Publications

Hydrogen is widely considered advantageous for long-duration storage applications however the conditions under which hydrogen outperforms batteries remain unclear. This study employs a novel load parameterisation approach to systematically examine the conditions under which integrating hydrogen significantly reduces the levelised cost of energy (LCOE). The study analyses a broad spectrum of 210 synthetic load profiles varying independently in duration frequency and timing at two Australian locations. This reveals that batteries dominate short frequent or wellaligned solar loads and that hydrogen becomes economically beneficial during prolonged infrequent or poorly aligned loads—achieving up to 122 % (Gladstone) and 97 % (Geelong) LCOE improvements under current fuel cell costs and even higher savings under reduced costs. This systematic method clarifies the load characteristics thresholds that define hydrogen’s advantage providing generalisable insights beyond individual case studies.

Hydrogen is being increasingly integrated into the international trade system as a clean and flexible energy carrier motivated by the global energy transition and carbon neutrality objectives. The rapid expansion of the global hydrogen trade network has simultaneously exposed several sustainability challenges including a centralized structure overdependence on key countries and limited resilience to external disruptions. Based on this we develop a risk propagation model that incorporates the absorption capacity of nodes to simulate the propagation of supply shortage risks within the global hydrogen trade network. Furthermore we propose a composite sustainability index constructed from structural economic and environmental resilience indicators enabling a systematic assessment of the network’s sustainable development capacity under external shock scenarios. Findings indicate the following: (1) The global hydrogen trade network is undergoing a structural shift from a Western Europe-dominated unipolar configuration to a more polycentric pattern. Countries such as China and Singapore are emerging as key hubs linking Eurasian regions with trade relationships among nations becoming increasingly dense and diversified. (2) Although supply shortage shocks trigger structural disturbances economic losses and risks of carbon rebound their impacts are largely concentrated in a limited number of hub countries with relatively limited disruption to the overall sustainability of the system. (3) Countries exhibit significant heterogeneity in structural economic and environmental resilience. Risk propagation demonstrates an uneven pattern characterized by hub-induced disruptions chain-like transmission and localized clustering. Accordingly policy recommendations are proposed including the establishment of a polycentric coordination mechanism the enhancement of regional emergency coordination mechanisms and the advancement of differentiated capacity-building efforts.

This study introduces a novel hydrogen production system using the three-step copper chlorine (Cu-Cl) cycle. The proposed thermochemical cycle offers an innovative configuration that performs hydrogen production without an electrolysis step eliminating high-cost components such as membranes catalysts and electricity. The Cu-Cl cycle enables large-scale hydrogen production and is examined in various configurations including two- three- four- and five-step Cu-Cl cycles. Microscale experimental studies are conducted on a novel three-step Cu-Cl thermochemical cycle that works entirely on thermal energy input without electrolysis. In experimental studies some parameters that directly affect the amount of hydrogen production are investigated. The effects of parameters such as temperature steam/copper (S/C) ratio and reaction time on hydrogen production in the hydrolysis step are evaluated. The investigation also examined the impact of increasing temperature in the hydrolysis reaction on the generation of undesirable byproducts. Additionally the effect of increased temperatures in the decomposition process on oxygen formation is examined. In the optimization studies the individual and interactive effects of the parameters are analyzed using the Response Surface Methodology (RSM) and BoxBehnken Design (BBD) of experimental methods. The results of this study further show that the conditions with the highest hydrogen production are a S/C ratio of 55 a temperature of 400 ◦C and a reaction time between 30 and 40 min. It is also observed that hydrogen concentration increases with the increase in temperature and time and that the maximum level of 134.8 ppm is reached under optimum conditions.

Growing energy demands and increasing concerns about climate change have spurred new approaches in both policy and industry with a focus on transforming current energy systems in modern energy hubs. In this context green hydrogen produced through electrolysis process powered by renewable energy sources emerges as a highly versatile and promising solution for decarbonising sectors and provide alternative fuels for process and transportation. This study models and simulates an integrated system comprising desalination brine treatment and electrolysis to generate green hydrogen fuelled entirely by solar energy. The desalination unit produces demineralised water suitable for electrolysis while alternative brine management strategies are explored for scenarios where brine discharge back to the sea is restricted. An economic analysis further evaluates cost-effective system configurations by varying component sizes. To demonstrate the model potential a case study for green hydrogen production based on seawater desalination was conducted for an Italian port city and extended to three other sites with different annual solar radiation. The objective is to determine configurations that minimise hydrogen cost and identify required incentives. The economic performance of the system in terms of the Levelized Cost of Hydrogen ranges from 5 to 8 €/kg while the required incentives to make green hydrogen competitive with blue hydrogen production systems vary between 7 and 12 M€ across the analysed configurations. Furthermore the analysis provides valuable insights into the potential of coastal areas to serve as critical hubs for green hydrogen production given the abundant availability of seawater. Ports with their existing infrastructure and proximity to maritime transport represent ideal locations for integrating renewable energy sources with hydrogen production facilities.

The combustion of liquid fossil fuels in the transportation sector disposal and incineration of municipal solid waste (MSW) are the main sources of greenhouse gas emissions in cities across the world. In an effort to decarbonize the transportation sector the South African government is dedicated to advancing green trans portation through the hydrogen economy. Waste-to-hydrogen production can simultaneously achieve the goals of green transportation and waste management through widespread availability of hydrogen refuelling stations. This study assesses the techno-economic and environmental viability of waste-to-hydrogen refuelling stations in five selected South Africa cities. The refuelling stations’ capacity was determined based on assumption that a 5 kg hydrogen-fuel-cell vehicle is refuelled per day. The economic feasibility was premised on net present value (NPV) payback period (PBP) internal rate of return (IRR) and levelized cost of hydrogen refuelling (LCOHr). The environmental analysis was based on ecological efficiency and carbon emission reduction potential. Some of the main findings indicate that the City of Tshwane and City of Johannesburg have refuelling station capacities of 356 thousand kg/day H2 and 395 thousand kg/day H2 respectively. Economically the project is viable with positive NPV between 1.099 and 8.0563 Billion $ LCOHr in the range of 3.99 $/kg - 5.63 $/kg PBP of 9.03–13.74 years and IRR of 18.16 %–39.88 %. An ecological efficiency of 99.982 % was obtained which in dicates an environmentally friendly system with the potential to save 1439 million litres and 1563 million litres of diesel fuel and gasoline respectively capable of preventing about 4 kilo-tons of CO2 into the atmosphere annually. Sensitivity analysis indicates that reforming efficiency selling price of hydrogen and station capacity are crucial parameters with great influence on the economic profitability of waste-to-hydrogen refuelling station.

To combat global warming the decarbonisation of energy systems is essential. Hydrogen (H2) is an established chemical feedstock in many industries (fertiliser production steel manufacturing etc.) and has emerged as a promising clean energy carrier due to its high energy density and carbon-free usage. However most H2 is currently produced from fossil fuels undermining its sustainability. Biomass offers a renewable carbon-neutral feedstock for H2 production potentially reducing its environmental impact. This review examines thermochemical biological and electrochemical methods of bio-H2 generation. Thermochemical processes - including gasification fast pyrolysis and steam reforming - are the most technologically advanced offering high H2 yields. However challenges such as catalyst deactivation tar formation and pre- and post-processing limit efficiency. Advanced strategies like chemical looping sorption enhancement and membrane reactors are being developed to address these issues. Biological methods including dark and photo fermentation operate under mild conditions and can process diverse waste feedstocks. Despite their potential low H2 yields and difficulties in microbial inhibitors hinder scalability. Ensuring that microbial populations remain stable through the use of additives and optimising the bioreactors hydraulic retention rate also remain a challenge Combined fermentation systems and valorising byproducts could enhance performance and commercial viability. Electrochemical reforming of biomass-derived compounds is an emerging method that may enhance water electrolysis by co-producing value-added by-products. However current studies focus on biomass-derived compounds rather than complex biomass feedstocks limiting commercial relevance. Future research should focus on feedstock complexity electrocatalyst development and system scaling. A technology readiness comparison shows that thermochemical methods are the most commercially mature followed by biological and electrochemical approaches. Each method holds promise within specific niches warranting continued innovation and interdisciplinary development.

