capacity details for each project and capturing project-specific characteristics such as technology type location and project type for the period 2005–2030. We apply the learning curve methodology to assess cost reductions across different electrolyser technologies and project sizes. Our findings indicate a significant learning effect for PEM and AEL electrolysers in the last 20 years with learning rates of 32.1% and 22.9% respectively. While AEL cost reductions are primarily driven by scaling effects PEM electrolysers benefit from both technological advancements and economies of scale. Small-scale electrolysers exhibit a stronger learning effect (25%) whereas large-scale projects show no clear cost reductions due to their early stage of deployment. Projections based on our learning rates suggest that reaching Europe’s 2030 target of 40 GW electrolyser capacity would require an estimated total investment of 14 billion EUR. These results align closely with previous studies and such predictions are closed to estimates from other organization. The dataset is publicly available allowing for further analysis and periodic updates to track cost trends.

The growing energy crisis and increasing threat of climate change are driving the need to take action regarding the use of alternative fuels in transport including public transport. Hydrogen is undoubtedly a fuel which is environmentally friendly and constitutes an alternative to fossil fuels. The wider deployment of hydrogen-powered vehicles involves the need to adapt infrastructure to support the operation of these vehicles. Such infrastructure includes refuelling stations for hydrogen-powered vehicles. The widespread use of hydrogen-powered vehicles is dependent on the development of a network of hydrogen refuelling stations. The aim of this article is to propose the conceptual location of infrastructure for fuelling public transport vehicles with hydrogen in selected cities of the West Pomeranian Voivodeship in particular the cities of Szczecin and Koszalin. The methodology used to determine the number of refuelling stations is described and the concept of the location for the refuelling stations has been proposed. Based on a set assumptions it was stated that two stations may be located in the Voivodeship in 2025 and seven stations in 2040. The research results will be of interest to infrastructure developers public transport companies and municipalities involved in making decisions related to the purchase and operation of hydrogen-powered buses.

Hydrogen (H2) is emerging as a key alternative to fossil fuels in the global energy transition. This study presents a comparative techno-economic analysis of H2 and natural gas (NG) focusing on safety hazards energy output CO2 emissions and cost-effectiveness aspects. Our analysis showed that compared to NG and other highly flammable gases like acetylene (C2 H2) and propane (C3 H8) H2 has a higher hazard potential due to factors such as its wide flammability range low ignition energy and high flame speed. In terms of energy output 1 kg of NG produces 48.60 MJ while conversion to liquefied natural gas (LNG) grey H2 and blue H2 reduces energy output to 45.96 MJ 35.45 MJ and 31.21 MJ respectively. Similarly while unconverted NG emits 2.72 kg of CO2 per kg emissions increase to 3.12 kg for LNG and 3.32 kg for grey H2. However blue H2 significantly reduces CO2 emissions to 1.05 kg per kg due to carbon capture and storage. From an economic perspective producing 1 kg of NG yields a profit of $0.011. Converting NG to grey H2 is most profitable yielding a net profit of $0.609 per kg of NG while blue H2 despite higher production costs remains viable with a profit of $0.390 per kg of NG. LNG conversion also shows profitability with $0.061 per kg of NG. This analysis highlights the trade-offs between energy efficiency environmental impact and economic viability providing valuable insights for stakeholders formulating hydrogen and LNG implementation strategies.

Transitioning to renewable energy is vital to achieving decarbonization at the global level but energy storage is still a major challenge. This review discusses the role of energy storage in the energy transition and the blue economy focusing on technological development challenges and directions. Effective storage is vital for balancing intermittent renewable energy sources like wind solar and marine energy with the power grid. The development of battery technologies hydrogen storage pumped hydro storage and emerging technologies like sodium-ion and metal-air batteries is discussed for their potential for large-scale deployment. Shortages in critical raw materials environmental impact energy loss and costs are some of the challenges to large-scale deployment. The blue economy promises opportunities for offshore energy storage notably through ocean thermal energy conversion (OTEC) and compressed air energy storage (CAES). Moreover the capacity of datadriven optimization and artificial intelligence to enhance storage efficiency is discussed. Policy interventions and economic incentives are necessary to spur the development and deployment of sustainable energy storage technology. Education and workforce training are also important in cultivating future researchers engineers and policymakers with the ability to drive energy innovation. Merging sustainability training with an interdisciplinary approach can potentially establish an efficient workforce that is capable of addressing energy issues. Future work needs to focus on higher energy density efficiency recyclability and cost-effectiveness of the storage technologies without sacrificing their environmental sustainability. The study underlines the need for converging technological economic and educational approaches to enable a sustainable and resilient energy future.

