China, People’s Republic

Green hydrogen plays a pivotal role in decarbonizing our energy system and achieving the Net-Zero Emissions goal by 2050. Offshore wind farms (OWFs) dedicated to green hydrogen production are currently recognized as the most feasible solution for scaling up the production of cost-effective electrolytic hydrogen. However the cost associated with distribution and transmission systems constitute a significant portion of the total cost in the large-scale wind-hydrogen system. This study pioneers the simultaneous optimization of the inter-array cable routing of OWFs and the location and capacity of offshore hydrogen production platforms (OHPPs) aiming to minimize the total cost of distribution and transmission systems. Considering the characteristics of hydrogen production efficiency this paper constructs a novel mathematical model for OHPPs across diverse wind scenarios. Subsequently we formulate the joint planning problem as a relaxed mixed-integer second-order cone programming (MISOCP) model and employ the Benders decomposition algorithm for the solution introducing three valid inequalities to expedite convergence. Through validation on real-world large-scale OWFs we demonstrate the validity and rapid convergence of our approach. Moreover we identify hydrogen production efficiency as a major bottleneck cost factor for the joint planning problem it decreases by 1.01% of total cost for every 1% increase in hydrogen production efficiency.

Water electrolyzers play a crucial role in green hydrogen production. However their efficiency and scalability are often compromised by bubble dynamics across various scales from nanoscale to macroscale components. This review explores multi-scale modeling as a tool to visualize multi-phase flow and improve mass transport in water electrolyzers. At the nanoscale molecular dynamics (MD) simulations reveal how electrode surface features and wettability influence nanobubble nucleation and stability. Moving to the mesoscale models such as volume of fluid (VOF) and lattice Boltzmann method (LBM) shed light on bubble transport in porous transport layers (PTLs). These insights inform innovative designs including gradient porosity and hydrophilic-hydrophobic patterning aimed at minimizing gas saturation. At the macroscale VOF simulations elucidate two-phase flow regimes within channels showing how flow field geometry and wettability affect bubble discharging. Moreover artificial intelligence (AI)-driven surrogate models expedite the optimization process allowing for rapid exploration of structural parameters in channel-rib flow fields and porous flow field designs. By integrating these approaches we can bridge theoretical insights with experimental validation ultimately enhancing water electrolyzer performance reducing costs and advancing affordable highefficiency hydrogen production.

Hydrogen as a clean energy source has gradually become an important choice for the energy transformation in the world. Utilizing existing natural gas pipelines for hydrogen-blended transportation is one of the most economical and effective ways to achieve large-scale hydrogen transportation. However hydrogen can easily penetrate into the pipe material during the hydrogen-blended transportation process causing damage to the properties of the pipe. The heat-affected zone (HAZ) of the weld being the weakest part of the pipeline is highly sensitive to hydrogen embrittlement. The microstructure and properties of the grains in the heat-affected zone undergoes changes during the welding process. Therefore this paper divides the HAZ of X80 welded pipes into three sub-HAZ namely the coarse-grained HAZ fine-grained HAZ and intercritical HAZ to study the hydrogen behavior. The results show that the degree of hydrogen damage in each sub-HAZ varies significantly at different strain rates. The coarse-grained HAZ has the highest hydrogen embrittlement sensitivity at low strain rates while the intercritical HAZ experiences the greatest hydrogen damage at high strain rates. By combining the microstructural differences within each sub-HAZ the plastic damage mechanism of hydrogen in each sub-HAZ is analyzed with the aim of providing a scientific basis for the feasibility of using X80 welded pipes in hydrogen-blended transportation.

This study investigates the effects of secondary jet-guided combustion on the combustion and emissions of a hydrogen direct-injection engine through numerical simulations. The results show that secondary jet-guided combustion which involves injecting and igniting the hydrogen jet at the end of the compression stroke significantly shortens the delay period improves combustion stability and brings the combustion center closer to the top dead center (TDC) achieving a maximum indicative thermal efficiency (ITE) of 46.55% (λ = 2.4). However this strategy results in higher NOx emissions due to high-temperature combustion. In contrast single and double injections lead to worsened combustion and reduced thermal efficiency under lean-burn conditions but with relatively lower NOx emissions. This study demonstrates that secondary jet-guided combustion can effectively enhance hydrogen engine performance by optimizing mixture stratification and flame propagation providing theoretical support for clean and efficient combustion.

To ensure the safe and reliable operation of hydrogen-blended natural gas (HBNG) pipelines in urban utility tunnels this study conducted a comprehensive CFD simulation of the leakage and diffusion characteristics of HBNG in confined underground environments. Utilizing ANSYS CFD software (2024R1) a three-dimensional physical model of a utility tunnel was developed to investigate the influence of key parameters such as leak sizes (4 mm 6 mm and 8 mm)—selected based on common small-orifice defects in utility tunnel pipelines (e.g. corrosion-induced pinholes and minor mechanical damage) and hydrogen blending ratios (HBR) ranging from 0% to 20%—a range aligned with current global HBNG demonstration projects (e.g. China’s “Medium-Term and Long-Term Plan for Hydrogen Energy Industry Development”) and ISO standards prioritizing 20% as a technically feasible upper limit for existing infrastructure on HBNG diffusion behavior. The study also evaluated the adequacy of current accident ventilation standards. The findings show that as leak orifice size increases the diffusion range of HBNG expands significantly with a 31.5% increase in diffusion distance and an 18.5% reduction in alarm time as the orifice diameter grows from 4 mm to 8 mm. Furthermore hydrogen blending accelerates gas diffusion with each 5% increase in HBR shortening the alarm time by approximately 1.6 s and increasing equilibrium concentrations by 0.4% vol. The current ventilation standard (12 h−1 ) was found to be insufficient to suppress concentrations below the 1% safety threshold when the HBR exceeds 5% or the orifice diameter exceeds 4 mm—thresholds derived from simulations showing that under 12 h−1 ventilation equilibrium concentrations exceed the 1% safety threshold under these conditions. To address these gaps this study proposes an adaptive ventilation strategy that uses variable-frequency drives to adjust ventilation rates in real time based on sensor feedback of gas concentrations ensuring alignment with leakage conditions thereby ensuring enhanced safety. These results provide crucial theoretical insights for the safe design of HBNG pipelines and ventilation optimization in utility tunnels.

Amidst the escalating global challenges presented by climate change carbon trading mechanisms have become critical tools for driving reductions in carbon emissions and optimizing energy systems. However existing carbon trading models constrained by fixed settlement cycles face difficulties in addressing the scheduling needs of energy systems that operate across multiple time scales. To address this challenge this paper proposes an optimal scheduling methodology for hydrogen-encompassing integrated energy systems that incorporates a multi-time-scale carbon trading mechanism. The proposed approach dynamically optimizes the scheduling and conversion of hydrogen energy electricity thermal energy and other energy forms by flexibly adjusting the carbon trading cycle. It accounts for fluctuations in energy demand and carbon emissions occurring both before and during the operational day. In the day-ahead scheduling phase a tiered carbon transaction cost model is employed to optimize the initial scheduling framework. During the day scheduling phase real-time data are utilized to dynamically adjust carbon quotas and emission ranges further refining the system’s operational strategy. Through the analysis of typical case studies this method demonstrates significant benefits in reducing carbon emission costs enhancing energy efficiency and improving system flexibility.