The increase in power generation facilities from nonprogrammable renewable sources is posing several challenges for the management of electrical systems due to phenomena such as congestion and reverse power flows. In mitigating these phenomena Power-to-Gas plants can make an important contribution. In this paper a linear optimisation study is presented for the sizing of a Power-to-Hydrogen plant consisting of a PEM electrolyser a hydrogen storage system composed of multiple compressed hydrogen tanks and a fuel cell for the eventual reconversion of hydrogen to electricity. The plant was sized with the objective of minimising reverse power flows in a medium-voltage distribution network characterised by a high presence of photovoltaic systems considering economic aspects such as investment costs and the revenue obtainable from the sale of hydrogen and excess energy generated by the photovoltaic systems. The study also assessed the impact that the electrolysis plant has on the power grid in terms of power losses. The results obtained showed that by installing a 737 kW electrolyser the annual reverse power flows are reduced by 81.61% while also reducing losses in the transformer and feeders supplying the ring network in question by 17.32% and 29.25% respectively on the day with the highest reverse power flows.

To address the issue of excessive pessimism caused by demand and supply uncertainties in the green hydrogen supply chain this study develops a two-tier green hydrogen supply chain model comprising upstream hydrogen production stations and downstream hydrogen refueling stations. This research work investigates optimal ordering and production strategies under stochastic demand and supply conditions. Additionally option contracts are introduced to share the risks associated with the stochastic output of green hydrogen. This study shows the following: (1) Under decentralized decision-making the optimal ordering quantity when the hydrogen refueling station is excessively pessimistic is not necessarily lower than the optimal ordering quantity when it is in a rational state and hydrogen production stations will only operate when the degree of excessive pessimism is relatively low. (2) The initial option ordering quantity is always larger than the minimum execution quantity under the option contract; higher first-order option prices and lower second-order option prices can help to increase the initial option ordering quantity. (3) The option contract is effective in circumventing the negative impact of excessive pessimism at hydrogen production stations on planned production quantities. This study addresses the gap in the existing research regarding excessively pessimistic behaviors and the application of option contracts within the green hydrogen supply chain providing both theoretical insights and practical guidance for decision-making optimization. This advancement further promotes the sustainable development of the green hydrogen industry.

The global transition towards clean energy sources is becoming essential to reduce reliance on conventional fuels and mitigate carbon emissions. In the future the clean energy storage landscape green hydrogen and green ammonia (powered by renewable energy sources) are emerging as key players. This study explores the prospectives and feasibility of producing and storing offshore green hydrogen and green ammonia. The potential power output of Hornsea one and Hornsea two winds farms in the United Kingdom was calculated using real wind data. The usable electricity from the Hornsea one wind farm was 5.83 TWh/year and from the Hornsea two wind farm it was 6.44 TWh/year harnessed to three different scenarios for the production and storage of green ammonia and green hydrogen. Scenario 1 fulfil the requirement of green hydrogen storage for flexible ammonia production but consumes more energy for green hydrogen compression. Scenario 2 does not offer any hydrogen storage which is not favourable in terms of flexibility and market demand. Scenario 3 offers both a direct routed supply of produced hydrogen for green ammonia synthesis and a storage facility for green hydrogen storage. Detailed mathematical calculations and sensitivity analysis was performed based on the total energy available to find out the energy storage capacity in terms of the mass of green hydrogen and green ammonia produced. Sensitivity analysis in the case of scenario 3 was conducted to determine the optimal percentage of green hydrogen going to the storage facility. Based on the cost evaluation of three different presented scenarios the levelized cost of hydrogen (LCOH) is between USD 5.30 and 5.97/kg and the levelized cost of ammonia (LCOA) is between USD 984.16 and USD 1197.11/tonne. These prices are lower compared to the current UK market. The study finds scenario 3 as the most appropriate way in terms of compression energy savings flexibility for the production and storage capacity that depends upon the supply and demand of these green fuels in the market and a feasible amount of green hydrogen storage.

This research aims to determine the position and the breakthrough trajectory of sustainable energy technologies. Fine-grained insights into these breakthrough positions and trajectories are limited. This research seeks to fill this gap by analyzing sustainable energy technologies’ breakthrough positions and trajectories in terms of development application and upscaling. To this end the breakthrough positions and trajectories of seven sustainable energy technologies i.e. hydrogen from seawater electrolysis hydrogen airplanes inland floating photovoltaics redox flow batteries hydrogen energy for grid balancing hydrogen fuel cell electric vehicles and smart sustainable energy houses are analyzed. This is guided by an extensively researched and literature-based model that visualizes and describes these technologies’ experimentation and demonstration stages. This research identifies where these technologies are located in their breakthrough trajectory in terms of the development phase (prototyping production process and organization and niche market creation and sales) experiment and demonstration stage (technical organizational and market) the form of collaboration (public–private private–public and private) physical location (university and company laboratories production sites and marketplaces) and scale-up type (demonstrative and first-order and second-order transformative). For scientists this research offers the opportunity to further refine the features of sustainable energy technologies’ developmental positions and trajectories at a detailed level. For practitioners it provides insights that help to determine investments in various sustainable energy technologies.

The integration of hydrogen technologies is widely regarded as a transformative step in the energy transition. Recently the German government unveiled a Power Plant Strategy to promote H2-Ready Combined-Cycle Gas Turbines (H2-CCGT) which are intended to initially run on natural gas and transition to green hydrogen by 2040 at the latest. This study assesses the role of H2-Ready power plants in a low-carbon transition and explores plausible pathways using a capacity expansion model for Germany. This topic is particularly relevant for other countries aiming to deploy a large share of renewables and considering H2-CCGT as a flexible backup solution to ensure system flexibility and achieve deep decarbonization. Our results indicate that H2-CCGT enhance system flexibility and significantly alleviate the investments need for additional flexibility and renewable generation capacity and reduce renewable-energy curtailment by more than 35 %. Moreover our results also demonstrate that allowing hydrogen in CCGT does not entirely reduce the need for fossil fueled power plants as hydrogen becomes economically viable only with deep decarbonization or direct subsidies. We show that policy interventions can alter the transition pathways for achieving a decarbonized energy system. Our research challenges a prevailing narrative that financial support for hydrogen is needed to ensure a cost-efficient system decarbonization. More straightforward market-based policy instruments such as intensified CO2 pricing or regulatory frameworks such as earlier mandatory hydrogen shifts in H2-CCGT prove more efficient at cutting emissions and costs.

Hydrogen is a pivotal driver of the green economy and clean energy transition and global efforts are underway to scale up hydrogen technology and its adoption. This study explores China’s hydrogen fuel cell vehicle (HFCV) city clusters policy launched in 2021 involving five clusters consisting of 44 cities to boost the country’s hydrogen economy. Drawing on cluster theory collaborative network literature and evolutionary economic geography we investigate the connections between hydrogen city clusters and historical geographically based and industrial-based clusters as well as the formation of collaborative networks among cities. By comparing these heterogeneous city networks our findings highlight the competitive edge of HFCV city clusters that capitalize on resource and innovation complementarity instead of relying solely on geographical positioning or pre-existing collaborations. The results of the Exponential Random Graph Analysis reveal that existing clusters economic strength of cities and their strategic positions within the hydrogen industrial chain significantly shape collaborative networks. This study contributes to cluster policy research by examining how China’s HFCV city clusters integrate historical advantages while fostering synergies with less connected cities offering valuable insights into inter-city collaboration and strategies for sustainable industrial development.

