Publications

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.

Green hydrogen generation driven by solar-wind hybrid power is a key strategy for obtaining the low-carbon energy while by considering the fluctuation natures of solar-wind energy resource the system capacity configuration of power generation hydrogen production and essential storage devices need to be comprehensively optimized. In this work a solar-wind hybrid green hydrogen production system is developed by combining the hydrogen storage equipment with the power grid the coordinated operation strategy of solar-wind hybrid hydrogen production is proposed furthermore the NSGA-III algorithm is used to optimize the system capacity configuration with the comprehensive performance criteria of economy environment and energy efficiency. Through the implemented case study with the hydrogen production capacity of 20000 tons/year the abandoned energy power rate will be reduced to 3.32% with the electrolytic cell average load factor of 64.77% and the system achieves the remarkable carbon emission reduction. In addition with the advantage of connect to the power grid the generated surplus solar/wind power can be readily transmitted with addition income when the sale price of produced hydrogen is suggested to 27.80 CNY/kgH2 the internal rate of return of the system reaches to 8% which present the reasonable economic potential. The research provides technical and methodological suggestions and guidance for the development of solar-wind hybrid hydrogen production schemes with favorable comprehensive performance.

Proposals for achieving net-zero emissions by 2050 include scaling-up electrolytic hydrogen production however this poses technical economic and environmental challenges. One such challenge is for policymakers to ensure a sustainable future for the environment including freshwater and land resources while facilitating low-carbon hydrogen production using renewable wind and solar energy. We establish a country-by-country reference scenario for hydrogen demand in 2050 and compare it with land and water availability. Our analysis highlights countries that will be constrained by domestic natural resources to achieve electrolytic hydrogen self-sufficiency in a net-zero target. Depending on land allocation for the installation of solar panels or wind turbines less than 50% of hydrogen demand in 2050 could be met through a local production without land or water scarcity. Our findings identify potential importers and exporters of hydrogen or conversely exporters or importers of industries that would rely on electrolytic hydrogen. The abundance of land and water resources in Southern and Central-East Africa West Africa South America Canada and Australia make these countries potential leaders in hydrogen export.

A quantitative risk assessment on a representative liquid hydrogen storage system was performed to identify the main drivers of individual risk and provide a technical basis for revised separation distances for bulk liquid hydrogen storage systems in regulations codes and standards requirements. The framework in the Hydrogen Plus Other Alternative Fuels Risk Assessment Models (HyRAM+) toolkit was used and multiple relevant inputs to the risk assessment (e.g. system pipe size ignition probabilities) were individually varied. For each set of risk assessment inputs the individual risk as a function of the distance away from the release point was determined and the risk-based separation distance was determined from an acceptable risk criterion. These risk-based distances were then converted to equivalent leak size using consequence models that would result in the same distance to selected hazard criteria (i.e. extent of flammable cloud heat flux and peak overpressure). The leak sizes were normalized to a fraction of the flow area of the source piping. The resulting equivalent fractional hole sizes for each sensitivity case were then used to inform selection of a conservative fractional flow area leak size of 5% that serves as the basis for consequence-based separation distance calculations. This work demonstrates a method for using a quantitative risk assessment sensitivity study to inform the selection of a basis for determining consequence-based separation distances.

The increase of using hydrogen as a replacement for fossil fuels in power generation and mobility is expected to witness a huge leap in the next decades. However several safety issues arise due to the physical and chemical properties of hydrogen especially its wide range of flammability. In case of Hydrogen leakage in confined areas Hydrogen clouds can accumulate in the space and their concentration can build up quickly to reach the lower flammability limit (LFL) in case of not applying a proper ventilation system. As a part of the Living Lab Energy Campus (LLEC) project at Jülich Research Centre the use of hydrogen mixed with natural gas as a fuel for the central heating system of the campus is being studied. The current research aims to investigate the release dispersion and formation and the spread of a hydrogen cloud inside the central utility building at the campus of Jülich Research Centre in case of hypothetical accidental leakage. Such a leakage is simulated using the opensource containmentFoam package base on OpenFOAM CFD code to numerically simulate the behavior of the air-hydrogen mixture. The critical locations where hydrogen concentrations can reach the LFL values are shown.

Hydrogen is a promising fuel for future aviation due to its CO2-free combustion. In addition its excellent cooling properties as it is heated from cryogenic conditions to the appropriate combustion temperatures provides a multitude of opportunities. This paper investigates the heat transfer potential of stator surfaces in a modern high-speed low-pressure compressor by incorporating cooling channels within the stator vane surfaces where hydrogen is allowed to flow and cool the engine core air. Computational Fluid Dynamics simulations were carried out to assess the aerothermal performance of this cooled compressor and were compared to heat transfer correlations. A core air temperature drop of 9.5 K was observed for this cooling channel design while being relatively insensitive to the thermal conductivity of the vane and cooling channel wall thickness. The thermal resistance was dominated by the air-side convective heat transfer and more surface area on the air-side would therefore be required in order to increase overall heat flow. While good agreement with established heat transfer correlations was found for both turbulent and transitional flow the correlation for the transitional case yielded decent accuracy only as long as the flow remains attached and while transition was dominated by the bypass mode. A system level analysis indicated a limited but favorable impact at engine performance level amounting to a specific fuel consumption improvement of up to 0.8% in cruise and an estimated reduction of 3.6% in cruise NOx. The results clearly show that although it is possible to achieve high heat transfer rate per unit area in compressor vanes the impact on cycle performance is constrained by the limited available wetted area in the low-pressure compressor.

Hydrogen is set to become an important energy carrier in Germany in the next decades in the country’s quest to reach the target of climate neutrality by 2045. To meet Germany’s potential green hydrogen demand of up to 587 to 1143 TWh by 2045 electrolyser capacities between 7 and 71 GW by 2030 and between 137 to 275 GW by 2050 are required. Presently the capacities for electrolysis are small (around 153 MW) and even with an increase in electrolysis capacity of >1 GW per year Germany will still need to import large quantities of hydrogen to meet its future demand. This work examines the expected green hydrogen demand in different sectors describes the available technologies and highlights the current situation and challenges that need to be addressed in the next years to reach Germany’s climate goals with regard to scaling up production infrastructure development and transport as well as developing the demand for green hydrogen.