Bio-hydrogen production (BHP) produced from renewable bio-resources is an attractive route for green energy production due to its compelling advantages of relative high efficiency cost-effectiveness and lower ecological impact. This study reviewed different BHP pathways and the most important enzymes involved in these pathways to identify technological gaps and effective approaches for process intensification in industrial applications. Among the various approaches reviewed in this study a particular focus was set on the latest methods of chemicals/metal addition for improving hydrogen generation during dark fermentation (DF) processes; the up-to-date findings of different chemicals/metal addition methods have been quantitatively evaluated and thoroughly compared in this paper. A new efficiency evaluation criterion is also proposed allowing different BHP processes to be compared with greater simplicity and validity

The widespread penetration of hydrogen in mainstream energy systems requires hydrogen production processes to be economically competent and environmentally efficient. Hydrogen if produced efficiently can play a pivotal role in decarbonizing the global energy systems. Therefore this study develops a framework which evaluates hydrogen production processes and quantifies deficiencies for improvement. The framework integrates slack-based data envelopment analysis (DEA) with fuzzy analytical hierarchy process (FAHP) and fuzzy technique for order of preference by similarity to ideal solution (FTOPSIS). The proposed framework is applied to prioritize the most efficient and sustainable hydrogen production in Pakistan. Eleven hydrogen production alternatives were analyzed under five criteria including capital cost feedstock cost O&M cost hydrogen production and CO2 emission. FAHP obtained the initial weights of criteria while FTOPSIS determined the ultimate weights of criteria for each alternative. Finally slack-based DEA computed the efficiency of alternatives. Among the 11 three alternatives (wind electrolysis PV electrolysis and biomass gasification) were found to be fully efficient and therefore can be considered as sustainable options for hydrogen production in Pakistan. The rest of the eight alternatives achieved poor efficiency scores and thus are not recommended.

Numerical simulations reveal the combustion dynamics of hydrogen-blended natural gas (H-BNG) in semi-open spaces. In the typical semi-open space scenario increasing the hydrogen blending ratio from 0% to 60% elevates peak internal pressure by 107% (259.3 kPa → 526.0 kPa) while reducing pressure rise time by 56.5% (95.8 ms → 41.7 ms). A vent size paradox emerges: 0.5 m openings generate 574.6 kPa internal overpressure whereas 2 m openings produce 36.7 kPa external overpressure. Flame propagation exhibits stabilized velocity decay (836 m/s → 154 m/s 81.6% reduction) at hydrogen concentrations ≥30% within 2–8 m distances. In street-front restaurant scenarios 80% H-BNG leaks reach alarm concentration (0.8 m height) within 120 s with sensor response times ranging from 21.6 s (proximal) to 40.2 s (distal). Forced ventilation reduces hazard duration by 8.6% (151 s → 138 s) while door status shows negligible impact on deflagration consequences (412 kPa closed vs. 409 kPa open) maintaining consistent 20.5 m hazard radius at 20 kPa overpressure threshold. These findings provide crucial theoretical insights and practical guidance for the prevention and management of H-BNG leakage and explosion incidents.

Hydrogen energy characterized by its abundant resources green and lowcarbon attributes and wide-ranging applications is a critical energy source for achieving carbon peaking and carbon neutrality goals. The operational efficiency of the hydrogen energy industrial chain is pivotal in determining the security of its supply chain and its contribution to China’s energy transition. This study investigates the efficiency of China’s hydrogen energy industrial chain by selecting 30 listed companies primarily engaged in hydrogen energy as the research sample. A three-stage data envelopment analysis (DEA) model is applied to assess the industry’s comprehensive technical efficiency pure technical efficiency and scale efficiency. Additionally kernel density estimation is utilized to analyze efficiency trends over time. Key factors influencing efficiency are identified and targeted recommendations are provided to enhance the performance and sustainability of the hydrogen energy industrial chain. These findings offer valuable insights to support the development and resilience of China’s hydrogen energy industry

This paper presents an improved Equivalent Consumption Minimization Strategy (ECMS) designed to optimize energy management for the hybrid hydrogen fuel power setups in multirotor drones. The proposed strategy aims to reduce hydrogen consumption and enhance the performance of the system consisting of Proton Exchange Membrane Fuel Cells (PEMFCs) and lithium batteries. Multirotor drones experience rapid power fluctuations due to their agile maneuvering but PEMFCs are unable to meet these demands swiftly due to their inherent limitations. To address this lithium batteries supplement peak power requirements and absorb excess energy on the DC bus. However this can lead to energy loss if the batteries are charged when not required. Our improved ECMS considers these inefficiencies and adjusts energy distribution to reduce hydrogen consumption and optimize the system’s performance. The proposed strategy effectively maintains the lithium batteries’ State of Charge (SOC) reduces hydrogen usage and enhances overall system efficiency when compared to traditional ECMS approaches.

Biogas (primarily biomethane) as a carbon-neutral renewable energy source holds great potential to replace fossil fuels for sustainable hydrogen production. Conventional biogas reforming systems adopt strategies similar to industrial natural gas reforming posing challenges such as high temperatures high energy consumption and high system complexity. In this study we propose a novel multi-product sequential separation-enhanced reforming method for biogas-derived hydrogen production which achieves high H2 yield and CO2 capture under mid-temperature conditions. The effects of reaction temperature steam-to-methane ratio and CO2/CH4 molar ratio on key performance metrics including biomethane conversion and hydrogen production are investigated. At a moderate reforming temperature of 425 ◦C and pressure of 0.1 MPa the conversion rate of CH4 in biogas reaches 97.1% the high-purity hydrogen production attains 2.15 mol-H2/mol-feed and the hydrogen yield is 90.1%. Additionally the first-law energy conversion efficiency from biogas to hydrogen reaches 65.6% which is 11 percentage points higher than that of conventional biogas reforming methods. The yield of captured CO2 reaches 1.88 kg-CO2/m3 -feed effectively achieving near-complete recovery of green CO2 from biogas. The mild reaction conditions allow for a flexible integration with industrial waste heat or a wide selection of other renewable energy sources (e.g. solar heat) facilitating distributed and carbonnegative hydrogen production.

Effective water management is crucial for the optimal performance and durability of proton exchange membrane fuel cells (PEMFCs) in automotive applications. Conventional techniques like electrochemical impedance spectroscopy (EIS) face challenges in accurately measuring high-frequency resistance (HFR) impedance during dynamic vehicle operations. This study proposes a novel stack water management stability control and vehicle energy control method to address these limitations. Simulation and experimental results demonstrate improved system and powertrain efficiency extended stack lifespan and optimized hydrogen consumption. These findings contribute to advancing robust water management strategies supporting the transition toward sustainable zero-emission fuel cell vehicles.