Hydrogen is a zero-carbon energy carrier with potential to decarbonize industrial and transportation sectors but its life-cycle greenhouse gas (GHG) emissions depend on its energy supply chain and carbon management measures (e.g. carbon capture and storage). Global support for clean hydrogen production and use has recently intensified. In the United States Congress passed several laws that incentivize the production and use of renewable and low-carbon hydrogen such as the Bipartisan Infrastructure Law (BIL) in 2021 and the Inflation Reduction Act (IRA) in 2022 which provides tax credits of up to $3/kg depending on the carbon intensity of the produced hydrogen. A comprehensive life-cycle accounting of GHG emissions associated with hydrogen production is needed to determine the carbon intensity of hydrogen throughout its value chain. In the United States Argonne’s R&D GREET® (Greenhouse Gases Regulated emissions and Energy use in Technologies) model has been widely used for hydrogen carbon intensity calculations. This paper describes the major hydrogen technology pathways considered in the United States and provides data sources and carbon intensity results for each of the hydrogen production and delivery pathways using consistent system boundaries and most recent technology performance and supply chain data.

The transition from fossil-based fuel to hydrogen combustion in steel reheating furnaces is a possible way to decrease the process-originated CO2 emissions significantly. This potential change alters the furnace gas atmo sphere’s composition impacting the oxide scale formation of the slab surface. Dynamic heating tests are per formed for three low-carbon steels using different simulated combustion atmospheres including natural gas coke oven gas and hydrogen combustion in air and hydrogen combustion in oxygen. Significant differences are found in the oxidation behavior of steel grades in the simulated hydrogen reheating scenario. A steel grade with low Mn content only has an 18% increase in oxidation between methane-air to hydrogen-oxygen methods while it is 41% for a high Mn and Si steel grade and 65% for a high-Mn steel grade. Thus in terms of material loss increase by oxidation the transition of the heating method causes the least problems for the low-Mn steel grade.

The report addresses the environmental challenges faced by European sea ports and aims to provide guidance to smaller ports for improving their environmental performance while achieving sustainability goals through experiences gained by implementing noteworthy green initiatives in practice. Larger ports possess significant advantages in terms of financial resources risk tolerance and organisational capacity. They often have the means to invest in innovative solutions and actively participate in research and development projects leading to co-funded pilot implementation of green initiatives. They typically have more skilled personnel stronger influence and stakeholder leverage which position them better to lead the way in sustainability efforts. Finally larger ports often form robust collaborations to drive collective action towards sustainable goals. Smaller ports face unique challenges stemming from typically limited resources and risk aversion. They often prioritise mature solutions relying on tested practices to mitigate potential risks. They may lack internal expertise requiring guidance and capacity-building programmes to navigate the selection and implementation of green practices. Also they require financial and technical support particularly as they may underutilise available funding mechanisms and have limited participation in R&D programmes. They may benefit from partnerships with other ports and stakeholders to create synergies and gain experience from their lessons learned to boost their capacity to implement green practices

The integration of electrolyzers into modern power systems is a critical step toward sustainable hydrogen production. However their dynamic power consumption and stringent operational constraints present considerable challenges. This article proposes a comprehensive multiphysics model of an alkaline electrolyzer emphasizing its interaction with a power electronic converter to ensure efficient and reliable power delivery. The study incorporates electrochemical principles to develop mathematical models that accurately represent the alkaline electrolyzer’s electrical behavior and dynamic response. A single-stage active front-end (AFE) rectifier based on SiC MOSFETs is employed as the power electronic interface offering improved energy efficiency enhanced system stability and reduced power quality issues compared to conventional approaches. Experimental results validate the performance of the proposed alkaline electrolyzer and converter models highlighting the potential for effective integration of alkaline electrolyzers into converter-based systems within renewable energy environments.

Ammonia (NH₃) presents a comprehensive energy storage solution for future energy demands. Its synthesis plays a pivotal role in the chemical industry acting as a fundamental precursor for fertilizers explosives and a wide range of industrial applications. In recent years there has been a growing interest in exploring novel catalyst materials to enhance the efficiency selectivity and sustainability of NH3 production technologies. Among these materials perovskite-based catalysts have emerged as promising candidates due to their unique properties. This review article aims to provide a sharp and short understanding of the role of perovskite-based catalysts in emerging NH3 production technologies and to stimulate further research and innovation in this rapidly evolving field. It provides an overview of recent advances in the synthesis and characterisation of perovskite-based cat alysts for NH3 production in terms of structural properties and catalytic performance of perovskite catalysts in NH3 synthesis. The review also discusses the underlying mechanisms involved in NH3 production on perovskite surfaces highlighting the role of surface chemistry and electronic structure. Furthermore the review examines the potential applications and prospects of perovskite-based catalysts in NH3 production technologies. It explores opportunities for integrating perovskite catalysts into existing NH3 synthesis processes as well as the develop ment of process configurations to maximise the efficiency and sustainability of NH3 production.

The availability of conventional fuels such as gasoline and methane which are used in spark-ignition (SI) engines is increasingly limited by the finite nature of fossil fuel reserves. The inefficiencies in combustion are associated with reduced engine effectiveness as incomplete combustion heightens the emissions of harmful pollutants including CO2 and CO while also negatively impacting fuel economy. The objective of this research is to undertake a comparative study of engine performance and emissions for a selection of conventional fuels and hydrogen while considering varying equivalence ratios and operational speeds. To accomplish this an extensive 3-dimensional numerical simulation was carried out using CONVERGE 3.0 simulation software to model a portfueled SI engine with the SI8 Engine Premix SAGE model facilitating the simulations. The performance metrics assessed in this research include cylinder pressure specific heat ratio heat rate thermal efficiency and mean temperature. The emission characteristics are analyzed in cases of NOx CO CO2 and HC emissions. The simulation results are obtained by varying the equivalence ratios of hydrogen (0.4 0.6 and 0.9) at different engine speeds (2000 2500 and 3000 rpm). The engine setup mesh creation boundary conditions turbulence combustion and species transport models were meticulously outlined to ensure accurate simulation results. Hydrogen fuel when operated at an equivalence ratio of 0.4 and an engine speed of 3000 rpm showcases the best overall performance among all tested conditions. It achieves the highest thermal efficiency of 40.94% optimal cylinder pressure and specific heat ratio a favorable mean temperature and the lowest fuel consumption. Additionally this configuration results in zero emissions of CO and HC along with a significant reduction in CO2 emissions due to the absence of carbon in the fuel structure. However due to the high combustion temperatures associated with hydrogen NOx emissions remained present and require further mitigation strategies.

