United States

To achieve carbon neutrality in Japan by 2050 renewable energy needs to be used as the main energy source. Based on the constraints of various renewable energies the importance of hydrogen cannot be ignored. This study aimed to investigate the diffusion of hydrogen demand technologies in various sectors and used projections and assumptions to investigate the hydrogen supply side. By performing simulations with the E3ME-FTT model and comparing various policy scenarios with the reference scenario the economic and environmental impacts of the policy scenarios for hydrogen diffusion were analyzed. Moreover the impact of realizing carbon neutrality by 2050 on the Japanese economy was evaluated. Our results revealed that large-scale decarbonization via hydrogen diffusion is possible (90% decrease of CO2 emissions in 2050 compared to the reference) without the loss of economic activity. Additionally investments in new hydrogen-based and other low-carbon technologies in the power sector freight road transport and iron and steel industry can improve the gross domestic product (1.6% increase in 2050 compared to the reference) as they invoke economic activity and require additional employment (0.6% increase in 2050 compared to the reference). Most of the employment gains are related to decarbonizing the power sector and scaling up the hydrogen supply sector while a lot of job losses can be expected in the mining and fossil fuel industries.

Hydrogen-fueled aircraft are a promising innovation for a sustainable future in aviation. While hydrogen aircraft design has been widely studied research on airport requirements for new infrastructure associated with hydrogen-fueled aircraft and its integration with existing facilities is scarce. This study analyzes the current body of knowledge and identifies the planning challenges which need to be overcome to enable the operation of hydrogen flights at airports. An investigation of the preparation of seven major international airports for hydrogen-powered flights finds that although there is commitment airports are not currently prepared for hydrogen-based flights. Major adjustments are required across airport sites covering land use plans airside development utility infrastructure development and safety security and training. Developments are also required across the wider aviation industry including equipment updates such as for refueling and ground support and supportive policy and regulations for hydrogen-powered aircraft. The next 5–10 years is identified from the review as a critical time period for airports given that the first commercial hydrogen-powered flight is likely to depart in 2026 and that the next generation of short-range hydrogen-powered aircraft is predicted to enter service between 2030 and 2035.

The increasingly severe energy crisis has strengthened the determination todevelop environmentally friendly energy. And hydrogen has emerged as a candi-date for clean energy. Among many hydrogen generation methods biohydrogenstands out due to its environmental sustainability simple operating environ-ment and cost advantages. This review focuses on the rational design of catalystsfor fermentative hydrogen production. The principles of microbial dark fermen-tation and photo-fermentation are elucidated exhaustively. Various strategiesto increase the efficiency of fermentative hydrogen production are summa-rized and some recent representative works from microbial dark fermentationand photo-fermentation are described. Meanwhile perspectives and discussionson the rational design of catalysts for fermentative hydrogen production areprovided.

Diesel fuel combustion results in exhaust containing air pollutants and greenhouse gas emissions. Many railway vehicles use diesel fuel as their energy source. Exhaust emissions as well as concerns about economical alternative power supply have driven efforts to move to hydrogen motive power. Hydrogen fuel cell technology applied to railways offers the opportunity to eliminate harmful exhaust emissions and the potential for a low- or zero-emission energy supply chain. Currently only multiple-unit trains with hydrail technology operate commercially. Development of an Integrated Hybrid Train Simulator for intercity railway is presented. The proposed tool incorporates the effect of powertrain components during the wheel-to-tank process. Compared to its predecessors the proposed reconfigurable tool provides high fidelity with medium requirements and minimum computation time. Single train simulation and the federal government’s Greenhouse gases Regulated Emissions and Energy use in Transportation (GREET) model are used in combination to evaluate the feasibility of various train and powertrain configurations. The Piedmont intercity service operating in North Carolina is used as a case study. The study includes six train configurations and powertrain options as well as nine hydrogen supply options in addition to the diesel supply. The results show that a hydrail option is not only feasible but a low- or zero-carbon hydrogen supply chain could be possible.

This paper presents a mathematical model for a multi-period hydrogen supply chain design problem considering several design features not addressed in other studies. The model is formulated as a mixed-integer program allowing the production and storage facilities to be extended over time. Pipeline and tube trailer transport modes are considered for carrying hydrogen. The model also allows finding the optimal pipeline routes and the number of transport units. The objective is to obtain an efficient supply chain design within a given time frame in a way that the demand and carbon dioxide emissions constraints are satisfied and the total cost is minimized. A computer program is developed to ease the problem-solving process. The computer program extracts the geographical information from Google Maps and solves the problem using an optimization solver. Finally the applicability of the proposed model is demonstrated in a case study from Oman.

Steam methane reforming (SMR) currently supplies 76% of the world’s hydrogen (H2) demand totaling ∼70 million tonnes per year. Developments in H2 production technologies are required to meet the rising demand for cleaner less costly H2. Therefore palladium membrane reactors (Pd-MR) have received significant attention for their ability to increase the efficiency of traditional SMR. This study performs novel economic analyses and constrained nonlinear optimizations on an intensified SMR process with a Pd-MR. The optimization extends beyond the membrane’s operation to present process set points for both the conventional and intensified H2 processes. Despite increased compressor and membrane capital costs along with electric utility costs the SMR-MR design offers reductions in the natural gas usage and annual costs. Economic comparisons between each plant show Pd membrane costs greater than $25 000/m2 are required to break even with the conventional design for membrane lifetimes of 1–3 years. Based on the optimized SMR-MR process this study concludes with sensitivity analyses on the design operational and cost parameters for the intensified SMR-MR process. Overall with further developments of Pd membranes for increased stability and lifetime the proposed SMR-MR design is thus profitable and suitable for intensification of H2 production.