Against the backdrop of ever‑increasing energy demand and growing awareness of en‑ vironmental protection the research and optimization of hydrogen‑related multi‑energy systems have become a key and hot issue due to their zero‑carbon and clean characteristics. In the scheduling of such multi‑energy systems a typical problem is how to describe and deal with the uncertainties of multiple types of energy. Scenario‑based methods and ro‑ bust optimization methods are the two most widely used methods. The first one combines probability to describe uncertainties with typical scenarios and the second one essentially selects the worst scenario in the uncertainty set to characterize uncertainties. The selection of these scenarios is essentially a trade‑off between the economy and robustness of the so‑ lution. In this paper to achieve a better balance between economy and robustness while avoiding the complex min‑max structure in robust optimization we leverage artificial in‑ telligence (AI) technology to generate enough scenarios from which economic scenarios and feasible scenarios are screened out. While applying a simple single‑layer framework of scenario‑based methods it also achieves both economy and robustness. Specifically first a Transformer architecture is used to predict uncertainty realizations. Then a Gener‑ ative Adversarial Network (GAN) is employed to generate enough uncertainty scenarios satisfying the actual operation. Finally based on the forecast data the economic scenar‑ ios and feasible scenarios are sequentially screened out from the large number of gener‑ ated scenarios and a balance between economy and robustness is maintained. On this ba‑ sis a multi‑energy collaborative optimization method is proposed for a hydrogen‑based multi‑energy microgrid with consideration of the coupling relationships between energy sources. The effectiveness of this method has been fully verified through numerical exper‑ iments. Data show that on the premise of ensuring scheduling feasibility the economic cost of the proposed method is 0.67% higher than that of the method considering only eco‑ nomic scenarios. It not only has a certain degree of robustness but also possesses good economic performance.

N-type sulfide semiconductors are promising photocatalysts due to their broad visible-light absorption facile synthesis and chemical diversity. However photocorrosion and limited electron transport in one-step excitation and solid-state Z-scheme systems hinder efficient overall water splitting. Liquidphase Z-schemes offer a viable alternative but sluggish mediator kinetics and interfacial side reactions impede their construction. Here we report a stable Z-scheme system integrating n-type CdS and BiVO₄ with a [Fe(CN)₆]³⁻/[Fe(CN)₆]⁴⁻ mediator achieving 10.2% apparent quantum yield at 450 nm with stoichiometric H₂/O₂ evolution. High activity reflects synergies between Pt@CrOx and Co3O4 cocatalysts on CdS and cobalt-directed facet asymmetry in BiVO₄ resulting in matched kinetics for hydrogen and oxygen evolution in a reversible mediator solution. Stability is dramatically improved through coating CdS and BiVO4 with different oxides to inhibit Fe4[Fe(CN)6]3 precipitation and deactivation by a hitherto unrecognized mechanism. Separate hydrogen and oxygen production is also demonstrated in a twocompartment reactor under visible light and ambient conditions. This work unlocks the long-sought potential of n-type sulfides for efficient durable and safe solar-driven hydrogen production.

Aiming at resolving the problem of stable and efficient operation of integrated green hydrogen production storage and supply hydrogen refueling stations at different time scales this paper proposes a multi-time-scale hierarchical energy management strategy for integrated green hydrogen production storage and supply hydrogen refueling station (HFS). The proposed energy management strategy is divided into two layers. The upper layer uses the hourly time scale to optimize the operating power of HFS equipment with the goal of minimizing the typical daily operating cost and proposes a parameter adaptive particle swarm optimization (PSA-PSO) solution algorithm that introduces Gaussian disturbance and adaptively adjusts the learning factor inertia weight and disturbance step size of the algorithm. Compared with traditional optimization algorithms it can effectively improve the ability to search for the optimal solution. The lower layer uses the minute-level time scale to suppress the randomness of renewable energy power generation and hydrogen load consumption in the operation of HFS. A solution algorithm based on stochastic model predictive control (SMPC) is proposed. The Latin hypercube sampling (LHS) and simultaneous backward reduction methods are used to generate and reduce scenarios to obtain a set of high-probability random variable scenarios and bring them into the MPC to suppress the disturbance of random variables on the system operation. Finally real operation data of a HFS in southern China are used for example analysis. The results show that the proposed energy management strategy has a good control effect in different typical scenarios.

This study systematically investigates the fracture behavior of X80 pipeline steel welded joints under hydrogen-induced cracking (HIC) conditions through combined experimental characterization and numerical simulation. Microstructural observations and Vickers hardness testing reveal significant heterogeneity in the base metal heat-affected zone (HAZ) and weld metal (WM) resulting in spatially non-uniform mechanical properties. A userdefined subroutine (USDFLD) was employed to assign continuous material property distributions within the finite element model accurately capturing mechanical heterogeneity and its influence on crack-tip mechanical fields and crack propagation paths. Results show that welding thermal cycles induce pronounced microstructural evolution significantly altering hardness and strength distributions which in turn affect the evolution of crack-tip stress and plastic strain fields. Crack propagation preferentially occurs toward regions of higher yield strength where limited plasticity leads to intensified cracktip stress concentration accelerating crack growth and extending propagation paths. Moreover crack growth is accompanied by local unloading near the crack tip reducing peak stress and strain compared to the initial stationary crack tip. The stress and strain field reconfiguration are primarily localized near the crack tip while the far-field mechanical response remains largely stable.

Hydrogen gas is a promising clean-energy vector that can alleviate the current imbalance between energy supply and demand diversify the energy portfolio and underpin the sustainable development of oil and gas resources. This study pinpoints the factors that govern hydrogen quantification by pulsed-neutron logging. Monte Carlo simulations were performed to map the spatial distribution of capture γ-rays in formations saturated with either water or hydrogen and to systematically assess the effects of pore-fluid composition hydrogen density gas saturation lithology and borehole-fluid type. The results show that the counts of capture γ-rays are litter in hydrogen-bearing formations. For lowto moderate-porosity rocks the dynamic response window for hydrogensaturated pores is approximately 10% wider than that for methane-saturated pores. Increasing hydrogen density or decreasing gas saturation raises the capture-γ ratio while narrowing the dynamic range. Changes in borehole fluid substantially affect the capture-γ ratio yet have only a minor impact on the dynamic range. Lithology imposes an additional control: serpentinite enriched in structural water generates markedly higher capture-γ ratios that may complicate the quantitative evaluation of hydrogen.

Proliferation of co-located petrol-hydrogen fueling stations is an effective solution for widespread deployment of hydrogen as a transportation fuel. Such combined fueling stations largely rely on existing infrastructure hence represent a low-cost option for setting up hydrogen fueling facilities. However optimizing the layout of dual petrol-hydrogen fueling stations and their rational site selection is critical for ensuring the efficient use of re sources. This paper investigates the site selection of combined hydrogen and petrol fueling stations at the ter minus of China’s "West-to-East Hydrogen Pipeline" project. A weighting model based on EWM-CRITIC-Game Theory is developed and the weight coefficients derived from game theory are used to perform the compre hensive ranking of potential sites. The combined evaluation results yield an overall ranking of A9 > A4 > A8 > A26 > A20 > A21 > A11. The effectiveness of this novel method is verified by comparing the results with those obtained from Copeland Borda Average and geometric mean methods. Considering the actual distance con straints the final site ranking is A9 > A4 > A8 > A20 > A21 > A11 > A14. This location offers optimal con ditions for infrastructure integration and hydrogen fueling service coverage. The reliability analysis indicates that the proposed game theory-based method delivers strong performance across various scenarios underscoring its reliability and versatility in consistently delivering accurate results.