The ecological transition in the transport sector is a major challenge to tackle environmental pollution and European legislation will mandate zero-emission new cars from 2035. To reduce the impact of petrol and diesel vehicles much emphasis is being placed on the potential use of synthetic fuels including electrofuels (e-fuels). This research aims to examine a levelised cost (LCO) analysis of e-fuel production where the energy source is renewable. The energy used in the process is expected to come from a photovoltaic plant and the other steps required to produce e-fuel: direct air capture electrolysis and Fischer-Tropsch process. The results showed that the LCOe-fuel in the baseline scenario is around 3.1 €/l and this value is mainly influenced by the energy production component followed by the hydrogen one. Sensitivity scenario and risk analyses are also conducted to evaluate alternative scenarios and it emerges that in 84% of the cases LCOe-fuel ranges between 2.8 €/l and 3.4 €/l. The findings show that the current cost is not competitive with fossil fuels yet the development of e-fuels supports environmental protection. The concept of pragmatic sustainability incentive policies technology development industrial symbiosis economies of scale and learning economies can reduce this cost by supporting the decarbonisation of the transport sector.

The transport of hydrogen in used natural gas pipelines is a strategic key element of a pan-European hydrogen infrastructure. At the same time accurate knowledge of the hydrogen quality is essential in order to be able to address a wide application range. Therefore an experimental investigation was carried out to find out which contaminants enter into the hydrogen from the used natural gas pipelines. Pipeline elements from the high pressure gas grid of Austria were exposed to hydrogen. Steel pipelines built between 1960 and 2018 which were operated with odorised and pure natural gas were examined. The hydrogen was analysed according to requirements of ISO14687: 2019 Grade D measurement standard. The results show that based on age odorization and sediments different contimenants are introduced. Odorants hydrocarbons but also sulphur compounds ammonia and halogenated hydrogen compounds were identified. Sediments are identified as the main source of impurities. However the concentrations of the introduced contaminants were low (6 nmol/mol to 10 μmol/mol). Quality monitoring with a wide range of detection options for different components (sulphur halogenated compounds hydrocarbons ammonia and atmospheric components) is crucial for real operation. The authors deduce that a Grade A hydrogen quality can be safely achieved in real operation.

The perspective of natural hydrogen as a clear carbon-free and renewable energy source appears very promising. There have been many studies reporting significant concentrations of natural hydrogen in different countries. However natural hydrogen is being extracted to generate electricity only in Mali. This issue originates from the fact that global attention has not been dedicated yet to the progression and promotion of the natural hydrogen field. Therefore being in the beginning stage natural hydrogen science needs further investigation especially in exploration techniques and exploitation technologies. The main incentive of this work is to analyze the latest advances and challenges pertinent to the natural hydrogen industry. The focus is on elaborating geological origins ground exposure types extraction techniques previous detections of natural hydrogen exploration methods and underground hydrogen storage (UHS). Thus the research strives to shed light on the current status of the natural hydrogen field chiefly from the geoscience perspective. The data collated in this review can be used as a useful reference for the scientists engineers and policymakers involved in this emerging renewable energy source.

Hydrogen has gained tremendous momentum worldwide as an energy carrier to transit to a net zero emission energy sector. It has been widely adopted as a promising large-scale renewable energy (RE) storage solution to overcome RE resources’ variability and intermittency nature. The fuel cell (FC) technology became in focus within the hydrogen energy landscape as a cost-effective pathway to utilize hydrogen for power generation. Therefore FC technologies’ research and development (R&D) expanded into many pathways such as cost reduction efficiency improvement fixed and mobile applications lifetime safety and regulations etc. Many publications and industrial reports about FC technologies and applications are available. This raised the necessity for a holistic review study to summarize the state-of-the-art range of FC stacks such as manufacturing the balance of plant types technologies applications and R&D opportunities. At the beginning the principal technologies to compare the well known types followed by the FC operating parameters are presented. Then the FC balance of the plant i.e. building components and materials with its functionality and purpose types and applications are critically reviewed with their limitations and improvement opportunities. Subsequently the electrical properties of FCs with their key features including advantages and disadvantages were investigated. Applications of FCs in different sectors are elaborated with their key characteristics current status and future R&D opportunities. Economic attributes of fuel cells with a pathway towards low cost are also presented. Finally this study identifies the research gaps and future avenues to guide researchers and the hydrogen industry.

The article presents the application of the metalog family of probability distributions to predict the energy production of photovoltaic systems for the purpose of generating small amounts of green hydrogen in distributed systems. It can be used for transport purposes as well as to generate energy and heat for housing purposes. The monthly and daily amounts of energy produced by a photovoltaic system with a peak power of 6.15 kWp were analyzed using traditional statistical methods and the metalog probability distribution family. On this basis it is possible to calculate daily and monthly amounts of hydrogen produced with accuracy from the probability distribution. Probabilistic analysis of the instantaneous power generated by the photovoltaic system was used to determine the nominal power of the hydrogen electrolyzer. In order to use all the energy produced by the photovoltaic system to produce green hydrogen the use of a stationary energy storage device was proposed and its energy capacity was determined. The calculations contained in the article can be used to design home green hydrogen production systems and support the climate and energy transformation of small companies with a hydrogen demand of up to ¾ kg/day.

Considering the mismatch between the renewable source availability and energy demand energy storage is increasingly vital for achieving a net-zero future. The daily/seasonal disparities produce a surplus of energy at specific moments. The question is how can this “excess” energy be stored? One promising solution is hydrogen. Conventional hydrogen storage relies on manufactured vessels. However scaling the technology requires larger volumes to satisfy peak demands enhance the reliability of renewable energies and increase hydrogen reserves for future technology and infrastructure development. The optimal solution may involve leveraging the large volumes of underground reservoirs like salt caverns and aquifers while minimizing the surface area usage and avoiding the manufacturing and safety issues inherent to traditional methods. There is a clear literature gap regarding the critical aspects of underground hydrogen storage (UHS) technology. Thus a comprehensive review of the latest developments is needed to identify these gaps and guide further R&D on the topic. This work provides a better understanding of the current situation of UHS and its future challenges. It reviews the literature published on UHS evaluates the progress in the last decades and discusses ongoing and carried-out projects suggesting that the technology is technically and economically ready for today’s needs.

The disruption associated with heat decarbonisation has been identified as a key opportunity for hydrogen technologies in temperate countries and regions where established distribution infrastructure and familiarity with natural gas boilers predominate. A key element of such claims is the empirically untested belief that citizens will prefer to minimise disruption and perceive hydrogen to be less disruptive than the network upgrades and retrofit measures needed to support electric and other low carbon heating technologies. This article reports on exploratory deliberative research with residents of Cardiff Wales which examined public perceptions of heating disruptions. Our findings suggest that concerns over public responses to disruption may be overstated particularly as they relate to construction and road excavation for network upgrade. Disruptions arising from permanent changes to building fabric may be more problematic for heat pump retrofit however these may be greatly overshadowed by anxieties over the cost implications of moving to hydrogen fuel. Furthermore the biographical patterning of citizen preferences raises significant questions for hydrogen roll-out strategies relying on regionalised network conversion. We conclude by arguing that far from a non-disruptive alternative to electrification hydrogen risks being seen as posing substantial disruptions to precarious household finances and lifestyles.