Green hydrogen is considered to be one of the best candidates for fossil fuels in the near future. Bio-hydrogen production from the dark fermentation of organic materials including organic wastes is one of the most cost-effective and promising methods for hydrogen production. One of the main challenges posed by this method is the low production rate. Therefore optimizing the operating parameters such as the initial pH value operating temperature N/C ratio and organic concentration (xylose) plays a significant role in determining the hydrogen production rate. The experimental optimization of such parameters is complex expensive and lengthy. The present research used an experimental data asset adaptive network fuzzy inference system (ANFIS) modeling and particle swarm optimization to model and optimize hydrogen production. The coupling between ANFIS and PSO demonstrated a robust effect which was evident through the improvement in the hydrogen production based on the four input parameters. The results were compared with the experimental and RSM optimization models. The proposed method demonstrated an increase in the biohydrogen production of 100 mL/L compared to the experimental results and a 200 mL/L increase compared to the results obtained using ANOVA.

Seasonal storage of natural gas (NG) which primarily consists of methane (CH4) has been practiced for more than a hundred years at underground gas storage (UGS) facilities that use depleted hydrocarbon reservoirs saline aquifers and salt caverns. To support a transition to a hydrogen (H2) economy similar facilities are envisioned for long-duration underground H2 storage (UHS) of either H2 or H2/CH4 mixtures. Experience with UGS can be used to guide the deployment of UHS so we identify and quantify factors (formation/fluid properties and engineering choices) that influence reservoir behavior (e.g. viscous fingering and gravity override) the required number of injection/withdrawal wells and required storage volume contrasting the differences between the storage of CH4 H2 and H2/CH4 mixtures. The most important engineering choices are found to be the H2 fraction in H2/CH4 mixtures storage depth and injection rate. Storage at greater depths (higher pressure) but with relatively lower temperature is more favorable because it maximizes volumetric energy-storage density while minimizing viscous fingering and gravity override due to buoyancy. To store an equivalent amount of energy storing H2/CH4 mixtures in UHS facilities will require more wells and greater reservoir volume than corresponding UGS facilities. We use our findings to make recommendations about further research needed to guide deployment of UHS in porous reservoirs.

A global energy shift to a carbon‐neutral society requires clean energy. Hydrogen can accelerate the process of expanding clean and renewable energy sources. However conventional hydrogen compression and storage technology still suffers from inefficiencies high costs and safety concerns. An electrochemical hydrogen compressor (EHC) is a device similar in structure to a water electrolyzer. Its most significant advantage is that it can accomplish hydrogen separation and compression at the same time. With no mechanical motion and low energy consumption the EHC is the key to future hydrogen compression and purification technology breakthroughs. In this study the compression performance efficiency and other related parameters of EHC are investigated through experiments and simulation calculations. The experimental results show that under the same experimental conditions increasing the supply voltage and the pressure in the anode chamber can improve the reaction rate of EHC and balance the pressure difference between the cathode and anode. The presence of residual air in the anode can impede the interaction between hydrogen and the catalyst as well as the proton exchange membrane (PEM) resulting in a decrease in performance. In addition it was found that a single EHC has a better compression ratio and reaction rate than a double EHC. The experimental results were compatible with the theoretical calculations within less than a 7% deviation. Finally the conditions required to reach commercialization were evaluated using the theoretical model.

At scale biomass-based fuels are seen as long-term alternatives to conventional shipping fuels to reduce greenhouse gas emissions in the maritime sector. While the operational benefits of renewable methanol as a marine fuel are well-known its cost and environmental performance depend largely on production method and geographic context. In this study a techno-economic and environmental assessment of renewable methanol produced by gasification of forestry residues is performed. Two biorefinery systems are modeled thermody namically for the first time integrating several design changes to extend past work: (1) methanol synthesized by gasification of torrefied biomass while removing and storing underground a fraction of the carbon initially contained in it and (2) integration of a polymer electrolyte membrane (PEM) electrolyzer for increased carbon efficiency via hydrogen injection into the methanol synthesis process. The chosen use case is set in California with forest residue biomass as the feedstock and the ports of Los Angeles and Long Beach as the shipping fuel demand point. Methanol produced by both systems achieves substantial lifecycle greenhouse gas emissions savings compared to traditional shipping fuels ranging from 38 to 165% from biomass roadside to methanol combustion. Renewable methanol can be carbon-negative if the CO2 captured during the biomass conversion process is sequestered underground with net greenhouse gas emissions along the lifecycle amounting to − 57 gCO2eq/MJ. While the produced methanol in both pathways is still more expensive than conventional fossil fuels the introduction of CO2eq abatement incentives available in the U.S. and California could bring down minimum fuel selling prices substantially. The produced methanol can be competitive with fossil shipping fuels at credit amounts ranging from $150 to $300/tCO2eq depending on the eligible credits.