Green hydrogen has become a core element of Europe’s energy transition to assist in lowering carbon emissions. However the transition to green hydrogen faces challenges including the cost of production availability of renewable energy sources public opposition and the need for supportive government policies and financial initiatives. While there are other alternatives for producing low-carbon hydrogen for example blue hydrogen German funding favours projects that involve hydrogen production via electrolysis. Beyond climate goals it is anticipated that a green hydrogen industry will create economic benefits and a wide-range of collaborative opportunities with key international partnerships increasing energy security if done appropriately. Germany a leader in green hydrogen technology will need to rely on imports to meet long-term demand due to limited renewable energy capacity. Despite the current obstacles to transitioning to green hydrogen it is felt that ultimately the benefits of this industry and reducing emissions will outweigh the associated costs of production. This study analyses the hydrogen transition in Germany by interviewing 37 European experts guided by the research question: What are the key perceived barriers and opportunities influencing the successful adoption and integration of hydrogen technologies in Germany’s hydrogen transition?

Injection timing in low-pressure hydrogen direct injection (H2LPDI) engines plays a critical role in optimising gas jet structure and mixture formation due to the complex and transient nature of ambient air flow and density inside the cylinder. This study systematically investigates the macroscopic characteristics of gas jet development at five distinct injection timings from 210 to 120 ◦CA bTDC with the intake valve closure (IVC) as a reference point in a motored inline four-cylinder spark-ignition engine at 2000 rpm and 160 Nm load using low-pressure injection of 3.5 MPa. Optical access was made with two endoscopes: one for high-speed imaging and the other for laser insertion to realise laser shadowgraph imaging of the gas jet delivered using a side-mounted outwardopening pintle nozzle injector. The experimental results reveal spatial and temporal variations in jet morphology penetration spreading angle and mixture dispersion as a function of injection timing. Pre-IVC injection (210 ◦CA bTDC) produced a narrow mean cone angle of ~40◦ and the highest penetration-rate proxy (0.49) whereas postIVC injection (120 ◦CA bTDC) retained a wider ~53◦ cone yet reduced the penetration rate to 0.28 while increasing the sheet-based mixing index from − 0.084 to − 0.106. Pre-IVC injection occurring under low ambient pressure and with active intake airflow was found to produce elongated jets with enhanced penetration and mixing rates though accompanied by substantial cyclic variations. Conversely post-IVC injection was strongly influenced by a fully developed tumble flow which redirected the jet trajectory towards the pent-roof and facilitated mixing through increased turbulence. However the elevated air density constrained the jet penetration. At-IVC injection resulted in a more uniform and stable jet structure. However the lack of convective flow constrained the overall mixing effectiveness. Quantitative analysis of jet spreading angle pixel intensity gradient and centroid movement using 100 consecutive cycles confirms the critical role of injection timing in shaping the gas jet development as suggested by the images.

This study discusses energy management in thermal and electrical microgrids while taking heat pumps renewable sources thermal and hydrogen storages into account. The weighted total of the operating cost grid emissions level voltage and temperature deviation function and other factors makes up the objective function of the suggested method. The restrictions include the operationflexibility model of resources and storages micro-grid flexibility limits and optimum power flow equations. Point Estimation Method is used in this work to simulate load energy price and renewable phenomenon uncertainty. A fuzzy decision-making methodology is used to arrive at a compromise solution that satisfies network operators’ operational environmental and financial goals. The innovations of this paper include energy management of various smart microgrids simultaneous modeling of several indicators especially flexibility investigation of optimal performance of resources and storage devices and modeling of uncertainty considering low computational time and an accurate flexibility model. Numerical findings indicate that the fuzzy decision-making approach has the capability to reach a compromise point in which the objective functions approach their minimum values. The integration of the proposed uncertainty modeling with precise flexibility modeling results in a reduction in computational time when compared to stochastic optimization based on scenarios. For the compromise point and uncertainty modeling with PEM by efficiently managing resources and thermal and hydrogen storages scheme is capable of attaining high flexibility conditions. Compared to load flow studies the approach can enhance the operational environmental and economic conditions of smart microgrids by approximately 33–57% 68% and 33–68% respectively under these circumstances.