Hydrogen is a promising energy carrier for a low-carbon future energy system as it can be stored on a megaton scale (equivalent to TWh of energy) in subsurface reservoirs. However safe and efficient underground hydrogen storage requires a thorough understanding of the geomechanics of the host rock under fluid pressure fluctuations. In this context we summarize the current state of knowledge regarding geomechanics relevant to carbon dioxide and natural gas storage in salt caverns and depleted reservoirs. We further elaborate on how this knowledge can be applied to underground hydrogen storage. The primary focus lies on the mechanical response of rocks under cyclic hydrogen injection and production fault reactivation the impact of hydrogen on rock properties and other associated risks and challenges. In addition we discuss wellbore integrity from the perspective of underground hydrogen storage. The paper provides insights into the history of energy storage laboratory scale experiments and analytical and simulation studies at the field scale. We also emphasize the current knowledge gaps and the necessity to enhance our understanding of the geomechanical aspects of hydrogen storage. This involves developing predictive models coupled with laboratory scale and field-scale testing along with benchmarking methodologies.

This paper investigates the untapped potential of the Permian Basin a multifaceted energy axis in Texas and adjoining states in the emerging era of decarbonization. Aligned with current policy directives on regional hydrogen hubs this study explores the viability of developing a hydrogen energy hub in the Permian Basin thereby producing low-carbon intensity hydrogen from natural gas in the Basin and transporting it to the Greater Houston area. Diverging from existing literature this study provides an integrated techno-economic evaluation of the entire hydrogen value chain in the Permian Basin encompassing production storage and transportation. Furthermore it comparatively analyzes the scenario of interest against an optimized base scenario thereby underlining comparative advantages and disadvantages. The paper concludes that the delivered cost of Permian based low-carbon intensity hydrogen to the Greater Houston area is $1.85/kg benchmarked to the scenario with hydrogen produced close to the Greater Houston area and delivered at $1.42/kg. Our findings reveal that Permian-based low-carbon intensity hydrogen production can achieve cost savings in feedstock ($0.25/kg) and potentially accrue a higher production tax credit due to a shorter gas supply chain to production ($0.33/kg). Nevertheless a significant cost barrier is the expense of long-haul pipeline transport ($0.90/kg) from the Permian Basin to Houston as opposed to local production. Despite the obstacles the study identifies a potential breakeven solution where increasing the production scale to at least 412000 metric ton per year (about 3 steam reforming plants) in the Permian Basin can effectively lower costs in the transport sector. Hence a scaled-up production can mitigate the cost difference and establish the Permian Basin as a competitive player in the hydrogen market. In conclusion a SWOT analysis presents Strengths Weaknesses Opportunities and Threats associated with Permian-based hydrogen production.

To achieve the European milestone of climate neutrality by 2050 the decarbonisation of energy-intensive industries is essential. In 2022 global energy-related CO2 emissions increased by 0.9% or 321 Mt reaching a peak of over 36.8 Gt. A large amount of these emissions is the result of fossil fuel usage in the motorised equipment used in mining. Heavy diesel vehicles like excavators wheel loaders and dozers are responsible for an estimated annual CO2 emissions of 400 Mt of CO2 accounting for approximately 1.1% of global CO2 emissions. In addition exhaust gases of CO2 and NOx endanger the personnel’s health in all mining operations especially in underground environments. To tackle these environmental concerns and enhance environmental health extractive industries are focusing on replacing fossil fuels with alternative fuels of low or zero CO2 emissions. In mining the International Council on Mining and Metals has committed to achieving net zero emissions by 2050 or earlier. Of the various alternative fuels hydrogen (H2 ) has seen a considerable rise in popularity in recent years as H2 combustion accounts for zero CO2 emissions due to the lack of carbon in the burning process. When combusted with pure oxygen it also accounts for zero NOx formation and near-zero emissions overall. To this end this study aims to examine the overall environmental performance of H2 -powered motorised equipment compared to conventional fossil fuel-powered equipment through Life Cycle Assessment. The assessment was conducted using the commercial software Sphera LCA for Experts following the conventionally used framework established by ISO 14040:2006 and 14044:2006/A1:2018 and the International Life Cycle Data Handbook consisting of (1) the goal and scope definition (2) the Life Cycle Inventory (LCI) preparation (3) the Life Cycle Impact Assessment (LCIA) and (4) the interpretation of the results. The results will offer an overview to support decision-makers in the sector.

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.

The rapid growth of global aviation emissions has significantly impacted the environment leading to an urgent need to use carbon reduction methods. This paper analyzes global aviation’s carbon dioxide (CO2) N2O and CH4 emission changes under different hydrogen energy application paths. The global warming potential over a 100-year period (GWP100) method is used to convert the emissions of N2O and CH4 into CO2-equivalent. Here we report the results: if the global aviation industry begins using hydrogen turbine engines by 2040 it could reduce cumulative CO2-equivalent emissions by 2.217E+10 tons by 2080 which is 2.12% higher than starting hydrogen fuel cell engines in 2045. However adopting hydrogen fuel cell engines 10 years earlier shows greater reduction capabilities than hydrogen turbine engines achieving an accumulated reduction of 3.006E+10 tons of CO2-equivalent emissions. Therefore the timing of adoption notably affects hydrogen fuel cell engines more than hydrogen turbine engines. Delaying adoption makes hydrogen fuel cell engines’ performance lag hydrogen turbine engines.

This paper presents an innovative Fuel Cell Combined Heat and Power (FC–CHP) system designed to enhance energy efficiency in hospital settings. The system primarily utilizes solar energy captured through photovoltaic (PV) panels for electricity generation. Excess electricity is directed to an electrolyzer for water electrolysis producing hydrogen which is stored in high-pressure tanks. This hydrogen serves a dual purpose: it fuels a boiler for heating and hot water needs and powers a fuel cell for additional electricity when solar production is low. The system also features an intelligent energy management system that dynamically allocates electrical energy between immediate consumption hydrogen production and storage while also managing hydrogen release for energy production. This study focuses on optimization using genetic algorithms to optimize key components including the peak power of photovoltaic panels the nominal power of the electrolyzer fuel cell and storage tank sizes. The objective function minimizes the sum of investment and electricity costs from the grid considering a penalty coefficient. This approach ensures optimal use of renewable energy sources contributing to energy efficiency and sustainability in healthcare facilities.