Hydrogen production from electrolytic water based on Renewable Energy has been found as a vital method for the local consumption of new energy and the utilization of hydrogen energy. In this paper the hydrogen production power supply matching the working characteristics of electrolytic water production was investigated. Through the analysis of the correlation between the electrolysis current and temperature of the proton exchange membrane electrolyzer and the electrolyzer port voltage energy efficiency and hydrogen production speed it was concluded that the hydrogen production power supply should be characterized by low output current ripple high output current and wide range voltage output. To meet the requirements of the system of hydrogen production from electrolytic water based on new energy a hydrogen production power supply scheme was proposed based on Y which is the type three is the phase staggered parallel LLC topology. In the proposed scheme the cavity with three is the phase staggered parallel output is resonated to meet the operating characteristics (high current and low ripple) of the electrolyzer and pulse frequency control is adopted to achieve resonant soft in the switching operation and increase conversion efficiency. Lastly a simulation model and a 6kW experimental prototype were built to verify the rationality and feasibility of the proposed scheme.

Methanol steam reforming (MSR) represents a highly promising pathway for sustainable hydrogen production due to its favorable hydrogen-to-carbon ratio and relatively low operating temperatures. The performance of the MSR process is strongly dependent on the selection and rational design of catalysts which govern methanol conversion hydrogen selectivity and the suppression of undesired side reactions such as carbon monoxide formation. Moreover advancements in reactor configuration and thermal management strategies play a vital role in minimizing heat loss and enhancing heat and mass transfer efficiency. Effective carbon monoxide removal technologies are indispensable for obtaining high-purity hydrogen particularly for applications sensitive to CO contamination. This review systematically summarizes recent progress in catalyst development reactor design and gas purification technologies for MSR. In addition the key technical challenges and potential future directions of the MSR process are critically discussed. The insights provided herein are expected to contribute to the development of more efficient stable and scalable MSR-based hydrogen production systems.

Underground hydrogen storage has gained interest in recent years due to the enormous demand for clean energy. Hydrogen is more diffusive than air with a smaller density and lower viscosity. These unique properties introduce distinctive hydrodynamic phenomena in hydrogen storage one of which is fingering. Fingering could induce the fluid trapped in small clusters of pores leading to a dramatic decrease in hydrogen saturation and a lower recovery rate. In this study numerical simulations are performed at the microscopic scale to understand the evolution of hydrogen saturation and the impacts of injection and withdrawal cycles. Two sets of micromodels with different porosity (0.362 and 0.426) and minimum sizes of pore throats (0.362 mm and 0.181 mm) are developed in the numerical model. A parameter analysis is then conducted to understand the influence of injection velocity (in the range of 10-2 m/s to 10-5 m/s) and porous structure on the fingering pattern followed by an image analysis to capture the evolution of the fingering pattern. Viscous fingering capillary fingering and crossover fingering are observed and identified under different boundary conditions. The fractal dimension specific area mean angle and entropy of fingers are proposed as geometric descriptors to characterize the shape of the fingering pattern. When porosity increases from 0.362 to 0.426 the saturation of hydrogen increases by 26.2%. Narrower pore throats elevate capillary resistance which hinders fluid invasion. These results underscore the importance of pore structures and the interaction between viscous and capillary forces for hydrogen recovery efficiency. This work illuminates the influence of the pore structures and the fluid properties on the immiscible displacement of hydrogen and can be further extended to optimize the injection strategy of hydrogen in underground hydrogen storage.

Hydrogen-powered unmanned aerial vehicles (UAVs) offer significant advantages such as environmental sustainability and extended endurance demonstrating broad application prospects. However the hydrogen fuel cells face prominent thermal management challenges during flight operations. This study established a numerical model of the fuel cell thermal management system (TMS) for a hydrogen-powered UAV. Computational fluid dynamics (CFD) simulations were subsequently performed to investigate the impact of various design parameters on cooling performance. First the cooling performance of different fan density configurations was investigated. It was found that dispersed fan placement ensures substantial airflow through the peripheral flow channels significantly enhancing temperature uniformity. Specifically the nine-fan configuration achieves an 18.5% reduction in the temperature difference compared to the four-fan layout. Additionally inlets were integrated with the fan-based cooling system. While increased external airflow lowers the minimum fuel cell temperature its impact on high-temperature zones remains limited with a temperature difference increase of more than 19% compared to configurations without inlets. Furthermore the middle inlet exhibits minimal vortex interference delivering superior thermal performance. This configuration reduces the maximum temperature and average temperature by 9.1% and 22.2% compared to the back configuration.

Photocatalytic membrane reactors (PMRs) which combine photocatalysis with membrane separation represent a pivotal technology for sustainable water treatment and resource recovery. Although extensive research has documented various configurations of photocatalytic-membrane hybrid processes and their potential in water treatment applications a comprehensive analysis of the interrelationships among reactor architectures intrinsic physicochemical mechanisms and overall process efficiency remains inadequately explored. This knowledge gap hinders the rational design of highly efficient and stable reactor systems—a shortcoming that this review seeks to remedy. Here we critically examine the connections between reactor configurations design principles and cutting-edge applications to outline future research directions. We analyze the evolution of reactor architectures relevantreaction kinetics and key operational parameters that inform rational design linking these fundamentals to recent advances in solar-driven hydrogen production CO2 conversion and industrial scaling. Our analysis reveals a significant disconnect between the mechanistic understanding of reactor operation and the system-level performance required for innovative applications. This gap between theory and practice is particularly evident in efforts to translate laboratory success into robust and economically feasible industrial-scale operations. We believe that PMRs willrealize theirtransformative potential in sustainable energy and environmental applications in future.

Environmental pollution caused by shipping has always received great attention from the international community. Currently due to the difficulty of fully electrifying medium- and large-scale ships the hybrid energy ship power system (HESPS) will be the main type in the future. Considering the economic and long-term energy efficiency of ships as well as the uncertainty of the output power of renewable energy units this paper proposes an improved design for an integrated power system for large cruise ships combining renewable energy and a hybrid energy storage system. An energy management strategy (EMS) based on time-gradient control and considering load dynamic response as well as an energy storage power allocation method that considers the characteristics of energy storage devices is designed. A bi-level power capacity optimization model grounded in comprehensive scenario planning and aiming to optimize maximum return on equity is constructed and resolved by utilizing an improved particle swarm optimization algorithm integrated with dynamic programming. Based on a large-scale cruise ship the aforementioned method was investigated and compared to the conventional planning approach. It demonstrates that the implementation of this optimization method can significantly decrease costs enhance revenue and increase the return on equity from 5.15% to 8.66%.

Thermo-chemical conversion of waste plastics offers a sustainable strategy for integrated waste management and clean energy generation. To address the challenges of low gas yield and rapid catalyst deactivation due to coking in conventional gasification processes an innovative three-stage chemical looping gasification (CLG) system specifically designed for enhanced hydrogen-rich syngas production was proposed in this work. A comparative analysis between conventional gasification and the staged CLG system were firstly conducted coupled with online gas analysis for mechanistic elucidation. The influence of Fe/Al molar ratios in oxygen carriers and their cyclic stability were systematically examined through multicycle experiments. Results showed that the three-stage CLG in the presence of Fe1Al2 demonstrated exceptional performance achieving 95.23 mmol/gplastic of H2 and 129.89 mmol/gplastic of syngas respectively representing 1.32-fold enhancement over conventional method. And the increased H2/CO ratio (2.68-2.75) reflected better syngas quality via water-gas shift. Remarkably the oxygen carrier maintained nearly 100% of its initial activity after 7 redox cycles attributed to the incorporation of Al2O3 effectively mitigating sintering and phase segregation through metal-support interactions. These findings establish a three-stage CLG configuration with Fe-Al oxygen carriers as an efficient platform for efficient hydrogen production from waste plastics contributing to sustainable waste valorisation and carbon-neutral energy systems.