To enable climate-neutral aviation improving the energy efficiency of aircraft is essential. The research project Synergies of Highly Integrated Transport Aircraft investigates cross-disciplinary synergies in aircraft and propulsion technologies to achieve energy savings. This study examines a fuel cell electric powered configuration with distributed electric propulsion. For this a reverse-engineered ATR 72-500 serves as a reference model for calibrating the methods and ensuring accurate performance modeling. A baseline configuration featuring a state-of-the-art turboprop engine with the same entry-into-service is also introduced for a meaningful performance comparison. The analysis uses an enhanced version of the Stanford University Aerospace Vehicle Environment (SUAVE) a Python-based aircraft design environment that allows for novel energy network architectures. This paper details the preliminary aircraft design process including calibration presents the resulting aircraft configurations and examines the integration of a fuel cell-electric energy network. The results provide a foundation for higher fidelity studies and performance comparisons offering insights into the trade-offs associated with hydrogen-based propulsion systems. All fundamental equations and methodologies are explicitly presented ensuring transparency clarity and reproducibility. This comprehensive disclosure allows the broader scientific community to utilize and refine these findings facilitating further progress in hydrogen-powered aviation technologies.

Electricity access deficits remain acute in Sub-Saharan Africa (SSA) where more than 600 million people lack reliable supply. Green hydrogen produced through renewablepowered electrolysis is increasingly recognized as a transformative energy carrier for decentralized systems due to its capacity for long-duration storage sector coupling and near-zero carbon emissions. This review adheres strictly to the PRISMA 2020 methodology examining 190 records and synthesizing 80 peer-reviewed articles and industry reports released from 2010 to 2025. The review covers hydrogen production processes hybrid renewable integration techno-economic analysis environmental compromises global feasibility and enabling policy incentives. The findings show that Alkaline (AEL) and PEM electrolyzers are immediately suitable for off-grid scenarios whereas Solid Oxide (SOEC) and Anion Exchange Membrane (AEM) electrolyzers present high potential for future deployment. For Sub-Saharan Africa (SSA) the levelized costs of hydrogen (LCOH) are in the range of EUR5.0–7.7/kg. Nonetheless estimates from the learning curve indicate that these costs could fall to between EUR1.0 and EUR1.5 per kg by 2050 assuming there is (i) continued public support for the technology innovation (ii) appropriate flexible and predictable regulation (iii) increased demand for hydrogen and (iv) a stable and long-term policy framework. Environmental life-cycle assessments indicate that emissions are nearly zero but they also highlight serious concerns regarding freshwater usage land occupation and dependence on platinum group metals. Namibia South Africa and Kenya exhibit considerable promise in the early stages of development while Niger demonstrates the feasibility of deploying modular community-scale systems in challenging conditions. The study concludes that green hydrogen cannot be treated as an integrated solution but needs to be regarded as part of blended off-grid systems. To improve its role targeted material innovation blended finance and policies bridging export-oriented applications to community-scale access must be established. It will then be feasible to ensure that hydrogen

Amid escalating global climate crises and the urgent imperative to meet the Paris Agreement’s carbon neutrality targets the steel industry—a leading contributor to global greenhouse gas emissions—confronts unprecedented challenges in driving sustainable industrial transformation through innovative low-carbon steelmaking technologies. This paper examines decarbonization technologies across three stages (source process and end-of-pipe) for two dominant steel production routes: the long process (BF-BOF) and the short process (EAF). For the BF-BOF route carbon reduction at the source stage is achieved through high-proportion pellet charging in the blast furnace and high scrap ratio utilization; at the process stage carbon control is optimized via bottom-blowing O2-CO2-CaO composite injection in the converter; and at the end-of-pipe stage CO2 recycling and carbon capture are employed to achieve deep decarbonization. In contrast the EAF route establishes a low-carbon production system by relying on green and efficient electric arc furnaces and hydrogen-based shaft furnaces. At the source stage energy consumption is reduced through the use of green electricity and advanced equipment; during the process stage precision smelting is realized through intelligent control systems; and at the end-of-pipe stage a closed-loop is achieved by combining cascade waste heat recovery and steel slag resource utilization. Across both process routes hydrogen-based direct reduction and green power-driven EAF technology demonstrate significant emission reduction potential providing key technical support for the low-carbon transformation of the steel industry. Comparative analysis of industrial applications reveals varying emission reduction efficiencies economic viability and implementation challenges across different technical pathways. The study concludes that deep decarbonization of the steel industry requires coordinated policy incentives technological innovation and industrial chain collaboration. Accelerating large-scale adoption of low-carbon metallurgical technologies through these synergistic efforts will drive the global steel sector toward sustainable development goals. This study provides a systematic evaluation of current low-carbon steelmaking technologies and outlines practical implementation strategies contributing to the industry’s decarbonization efforts.