The maritime industry is recognized as a major pollution source to the environment. The use of low- or zero-carbon marine alternative fuel is a promising measure to reduce emissions of greenhouse gases and toxic pollutants leading to net-zero carbon emissions by 2050. Hydrogen (H2 ) fuel cells particularly proton exchange membrane fuel cell (PEMFC) and ammonia (NH3 ) are screened out to be the feasible marine gaseous alternative fuels. Green hydrogen can reduce the highest carbon emission which might amount to 100% among those 5 types of hydrogen. The main hurdles to the development of H2 as a marine alternative fuel include its robust and energy-consuming cryogenic storage system highly explosive characteristics economic transportation issues etc. It is anticipated that fossil fuel used for 35% of vehicles such as marine vessels automobiles or airplanes will be replaced with hydrogen fuel in Europe by 2040. Combustible NH3 can be either burned directly or blended with H2 or CH4 to form fuel mixtures. In addition ammonia is an excellent H2 carrier to facilitate its production storage transportation and usage. The replacement of promising alternative fuels can move the marine industry toward decarbonization emissions by 2050.

Growing renewable energy deployment worldwide has sparked a shift in the energy landscape with far-reaching geopolitical ramifications. Hydrogen’s role as an energy carrier is central to this change facilitating global trade and the decarbonisation of hard-to-abate sectors. This analysis offers a new method for optimally sizing solar/wind-to-hydrogen systems in specifically suitable locations. These locations are limited to the onshore and offshore regions of selected countries as determined by a bespoke geospatial analysis developed to be location-agnostic. Furthermore the research focuses on determining the best configurations for such systems that minimise the cost of producing hydrogen with the optimisation algorithm expanding from the detailed computation of the classic levelised cost of hydrogen. One of the study’s main conclusions is that the best hybrid configurations obtained provide up to 70% cost savings in some areas. Such findings represent unprecedented achievements for Italy and Portugal and can be a valuable asset for economic studies of this kind carried out by local and national governments across the globe. These results validate the optimisation model’s initial premise significantly improving the credibility of this work by constructively challenging the standard way of assessing large-scale green hydrogen projects.

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.

This paper took the actual bus transportation system as the object simulated the operating state of the system replaced all the current diesel engine buses with fuel cell buses using electrolysis-produced hydrogen and completed the existing timetable and routes. In the study the numbers of hydrogen production stations and hydrogen storage stations the maximum hydrogen storage capacity of the buses the supplementary hydrogen capacity of the buses and the hydrogen production capacity of the hydrogen storage stations were used as the optimal adjustment parameters for minimizing the ten-year construction and operating costs of the fuel cell bus transportation system by the artificial bee colony algorithm. Two hydrogen supply methods decentralized and centralized hydrogen production were analyzed. This paper used the actual bus timetable to simulate the operation of the buses including 14 transfer stations and 112 routes. The results showed that the use of centralized hydrogen production and partitioned hydrogen production transfer stations could indeed reduce the construction and operating costs of the fuel cell bus transportation system. Compared with the decentralized hydrogen production case the construction and operating costs could be reduced by 6.9% 12.3% and 14.5% with one two and three zones for centralized hydrogen production respectively.

This paper investigates hydrogen’s potential to accelerate the energy transition in hardto-abate sectors such as steel petrochemicals glass cement and paper. The goal is to assess how hydrogen produced from renewable sources can foster both industrial decarbonization and the expansion of renewable energy installations especially solar and wind. Hydrogen’s dual role as a fuel and a chemical agent for process innovation is explored with a focus on its ability to enhance energy efficiency and reduce CO2 emissions. Integrating hydrogen with continuous industrial processes minimizes the need for energy storage making it a more efficient solution. Advances in electrolysis achieving efficiencies up to 60% and storage methods consuming about 10% of stored energy for compression are discussed. Specifically in the steel sector hydrogen can replace carbon as a reductant in the direct reduced iron (DRI) process which accounts for around 7% of global steel production. A next-generation DRI plant producing one million tons of steel annually would require approximately 3200 MW of photovoltaic capacity to integrate hydrogen effectively. This study also discusses hydrogen’s role as a co-fuel in steel furnaces. Quantitative analyses show that to support typical industrial plants hydrogen facilities of several hundred to a few thousand MW are necessary. “Virtual” power plants integrating with both the electrical grid and energy-intensive systems are proposed highlighting hydrogen’s critical role in industrial decarbonization and renewable energy growth.

Hydrogen threatens the structural integrity of metals and thus predicting hydrogen-material interactions is key to unlocking the role of hydrogen in the energy transition. Quantifying the interplay between material deformation and hydrogen diffusion ahead of cracks and other stress concentrators is key to the prediction and prevention of hydrogen-assisted failures. In this work a generalised theoretical and computational framework is presented that for the first time encompasses: (i) stress-assisted diffusion (ii) hydrogen trapping due to multiple trap types rigorously accounting for the rate of creation of dislocation trap sites (iii) hydrogen transport through dislocations (iv) equilibrium (Oriani) and non-equilibrium (McNabb-Foster) trapping kinetics (v) hydrogen-induced softening and (vi) hydrogen uptake considering the role of hydrostatic stresses and local electrochemistry. Particular emphasis is placed on the numerical implementation in COMSOL Multiphysics releasing the relevant models and discussing stability discretisation and solver details. Each of the elements of the framework is independently benchmarked against results from the literature and implications for the prediction of hydrogen-assisted fractures are discussed. The second part of this work (Part II) shows how these crack tip predictions can be combined with crack growth simulations.

Considering the clean renewable and ecologically friendly characteristics of hydrogen gas as well as its high energy density hydrogen energy is thought to be the most potent contender to locally replace fossil fuels. The creation of a sustainable energy system is currently one of the critical industrial challenges and electrocatalytic hydrogen evolution associated with appropriate safe storage techniques are key strategies to implement systems based on hydrogen technologies. The recent progress made possible through nanotechnology incorporation either in terms of innovative methods of hydrogen storage or production methods is a guarantee of future breakthroughs in energy sustainability. This manuscript addresses concisely and originally the importance of including nanotechnology in both green electroproduction of hydrogen and hydrogen storage in solid media. This work is mainly focused on these issues and eventually intends to change beliefs that hydrogen technologies are being imposed only for reasons of sustainability and not for the intrinsic value of the technology itself. Moreover nanophysics and nano-engineering have the potential to significantly change the paradigm of conventional hydrogen technologies.