Many small Canadian communities lack access to electricity grids relying instead on costly and polluting diesel generators despite the local availability of renewable energies like solar and wind. The intermittent nature of these sources limits reliable power supply; thus hydrogen is proposed as a cost-effective and ecofriendly long-term energy storage solution. However it remains uncertain whether hydrogen storage can significantly contribute to a 100% renewable energy system (100RES) given the diverse characteristics of these communities. Additionally the potential for fully renewable infrastructure to reduce costs mitigate adverse environmental impacts and enhance social impact is still unclear. A multi-period optimization model that balances economic environmental and social objectives to determine the optimal configuration of 100RESs for isolated communities is introduced and utilized to evaluate hydrogen as an energy storage solution to seasonal fluctuations. By identifying the best combinations of technologies tailored to local conditions and priorities this study offers valuable insights for policymakers supporting the transition to sustainable energy and achieving national climate goals. The results demonstrate that hydrogen could serve as an excellent longterm energy storage option to address energy shortages during the winter. Different combinations and sizes of energy generation and storage technologies are selected based on the characteristics of each community. For instance a community in the northern territories with high wind speeds low solar radiation extremely low temperatures and limited biomass resources should optimally rely on wind turbines to meet 80.7% of its total energy demand resulting in a 62.0% cost reduction and a 49.5% decrease in environmental impact compared to the existing diesel-based system. By 2050 all communities are projected to reduce energy costs per capita with northern territories achieving 33% and coastal areas achieving 55% cost reductions eventually leading to the utilization of hydrogen as the main energy storage medium.

As the global shift toward a low-carbon economy accelerates hydrogen is emerging as a crucial energy source. Among conventional methods for hydrogen production steam methane reforming (SMR) commonly paired with pressure swing adsorption (PSA) for hydrogen purification stands out due to its established infrastructure and technological maturity. This comprehensive techno-economic analysis focuses on membrane-based hydrogen production evaluating four configurations namely SMR SMR with PSA SMR with a palladium membrane and SMR with a ceramic–carbonate membrane coupled with a carbon capture system (CCS). The life cycle cost (LCC) of each configuration was assessed by analyzing key factors including production rate hydrogen pricing equipment costs and maintenance expenses. Sensitivity analysis was also conducted to identify major cost drivers influencing the LCC providing insights into the economic and operational feasibility of each configuration. The analysis reveals that SMR with PSA has the lowest LCC and is significantly more cost-efficient than configurations involving the palladium and ceramic–carbonate membranes. SMR with a ceramic–carbonate membrane coupled with CCS also demonstrates the most sensitive to energy variations due to its extensive infrastructure and energy requirement. Sensitivity analysis confirms that SMR with PSA consistently provides the greatest cost efficiency under varying conditions. These findings underscore the critical balance between cost efficiency and environmental considerations in adopting membrane-based hydrogen production technologies.

Eco-design is an innovative design methodology that focuses on minimizing the environmental footprint of industries including aviation right from the conceptual and development stages. However rising industrial demand calls for a more comprehensive strategy wherein beyond environmental considerations competitiveness becomes a critical factor supported by additional pillars of sustainability such as economic viability circularity and social impact. By incorporating sustainability as a primary design driver at the initial design stages this study suggests a shift from eco-driven to sustainability-driven design approaches for aircraft components. This expanded strategy considers performance and safety goals environmental impact costs social factors and circular economy considerations. To provide the most sustainable design that balances all objectives these aspects are rigorously quantified and optimized during the design process. To efficiently prioritize different variables methods such as multi-criteria decision-making (MCDM) are employed and a sustainability index is developed in this framework to assess the overall sustainability of each design alternative. The most sustainable design configurations are then identified through an optimization process. A typical aircraft component namely a hat-stiffened panel is selected to demonstrate the proposed approach. The study highlights how effectively sustainability considerations can be integrated from the early stages of the design process by exploring diverse material combinations and geometric configurations. The findings indicate that the type of fuel used and the importance given to the sustainability pillars—which are ultimately determined by the particular requirements and goals of the user—have a significant impact on the sustainability outcome. When equal prioritization is given across the diverse dimensions of sustainability the most sustainable option appears to be the full thermoplastic component when kerosene is used. Conversely when hydrogen is considered the full aluminum component emerges as the most sustainable choice. This trend also holds when environmental impact is prioritized over the other aspects of sustainability. However when costs are prioritized the full thermoplastic component is the most sustainable option whether hydrogen or kerosene is used as the fuel in the use phase. This innovative approach enhances the overall sustainability of aircraft components emphasizing the importance and benefits of incorporating a broader range of sustainability factors at the conceptual and initial design phases.

Introduction: The transition towards electrolysis-produced hydrogen in refineries and chemical industries is expected to have a potent impact on the local energy system of which these industries are part. In this study three urban areas with hydrogen-intense industries are studied regarding how the energy system configuration is affected if the expected future hydrogen demand is met in each node individually as compared to forming a “Hydrogen Valley” in which a pipeline can be used to trade hydrogen between the nodes.<br/>Method: A technoeconomic mixed-integer linear optimization model is used to study the investments in and dispatch of the included technologies with an hourly time resolution while minimizing the total system cost. Four cases are investigated based on the availability of offshore wind power and the possibility to invest in a pipeline.<br/>Results: The results show that investments in a pipeline reduces by 4%–7% the total system cost of meeting the demands for electricity heating and hydrogen in the cases investigated. Furthermore investments in a pipeline result in greater utilization of local variable renewable electricity resources as compared to the cases without the possibility to invest in a pipeline.<br/>Discussion: The different characteristics of the local energy systems of the three nodes in local availability of variable renewable electricity grid capacity and available storage options compared to local demands of electricity heating and hydrogen are found to be the driving forces for forming a Hydrogen Valley.

Due to hydrogen’s beneficial characteristics as a sustainable energy carrier the application of pulsing electric fields has been researched for its effectiveness during water electrolysis. Although there have been conflicting findings on the benefits of the application of pulsing electric fields this research highlights the potential it has to enhance the efficiency of water electrolysis while providing clarity on past discrepancies. This research achieves this by identifying distinctive energy flow profiles that result from various power input waveforms along with subsequent hydrogen production rates and efficiencies while also utilising a novel method of measuring the capacitance of the electrolyte to detect shifts in the molecular energy. The results indicate that pulsing electric fields can increase efficiency by up to 20 % or decrease efficiency by over 40 % depending on the energy flow profiles of the electrical molecular and electrochemical dynamics. Furthermore the use of pulsing electric fields also enabled load adaptability by allowing the electrolyser to operate effectively throughout a range of power inputs. For example the power input could be increased to cause a 279 % increase in hydrogen production without compromising efficiency; while conversely enabling electrolysis at >65 % efficiency using power input levels which were otherwise too low to drive electrochemical reactions. This study provides another step towards making renewable hydrogen viable as a sustainable energy carrier by identifying factors which influence and are influenced by changing electrical molecular and electrochemical dynamics while also providing a foundation for further research into more efficient use of energy to produce hydrogen gas.

In order to improve energy utilization efficiency and the flexibility of resource transfer in oceanic-island-group microgrids a water–electricity–hydrogen flexible scheduling strategy based on a multi-rate hydrogen-powered ship is proposed. First the characteristics of the seawater desalination unit (SDU) proton exchange membrane electrolyzer (PEMEL) and battery system (BS) in consuming surplus renewable energy on resource islands are analyzed. The variable-efficiency operation characteristics of the SDU and PEMEL are established and the effect of battery life loss is also taken into account. Second a spatiotemporal model for the multi-rate hydrogen-powered ship is proposed to incorporate speed adjustment into the system optimization framework for flexible resource transfer among islands. Finally with the goal of minimizing the total cost of the system a flexible water–electricity–hydrogen hybrid resource transfer model is constructed and a certain island group in the South China Sea is used as an example for simulation and analysis. The results show that the proposed scheduling strategy can effectively reduce energy loss promote renewable energy absorption and improve the flexibility of resource transfer.