High-temperature proton exchange membranes (HT-PEMs) for fuel cells are considered transformative technologies for efficient energy conversion particularly in hydrogen-based transportation owing to their ability to deliver high power density and operational efficiency in harsh environments. However several critical challenges limit their broader adoption notably the limited durability and high costs associated with core components such as membranes and electrocatalysts under elevated temperature conditions. This review systematically addresses these challenges by examining the role of engineered nanomaterials in overcoming performance and stability limitations. The potential of nanomaterials to improve catalytic activity proton conductivity and thermal stability is discussed in detail emphasizing their impact on the optimization of catalyst layer composition including catalysts binders phosphoric acid electrolytes and additives. Recent advancements in nanostructured assemblies and 3D morphologies are explored to enhance fuel cell efficiency through synergistic interactions of these components. Additionally ongoing issues such as catalyst degradation long-term stability and resistance to high-temperature operation are critically analyzed. This manuscript offers a comprehensive overview of current HT-PEMs research and proposes future material design strategies that could bridge the gap between laboratory prototypes and large-scale industrial applications.

We combine state-of-the-art thermo-metallurgical welding process modeling with coupled diffusion-elastic– plastic phase field fracture simulations to predict the failure states of hydrogen transport pipelines. This enables quantitatively resolving residual stress states and the role of brittle hard regions of the weld such as the heat affected zone (HAZ). Failure pressures can be efficiently quantified as a function of asset state (existing defects) materials and weld procedures adopted and hydrogen purity. Importantly simulations spanning numerous relevant conditions (defect size and orientations) are used to build Virtual Failure Assessment Diagrams (FADs) enabling a straightforward uptake of this mechanistic approach in fitness-for-service assessment. Model predictions are in very good agreement with FAD approaches from the standards but show that the latter are not conservative when resolving the heterogeneous nature of the weld microstructure. Appropriate mechanistic FAD safety factors are established that account for the role of residual stresses and hard brittle weld regions.

Green hydrogen is gaining global attention as a zero-carbon energy carrier with the potential to drive sustainable energy transitions particularly in regions facing rising fossil fuel costs and resource depletion. In sub-Saharan Africa financing mechanisms and structured off-take agreements are critical to attracting investment across the green hydrogen value chain from advisory and pilot stages to full-scale deployment. While substantial funding is required to support a green economic transition success will depend on the effective mobilization of capital through smart public policies and innovative financial instruments. This review evaluates financing mechanisms relevant to sub-Saharan Africa including green bonds public–private partnerships foreign direct investment venture capital grants and loans multilateral and bilateral funding and government subsidies. Despite their potential current capital flows remain insufficient and must be significantly scaled up to meet green energy transition targets. This study employs a mixed-methods approach drawing on primary data from utility firms under the H2Atlas-Africa project and secondary data from international organizations and the peer-reviewed literature. The analysis identifies that transitioning toward Net-Zero emissions economies through hydrogen development in sub-Saharan Africa presents both significant opportunities and measurable risks. Specifically the results indicate an estimated investment risk factor of 35% reflecting potential challenges such as financing infrastructure and policy readiness. Nevertheless the findings underscore that green hydrogen is a viable alternative to fossil fuels in subSaharan Africa particularly if supported by targeted financing strategies and robust policy frameworks. This study offers practical insights for policymakers financial institutions and development partners seeking to structure bankable projects and accelerate green hydrogen adoption across the region.

Hydrogen is widely recognized as a key enabler of the clean energy transition but the lack of safe efficient and scalable storage technologies continues to hinder its broad deployment. Conventional hydrogen storage approaches such as compressed hydrogen storage cryo-compressed hydrogen storage and liquid hydrogen storage face limitations including high energy consumption elevated cost weight and safety concerns. In contrast solid-state hydrogen storage using carbon-based adsorbents has gained growing attention due to their chemical tunability low cost and potential for modular integration into energy systems. This review provides a comprehensive evaluation of hydrogen storage using carbon-based materials covering fundamental adsorption mechanisms classical materials emerging architectures and recent advances in computationally AI-guided material design. We first discuss the physicochemical principles driving hydrogen physisorption chemisorption Kubas interaction and spillover effects on carbon surfaces. Classical adsorbents such as activated carbon carbon nanotubes graphene carbon dots and biochar are evaluated in terms of pore structure dopant effects and uptake capacity. The review then highlights recent progress in advanced carbon architectures such as MXenes three-dimensional architectures and 3D-printed carbon platforms with emphasis on their gravimetric and volumetric performance under practical conditions. Importantly this review introduces a forward-looking perspective on the application of artificial intelligence and machine learning tools for data-driven sorbent design. These methods enable high-throughput screening of materials prediction of performance metrics and identification of structure– property relationships. By combining experimental insights with computational advances carbon-based hydrogen storage platforms are expected to play a pivotal role in the next generation of energy storage systems. The paper concludes with a discussion on remaining challenges utilization scenarios and the need for interdisciplinary efforts to realize practical applications.