Hydrogen-powered aircraft as a cutting-edge exploration of clean-energy air transportation have more stringent requirements for lightweight hydrogen storage equipment due to the limitations of aircraft weight and volume. Composite hydrogen storage cylinders have become one of the preferred solutions for hydrogen storage systems in hydrogen-powered aircraft due to their light weight and high strength. However during the automated placement of high-stiffness thermoplastic composites (T700/PEEK) fibers can buckle or fracture in the header section. As the header radius decreases the overlap of adjacent tows increases resulting in buildup in the thickness of the polar pores which contradicts the lightweight requirements. To solve this problem this paper derives the trajectory algorithm as a manufacturing process limitation when thermoplastic fiber bundles are laid without wrinkles and the effect of different ellipsoid ratios of head profile changes on the overlap of fiber bundles is investigated. The larger the ellipsoid ratio of the prolate ellipsoid is the smaller overlap of gaps generated by neighboring fiber bundles is and the overlap at the pole holes is also smaller whereas the change of the oblate ellipsoid is not significant. The prolate ellipsoid has more application and research value than the oblate ellipsoid in terms of processability which is of great exploration significance for the design and fabrication of thermoplastic composite hydrogen storage cylinders for hydrogen-powered aircraft.

To mitigate explosion hazards arising from hydrogen leakage and subsequent mixing with air the injection of inert gases can substantially diminish explosion risk. However prevailing research has predominantly characterized inert gas dilution effects on explosion behavior under quiescent conditions largely neglecting the turbulence-mediated explosion enhancement inherent to dynamic mixing scenarios. A comprehensive investigation was conducted on the combustion behavior of 30% 50% and 70% H2-air mixtures subjected to jet-induced (CO2 N2 He) turbulent flow incorporating quantitative characterization of both the evolving turbulent flow field and flame front dynamics. Research has demonstrated that both an increased H2 concentration and a higher jet medium molecular weight increase the turbulence intensity: the former reduces the mixture molecular weight to accelerate diffusion whereas the latter results in more pronounced disturbances from heavier molecules. In addition when CO2 serves as the jet medium a critical flame radius threshold emerges where the flame propagation velocity decreases below this threshold because CO2 dilution effects suppress combustion whereas exceeding it leads to enhanced propagation as initial disturbances become the dominant factor. Furthermore at reduced H2 concentrations (30–50%) flow disturbances induce flame front wrinkling while preserving the spherical geometry; conversely at 70% H2 substantial flame deformation occurs because of the inverse correlation between the laminar burning velocity and flame instability governing this transition. Through systematic quantitative analysis this study elucidates the evolutionary patterns of both turbulent fields and flame fronts offering groundbreaking perspectives on H2 combustion and explosion propagation in turbulent environments.

With the accelerating global transition to clean energy underground hydrogen storage (UHS) has gained significant attention as a flexible and renewable energy storage technology. Ontario Canada as a pioneer in energy transition offers substantial underground storage potential with its geological conditions of salt limestone and sandstone providing diverse options for hydrogen storage. However the hydrogen transport characteristics of different rock media significantly affect the feasibility and safety of energy storage projects warranting in-depth research. This study simulates the hydrogen flow and transport characteristics in typical energy storage digital rock core models (salt rock limestone and sandstone) from Ontario using the improved quartet structure generation set (I-QSGS) and the lattice Boltzmann method (LBM). The study systematically investigates the distribution of flow velocity fields directional characteristics and permeability differences covering the impact of hydraulic changes on storage capacity and the mesoscopic flow behavior of hydrogen in porous media. The results show that salt rock due to its dense structure has the lowest permeability and airtightness with extremely low hydrogen transport velocity that is minimally affected by pressure differences. The microfracture structure of limestone provides uneven transport pathways exhibiting moderate permeability and fracture-dominated transport characteristics. Sandstone with its higher porosity and good connectivity has a significantly higher transport rate compared to the other two media showing local high-velocity preferential flow paths. Directional analysis reveals that salt rock and sandstone exhibit significant anisotropy while limestone’s transport characteristics are more uniform. Based on these findings salt rock with its superior sealing ability demonstrates the best hydrogen storage performance while limestone and sandstone also exhibit potential for storage under specific conditions though further optimization and validation are required. This study provides a theoretical basis for site selection and operational parameter optimization for underground hydrogen storage in Ontario and offers valuable insights for energy storage projects in similar geological settings globally.

The maritime sector’s transition to sustainable energy is critical for achieving global carbon neutrality with container terminals representing a key focus due to their high energy consumption and emissions. This study explores the potential of hydrogen energy as a decarbonization solution for port operations using the Chuanshan Port Area of Ningbo Zhoushan Port (CPANZP) as a case study. Through a comprehensive analysis of hydrogen production storage refueling and consumption technologies we demonstrate the feasibility and benefits of integrating hydrogen systems into port infrastructure. Our findings highlight the successful deployment of a hybrid “wind-solar-hydrogen-storage” energy system at CPANZP which achieves 49.67% renewable energy contribution and an annual reduction of 22000 tons in carbon emissions. Key advancements include alkaline water electrolysis with 64.48% efficiency multi-tier hydrogen storage systems and fuel cell applications for vehicles and power generation. Despite these achievements challenges such as high production costs infrastructure scalability and data integration gaps persist. The study underscores the importance of policy support technological innovation and international collaboration to overcome these barriers and accelerate the adoption of hydrogen energy in ports worldwide. This research provides actionable insights for port operators and policymakers aiming to balance operational efficiency with sustainability goals.

In response to increasingly stringent emission regulations low-carbon fuels have received significant attention as sustainable energy sources for internal combustion engines. This study investigates four representative low-carbon fuels methane methanol hydrogen and ammonia by systematically summarizing their combustion characteristics and emission profiles along with a review of existing after-treatment technologies tailored to each fuel type. For methane engines unburned hydrocarbon (UHC) produced during lowtemperature combustion exhibits poor oxidation reactivity necessitating integration of oxidation strategies such as diesel oxidation catalyst (DOC) particulate oxidation catalyst (POC) ozone-assisted oxidation and zoned catalyst coatings to improve purification efficiency. Methanol combustion under low-temperature conditions tends to produce formaldehyde and other UHCs. Due to the lack of dedicated after-treatment systems pollutant control currently relies on general-purpose catalysts such as three-way catalyst (TWC) DOC and POC. Although hydrogen combustion is carbon-free its high combustion temperature often leads to elevated nitrogen oxide (NOx) emissions requiring a combination of optimized hydrogen supply strategies and selective catalytic reduction (SCR)-based denitrification systems. Similarly while ammonia offers carbon-free combustion and benefits from easier storage and transportation its practical application is hindered by several challenges including low ignitability high toxicity and notable NOx emissions compared to conventional fuels. Current exhaust treatment for ammonia-fueled engines primarily depends on SCR selective catalytic reduction-coated diesel particulate filter (SDPF). Emerging NOx purification technologies such as integrated NOx reduction via hydrogen or ammonia fuel utilization still face challenges of stability and narrow effective temperatures.