Access to renewable energy is vital for rural development and climate change mitigation. The intermittency of renewable sources necessitates efficient energy storage especially in off-grid applications. This study evaluates the technical economic and environmental performance of an off-grid hybrid system for the rural settlement of Soma Turkey. Using HOMER Pro 3.14.2 software a system consisting of solar wind battery and hydrogen components was modeled under four scenarios with Cyclic Charging (CC) and Load Following (LF) control strategies for optimization. Life cycle assessment (LCA) and hydrogen leakage impacts were calculated separately through MATLAB R2019b analysis in accordance with ISO 14040 and ISO 14044 standards. Scenario 1 (PV + wind + battery + H2) offered the most balanced solution with a net present cost (NPC) of USD 297419 with a cost of electricity (COE) of USD 0.340/kWh. Scenario 2 without batteries increased hydrogen consumption despite a similar COE. Scenario 3 with wind only achieved the lowest hydrogen consumption and the highest efficiency. In Scenario 4 hydrogen consumption decreased with battery reintegration but COE increased. Specific CO2 emissions ranged between 36–45 gCO2-eq/kWh across scenarios. Results indicate that the control strategy and component selection strongly influence performance and that hydrogen-based hybrid systems offer a sustainable solution in rural areas.

To advance the hydrogen energy-driven low-altitude aviation sector it is imperative to establish sophisticated risk assessment frameworks tailored for hydrogen-powered aircraft. Such methodologies will deliver fundamental guidelines for the preliminary design phase of onboard hydrogen systems by leveraging rigorous risk quantification and scenario-based analytical models to ensure operational safety and regulatory compliance. In this context this study proposes a comprehensive hazard and operability analysis-fuzzy dynamic Bayesian network (HAZOP-FDBN) framework which quantifies risk without relying on historical data. This framework systematically maps the risk factor relationships identified in HAZOP results into a dynamic Bayesian network (DBN) graphical structure showcasing the risk propagation paths between subsystems. Expert knowledge is processed using a similarity aggregation method to generate fuzzy probabilities which are then integrated into the FDBN model to construct a risk factor relationship network. A case study on low-altitude aircraft hydrogen storage systems demonstrates the framework’s ability to (1) visualize time-dependent failure propagation mechanisms through bidirectional probabilistic reasoning and (2) quantify likelihood distributions of system-level risks triggered by component failures. Results validate the predictive capability of the model in capturing emergent risk patterns arising from subsystem interactions under low-altitude operational constraints thereby providing critical support for safety design optimization in the absence of historical failure data.

Within the framework of “dual carbon” intending to enhance the use of green energies and minimize the emissions of carbon from energy systems this study suggests a cost-effective low-carbon scheduling model that accounts for stepwise carbon trading for an integrated electricity heat gas cooling and hydrogen energy system. Firstly given the clean and low-carbon attributes of hydrogen energy a refined two-step operational framework for electricity-to-gas conversion is proposed. Building upon this foundation a hydrogen fuel cell is integrated to formulate a multi-energy complementary coupling network. Second a phased carbon trading approach is established to further explore the mechanism’s carbon footprint potential. And then an environmentally conscious and economically viable power dispatch model is developed to minimize total operating costs while maintaining ecological sustainability. This objective optimization framework is effectively implemented and solved using the CPLEX solver. Through a comparative analysis involving multiple case studies the findings demonstrate that integrating electrichydrogen coupling with phased carbon trading effectively enhances wind and solar energy utilization rates. This approach concurrently reduces the system’s carbon emissions by 34.4% and lowers operating costs by 58.6%.

Hydrogen is recognized as a key alternative fuel for mitigating greenhouse-gas emissions owing to its high fuel efficiency and carbon-free combustion. In the stratified charge combustion (SCC) mode ensuring optimal air-fuel mixing in the combustion chamber is crucial because the local equivalence ratio has a dominant influence on combustion characteristics. Therefore this study aims to build a detailed understanding of stratified hydrogen combustion under various local equivalence ratios. Laser-induced breakdown spectroscopy (LIBS) was used to measure the local equivalence ratios in hydrogen jets at different mixture-formation times (MFTs) and laserignition points (LIPs). The results showed that shorter MFTs induced highly stratified mixtures with elevated local equivalence ratios exceeding 2.0 enhancing the laminar flame speed and maximizing the conversion of chemical energy into pressure gain resulting in a representative total heat release over three times higher compared to longer MFTs. Furthermore ignition near the injector tip produced leaner mixtures with equivalence ratios around 0.3 whereas downstream LIPs generated peak local equivalence ratios around 2.0 facilitating rapid flame propagation and increased heat release by 25 %.

With the advancement of Fuel Cell Vehicles (FCVs) detecting hydrogen leaks is critically important in facilities such as hydrogen refilling stations. Despite its significance the dynamic response performance of hydrogen sensors in confined spaces particularly under ceilings has not been comprehensively assessed. This study utilizes a catalytic combustion hydrogen sensor to monitor hydrogen leaks in a confined area. It examines the effects of leak size and placement height on the distribution of hydrogen concentrations beneath the ceiling. Results indicate that hydrogen concentration rapidly decreases within a 0.5–1.0 m range below the ceiling and declines more gradually from 1.0 to 2.0 m. The study further explores the attenuation pattern of hydrogen concentration radially from the hydrogen jet under the ceiling. By normalizing the radius and concentration it was determined that the distribution conforms to a Gaussian model akin to that observed in open space jet flows. Utilizing this Gaussian assumption the model is refined by incorporating an impact reflux term thereby enhancing the accuracy of the predictive formula.

Microgrids enable the integration of renewable energy sources; however managing electricity from intermittent wind and solar power remains a significant challenge. This study investigates two storage strategies for managing surplus renewable electricity in an IEEE 84-Bus microgrid with wind turbines and photovoltaic units. The first option involves producing hydrogen via electrolyzers which is stored for later electricity generation through fuel cells. The second option involves converting surplus electricity into heat using heat pumps which is then stored in thermal energy storage systems to efficiently meet the microgrid's thermal load requirements. A scenariobased day-ahead scheduling model is proposed to optimize the microgrid's electrical and thermal load management while considering uncertainties in market prices wind speeds and solar irradiance. The resulting large-scale optimization challenge is effectively tackled using the self-adaptive charge system search algorithm. The results indicate that for the optimal utilization of excess renewable electricity heat generation via heat pumps is more cost-effective than hydrogen production primarily due to the inefficiencies in hydrogen conversion and the ability of heat pumps to produce several units of heat for each unit of electricity consumed. Moreover heat pumps prove to be more economical than natural gas combustion in boilers for meeting the thermal demands across a wide range of gas prices. These findings highlight the economic benefits of integrating heat pumps and thermal energy storage systems into renewable energy microgrids.

A new type of hydrogen produced in situ in petroleum reservoirs is proposed. This technology is based on ex situ catalytic gasification of biomass combining two thermal enhanced oil recovery techniques currently used in industrial fields: cyclic steam stimulation and in situ combustion. This hydrogen named “light-blue hydrogen” is produced in reservoirs like naturally occurring white hydrogen and from fossil fuels like blue hydrogen. The color light blue results from the blending of white and blue. This approach is particularly suitable for mature petroleum reservoirs which are in the final stages of production or no longer producing oil. This manuscript describes the method for producing light-blue hydrogen in situ its commercial application prospects and the challenges for developing and scaling up this technology.