This article analyzes a power-to-hydrogen system designed to provide high-temperature heat to hard-to-abate industries. We leverage on a geospatial analysis for wind and solar availability and different industrial demand profiles with the aim to identify the ideal sizing of plant components and the resulting Levelized Cost of Hydrogen (LCOH). We assess the carbon intensity of the produced hydrogen especially when grid electricity is utilized. A methodology is developed to size and optimize the PV and wind energy capacity the electrolyzer unit and hybrid storage by combining compressed hydrogen storage with lithium-ion batteries. The hydrogen demand profile is generated synthetically thus allowing different industrial consumption profiles to be investigated. The LCOH in a baseline scenario ranges from 3.5 to 8.9 €/kg with the lowest values in wind-rich climates. Solar PV only plays a role in locations with high PV full-load hours. It was found that optimal hydrogen storage can cover the users’ demand for 2–3 days. Most of the considered scenarios comply with the emission intensity thresholds set by the EU. A sensitivity analysis reveals that a lower variability of the demand profile is associated with cost savings. An ideally constant demand profile results in a cost reduction of approximately 11 %.

Hydrogen is a promising solution for the decarbonisation of several hard-to-abate end uses which are mainly in the industrial and transport sectors. The development of an extensive hydrogen delivery infrastructure is essential to effectively activate and deploy a hydrogen economy connecting production storage and demand. This work adopts a mixed-integer linear programming model to study the cost-optimal design of a future hydrogen infrastructure in presence of cross-sectoral hydrogen uses taking into account spatial and temporal variations multiple production technologies and optimised multi-mode transport and storage. The model is applied to a case study in the region of Sicily in Italy aiming to assess the infrastructural needs to supply the regional demand from transport and industrial sectors and to transfer hydrogen imported from North Africa towards Europe thus accounting for the region’s role as transit point. The analysis integrates multiple production technologies (electrolysis supplied by wind and solar energy steam reforming with carbon capture) and transport options (compressed hydrogen trucks liquid hydrogen trucks pipelines). Results show that the average cost of hydrogen delivered to demand points decreases from 3.75 €/kgH2 to 3.49 €/kgH2 when shifting from mobilityonly to cross-sectoral end uses indicating that the integrated supply chain exploits more efficiently the infrastructural investments. Although pipeline transport emerges as the dominant modality delivery via compressed hydrogen trucks and liquid hydrogen trucks remains relevant even in scenarios characterised by large hydrogen flows as resulting from cross-sectoral demand demonstrating that the system competitiveness is maximised through multi-mode integration.

This report outlines the methods and assumptions used in the hydrogen technology market analysis. The results of the analysis are presented in The UK Hydrogen Innovation Opportunity and the supporting report Hydrogen technology roadmaps. They include forecasts for the following market data:

○ Global hydrogen economy The overall size of the global hydrogen economy in 2023 2030 and 2050.

○ Global and UK hydrogen technology market by technology family

This is the proportion of the total future hydrogen economy attributable to hydrogen-related technologies in 2023 2030 and 2050. The hydrogen economy is defined as the ‘end-to-end’ value created from hydrogen production storage & distribution and use. This includes the direct economic value associated with production and distribution of hydrogen as a fuel or chemical feedstock hydrogen infrastructure technologies products services and the indirect economic value created through products and services that indirectly support the use of hydrogen in industry transport power generation and heating. This endto-end definition of the hydrogen economy is represented in Figure 1 overleaf.

This report can also be downloaded for free on the Hydrogen Innovation Initiative website.

Small modular reactors (SMRs) are nuclear reactors with a smaller capacity than traditional large-scale nuclear reactors offering advantages such as increased safety flexibility and cost-effectiveness. By producing zero carbon emissions SMRs represent an interesting alternative for the decarbonization of power grids. Additionally they present a promising solution for the production of hydrogen by providing large amounts of energy for the electrolysis of water (pink hydrogen). The above hint at the attractiveness of coupling SMRs with hydrogen production and consumption centers in order to form clusters of applications which use hydrogen as a fuel. This work showcases the techno-economic feasibility of the potential installation of an SMR system coupled with hydrogen production the case study being the island of Crete. The overall aim of this approach is the determination of the optimal technical characteristics of such a system as well as the estimation of the potential environmental benefits in terms of reduction of CO2 emissions. The aforementioned system which is also connected to the grid is designed to serve a portion of the electric load of the island while producing enough hydrogen to satisfy the needs of the nearby industries and hotels. The results of this work could provide an alternative sustainable approach on how a hydrogen economy which would interconnect and decarbonize several industrial sectors could be established on the island of Crete. The proposed systems achieve an LCOE between EUR 0.046/kWh and EUR 0.052/kWh while reducing carbon emissions by more than 5 million tons per year in certain cases.

This article discusses possible strategies for decarbonizing the energy systems of an existing port. The approach consists in creating a complete superstructure that includes the use of renewable and fossil energy sources the import or local production of hydrogen vehicles and other equipment powered by Diesel electricity or hydrogen and the associated refuelling and storage units. Two substructures are then identified one including all these options the other considering also the addition of the energy demand of an adjacent steel industry. The goal is to select from each of these two substructures the most cost-effective configurations for 2030 and 2050 that meet the emission targets for those years under different cost scenarios for the energy sources and conversion/storage units obtained from the most reliable forecasts found in the literature. To this end the minimum total cost of all the energy conversion and storage units plus the associated infrastructures is sought by setting up a Mixed Integer Linear Programming optimization problem where integer variables handle the inclusion of the different generation and storage units and their activation in the operational phases. The comprehensive picture of possible solutions set allows identifying which options can most realistically be realized in the years to come in relation to the different assumed cost scenarios. Optimization results related to the scenario projected to 2030 indicate the key role played by Diesel hybrid and electric systems while considering the most stringent or much more stringent scenarios for emissions in 2050 almost all vehicles energy demand and industry hydrogen demand is met by hydrogen imported as ammonia by ship.