Energy management in hybrid fuel cell ship systems faces the dual challenges of optimizing hydrogen consumption and ensuring power quality. This study proposes an Improved Weighted Antlion Optimization (IW-ALO) algorithm for multi-objective problems. The method incorporates a dynamic weight adjustment mechanism and an elite-guided strategy which significantly enhance global search capability and convergence performance. By integrating IW-ALO with the Equivalent Consumption Minimization Strategy (ECMS) an improved weighted ECMS (IW-ECMS) is developed enabling real-time optimization of the equivalence factor and ensuring efficient energy sharing between the fuel cell and the lithium-ion battery. To validate the proposed strategy a system simulation model is established in Matlab/Simulink 2017b. Compared with the rule-based state machine control and optimization-based ECMS methods over a representative 300 s ferry operating cycle the IW-ECMS achieves a hydrogen consumption reduction of 43.4% and 42.6% respectively corresponding to a minimum total usage of 166.6 g under the specified load profile while maintaining real-time system responsiveness. These reductions reflect the scenario tested characterized by frequent load variations. Nonetheless the results highlight the potential of IW-ECMS to enhance the economic performance of ship power systems and offer a novel approach for multi-objective cooperative optimization in complex energy systems.

As the global demand for energy increases and the transition to renewable and clean sources accelerates microgrid (MG) has emerged as a promising solution. Hydrogen fuel cell vehicles (HFCVs) offer significant advantages over gasoline vehicles in terms of reducing carbon dioxide emissions. However the development of HFCVs is hindered by the substantial up-front costs of hydrogen refueling stations (HRSs) coupled with the high cost of hydrogen transportation and the limitations of the hydrogen supply chain. This research proposes a multimicrogrid (MMG) system that integrates hydrogen energy and utilizes it as the HRS for fuel vehicle refueling. An adaptive hydrogen energy management method is employed for fuel cell vehicles to optimize the coupling between the transportation network and the power system. An integrated transportation state assessment model is developed and a smart MMG system is deployed to receive information from the transportation network. Building on this foundation an adaptive hydrogen scheduling model is developed. HFCVs are influenced by the hydrogen price adjustments leading them to travel to different MGs for refueling which in turn regulates the unit output of the MMG system. The MMG system is then integrated with the IEEE 33 bus distribution system to analyze the daily load balance. This integrated approach results in reduced traffic congestion lower MG costs and optimized power distribution network load balance.

In order to study the flow blending and transporting process of hydrogen that injects into the natural gas pipelines a three-dimensional T-pipe blending model is established and the flow characteristics are investigated systematically by the large eddy simulation (LES). Firstly the mathematical formulation of hydrogen-methane blending process is provided and the LES method is introduced and validated by a benchmark gas blending model having experimental data. Subsequently the T-pipe blending model is presented and the effects of key parameters such as the velocity of main pipe hydrogen blending ratio diameter of hydrogen injection pipeline diameter of main pipe and operating pressure on the hydrogen-methane blending process are studied systematically. The results show that under certain conditions the gas mixture will be stratified downstream of the blending point with hydrogen at the top of the pipeline and methane at the bottom of the pipeline. For the no-stratified scenarios the distance required for uniformly mixing downstream the injection point increases when the hydrogen mixing ratio decreases the diameter of the hydrogen injection pipe and the main pipe increase. Finally based on the numerical results the underlying physics of the stratification phenomenon during the blending process are explored and an indicator for stratification is proposed using the ratio between the Reynolds numbers of the natural gas and hydrogen.

A proton exchange membrane electrolyzer can effectively utilize the electricity generated by intermittent solar power. Different methods of generating electricity may have different efficiencies and hydrogen production rates. Two coupled systems namely PV/T- and CPV/T-coupling PEMEC respectively are presented and compared in this study. A maximum power point tracking algorithm for the photovoltaic system is employed and simulations are conducted based on the solar irradiation intensity and ambient temperature of a specific location on a particular day. The simulation results indicate that the hydrogen production is relatively high between 11:00 and 16:00 with a peak between 12:00 and 13:00. The maximum hydrogen production rate is 99.11 g/s and 29.02 g/s for the CPV/T-PEM and PV/T-PEM systems. The maximum energy efficiency of hydrogen production in CPV/T-PEM and PV/T-PEM systems is 66.7% and 70.6%. Under conditions of high solar irradiation intensity and ambient temperature the system demonstrates higher total efficiency and greater hydrogen production. The CPV/T-PEM system achieves a maximum hydrogen production rate of 2240.41 kg/d with a standard coal saving rate of 15.5 tons/day and a CO2 reduction rate of 38.0 tons/day. Compared to the PV/T-PEM system the CPV/T-PEM system exhibits a higher hydrogen production rate. These findings provide valuable insights into the engineering application of photovoltaic/thermal-coupled hydrogen production technology and contribute to the advancement of this field.

To improve the recovery of waste heat and avoid the problem of abandoning wind and solar energy a multi-energy complementary distributed energy system (MECDES) is proposed integrating waste heat and surplus electricity for hydrogen storage. The system comprises a combined cooling heating and power (CCHP) system with a gas engine (GE) solar and wind power generation and miniaturized natural gas hydrogen production equipment (MNGHPE). In this novel system the GE’s waste heat is recycled as water vapor for hydrogen production in the waste heat boiler while surplus electricity from renewable sources powers the MNGHPE. A mathematical model was developed to simulate hydrogen production in three building types: offices hotels and hospitals. Simulation results demonstrate the system’s ability to store waste heat and surplus electricity as hydrogen thereby providing economic benefit energy savings and carbon reduction. Compared with traditional energy supply methods the integrated system achieves maximum energy savings and carbon emission reduction in office buildings with an annual primary energy reduction rate of 49.42–85.10% and an annual carbon emission reduction rate of 34.88–47.00%. The hydrogen production’s profit rate is approximately 70%. If the produced hydrogen is supplied to building through a hydrogen fuel cell the primary energy reduction rate is further decreased by 2.86–3.04% and the carbon emission reduction rate is further decreased by 12.67–14.26%. This research solves the problem of waste heat and surplus energy in MECDESs by the method of hydrogen storage and system integration. The economic benefits energy savings and carbon reduction effects of different building types and different energy allocation scenarios were compared as well as the profitability of hydrogen production and the factors affecting it. This has a positive technical guidance role for the practical application of MECDESs.

As a key link in the application of hydrogen energy hydrogen refueling stations are significant for their safe operation. This paper established a three-dimensional 1:1 model for a seaport hydrogen refueling station in Ningbo City. In this work the CFD software FLUENT was used to study the influence of leakage angles on the leakage of high-pressure hydrogen through a small hole. Considering the calculation accuracy and efficiency this paper adopted the pseudo-diameter model. When the obstacle was far from the leakage hole it had almost no obstructive effect on the jet's main body. Still it affected the hydrogen whose momentum in the outer layer of the jet has been significantly decayed. In this condition there would be more hydrogen in stagnation. Thus the volume of the flammable hydrogen cloud was hardly affected while there was a significant increase in the volume of the hazardous hydrogen cloud. When the obstacle was close to the leakage hole it directly affected the jet's main body. Therefore the volume of the flammable hydrogen cloud increased. However the air impeded the hydrogen jet relatively less because the hydrogen jet contacted the obstacle more quickly. The hydrogen jet blocked by the obstacle still has some momentum. Therefore there was no more hydrogen in stagnation and no significant increase in the volume of the hazardous hydrogen cloud.