Hydrogen-based steelmaking using green hydrogen can achieve above 95 % CO2 emission reductions. Low-cost renewable electricity is a prerequisite and research has found that access to renewable energy resources could pull energy-intensive industry to new locations the “renewables pull”-effect. However previous studies on hydrogen-based steel differ on key assumptions and analyse a wide range of energy costs (10–105 EUR/MWh) making conclusions hard to compare. In this paper we assess techno-economic and strategic drivers for and against such a pull-effect by calculating the levelized cost of green hydrogen-based steel across five archetypical new value chain configurations. We find that the strength of the pull-effect is sensitive to assumptions and that the cost of hydrogen-based steel vary across geographies and value chain configurations to a similar degree as conventional steel. Other geographically varying factors such as labour costs can be as important for relocation and introducing globally varying cost of capital moderates the effect. The renewables pull effect can enable faster access to low-cost renewables and export of green iron ore is an important option to consider. However it is not clear how strong a driver the pull-effect will actually be compared to other factors and polices implemented for strategic reasons. A modest “strategic push“ implemented through various subsidies such as lowering the cost of hydrogen or capital will reduce the pull-effect. In addition focusing on the renewables pull effect as enabling condition risk slowing innovation and upscaling by 2030 in line with climate goals which is currently initiated in higher cost regions.

As one of the most promising clean energy sources hydrogen power has gradually emerged as a viable alternative to traditional energy sources. However hydrogen safety remains a significant concern due to the potential for explosions and the associated risks. This review systematically examines hydrogen explosions with a focus on high-pressure and low-temperature storage transportation and usage processes mostly based on the published papers from 2020. The fundamental principles of hydrogen explosions classifications and analysis methods including experimental testing and numerical simulations are explored. Key factors influencing hydrogen explosions are also discussed. The safety issues of hydrogen power on railway applications are focused and finally recommendations are provided for the safe application of hydrogen power in railway transportation particularly for long-distance travel and heavy-duty freight trains with an emphasis on storage safety considerations.

Methane cracking (MC) is emerging as a low-carbon hydrogen production technology. This review conducts a comprehensive bibliometric analysis of 46 studies examining the sustainability of MC process. The review employs Life Cycle Assessment (LCA) Life Cycle Cost (LCC) Techno-Economic Analysis (TEA) and Social Life Cycle Assessment (SLCA) methodologies. The findings reveal that LCOH for MC technologies ranges from 0.9 to 6.6 $/kg H2 at the same time GHG emissions span 0.8–14.5 kg CO2eq/kg H2 depending on the specific reactor configurations plant geographical locations and carbon revenues. These results indicate that MC can be competitive with steam methane reforming with carbon capture and electrolysis under certain conditions. However the review identifies significant research gaps including limited comprehensive LCA studies a lack of social impact assessments insufficient environmental impact analysis of molten media catalysts and particulate matter formation in MC processes as well as insufficient analysis of the potential of biomethane cracking.

The large-scale utilization of hydrogen energy is currently hindered by challenges in lowcost production storage and transportation. This study focused on investigating the impact of the diaphragm cavity profile on the movement behavior and stress distribution of a dual-stage diaphragm compressor. Firstly an experimental platform was established to test the gas mass flowrate and fluid pressures under various preset conditions. Secondly a simulation path integrating the finite element method simulation theoretical stress model and movement model was developed and experimentally validated to analyze the diaphragm stress distribution and deformation characteristics. Finally comparative optimization analyses were conducted on different types of diaphragm cavity profiles. The results indicated that the driving pressure differences at the top dead center position reached 85.58 kPa for the first-stage diaphragm and 75.49 kPa for the second-stage diaphragm. Under experimental conditions of 1.6 MPa suction pressure 8 MPa second-stage discharge pressure and 200 rpm rotational speed the first-stage and second-stage diaphragms reached the maximum center deflections of 4.14 mm and 2.53 mm respectively at the bottom dead center position. Moreover the cavity profile optimization analysis indicated that the double-arc profile (DAP) achieved better cavity volume and diaphragm stress characteristics. The first-stage diaphragm within the optimized DAP-type cavity exhibited 173.95 MPa maximum principal stress with a swept volume of 0.001129 m3 whereas the second-stage optimized configuration reached 172.57 MPa stress with a swept volume of 0.0003835 m3 . This research offers valuable insights for enhancing the reliability and performance of diaphragm compressors.

Rail transit as a high-energy consumption field urgently requires the adoption of clean energy innovations to reduce energy consumption and accelerate the transition to new energy applications. As an energy-saving fluid machinery the ejector exhibits significant application potential and academic value within this field. This paper reviewed the recent advances technical challenges research hotspots and future development directions of ejector applications in rail transit aiming to address gaps in existing reviews. (1) In waste heat recovery exhaust heat is utilized for propulsion in vehicle ejector refrigeration air conditioning systems resulting in energy consumption being reduced by 12~17%. (2) In vehicle pneumatic pressure reduction systems the throttle valve is replaced with an ejector leading to an output power increase of more than 13% and providing support for zero-emission new energy vehicle applications. (3) In hydrogen supply systems hydrogen recirculation efficiency exceeding 68.5% is achieved in fuel cells using multi-nozzle ejector technology. (4) Ejector-based active flow control enables precise ± 20 N dynamic pantograph lift adjustment at 300 km/h. However current research still faces challenges including the tendency toward subcritical mode in fixed geometry ejectors under variable operating conditions scarcity of application data for global warming potential refrigerants insufficient stability of hydrogen recycling under wide power output ranges and thermodynamic irreversibility causing turbulence loss. To address these issues future efforts should focus on developing dynamic intelligent control technology based on machine learning designing adjustable nozzles and other structural innovations optimizing multi-system efficiency through hybrid architectures and investigating global warming potential refrigerants. These strategies will facilitate the evolution of ejector technology toward greater intelligence and efficiency thereby supporting the green transformation and energy conservation objectives of rail transit.

Lead–acid batteries are widely used in modern battery-powered ships. During the charging process of lead–acid batteries hydrogen gas is released which poses a potential hazard to ship safety. To address this this paper first establishes a turbulent flow model for hydrogen deflagration. Then using FDS6.7.9 software simulations of hydrogen deflagration are conducted and a simulation model of the ship’s cabin is constructed. The changes in temperature and pressure during the hydrogen deflagration process in the ship’s cabin are analyzed and the evolution process of hydrogen deflagration in the ship’s cabin is derived. Hydrogen deflagration poses a significant threat to the fire safety of battery-powered ships. Additionally a comparative analysis of hydrogen deflagration under different hydrogen concentrations is performed. It is concluded that battery-powered ships using lead–acid batteries should pay attention to controlling the hydrogen concentration below 4%.

Hydrogen is an abundant element and a flexible energy carrier offering substantial potential as an environmentally friendly energy source to tackle global energy issues. When used as a fuel hydrogen generates only water vapor upon combustion or in fuel cells presenting a means to reduce carbon emissions in various sectors including transportation industry and power generation. Nevertheless conventional hydrogen production methods often depend on fossil fuels leading to carbon emissions unless integrated with carbon capture and storage solutions. Conversely green hydrogen is generated through electrolysis powered by renewable energy sources like solar and wind energy. This production method guarantees zero carbon emissions throughout the hydrogen’s lifecycle positioning it as a critical component of global sustainable energy transitions. In Africa where there are extensive renewable energy resources such as solar and wind power green hydrogen is emerging as a viable solution to sustainably address the increasing energy demands. This research explores the influence of policy frameworks technological innovations and market forces in promoting green hydrogen adoption across Africa. Despite growing investments and favorable policies challenges such as high production costs and inadequate infrastructure significantly hinder widespread adoption. To overcome these challenges and speed up the shift towards a sustainable hydrogen economy in Africa strategic investments and collaborative efforts are essential. By harnessing its renewable energy potential and establishing strong policy frameworks Africa can not only fulfill its energy requirements but also support global initiatives to mitigate climate change and achieve sustainable development objectives.