Current climate crisis makes the need for reducing carbon emissions more than evident. For this reason renewable energy sources are expected to play a fundamental role. However these sources are not controllable but depend on the weather conditions. Therefore green hydrogen (hydrogen produced from water electrolysis using renewable energies) is emerging as the key energy carrier to solve this problem. Although different properties of hydrogen have been widely studied some key aspects such as the water and energy footprint as well as the technological development and the regulatory framework of green hydrogen in different parts of the world have not been analysed in depth. This work performs a data-driven analysis of these three pillars: water and energy footprint technological maturity and regulatory framework of green hydrogen technology. Results will allow the evaluation of green hydrogen deployment both the current situation and expectations. Regarding the water footprint this is lower than that of other fossil fuels and competitive with other types of hydrogen while the energy footprint is higher than that of other fuels. Additionally results show that technological and regulatory framework for hydrogen is not fully developed and there is a great inequality in green hydrogen legislation in different regions of the world.

Electrification using renewable energy sources represents a clear path toward solving the current global energy crisis. In Colombia this challenge also involves the diversification of the electrical energy sources to overcome the historical dependence on hydropower. In this context green hydrogen represents a key energy carrier enabling the storage of renewable energy as well as directly powering industrial and transportation sectors. This work explores the realistic potential of the main renewable energy sources including solar photovoltaics (8172 GW) hydropower (56 GW) wind (68 GW) and biomass (14 GW). In addition a case study from abroad is presented demonstrating the feasibility of using each type of renewable energy to generate green hydrogen in the country. At the end an analysis of the most likely regions in the country and paths to deploy green hydrogen projects are presented favoring hydropower in the short term and solar in the long run. By 2050 this energy potential will enable reaching a levelized cost of hydrogen (LCOH) of 1.7 1.5 3.1 and 1.4 USD/kg-H2 for solar photovoltaic wind hydropower and biomass respectively.

Heat flux on walls from under-expanded H2/AIR jet flames have been numerically investigated. The thermal behaviour of a plate close to different under-expanded jet flames has been compared with rear-face plate temperature measurements. In this study two straight nozzles with millimetric diameter were selected with H2 reservoir pressure in a range from 2 to 10 bar. The CFD study of these two quite different horizontal jet flames employs the Large Eddy Simulation (LES) formalism to capture the turbulent flame-wall interaction. The results demonstrated a good agreement with experimental wall heat fluxes computed from plate temperature measurements. The present study assesses the prediction capability of LES for flame-wall heat transfer.

Plastics have become integral to modern life playing crucial roles in diverse industries such as agriculture electronics automotive packaging and construction. However their excessive use and inadequate management have had adverse environmental impacts posing threats to terrestrial and marine ecosystems. Consequently researchers are increasingly searching for more sustainable ways of managing plastic wastes. Pyrolysis a chemical recycling method holds promise for producing valuable fuel sustainably. This study explores the process of the pyrolysis of plastic and incorporates recent advancements. Additionally the study investigates the integration of reforming into the pyrolysis process to improve hydrogen production. Hydrogen a clean and eco-friendly fuel holds significance in transport engines power generation fuel cells and as a major commodity chemical. Key process parameters influencing the final products for pyrolysis and in-line reforming are evaluated. In light of fossil fuel depletion and climate change the pyrolysis and in-line reforming strategy for hydrogen production is anticipated to gain prominence in the future. Amongst the various strategies studied the pyrolysis and in-line steam reforming process is identified as the most effective method for optimising hydrogen production from plastic wastes.

Acting in accordance with the requirements of the 2015 Paris Agreement Poland as well as other European Union countries have committed to achieving climate neutrality by 2050. One of the solutions to reduce emissions of harmful substances into the environment is the implementation of large-scale hydrogen technologies. This article presents the cost of producing green hydrogen produced using an alkaline electrolyzer with electricity supplied from a photovoltaic farm. The analysis was performed using the Monte Carlo method and for baseline assumptions including an electricity price of 0.053 EUR/kWh the cost of producing green hydrogen was 5.321 EUR/kgH2 . In addition this article presents a sensitivity analysis showing the impact of the electricity price before and after the energy crisis and other variables on the cost of green hydrogen production. The large change occurring in electricity prices (from 0.035 EUR/kWh to 0.24 EUR/kWh) significantly affected the levelized cost of green hydrogen (LCOH) which could change by up to 14 EUR/kgH2 in recent years. The results of the analysis showed that the parameters that successively have the greatest impact on the cost of green hydrogen production are the operating time of the plant and the unit capital expenditure. The development of green hydrogen production facilities along with the scaling of technology in the future can reduce the cost of its production.

Hydrogen produced from renewable energy sources is a valuable energy carrier for linking growing renewable electricity generation with the hard-to-abate sectors such as cement steel glass chemical and ceramics industries. In this context this paper presents a new model of hydrogen production based on solar photovoltaics and wind energy with application to a real-world ceramics factory. For this task a novel multipurpose profit-maximizing model is implemented using GAMS. The developed model explores hydrogen production with multiple value streams that enable technical and economical informed decisions under specific scenarios. Our results show that it is profitable to sell the hydrogen produced to the gas grid rather than using it for self-consumption for low-gas-price scenarios. On the other hand when the price of gas is significantly high it is more profitable to use as much hydrogen as possible for self-consumption to supply the factory and reduce the internal use of natural gas. The role of electricity self-consumption has proven to be key for the project’s profitability as without this revenue stream the project would not be profitable in any analysed scenario.

Increasing the share of renewable energy sources (RESs) in the energy mix of countries is one of the main objectives of the energy transition in national economies which must be established on circular economy principles. In the natural gas storage in geological structures (UGSs) natural gas is stored in a gas reservoir at high reservoir pressure. During a withdrawal cycle the energy of the stored pressurised gas is irreversibly lost at the reduction station chokes. At the same time there is a huge amount of produced reservoir water which is waste and requires energy for underground disposal. The manuscript explores harnessing the exergy of the conventional UGS reduction process to generate electricity and produce hydrogen via electrolysis using reservoir-produced water. Such a model which utilises sustainable energy sources within a circular economy framework is the optimal approach to achieve a clean energy transition. Using an innovative integrated mathematical model based on real UGS production data the study evaluated the application of a turboexpander (TE) for electricity generation and hydrogen production during a single gas withdrawal cycle. The simulation results showed potential to produce 70 tonnes of hydrogen per UGS withdrawal cycle utilising 700 m3 of produced field water. The analysis showed that hydrogen production was sensitive to gas flow changes through the pressure reduction station underscoring the need for process optimisation to maximise hydrogen production. Furthermore the paper considered the categorisation of this hydrogen as “green” as it was produced from the energy of pressurised gas a carbon-free process.