Hydrogen (H2) will play a vital role in the global shift towards sustainable energy systems. Due to the high cost and challenges associated with storing hydrogen in large quantities for industrial applications Underground Hydrogen Storage (UHS) in geological formations has emerged as a promising solution. Clay minerals abundant in subsurface environments play a critical role in UHS by providing low permeability cation exchange capacity and stability essential for preventing hydrogen leakage. However microorganisms in the subsurface particularly hydrogenotrophic species interact with clay minerals in ways that can affect the integrity of these storage systems. Microbes form biofilms on clay surfaces which can cause pore clogging and reduce the permeability of the reservoir potentially stabilizing H2 storage and limiting injectivity. Microbial-induced chemical weathering through the production of organic acids and redox reactions can degrade clay minerals releasing metal ions and destabilizing the storage site. These interactions raise concerns about the long-term storage capacity of UHS as microbial processes could lead to H2 loss and caprock degradation compromising the storage system’s effectiveness. This mini review aims to cover the current understanding of the interactions between clay minerals and microorganisms and how these dynamics can affect the safe and sustainable deployment of UHS.

Today hydrogen (H2) is overwhelmingly produced through steam methane reforming (SMR) of natural gas which emits about 12 kg of carbon dioxide (CO2) for 1 kg of H2 (∼12 kg-CO2/kg-H2). Water electrolysis offers an alternative for H2 production but today’s electrolyzers consume over 55 kWh of electricity for 1 kg of H2 (>55 kWh/kg-H2). Electric grid-powered water electrolysis would emit less CO2 than the SMR process when the carbon intensity for grid power falls below 0.22 kg-CO2/kWh. Solar- and wind-powered electrolytic H2 production promises over 80% CO2 reduction over the SMR process but large-scale (megawatt to gigawatt) direct solar- or wind-powered water electrolysis has yet to be demonstrated. In this paper several approaches for solar-powered electrolysis are analyzed: (1) coupling a photovoltaic (PV) array with an electrolyzer through alternating current; (2) direct-current (DC) to DC coupling; and (3) direct DC-DC coupling without a power converter. Co-locating a solar or wind farm with an electrolyzer provides a lower power loss and a lower upfront system cost than long-distance power transmission. A load-matching PV system for water electrolysis enables a 10%–50% lower levelized cost of electricity than the other systems and excellent scalability from a few kilowatts to a gigawatt. The concept of maximum current point tracking is introduced in place of maximum power point tracking to maximize the H2 output by solarpowered electrolysis.

Hydrogen storage remains the main barrier to the broader use of hydrogen as an energy carrier despite hydrogen’s high energy density and clean combustion. This study presents a comparative evaluation of conventional and emerging storage methods integrating thermodynamic kinetic economic and environmental metrics to assess capacity efficiency cost and reversibility. Physisorption analysis reveals that metal organic frameworks can achieve storage capacities up to 14.0 mmol/g. Chemical storage systems are evaluated including nanostructured MgH2 (7.6 wt%) catalyzed reversible complex hydrides liquid organic hydrogen carriers and clathrate hydrates. Techno-economic analysis shows storage costs from $500–700/kg H2 to $30–50/kg H2 with energy efficiencies of 50%–90%. Life cycle assessment identifies manufacturing as the primary source of emissions with carbon footprints varying from 150 to 2057 kg CO2 -eq/kg H2 . Cryo-compressed is the most practical transportation option while metal hydrides suit stationary use. This study provides a quantitative foundation to guide material selection and system design for next-generation hydrogen storage technologies.

Materials-based H2 storage plays a critical role infacilitating H2 as a low-carbon energy carrier but there remainslimited guidance on the technical performance necessary for specificapplications. Metal−organic framework (MOF) adsorbents haveshown potential in power applications but need to demonstrateeconomic promises against incumbent compressed H2 storage.Herein we evaluate the potential impact of material propertiescharge/discharge patterns and propose targets for MOFs’ deploy-ment in long-duration energy storage applications including backupload optimization and hybrid power. We find that state-of-the-artMOF could outperform cryogenic storage and 350 bar compressedstorage in applications requiring ≤8 cycles per year but need ≥5 g/Lincrease in uptake to be cost-competitive for applications thatrequire ≥30 cycles per year. Existing challenges include manufacturing at scale and quantifying the economic value of lower-pressure storage. Lastly future research needs are identified including integrating thermodynamic effects and degradation mechanisms.

The teams sits down with Johannah Christensen to discuss regulatory policies and risk mitigation for vessel owners switching to green fuels and what we can do to encourage that jump as well as ensure a Just Transition.

The podcast can be found on their website.

Photoelectrochemical (PEC) water splitting is a promising technology for green hydrogen production by harnessing solar energy. Traditionally this sustainable approach is studied under light intensity of 100 mW/cm2 mimicking the natural solar irradiation at the Earth’s surface. Sunlight can be easily concentrated using simple optical systems like Fresnel lens to enhance charge carrier generation and hydrogen production in PEC water splitting. Despite the great potentials this strategy has not been extensively studied and faces challenges related to the stability of photoelectrodes. To prompt the investigations and applications this work outlines the best practices and protocols for conducting PEC solar water splitting under concentrated sunlight illumination incorporating our recent advancements and providing some experimental guidelines. The key factors such as light source calibration photoelectrode preparation PEC cell configuration and long-term stability test are discussed to ensure reproducible and high performance. Additionally the challenges of the expected photothermal effect and the heat energy utilization strategy are discussed.