Aviation is of crucial importance for the transportation sector and fundamental for the economy as it facilitates trade and private travel. Nonetheless this sector is responsible for a great amount of global carbon dioxide emissions exceeding 920 million tonnes annually. Alternative energy fuels (AEFs) can be considered as a promising solution to tackle this issue with the potential to lower greenhouse gas emissions and reduce reliance on fossil fuels in the aviation industry. A life cycle analysis is performed considering an aircraft running on conventional jet fuel and various alternative fuels (biojet methanol and DME) including hydrogen and ammonia. The comparative assessment investigates different fuel production pathways including the following: JETA-1 and biojet fuels via hydrotreated esters and fatty acids (HEFAs) as well as hydrogen and ammonia employing water electrolysis using wind and solar photovoltaic collectors. The outputs of the assessment are quantified in terms of carbon dioxide equivalent emissions acidification eutrophication eco-toxicity human toxicity and carcinogens. The life cycle phases included the following: (i) the construction maintenance and disposal of airports; (ii) the operation and maintenance of aircrafts; and (iii) the production transportation and utilisation of aviation fuel in aircrafts. The results suggest that hydrogen is a more environmentally benign alternative compared to JETA-1 biojet fuel methanol DME and ammonia.

Climate policy will inevitably lead to the stranding of fossil energy assets such as production and transport assets for coal oil and natural gas. Resourcerich developing countries are particularly aected as they have a higher risk of asset stranding due to strong fossil dependencies and wider societal consequences beyond revenue disruption. However there is only little academic and political awareness of the challenge to manage the asset stranding in these countries as research on transition risk like asset stranding is still in its infancy. We provide a research framework to identify wider societal consequences of fossil asset stranding. We apply it to a case study of Nigeria. Analyzing dierent policy measures we argue that compensation payments come with implementation challenges. Instead of one policy alone to address asset stranding a problem-oriented mix of policies is needed. Renewable hydrogen and just energy transition partnerships can be a contribution to economic development and SDGs. However they can only unfold their potential if fair benefit sharing and an improvement to the typical institutional problems in resource-rich countries such as the lack of rule of law are achieved. We conclude with presenting a future research agenda for the global community and acade

Clean hydrogen is expected to play a crucial role in the future decarbonized energy mix. This places the gasification of biomass as a critical conversion pathway for hydrogen production owing to its carbon neutrality. However there is limited research on the direction of the body of literature on this subject matter. Utilising the Bibliometrix package R this paper conducts a systematic review and bibliometric analysis of the literature on gasification-derived hydrogen production over the previous three decades. The results show a decade-wise spike in hydrogen research mostly contributed by China the United States and Europe whereas the scientific contribution of Africa on the topic is limited with less than 6% of the continent’s research output on the subject matter sponsored by African institutions. The current trend of the research is geared towards alignment with the Paris Agreement through feedstock diversification to include renewable sources such as biomass and municipal solid waste and decarbonising the gasification process through carbon-capture technologies. This review reveals a gap in the experimental evaluation of heterogenous organic municipal solid waste for hydrogen production through gasification within the African context. The study provides an incentive for policy actors and researchers to advance the green hydrogen economy in Africa.

The production of green hydrogen requires renewable electricity and a supply of sustainable water. Due to global water scarcity using seawater to produce green hydrogen is particularly important in areas where freshwater resources are scarce. This study establishes a system model to simulate and optimize the integrated technology of seawater desalination by membrane distillation and hydrogen production by alkaline water electrolysis. Technical economics is also performed to evaluate the key factors affecting the economic benefits of the coupling system. The results show that an increase in electrolyzer power and energy efficiency will reduce the amount of pure water. An increase in the heat transfer efficiency of the membrane distillation can cause the breaking of water consumption and production equilibrium requiring a higher electrolyzer power to consume the water produced by membrane distillation. The levelized costs of pure water and hydrogen are US$1.28 per tonne and $1.37/kg H2 respectively. The most important factors affecting the production costs of pure water and hydrogen are electrolyzer power and energy efficiency. When the price of hydrogen rises the project’s revenue increases significantly. The integrated system offers excellent energy efficiency compared to conventional desalination and hydrogen production processes and advantages in terms of environmental protection and resource conservation.

Ammonia is a particularly promising hydrogen carrier due to its relatively low cost high energy density its liquid storage and to its production from renewable sources. Thus in recent years great attention is devoted to this fuel for realizing next generation refueling stations according to a carbon-free energy economy. In this paper a distributed onsite refueling station (200 kg/day of hydrogen filling 700-bar HFCEVs (Hybrid Fuel Cell Electric Vehicles) with about 5 kg of hydrogen in 5 min) based on ammonia feeding is studied from the energy and economic point of views. The station is designed with a modular configuration consisting of more sections: i) the hydrogen production section ii) the electric energy supplier section iii) the compression and storage section and the refrigeration/dispenser section. The core of the station is the hydrogen production section that is based on an ammonia cracking reactor and its auxiliaries; the electric energy demand necessary for the station operation (i.e. the hydrogen compression and refrigeration) is satisfied by a PEMFC (Proton-Exchange Membrane Fuel Cell) power module. Energy performance according to the hydrogen daily demand has been evaluated and the estimation of the levelized cost of hydrogen (LCOH) has been carried out in order to establish the cost of the hydrogen at the pump that can assure the feasibility of this novel refueling station.

The increasing global demand for sustainable energy solutions has intensified the need to replace fossil fuels in gas turbines particularly in aviation and power generation where alternatives to gas turbines are currently limited. This review explores the feasibility of utilizing sustainable liquid and gaseous fuels in gas turbines by evaluating their environmental impacts performance characteristics and technical integration potential. The study examines a broad range of alternatives including biofuels hydrogen alcohols ethers synthetic fuels and biogas focusing on their production methods combustion behavior and compatibility with existing turbine technology. Key findings indicate that several bioderived and synthetic fuels can serve as viable drop-in replacements for conventional jet fuels especially under ASTM D7566 standards. Hydrogen and other gaseous alternatives show promise for industrial applications but require significant combustion system adaptations. The study concludes that a transition to sustainable fuels in gas turbines is achievable through coordinated advancements in combustion technology fuel infrastructure and regulatory support thus enabling meaningful reductions in greenhouse gas emissions and advancing global decarbonization efforts.

Hydrogen is a promising fuel to decarbonise aviation. Storage in liquid form is favoured for long-haul aircraft; storage as a high-pressure gas is preferred otherwise. The exergy expended during the compression or liquefaction process is stored as physical exergy in the fuel. Most discussions around hydrogen-fuelled aviation ignore this very significant exergy content. When combusted in an engine the chemical energy of hydrogen can produce around 60 MJ of work per kg. The work that can be extracted from the physical exergy depends strongly on the method used. This paper presents an exergy analysis considering a range of storage conditions operating conditions and work-extraction methods. For reasonable gas-turbine operating conditions upwards of 16 MJ/kg might be extracted from compressed hydrogen (at 700 bar) and 30 MJ/kg from LH2. This additional work representing 25–50 % of the shaft work produced by combustion has been by and large neglected.