As the country that emits the most carbon in the world China needs significant and urgent changes in carbon emission control in the transportation sector in order to achieve the goals of reaching peak carbon emissions before 2030 and achieving carbon neutrality by 2060. Therefore the promotion of new energy vehicles has become the key factor to achieve these two objectives. For the reason that the comprehensive transportation cost directly affects the end customer’s choice of heavy truck models this work compares the advantages disadvantages and economic feasibility of diesel liquefied natural gas (LNG) electric hydrogen and methanol heavy trucks from a total life cycle cost and end-user perspective under various scenarios. The study results show that when the prices of diesel LNG electricity and methanol fuels are at their highest and the price of hydrogen is 35 CNY/kg the total life cycle cost of the five types of heavy trucks from highest to lowest are hydrogen heavy trucks (HHT) methanol heavy trucks (MHT) diesel heavy trucks (DHT) electric heavy trucks (EHT) and LNG heavy trucks (LNGHT) ignoring the adverse effects of cold environments on car batteries. When the prices of diesel LNG electricity and methanol fuels are at average or lowest levels and the price of hydrogen is 30 CNY/kg or 25 CNY/kg the life cycle cost of the five heavy trucks from highest to lowest are HHT DHT MHT EHT and LNGHT. When considering the impact of cold environments even with lower electricity prices EHT struggle to be economical when LNG prices are low. If the electricity price is above 1 CNY/kWh regardless of the impact of cold environments the economic viability of EHT is lower than that of HHT with a purchase cost of 500000 CNY and a hydrogen price of 25 CNY/kg. Simultaneously an exhaustive competitiveness analysis of heavy trucks powered by diverse energy sources highlights the specific categories of heavy trucks that ought to be prioritized for development during various periods and the challenges they confront. Finally based on the analysis results and future development trends the corresponding policy recommendations are proposed to facilitate high decarbonization in the transportation sector.

With the development of an energy sector based on renewable primary sources structural changes are emerging for the entire national energy system. Initially it was estimated that energy generation based on fossil fuels would decrease until its disappearance. However the evolution of CO2 capture capacity leads to a possible coexistence for a certain period with the renewable energy sector. The paper develops this concept of the coexistence of the two systems with the positioning of green hydrogen not only within the renewable energy sector but also as a transformation vector for carbon dioxide captured in the form of synthetic fuels such as CH4 and CH3OH. The authors conducted pilot-scale research on CO2 capture with green H2 both for pure (captured) CO2 and for CO2 found in combustion gases. The positive results led to the respective recommendation. The research conducted by the authors meets the strict requirements of the current energy phase with the authors considering that wind and solar energy alone are not sufficient to meet current energy demand. The paper also analyzes the economic aspects related to price differences for energy produced in the two sectors as well as their interconnection. The technical aspect as well as the economic aspect of storage through various other solutions besides hydrogen has been highlighted. The development of the renewable energy sector and its demarcation from the fossil fuel energy sector even with the transcendent vector represented by green hydrogen leads to the deepening of dispersion aspects between the electricity sector and the thermal energy sector a less commonly mentioned aspect in current works but of great importance. The purpose of this paper is to highlight energy challenges during the current transition period towards climate neutrality along with solutions proposed by the authors to be implemented in this phase. The current stage of combustion of the CH4 − H2 mixture imposes requirements for the capture of the resulting CO2.

This paper presents an innovative approach to fast frequency control in electric grids by leveraging parked fuel cell electric vehicles (FCEVs) especially heavy-duty vehicles such as trucks. Equipped with hydrogen storage tanks and fuel cells these vehicles can be repurposed as dynamic grid-support assets while parked in designated areas. Using an external cable and inverter system FCEVs inject power into the grid by converting DC from fuel cells into AC to be compatible with grid requirements. This functionality addresses sudden power imbalances providing a rapid and efficient solution for frequency stabilization. The system’s external inverter serves as a central control hub monitoring real-time grid frequency and directing FCEVs to supply virtual inertia and primary reserves through droop control as required. Simulation results validate that FCEVs could effectively complement thermal generators preventing unacceptable frequency drops load shedding and network blackouts. A techno-economic analysis demonstrates the economic feasibility of the concept concluding that each FCEV consumes approximately 0.3 kg of hydrogen per day incurring a daily cost of around EUR 1.5. For an island grid with a nominal power of 100 MW maintaining frequency stability requires a fleet of 100 FCEVs resulting in a total daily cost of EUR 150. Compared to a grid-scale battery system offering equivalent frequency response services the proposed solution is up to three times more cost-effective highlighting its economic and technical potential for grid stabilization in renewable-rich non-interconnected power systems.

In this study we evaluate the technical viability of storing hydrogen in a deep UKCS aquifer formation through a series of numerical simulations utilising the compositional simulator CMG-GEM. Effects of various operational parameters such as injection and production rates number and length of storage cycles and shut-in periods on the performance of the underground hydrogen storage (UHS) process are investigated in this study. Results indicate that higher H2 operational rates degrade both the aquifer's working capacity and H2 recovery during the withdrawal phase. This can be attributed to the dominant viscous forces at higher rates which lead to H2 viscous fingering and gas gravity override of the native aquifer water resulting in an unstable displacement of water by the H2 gas. Furthermore analysis of simulation results shows that longer and less frequent storage cycles lead to higher storage capacity and decreased H2 retrieval. We conclude that UHS in the studied aquifer is technically feasible however a thorough evaluation of the operational parameters is necessary to optimise both storage capacity and H2 recovery efficiency.

Given the global effort to embrace research actions and technology enhancement for the energy transition innovative sustainable systems are needed both for energy production and for those sectors that are responsible for high pollution and CO2 emissions. In this context electrolytic cells and fuel cells in their variety and flexibility are energy systems characterized by high efficiency and important performance guaranteeing a sustainable solution for future energy systems and for the circular economy. The scope of this paper is therefore to present the state of the art of such systems. An overview of the electrolyzers for hydrogen production is presented by detailing the level of applications for their different technologies from low-temperature units to high-temperature units the fuel flexibility the electrolysis and co-electrolysis mode and the potential coupling with renewable sources. Fuel cell-based systems are also presented and their application in the mobility sector is investigated by considering road transport with light-duty and heavy-duty applications and marine transport. A comparison with conventional technologies will be also presented providing some hints on the potential applications of electrolytic cells and fuel cell systems given their important contribution to the sustainable and circular economy.