To reduce carbon dioxide emissions from the steel industry efforts are made to introduce a steelmaking route based on hydrogen reduction of iron ore instead of the commonly used cokebased reduction in a blast furnace. Changing fundamental pieces of steelworks affects the functions of most every system unit involved and thus warrants the question of how such a transition could optimally take place over time and no rigorous attempts have until now been made to tackle this problem mathematically. This article presents a steel plant optimization model written as a mixed-integer non-linear programming problem where aging blast furnaces and basic oxygen furnaces could potentially be replaced with shaft furnaces and electric arc furnaces minimizing costs or emissions over a long-term time horizon to identify possible transition pathways. Example cases show how various parameters affect optimal investment pathways stressing the necessity of appropriate planning tools for analyzing diverse cases.

Carbon capture utilization and storage (CCUS) technology plays a pivotal role in China’s “Carbon Peak” and “Carbon Neutrality” goals. This approach offers low-carbon zero-carbon and even negative-carbon solutions. This paper employs bibliometric analysis using the Web of Science to comprehensively review global CCUS progress and discuss future development prospects in China. The findings underscore it as a prominent research focus attracting scholars from both domestic and international arenas. China notably leads the global landscape in terms of research paper output with the Chinese Academy of Sciences holding a prominent position in total published papers. The research predominantly centers on refining geological storage techniques and optimizing oil and gas recovery rates. Among the CCUS pathways enhanced oil recovery technology stands out due to its relative maturity and commercial applicability particularly within the conventional oil and gas reservoirs. The application potential of enhanced gas recovery technology especially in the Sichuan and Ordos Basins in China necessitates robust research and demonstration efforts. Within China’s current energy landscape “Blue Hydrogen” emerges as the primary solution for hydrogen production in conjunction with CCUS technology. The underground coal gasification approach holds significant promise as a hydrogen production avenue albeit with inherent ecological and environmental challenges tied to geological storage that require meticulous consideration. The establishment of effective risk identification and evaluation methodologies for geological storage is imperative. The trajectory ahead involves a strategic convergence of policy technology and market dynamics to enhance China’s CCUS policy framework legislative framework standardization initiatives and pioneering technological advancements. These collective efforts converge to outline an exclusive development pathway in China. This study assumes a pivotal role in accelerating CCUS technology research and deployment enhancing oil and gas recovery efficiency and ultimately realizing the overarching goals of a “Dual Carbon” future.

In order to realize carbon mitigation and the efficient utilization of waste biogas the biogas-to-methanol process is an important method. The syngas produced by the conventional biogas reforming technology is rich in CO2 and CO whereas it is poor in hydrogen. Therefore additional H2 is introduced into the system to adjusted the syngas ratio promoting the efficient conversion of the biogas. However the use of traditional H2 production technologies generally results in considerable carbon emissions. Given these points low-carbon H2 production technologies namely methane pyrolysis technology and chemical looping reforming technology are integrated with the biogas-to-methanol process to enhance carbon conversion carbon reduction and cost-saving potentials. Comprehensive technical and economic comparisons of the integrated processes are conducted. The process coupled with chemical looping reforming technology has a higher carbon conversion efficiency (73.52%) and energy efficiency (70.41%) and lower unit carbon emissions (0.73 t CO2/t methanol). Additionally the process coupled with methane pyrolysis technology has higher product revenue whereas that including chemical looping reforming technology has a lower net production cost (571.33 USD/t methanol). In summary the novel chemical looping reforming technology provides a cleaner and more sustainable pathway with which to promote the efficient conversion of biogas into methanol.

The yield of photovoltaic hydrogen production systems is influenced by a number of factors including weather conditions the cleanliness of photovoltaic modules and operational efficiency. Temporal variations in weather conditions have been shown to significantly impact the output of photovoltaic systems thereby influencing hydrogen production. To address the inaccuracies in hydrogen production capacity predictions due to weather-related temporal variations in different regions this study develops a method for predicting photovoltaic hydrogen production capacity using the long short-term memory (LSTM) neural network model. The proposed method integrates meteorological parameters including temperature wind speed precipitation and humidity into a neural network model to estimate the daily solar radiation intensity. This approach is then integrated with a photovoltaic hydrogen production prediction model to estimate the region’s hydrogen production capacity. To validate the accuracy and feasibility of this method meteorological data from Lanzhou China from 2013 to 2022 were used to train the model and test its performance. The results show that the predicted hydrogen production agrees well with the actual values with a low mean absolute percentage error (MAPE) and a high coefficient of determination (R2 ). The predicted hydrogen production in winter has a MAPE of 0.55% and an R2 of 0.985 while the predicted hydrogen production in summer has a slightly higher MAPE of 0.61% and a lower R2 of 0.968 due to higher irradiance levels and weather fluctuations. The present model captures long-term dependencies in the time series data significantly improving prediction accuracy compared to conventional methods. This approach offers a cost-effective and practical solution for predicting photovoltaic hydrogen production demonstrating significant potential for the optimization of the operation of photovoltaic hydrogen production systems in diverse environments.

This paper presents a quantitative study on electric-thermal collaborative system for hydrogen-powered train reutilising the waste heat from fuel cell system for Heating Ventilation and Air Conditioning (HVAC). Firstly a hybrid train simulator is developed to simulate the train’s motion state. Heat generation from fuel cell is estimated using a fuel cell model while a detailed thermodynamic model for railway passenger coach is established to predict the heat demand. Furthermore an electric-thermal collaborative energy management strategy (ETCEMS) is proposed for the system to comprehensively optimise the on-train power distribution considering traction and auxiliary power. Finally comparative analysis is performed among the train with electric heater (EH) heat pump (HP) and heat pump-heat reuse (HP-HR). The results demonstrate that over a round trip the proposed HP-HR with ETC-EMS recovers over 22.88% residual heat and saves 16.17% of hydrogen consumption. For the daily operation it reduces hydrogen and energy consumption by 12.06% and 12.82 % respectively. The findings indicate that collaborative optimisation brings significant improvements on the global energy utilisation. The proposed design with ETC-EMS is potential to further enhance the economic viability of hydrail and contributes to the rail decarbonisation.

Pilot-diesel-ignition ammonia combustion engines have attracted widespread attentions from the maritime sector but there are still bottleneck problems such as high unburned NH3 and N2O emissions as well as low thermal efficiency that need to be solved before further applications. In this study a concept termed as in-cylinder reforming gas recirculation is initiated to simultaneously improve the thermal efficiency and reduce the unburned NH3 NOx N2O and greenhouse gas emissions of pilot-diesel-ignition ammonia combustion engine. For this concept one cylinder of the multi-cylinder engine operates rich of stoichiometric and the excess ammonia in the cylinder is partially decomposed into hydrogen then the exhaust of this dedicated reforming cylinder is recirculated into the other cylinders and therefore the advantages of hydrogen-enriched combustion and exhaust gas recirculation can be combined. The results show that at 3% diesel energetic ratio and 1000 rpm the engine can increase the indicated thermal efficiency by 15.8% and reduce the unburned NH3 by 89.3% N2O by 91.2% compared to the base/traditional ammonia engine without the proposed method. At the same time it is able to reduce carbon footprint by 97.0% and greenhouse gases by 94.0% compared to the traditional pure diesel mode.