This study presents the design and techno-economic comparison of two standalone photovoltaic (PV) systems each supplying a 1 kW critical load with 100% reliability under Cairo’s climatic conditions. These systems are modeled for both the constant and the night load scenarios accounting for the worst-case weather conditions involving 3.5 consecutive cloudy days. The primary comparison focuses on traditional lead-acid battery storage versus green hydrogen storage via electrolysis compression and fuel cell reconversion. Both the configurations are simulated using a Python-based tool that calculates hourly energy balance component sizing and economic performance over a 21-year project lifetime. The results show that the PV/H2 system significantly outperforms the PV/lead-acid battery system in both the cost and the reliability. For the constant load the Levelized Cost of Electricity (LCOE) drops from 0.52 USD/kWh to 0.23 USD/kWh (a 56% reduction) and the payback period is shortened from 16 to 7 years. For the night load the LCOE improves from 0.67 to 0.36 USD/kWh (a 46% reduction). A supplementary cost analysis using lithium-ion batteries was also conducted. While Li-ion improves the economics compared to lead-acid (LCOE of 0.41 USD/kWh for the constant load and 0.49 USD/kWh for the night load) this represents a 21% and a 27% reduction respectively. However the green hydrogen system remains the most cost-effective and scalable storage solution for achieving 100% reliability in critical off-grid applications. These findings highlight the potential of green hydrogen as a sustainable and economically viable energy storage pathway capable of reducing energy costs while ensuring long-term resilience.

Stringent CO2 reduction targets and tightening emission regulations have intensified interest in hydrogen internal combustion engines (H2ICEs) as a clean and robust solution for the heavy-duty (HD) sector. This study experimentally compares port fuel injection (PFI) early low-pressure direct injection (LPDI) and late LPDI strategies on a single-cylinder HD H2ICE under steady-state medium and high loads. The injection timing and fuel pressure are varied to study the overall influences on a single-cylinder heavy-duty H2ICE. PFI and early LPDI deliver high charge homogeneity but reduced volumetric efficiency compared to late LPDI. At medium load all three strategies achieve ~41 % gross indicated thermal efficiency (gITE). Increasing LPDI pressure from 12.8 to 20 bar enhances mixture uniformity cutting BSNOx emissions by up to 75 %. At high load early LPDI reaches 41.7 % gITE with low NOx (0.72 g/kWh) while late LPDI benefits from reduced heat transfer loss and compression work achieving 42.4 % gITE. However late injection also increases BSNOx (9.3 g/kWh) unburnt H2 (435 ppm) and pressure rise rate (19.7 bar/◦CA). These results highlight LPDI’s potential for high efficiency with injection timing and pressure as key levers to balance emissions and performance.

Global climate change caused by geological processes is one of the main causes of the 5 global mass extinctions in geological history. Human industrialization activities have caused serious damage to the ecosystem the greenhouse effect of atmospheric CO2 has intensified and the living environment is facing threats and challenges. Carbon neutrality is the active action and common goal of mankind in the face of the climate change crisis therefore probing into its theoretical and technological connotation scientific and technological innovation system has far-reaching significance and broad prospects. Studies indicate that (1) Carbon neutrality reflects the theoretical connotations of “energy science” and “carbon neutrality science” including technical connotations of carbon emission reduction zero carbon emission negative carbon emission and carbon trading. (2) Carbon neutrality spawns new industries such as carbon industry centering on CO2 capture utilization and storage (CCUS or CO2 capture and storage CCS) and hydrogen industry centering on green hydrogen. “Gray carbon” and “black carbon” are the two application attributes of CO2. “Carbonþ” “Carbon” and “Carbon¼” are three carbon-neutral products and technologies. (3) China faces three major challenges in achieving the goal of carbon neutrality: first energy transition is large in scale and the cycle is short; Second there are many problems in the process of energy transition such as security uncertainties economic utilization and unpredictable disruptive technologies; Third after transition we may face new key techno-logical “bottlenecks” and “broken chain” of key mineral resources. (4) Based on current knowledge to predict the top 10 disruptive technologies and industries in the energy field: underground coal gasification in-situ conversion process of medium and low-mature shale oil CCUS/CCS hydrogen energy and fuel cells bio-photovoltaic power generation space-based solar power generation optical storage smart micro-grid super energy storage controllable nuclear fusion wisdom energy Internet. Five strategic projects will be implemented including energy conservation and efficiency improvement carbon reduction and sequestration scientific and technological innovation emergency reserve and policy support. (5) In the future different types of energy will have different orientations. Coal will play the role of ensuring the national energy strategy “reserve” and “guarantee the bottom line”. Petroleum will play the role of ensuring national energy security “urgent need” and the “cornerstone” of raw materials in people's livelihood. Natural gas will play the role in ensuring national energy “safety” and “best partner” of new energy. New energy will play the role in ensuring the “replacement” and “main force” of the national energy strategy. (6) Carbon neutrality is a major practice of the green industrial revolution carbon reduction energy revolution and ecological technology revolution which will bring new and profound changes to human society the environment and the economy. (7) Carbon neutrality needs to follow the four principles of “disruptive breakthroughs in technology guarantee of energy security realization of economic feasibility and controllable social stability”. We should rely on technological innovation and management changes to ensure the realization of national energy “independence” and carbon neutrality goal and make China's contribution to the construction of a livable earth green development and ecological civilization.

In this paper we analyze the autothermal reforming (ATR) of methane through Gibbs energy minimization and entropy maximization methods to analyze isothermic and adiabatic systems respectively. The software GAMS® 23.9 and the CONOPT3 solver were used to conduct the simulations and thermodynamic analyses in order to determine the equilibrium compositions and equilibrium temperatures of this system. Simulations were performed covering different pressures in the range of 1 to 10 atm temperatures between 873 and 1073 K steam/methane ratio was varied in the range of 1.0/1.0 and 2.0/1.0 and oxygen/methane ratios in the feed stream in the range of 0.5/1.0 to 2.0/1.0. The effect of using pure oxygen or air as oxidizer agent to perform the reaction was also studied. The simulations were carried out in order to maintain the same molar proportions of oxygen as in the simulated cases considering pure oxygen in the reactor feed. The results showed that the formation of hydrogen and synthesis gas increased with temperature average composition of 71.9% and 56.0% using air and O2 respectively. These results are observed at low molar oxygen ratios (O2/CH4 = 0.5) in the feed. Higher pressures reduced the production of hydrogen and synthesis gas produced during ATR of methane. In general reductions on the order of 19.7% using O2 and 14.0% using air were observed. It was also verified that the process has autothermicity in all conditions tested and the use of air in relation to pure oxygen favored the compounds of interest mainly in conditions of higher pressure (10 atm). The mean reductions with increasing temperature in the percentage increase of H2 and syngas using air under 1.5 and 10 atm at the different O2/CH4 ratios were 5.3% 13.8% and 16.5% respectively. In the same order these values with the increase of oxygen were 3.6% 6.4% and 9.1%. The better conditions for the reaction include high temperatures low pressures and low O2/CH4 ratios a region in which there is no swelling in terms of the oxygen source used. In addition with the introduction of air the final temperature of the system was reduced by 5% which can help to reduce the negative impacts of high temperatures in reactors during ATR reactions.

Due to increasing energy demand limited fossil fuels and increasing greenhouse gasses people is in need for alternative energy sources to have a sustainable world. The objective of this study is to look for alternative solutions and design a hybrid energy system to meet any energy needs of a single family house including both utility and transportation. The system is designed and optimized using HOMER software. According to the optimization studies levelized cost of electricity and hydrogen production was found to be 0.685$/kWh and 6.85$/kg respectively and the cost of hydrogen which is half of its market price is very attractive. To project possible future costs in advance sensitivity analysis was carried out and the results show that when the main components’ price decays to the half both costs of energy will be reduced by 26.4%. This implies that further decrease on the components’ cost would bring the cost of energy to the level of energy produced by fossil fuels or even lower. Hydrogen would also be produced with much lower and tempting price. It is important to note that energy used by residential electrical load and fuel cell electric car in this study was generated by sole renewable energies and the system consumes zero fossil fuels thus emitting no greenhouse gasses. The study considering both utility and transportation simultaneously is believed to be the first on a small scale and to attract the interest of everyone.