The increase in industrial production and energy consumption has led to excessive exploitation of non-renewable resources resulting in serious environmental problems such as greenhouse gas emissions. In response there’s a growing investment in renewable energies such as hydroelectric wind and solar power. However these sources are unable to fully meet demand leading to imbalances between consumption and production. An emerging solution to this challenge is green hydrogen produced from clean sources reducing dependence on fossil fuels and mitigating greenhouse gas emissions. The S-LCA methodology presented in the UNEP/SETAC Guidelines for the Social Life Cycle Assessment is applied to the production of green hydrogen via the electrolytic separation of water using a proton exchange electrolyser. The process involves the extraction and processing of raw materials from the electrolyser BOP and reverse osmosis system the manufacture of the systems and the production of green hydrogen. The data from each stage is inventoried and entered into the PSILCA v.3.1 and SHDB 2022FV5 databases integrated into the SimaPro software version 9.3.0.2 enabling a complete analysis of the social im pacts associated with the production of green hydrogen. The data was evaluated considering 4 stakeholder categories: workers value chain actors society and local community. The results indicate that the extraction and processing of raw materials for the electrolyser was the primary stage responsible for the social impacts in both databases. However the electrolyser manufacturing stage was the main contributor to the indicators “weekly working hours per employee” and “union density” in the PSILCA database. Nafion® and Iridium were identified as the major contributors among components in both databases. The study highlights the significant role played by countries like China and South Africa in social impacts particularly in the extraction and processing of raw materials. Despite this Portugal emerged as the largest contributor to five out of fourteen indicators in the PSILCA database while its contributions in the SHDB database were less than 7 %. Moreover a comparison between the two databases revealed that PSILCA exhibited a greater distribution of results across various stages components and countries assessed whereas SHDB showed more centralized results. The observed discrepancies between the results obtained from different databases can be attributed to three main factors: the input-output database utilized in each S-LCA tool the assumed risk levels for each indicator and the equivalence between indicators and subcategories. This exploratory study offers valuable insights for guiding strategic decisions regarding the social component of sustainability providing a detailed understanding of the social impacts associated with the specific case of green hydrogen production in a planned hub in Portugal.

Hydrogen fuel cell vehicles (HFCVs) represent an important breakthrough in the hydrogen energy industry. The safe utilization of hydrogen is critical for the sustainable and healthy development of hydrogen fuel cell vehicles. In this study risk factors and preventive measures are proposed for on-board hydrogen systems during the process of transportation storage and use of fuel cell vehicles. The relevant hydrogen safety standards in China are also analyzed and suggestions involving four safety strategies and three safety standards are proposed.

This study investigates the spillover effects between hydrogen energy nuclear energy and artificial intelligence (AI) sectors in the context of the global clean energy transition with a particular focus on the impact of climate policy uncertainty (CPU) and geopolitical risks (GPR). Employing the TVP-VAR extended joint connectedness approach the findings show a high connectedness that indicates significant spillovers among these sectors. Hydrogen energy emerges as a dominant transmitter of shocks reflecting its sensitivity to regulatory changes and fluctuating demand. However nuclear energy acts as a stabilising force that offers hedging opportunities and resilience against market turbulence. The AI sector exhibits strong connectedness primarily as a net receiver of shocks driven by its dependency on clean energy sources and vulnerability to energy market volatility. Using the GARCHMIDAS framework the study identifies a temporal asymmetry in market responses to CPU and GPR. CPU triggers immediate but short-lived disruptions while GPR induces delayed yet persistent effects that intensify cross-sector spillovers over time. These results underline the vulnerabilities of sectors reliant on regulatory clarity and geopolitical stability. This study provides practical insights for investors policymakers technology and energy companies to better manage systemic risks at the crossroads of clean energy technological innovation and uncertainty.

Over the last few years hydrogen has emerged as a promising solution for problems related to energy sources and pollution concerns. The integration of hydrogen in the transport sector is one of the possible various applications and involves the implementation of hydrogen refueling stations (HRSs). A key obstacle for HRS deployment in addition to the need for well-developed technologies is the economic factor since these infrastructures require high capital investments costs and are largely dependent on annual operating costs. In this study we review hydrogen’s application as a fuel summarizing the principal systems involved in HRS from production to the final refueling stage. In addition we also analyze the main equipment involved in the production compression and storage processes of hydrogen. The current work also highlights the main refueling processes that impact energy consumption and the methodologies presented in the literature for energy management strategies in HRSs. With the aim of reducing energy costs due to processes that require high energy consumption most energy management strategies are based on the use of renewable energy sources in addition to the use of the power grid.

This review explores recent advancements in hydrogen gas (H2 ) safety through the lens of artificial intelligence (AI) techniques. As hydrogen gains prominence as a clean energy source ensuring its safe handling becomes paramount. The paper critically evaluates the implementation of AI methodologies including artificial neural networks (ANN) machine learning algorithms computer vision (CV) and data fusion techniques in enhancing hydrogen safety measures. By examining the integration of wireless sensor networks and AI for real-time monitoring and leveraging CV for interpreting visual indicators related to hydrogen leakage issues this review highlights the transformative potential of AI in revolutionizing safety frameworks. Moreover it addresses key challenges such as the scarcity of standardized datasets the optimization of AI models for diverse environmental conditions etc. while also identifying opportunities for further research and development. This review foresees faster response times reduced false alarms and overall improved safety for hydrogen-related applications. This paper serves as a valuable resource for researchers engineers and practitioners seeking to leverage state-of-the-art AI technologies for enhanced hydrogen safety systems.

During the last decade developing more sustainable transportation modes has become a primary objective for car manufacturers and governments around the world to mitigate environmental issues such as climate change the continuous increase in greenhouse gas (GHG) emissions and energy depletion. The use of hydrogen fuel cell technology as a source of energy in electric vehicles is considered an emerging and promising technology that could contribute significantly to addressing these environmental issues. In this study the effects of Hydrogen Fuel Cell Battery Electric Vehicles (HFCBEVs) on global GHG emissions compared to other technologies such as BEVs were determined based on different relevant factors such as predicted sales for 2050 (the result of the developed prediction model) estimated daily traveling distance estimated future average global electricity emission factors future average Battery Electric Vehicle (BEV) emission factors future global hydrogen production emission factors and future average HFCBEV emission factors. As a result the annual GHG emissions produced by passenger cars that are expected to be sold in 2050 were determined by considering BEV sales in the first scenario and HFCBEV replacement in the second scenario. The results indicate that the environmental benefits of HFCBEVs are expected to increase over time compared to those of BEVs due to the eco-friendly methods that are expected to be used in hydrogen production in the future. For instance in 2021 HFCBEVs could produce more GHG emissions than BEVs by 54.9% per km of travel whereas in 2050 BEVs could produce more GHG emissions than HFCBEVs by 225% per km of travel.