As the global economy moves toward net-zero carbon emissions large-scale energy storage becomes essential to tackle the seasonal nature of renewable sources. Underground hydrogen storage (UHS) offers a feasible solution by allowing surplus renewable energy to be transformed into hydrogen and stored in deep geological formations such as aquifers salt caverns or depleted reservoirs making it available for use on demand. This study thoroughly evaluates UHS concepts procedures and challenges. This paper analyzes the most recent breakthroughs in UHS technology and identifies special conditions needed for its successful application including site selection guidelines technical and geological factors and the significance of storage characteristics. The integrity of wells and caprock which is important for safe and efficient storage can be affected by the operating dynamics of the hydrogen cycle notably the fluctuations in pressure and stress within storage formations. To evaluate its potential for broader adoption we also examined economic elements such as cost-effectiveness and the technical practicality of large-scale storage. We also reviewed current UHS efforts and identified key knowledge gaps primarily in the areas of hydrogen–rock interactions geochemistry gas migration control microbial activities and geomechanical stability. Resolving these technological challenges regulatory frameworks and environmental sustainability are essential to UHS’s long-term and extensive integration into the energy industry. This article provides a roadmap for UHS research and development emphasizing the need for further research to fully realize the technology’s promise as a pillar of the hydrogen economy

The reliance on hydrogen as part of the transition towards a low-carbon economy will require developing dedicated pipeline infrastructure. This deployment will be shaped by regulatory frameworks governing investment and access conditions ultimately structuring how the commodity is traded. The paper assesses the market design for hydrogen infrastructure assuming the application of unbundling requirements. For this purpose it develops a general economic framework for regulating pipeline infrastructure focusing on asset specificity market power and access rules. The paper assesses the scope of application of infrastructure regulation which can be set to individual pipelines or to entire networks. When treated as entire networks the infrastructure can provide flexibility to enhance market liquidity. However this requires establishing network monopolies which rely on central planning and reduce the overall dynamic efficiency of the sector. The paper further compares the regulation applied to US and EU natural gas pipeline infrastructure. Based on the different challenges faced by the EU hydrogen sector including absence of wholesale concentration and large infrastructure needs the paper draws lessons for a regulatory framework establishing the main building blocks of a hydrogen target model. The paper recommends a review of the current EU regulatory framework in the Hydrogen and Decarbonised Gas Package to enable i) the application of regulation to individual pipelines rather than entire networks; ii) the use of negotiated third-party access light-touch regulation and possibly marketbased coordination mechanisms for the access to the infrastructure and iii) a more significant role for long-term capacity contracts to underpin infrastructure investments.

This study conducts a thorough review of fuel cell technology including types economy applications and V2G scheme. Fuel cells have been considered for diverse applications namely electric vehicles specialty vehicles such as warehouse forklifts public transportation including buses trains and ferries. Other applications include grid-related stationary and portable applications. Among available five types of fuel cells PEMFC is presently the optimal choice for electric vehicle usage due to its low operating temperature and durability. Meanwhile high temperature fuel cells such as MCFC and SOFC currently remain the best choice for utility and grid related applications. The economy of fuel cells has been continuously improving and has been illustrated to only grow into a potential main source of sustainable energy soon. With the transportation sector as fuel cell electric ve hicles evolve V2G technology is beneficial towards energy efficiency and fuel cell economy. There is evidence for V2G using FCEV being more advantageous in comparison to conventional BEVs. The costs of the five types of fuel cell vary from US$1784 to US$4500 per kW capacity. The findings are beneficial for researchers and industry professionals who wish to gain comprehensive understanding of fuel cells for adoption and development of the emerging low-emission energy solutions.

Green hydrogen presents a promising solution for decarbonisation but its widespread adoption faces significant challenges. To meet Europe’s 2030 targets a 250-fold increase in electrolyser capacity is required necessitating an investment of €170-240 billion. This involves constructing 20-40 pioneering megaprojects each with a 1-5 GW capacity. Historically pioneering energy projects have seen capital costs double or triple from initial estimates with over 50% failing to meet production goals at startup due to new technology introductions site-specific characteristics and project complexity. Additionally megaprojects costing more than €1 billion frequently succumb to the "iron law" which states they are often over budget take longer than anticipated and yield fewer benefits than expected mainly because key players consistently underestimate costs and risks. Pursuing multiple pioneering megaprojects simultaneously restricts opportunities for iterative learning which raises risks related to untested technologies and infrastructure demands. This vision paper introduces a novel risk assessment framework that combines insights from pioneering and megaprojects with technology readiness evaluations and comparative CO2 reduction analyses to tackle these challenges. The framework aims to guide investment decisions and risk mitigation strategies such as staged scaling and limiting the introduction of new technology. The analysis highlights that using green ammonia for fertiliser production can reduce CO2 emissions by 51 tons of CO2 per ton of hydrogen significantly outperforming hydrogen use in transportation and heating. This structured approach considers risks and environmental benefits while promoting equitable risk distribution between developed and developing nations.