Hydrogen holds an important strategic position in the energy systems of many countries. Many studies have analyzed the acceptance of hydrogen energy technology from the public’s perspective but few have examined it from the corporate perspective. This paper establishes a technology acceptance model and employs structural equation modeling to investigate the factors affecting the acceptance of hydrogen energy technology within enterprises. After conducting questionnaire surveys among employees of energy enterprises electric power companies and new energy vehicle manufacturers the results indicate that while most of the interviewed enterprises have positive attitudes towards hydrogen technology their willingness to develop hydrogen business does not appear to be correspondingly positive. In addition government trust perceived benefit and social influence positively impact corporate acceptability indirectly whereas perceived risk exhibits a negative indirect effect on corporate acceptance. Finally this paper discusses the results of the above studies and makes corresponding policy recommendations.

Accidental hydrogen releases from pipelines pose significant risks particularly with the expanding deployment of hydrogen infrastructure. Despite this there has been a lack of thorough investigation into hydrogen leakage from pipelines especially under complex real-world conditions. This study addresses this gap by modeling hydrogen gas dispersion jet fires and explosions based on practical scenarios. Various factors influencing accident consequences such as leak hole size wind speed wind direction and trench presence were systematically examined. The findings reveal that both hydrogen dispersion distance and jet flame thermal radiation distance increase with leak hole size and wind speed. Specifically the longest dispersion and radiation distances occur when the wind direction aligns with the trench which is 110 m where the hydrogen concentration is 4% and 76 m where the radiation is 15.8 kW/m2 in the case of a 325 mm leak hole and wind under 10 m/s. Meanwhile pipelines lacking trenching exhibit the shortest distances 0.17 m and 0.98 m at a hydrogen concentration of 4% and 15.8 kW/m2 radiation with a leak hole size of 3.25 mm and no wind. Moreover under relatively higher wind speeds hydrogen concentration stratification occurs. Notably the low congestion surrounding the pipeline results in an explosion overpressure too low to cause damage; namely the highest overpressure is 8 kPa but this lasts less than 0.2 s. This comprehensive numerical study of hydrogen pipeline leakage offers valuable quantitative insights serving as a vital reference for facility siting and design considerations to eliminate the risk of fire incidents.

To address the issue of imbalanced electricity and hydrogen supply and demand in the flexible multi-energy port area system a multi-regional operational optimization and energy storage capacity allocation strategy considering the working status of flexible multi-status switches is proposed. Firstly based on the characteristics of the port area system models for system operating costs generation equipment energy storage devices flexible multi-status switches and others are established. Secondly the system is subjected to a first-stage optimization where different regions are optimized individually. The working periods of flexible multi-status switches are determined based on the results of this first-stage optimization targeting the minimization of the overall daily operating costs while ensuring 100% integration of renewable energy in periods with electricity supply-demand imbalances. Subsequently additional constraints are imposed based on the results of the first-stage optimization to optimize the entire system obtaining power allocation during system operation as well as power and capacity requirements for energy storage devices and flexible multi-status switches. Finally the proposed approach is validated through simulation examples demonstrating its advantages in terms of economic efficiency reduced power and capacity requirements for energy storage devices and carbon reduction.

Thanks to the advantages of cleanliness high efficiency extensive sources and renewable energy hydrogen energy has gradually become the focus of energy development in the world’s major economies. At present the natural gas transportation pipeline network is relatively complete while hydrogen transportation technology faces many challenges such as the lack of technical specifications high safety risks and high investment costs which are the key factors that hinder the development of hydrogen pipeline transportation. This paper provides a comprehensive overview and summary of the current status and development prospects of pure hydrogen and hydrogen-mixed natural gas pipeline transportation. Analysts believe that basic studies and case studies for hydrogen infrastructure transformation and system optimization have received extensive attention and related technical studies are mainly focused on pipeline transportation processes pipe evaluation and safe operation guarantees. There are still technical challenges in hydrogen-mixed natural gas pipelines in terms of the doping ratio and hydrogen separation and purification. To promote the industrial application of hydrogen energy it is necessary to develop more efficient low-cost and low-energy-consumption hydrogen storage materials.

Currently the global energy structure is undergoing a transition from fossil fuels to renewable energy sources with the hydrogen economy playing a pivotal role. Hydrogen is not only an important energy carrier needed to achieve the global goal of energy conservation and emission reduction it represents a key object of the future international energy trade. As hydrogen trade expands nations are increasingly allocating resources to enhance the international competitiveness of their respective hydrogen industries. This paper introduces an index that can be used to evaluate international hydrogen competitiveness and elucidate the most competitive countries in the hydrogen trade. To calculate the competitiveness scores of seven major prospective hydrogen market participants we employed the entropy weight method. This method considers five essential factors: potential resources economic and financial base infrastructure government support and institutional environment and technological feasibility. The results indicate that the USA and Australia exhibit the highest composite indices. These findings can serve as a guide for countries in formulating suitable policies and strategies to bolster the development and international competitiveness of their respective hydrogen industries.

Proton exchange membrane (PEM) based electrochemical systems have the capability to operate in fuel cell (PEMFC) and water electrolyser (PEMWE) modes enabling efficient hydrogen energy utilisation and green hydrogen production. In addition to the essential cell stacks the system of PEMFC or PEMWE consists of four sub-systems for managing gas supply power thermal and water respectively. Due to the system’s complexity even a small fluctuation in a certain sub-system can result in an unexpected response leading to a reduced performance and stability. To improve the system’s robustness and responsiveness considerable efforts have been dedicated to developing advanced control strategies. This paper comprehensively reviews various control strategies proposed in literature revealing that traditional control methods are widely employed in PEMFC and PEMWE due to their simplicity yet they suffer from limitations in accuracy. Conversely advanced control methods offer high accuracy but are hindered by poor dynamic performance. This paper highlights the recent advancements in control strategies incorporating machine learning algorithms. Additionally the paper provides a perspective on the future development of control strategies suggesting that hybrid control methods should be used for future research to leverage the strength of both sides. Notably it emphasises the role of artificial intelligence (AI) in advancing control strategies demonstrating its significant potential in facilitating the transition from automation to autonomy.

The aim of this paper is the design and implementation of an advanced model predictive control (MPC) strategy for the management of a wind–solar microgrid (MG) both in the islanded and grid-connected modes. The MG includes energy storage systems (ESSs) and interacts with external hydrogen and electricity consumers as an extra feature. The system participates in two different electricity markets i.e. the daily and real-time markets characterized by different time-scales. Thus a high-layer control (HLC) and a low-layer control (LLC) are developed for the daily market and the real-time market respectively. The sporadic characteristics of renewable energy sources and the variations in load demand are also briefly discussed by proposing a controller based on the stochastic MPC approach. Numerical simulations with real wind and solar generation profiles and spot prices show that the proposed controller optimally manages the ESSs even when there is a deviation between the predicted scenario determined at the HLC and the real-time one managed by the LLC. Finally the strategy is tested on a lab-scale MG set up at Khalifa University Abu Dhabi UAE.