This study presents a techno-economic environmental risk analysis (TERA) of large-scale green hydrogen production using Alkaline Water Electrolysis (AWE) and Proton Exchange Membrane (PEM) systems. The analysis integrates commercial data market insights and academic forecasts to capture variability in capital expenditure (CAPEX) efficiency electricity cost and capacity factor. Using Libya as a case study 81 scenarios were modelled for each technology to assess financial and operational trade-offs. For AWE CAPEX is projected between $311 billion and $905.6 billion for 519 GW (gigawatts) of installed capacity equivalent to 600–1745 $/kW. PEM systems show a wider range of $612 billion to $1020 billion for 510 GW translating to 1200–2000 $/kW. Results indicate that AWE while requiring greater land use provides significant cost advantages due to lower capital intensity and scalability. In contrast PEM systems offer compact design and operational flexibility but at substantially higher costs. The five most economical scenarios for both technologies consistently feature low CAPEX and high efficiency while sensitivity analyses confirm these two parameters as the dominant cost drivers. The findings emphasise that technology choice should reflect context-specific priorities such as land availability budget and performance needs. This study provides actionable guidance for policymakers and investors developing cost-effective hydrogen infrastructure in emerging green energy markets.

Underground Hydrogen Storage (UHS) is a promising solution to maximize the use of hydrogen as an energy carrier. This study presents a standardized methodology for assessing UHS quality by introducing the Underground Hydrogen Storage Suitability Index (UHSSI) which integrates three sub-indices: the Caprock Potential Index (CPI) the Reservoir Quality Index (RQI) and the Site Potential Index (SPI). Parameters such as porosity permeability lithology caprock thickness depth temperature and salinity are evaluated and ranked from 0 (unsuitable) to 5 (excellent). The methodology was validated using data from six worldwide sites including salt caverns and aquifers. Sites like Moss Bluff Clemens Dome and Spindletop (USA) scored highly while Teesside (UK) Lobodice (Czech Republic) and Beynes (France) were classified as unsuitable due to shallow depths and microbial activity. A software tool the UHSSI Calculator was developed to automate site evaluations. This approach offers a cost-effective tool for preliminary screening and supports the safer development of UHS.

Emissions from fossil fuel extraction conveyance and combustion are among the most significant causes of air pollution and climate change leading to arguably the most acute crises mankind has ever faced. The transition from fossil fuel-based energy systems to hydrogen is essential for meeting a portion of global decarbonization goals. Hydrogen offers certain features such as high gravimetric energy density that is required for heavy-duty shipping and freight applications and chemical properties such as high temperature combustion and reducing capabilities that are required for steel chemicals and fertilizer industries. However hydrogen that leaks has indirect climate implications stemming from atmospheric interactions that are emerging as a critical area of research. This study reviews recent literature on hydrogen’s global warming potential (GWP) highlighting its indirect contributions to radiative forcing via methane’s extended atmospheric lifetime tropospheric ozone formation and stratospheric water vapor formation. The 100-year GWP (GWP100) of hydrogen estimated to range between 8 and 12.8 underscores the need to minimize leakage throughout the hydrogen supply chain to maximize the climate benefits of using hydrogen instead of fossil fuels. Comparisons with methane reveal hydrogen’s shorter atmospheric lifetime and reduced long-term warming effects establishing it as a viable substitute for fossil fuels in sectors such as steel cement and heavy-duty transport. The analysis emphasizes the importance of accurate leakage assessments robust policy frameworks and advanced infrastructure to ensure hydrogen realizes its potential as a sustainable energy carrier that displaces the use of fossil fuels. Future research is recommended to refine climate models better understand atmospheric sinks and hydrogen leakage phenomena and develop effective strategies to minimize hydrogen emissions paving the way for environmentally sound use of hydrogen.