To round off Season 5 the team are taking the podcast to COP28 in Dubai and providing listeners with a bit of texture including what the event was like to attend as well as sharing a snapshot of some of the varied voices and discussions that took place. Having had a little time for reflection Alicia Chris and Patrick also offer their thoughts and takeaways on what this COP might mean for the future.

COP28 was the first in nearly 30 years to feature hydrogen as part of the Presidential Action Agenda.

The podcast can be found on their website.

Nanomaterials have attracted great interest in recent years because of the unusual mechanical electrical electronic opticalmagnetic and surface properties. The high surface/volume ratio of these materials has significant implications with respectto energy storage. Both the high surface area and the opportunity for nanomaterial consolidation are key attributes of thisnew class of materials for hydrogen storage devices. Nanostructured systems including carbon nanotubes nano-magnesiumbased hydrides complex hydride/carbon nanocomposites boron nitride nanotubes TiS2/MoS2 nanotubes alanates polymernanocomposites and metal organic frameworks are considered to be potential candidates for storing large quantities of hydrogen.Recent investigations have shown that nanoscale materials may offer advantages if certain physical and chemical effects related tothe nanoscale can be used efficiently. The present review focuses the application of nanostructured materials for storing atomicor molecular hydrogen. The synergistic effects of nanocrystalinity and nanocatalyst doping on the metal or complex hydrides forimproving the thermodynamics and hydrogen reaction kinetics are discussed. In addition various carbonaceous nanomaterialsand novel sorbent systems (e.g. carbon nanotubes fullerenes nanofibers polyaniline nanospheres and metal organic frameworksetc.) and their hydrogen storage characteristics are outlined.

This research undertakes a comparative analysis of current and emerging hydrogen (H2) production technologies evaluating them based on quantitative and qualitative decision criteria. The quantitative criteria include cost of H2 production (USD/kg H2) energy consumption (MJ/kg H2) global warming potential (kg CO2-eq/kg H2) and technology energy efficiency (%). The qualitative criteria encompass technology readiness level (TRL) and availability of supply chain materials (classified as low medium or high). To achieve these objectives an extensive literature review has been conducted systematically assessing the selected H2 production technologies against the aforementioned criteria. The insights synthesized from the literature provide a foundation for an informed science-based evaluation of the potentials and techno-economic challenges that these technologies face in achieving the 1-1-1 goal set by the U.S. Department of Energy (DOE) in 2021. This target aims for a H2 production cost of USD 1/kg H2 within one decade (by 2031) including costs associated with production delivery and dispensing at H2 fueling stations (HRSs). Also the DOE established an interim goal of USD 2/kg H2 by 2026. This research concludes that among the examined H2 production technologies water electrolysis and biomass waste valorization emerge as the most promising near-term solutions to meet the DOE’s goal.

A holistic approach to decision-making in modern energy systems is vital due to their increase in complexity and interconnectedness. However decision makers often rely on narrowlyfocused strategies such as economic assessments for energy system strategy selection. The approach in this paper helps considers various factors such as economic viability technological feasibility environmental impact and social acceptance. By integrating these diverse elements decision makers can identify more economically feasible sustainable and resilient energy strategies. While existing focused approaches are valuable since they provide clear metrics of a potential solution (e.g. an economic measure of profitability) they do not offer the much needed system-as-a-whole understanding. This lack of understanding often leads to selecting suboptimal or unfeasible solutions which is often discovered much later in the process when a change may not be possible. This paper presents a novel evaluation framework to support holistic decision-making in energy systems. The framework is based on a systems thinking approach applied through systems engineering principles and model-based systems engineering tools coupled with a multicriteria decision analysis approach. The systems engineering approach guides the development of feasible solutions for novel energy systems and the multicriteria decision analysis is used for a systematic evaluation of available strategies and objective selection of the best solution. The proposed framework enables holistic multidisciplinary and objective evaluations of solutions and strategies for energy systems clearly demonstrates the pros and cons of available options and supports knowledge collection and retention to be used for a different scenario or context. The framework is demonstrated in case study evaluation solutions for a novel energy system of clean hydrogen generation.

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.

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.

This study emphasises the growing relevance of hydrogen as a green energy source in meeting the growing need for sustainable energy solutions. It foregrounds the importance of assessing the environmental consequences of hydrogen-generating processes for their long-term viability. The article compares several hydrogen production processes in terms of scalability costeffectiveness and technical improvements. It also investigates the environmental effects of each approach considering crucial elements such as greenhouse gas emissions water use land needs and waste creation. Different industrial techniques have distinct environmental consequences. While steam methane reforming is cost-effective and has a high production capacity it is coupled with large carbon emissions. Electrolysis a technology that uses renewable resources is appealing but requires a lot of energy. Thermochemical and biomass gasification processes show promise for long-term hydrogen generation but further technological advancement is required. The research investigates techniques for improving the environmental friendliness of hydrogen generation through the use of renewable energy sources. Its ultimate purpose is to offer readers a thorough awareness of the environmental effects of various hydrogen generation strategies allowing them to make educated judgements about ecologically friendly ways. It can ease the transition to a cleaner hydrogen-powered economy by considering both technological feasibility and environmental issues enabling a more ecologically conscious and climate-friendly energy landscape.

Hydrogen vehicles encompassing fuel cell electric vehicles (FCEVs) are pivotal within the UK’s energy landscape as it pursues the goal of net-zero emissions by 2050. By markedly diminishing dependence on fossil fuels FCEVs including hydrogen vehicles wield substantial influence in shaping the circular economy (CE). Their impact extends to optimizing resource utilization enabling zero-emission mobility facilitating the integration of renewable energy sources supplying adaptable energy storage solutions and interconnecting diverse sectors. The widespread adoption of hydrogen vehicles accelerates the UK’s transformative journey towards a sustainable CE. However to fully harness the benefits of this transition a robust investigation and implementation of safety measures concerning hydrogen vehicle (HV) use are indispensable. Therefore this study takes a holistic approach integrating quantitative risk assessment (QRA) and an adaptive decision-making trial and evaluation laboratory (DEMATEL) framework as pragmatic instruments. These methodologies ensure both the secure deployment and operational excellence of HVs. The findings underscore that the root causes of HV failures encompass extreme environments material defects fuel cell damage delivery system impairment and storage system deterioration. Furthermore critical driving factors for effective safety intervention revolve around cultivating a safety culture robust education/training and sound maintenance scheduling. Addressing these factors is pivotal for creating an environment conducive to mitigating safety and risk concerns. Given the intricacies of conducting comprehensive hydrogen QRAs due to the absence of specific reliability data this study dedicates attention to rectifying this gap. A sensitivity analysis encompassing a range of values is meticulously conducted to affirm the strength and reliability of our approach. This robust analysis yields precise dependable outcomes. Consequently decision-makers are equipped to discern pivotal underlying factors precipitating potential HV failures. With this discernment they can tailor safety interventions that lay the groundwork for sustainable resilient and secure HV operations. Our study navigates the intersection of HVs safety and sustainability amplifying their importance within the CE paradigm. Using the careful amalgamation of QRA and DEMATEL methodologies we chart a course towards empowering decision-makers with the insights to steer the hydrogen vehicle domain to safer horizons while ushering in an era of transformative eco-conscious mobility.

Logistics is becoming more cost competitive while customers and regulatory bodies pressure businesses to disclose their carbon footprints creating interest in alternative fuels as a decarbonization strategy. This paper provides a thematic review of the role of alternative fuels in sustainable air land and sea logistics their challenges and potential mitigations. Through an extensive literature survey we determined that biofuels synthetic kerosene natural gas ammonia alcohols hydrogen and electricity are the primary alternative fuels of interest in terms of environmental sustainability and techno-economic feasibility. In air logistics synthetic kerosene from hydrogenated esters and fatty acids is the most promising route due to its high technical maturity although it is limited by biomass sourcing. Electrical vehicles are favorable in road logistics due to cheaper green power and efficient vehicle designs although they are constrained by recharging infrastructure deployment. In sea logistics liquified natural gas is advantageous owing to its supply chain maturity but it is limited by methane slip control and storage requirements. Overall our examination indicates that alternative fuels will play a pivotal role in the logistics networks of the future.

To identify lower-carbon and cost-effective hydrogen supplies for fuel and power generation in Singapore we assessed the cradle-to-gate greenhouse gas (GHG) emissions and the landed costs of over fifty supply chains from Malaysia and Australia with current and emerging blue turquoise and green hydrogen production and carrier technologies. We found that with current technologies the total life cycle global warming potential of local H2 production using steam methane reforming with carbon capture (4.47 kg CO2e/kg H2) is lower than importing solar-generated green H2 from Australia transported as NH3 (6.48 kg CO2e/kg H2) due to large emissions from conversion and transportation processes in the latter supply chain. When also considering emerging technologies turquoise H2 produced with the thermal decomposition of methane locally or in Malaysia is the most economical solution while wind-generated H2 from Australia transported as liquefied H2 or NH3 produce the least GHG emissions. In addition we projected the impacts of the Singapore carbon tax methane abatement in NG production and reduction of renewable energy embodied emissions and costs on the supply chains in the year 2030. We estimated that with the expected renewable energy improvements the emissions and costs of power generated from imported solar-powered H2 could drop by as much as 74% and 70% respectively.

Well characterized experimental data for consequence model validation is important in progressing the use of liquid hydrogen as an energy carrier. In 2019 the Health and Safety Executive (HSE) undertook a series of liquid hydrogen dispersion and combustion experiments as a part of the Pre-normative Research for Safe Use of Liquid Hydrogen (PRESLHY) project. In partnership between the National Renewable Energy Laboratory (NREL) and HSE time and spatially varying hydrogen concentration measurements were made in 25 dispersion experiments and 23 congested ignition experiments associated with PRESLHY WP3 and WP5 respectively. These measurements were undertaken using the hydrogen wide area monitoring system developed by NREL. During the 23 congested ignition experiments high variability was observed in the measured explosion severity during experiments with similar initial conditions. This led to the conclusion that wind including localized gusts had a large influence on the dispersion of the hydrogen and therefore the quantity of hydrogen that was present in the congested region of the explosions. Using the hydrogen concentration measurements taken immediately prior to ignition the hydrogen clouds were visualized in an attempt to rationalize the variability in overpressure between the tests. Gaussian process regression was applied to quantify the variability of the measured hydrogen concentrations. This analysis could also be used to guide modifications in experimental designs for future research on hydrogen combustion behavior.