The transportation sector is a significant contributor to global carbon emissions thus necessitating a transition toward renewable energy sources (RESs) and electric vehicles (EVs). Among EV technologies fuel-cell EVs (FCEVs) offer distinct advantages in terms of refueling time and operational efficiency thus rendering them a promising solution for sustainable transportation. Nevertheless the integration of FCEVs in rural areas poses challenges due to the limited availability of refueling infrastructure and constraints in energy access. In order to address these challenges this study proposes a multi-objective energy management model for a hydrogen refueling station (HRS) integrated with RESs a battery storage system an electrolyzer (EL) a fuel cell (FC) and a hydrogen tank serving diverse FCEVs in rural areas. The model formulated using mixed-integer linear programming (MILP) optimizes station operations to maximize both cost and load factor performance. Additionally bi-directional trading with the power grid and hydrogen network enhances energy flexibility and grid stability enabling a more resilient and self-sufficient energy system. To the best of the authors’ knowledge this study is the first in the literature to present a multi-objective optimal management approach for grid-interactive renewablesupported HRSs serving hydrogen-powered vehicles in rural areas. The simulation results demonstrate that RES integration improves economic feasibility by reducing costs and increasing financial gains while maximizing the load factor enhances efficiency cost-driven strategies that may impact stability. The impact of the EL on cost is more significant while RES capacity has a relatively smaller effect on cost. However its influence on the load factor is substantial. The optimization of RES-supported hydrogen production has been demonstrated to reduce external dependency thereby enabling surplus trading and increasing financial gains to the tune of USD 587.83. Furthermore the system enhances sustainability by eliminating gasoline consumption and significantly reducing carbon emissions thus supporting the transition to a cleaner and more efficient transportation ecosystem.

The safe removal transportation and long-term storage of fuel debris in the decommissioning of Fukushima Daiichi is the biggest challenge facing Japan. In the nuclear power field passive autocatalytic recombiners (PARs) have become established as a technology to prevent hydrogen explosions inside the containment vessel. To utilize PAR as a measure to reduce the concentration of hydrogen generated in the fuel debris storage canister which is currently an issue it is required to perform in a sealed environment with high doses of radiation low temperature and high humidity and there are many challenges different from conventional PAR. A honeycombshaped catalyst based on automotive catalyst technology has been newly designed as a PAR and research has been conducted to solve unique problems such as high dose radiation low temperature high humidity coexistence of hydrogen and low oxygen and catalyst poisons. This paper summarizes the challenges of hydrogen generation in a sealed container the results of research and a guide to how to use the PAR for fuel debris storage canisters.

Proton exchange membrane water electrolyzers (PEMWEs) are a promising technology for green hydrogen production. However the adoption of PEMWE-based hydrogen production systems remains limited due to several challenges including high material costs limited performance and durability and difficulties in scaling the technology. Computational modeling serves as a powerful tool to address these challenges by optimizing system design improving material performance and reducing overall costs thereby accelerating the commercial rollout of PEMWE technology. Despite this conventional models often oversimplify key components such as porous transport and catalyst layers by assuming constant porosity and neglecting the spatial heterogeneity found in real electrodes. This simplification can significantly impact the accuracy of performance predictions and the overall efficiency of electrolyzers. This study develops a mathematical framework for modeling variable porosity distributions—including constant linearly graded and stepwise profiles—and derives analytical expressions for permeability effective diffusivity and electrical conductivity. These functions are integrated into a three-dimensional multi-domain COMSOL simulation to assess their impact on electrochemical performance and transport behavior. The results reveal that although porosity variations have minimal effect on polarization at low voltages they significantly influence internal pressure species distribution and gas evacuation at higher loads. A notable finding is that reversing stepwise porosity—placing high porosity near the membrane rather than the channel—can alleviate oxygen accumulation and improve current density. A multi-factor comparison highlights this reversed configuration as the most favorable among the tested strategies. The proposed modeling approach effectively connects porous media theory and systemlevel electrochemical analysis offering a flexible platform for the future design of porous electrodes in PEMWE and other energy conversion systems.

Green hydrogen produced through renewable energy sources is emerging as a pivotal element in global energy transitions. Despite its potential public acceptance remains a critical barrier to its large-scale implementation. This study aims to identify the socio-political and demographic determinants of public acceptance of green hydrogen. Using advanced variable selection methods including ridge lasso and elastic net regression we analyzed perceptions of climate change trust in government policies and demographic characteristics. The findings reveal that individuals prioritizing climate change over economic growth perceiving its impacts as severe and recognizing it as South Korea’s most pressing issue are more likely to accept green hydrogen. Trust in the government’s climate change response also emerged as a key factor. Demographic characteristics such as younger age higher income advanced education smaller family size and conservative political ideology were significantly associated with greater acceptance. These results highlight the importance of raising public awareness about the urgency of climate change and enhancing trust in government policies to promote societal acceptance of green hydrogen. Policymakers should consider these factors when developing strategies to advance the adoption of green hydrogen technologies and foster sustainable energy transitions.