In 2015 during the lead up to the Paris Climate Agreement the United States set forth a Nationally Determined Contribution that outlines national goals for greenhouse gas emission reductions. It was not until 2021 that the US put forth a long-term strategy that lays out the pathway to reach these goals. The US long-term strategy lays the framework for research needs to meet the greenhouse gas emission reduction goals and incentivizes industry to meet the goals using a variety of policies. The five US long term strategy core elements are to decarbonize electricity electrify end uses and switch to clean fuels cut energy waste reduce methane and other non-carbon dioxide greenhouse gas emissions and to scale up carbon dioxide removal. Implementation of the long term strategy has generally been funded by tax incentives and government grants that were approved as part of the Inflation Reduction Act. Political headwinds societal Not in My Backyard resistance long-term economic funding cumbersome permitting requirements and incentives vs. taxation debate are significant policy/nontechnical hurdles. Technical challenges remain regarding effective energy efficiency implementation the use of hydrogen as a fuel cost effective carbon emission treatment nuclear energy expansion renewables expansion and grid integration biofuel integration efficient and safe energy storage and electrical grid adequacy/expansion. This review article condenses the multitude of technical and policy issues facing the US long-term strategy providing readers with an overview of the extent and magnitude of the challenges while outlining possible solutions.

Hydrogen (H2) is widely viewed as critical to the decarbonization of industry and transportation. Water electrolysis powered by renewable electricity commonly referred to as green H2 can be used to generate H2 with low carbon dioxide emissions. Herein we analyze the critical mineral and energy demands associated with green H2 production under three different hypothetical future demand scenarios ranging from 100–1000 Mtpa H2. For each scenario we calculate the critical mineral demands required to build water electrolyzers (i.e. electrodes and electrolyte) and to build dedicated or additional renewable electricity sources (i.e. wind and solar) to power the electrolyzers. Our analysis shows that scaling electrolyzer and renewable energy technologies that use platinum group metals and rare earth elements will likely face supply constraints. Specifically larger quantities of lanthanum yttrium or iridium will be needed to increase electrolyzer capacity and even more neodymium silicon zinc molybdenum aluminum and copper will be needed to build dedicated renewable electricity sources. We find that scaling green H2 production to meet projected netzero targets will require ~24000 TWh of dedicated renewable energy generation which is roughly the total amount of solar and wind projected to be on the grid in 2050 according to some energy transition models. In summary critical mineral constraints may hinder the scaling of green H2 to meet global net-zero emissions targets motivating the need for the research and development of alternative lowemission methods of generating H2

Many off-grid communities in Canada are dependent on diesel generators to fulfill their utility and transportation needs causing destructive environmental impact. This study aims to optimize and investigate the technoeconomic feasibility of a hybrid renewable energy system to satisfy the 1.6 MWh/day electricity 184.2 kWh/day thermal and 428.38 kg/year hydrogen demand simultaneously Trout Lake a remote community of Northern Alberta. A novel hybrid energy system consisting of solar PV wind turbine electrolyzer hydrogen tank battery fuel cell hydrogen boiler and thermal load controller has been proposed to generate electricity heat and hydrogen by renewables which reduce carbon emission utilizing the excess energy (EE). Five different scenarios were developed in HOMER Pro software and the results were compared to identify the best combination of hybrid renewable energy systems. The results indicate that the fifth scenario is the optimal renewable energy system that provides a lower cost of energy (COE) at $0.675/kWh and can reduce 99.99% carbon emission compared to the diesel-based system. Additionally the utilization of thermal load controller battery and fuel cell improved the system’s reliability increasing renewable fraction (RF) (93.5%) and reducing EE (58.3%) significantly. In comparison to the diesel-based systems it is also discovered that battery energy storage is the most affordable option while fuel cells are the more expensive choice for remote community. Sensitivity analyses are performed to measure the impact of different dominating factors on COE EE and RF.

Recent advancements in membrane-assisted seawater electrolysis powered by renewable energy offer a sustainable path to green hydrogen production. However its large-scale implementation faces challenges due to slow powerto-hydrogen (P2H) conversion rates. Here we report a modular forward osmosis-water splitting (FOWS) system that integrates a thin-film composite FO membrane for water extraction with alkaline water electrolysis (AWE) denoted as FOWSAWE. This system generates high-purity hydrogen directly from wastewater at a rate of 448 Nm3 day−1 m−2 of membrane area over 14 times faster than the state-of-the-art practice with specific energy consumption as low as 3.96 kWh Nm−3 . The rapid hydrogen production rate results from the utilisation of 1 M potassium hydroxide as a draw solution to extract water from wastewater and as the electrolyte of AWE to split water and produce hydrogen. The current system enables this through the use of a potassium hydroxide-tolerant and hydrophilic FO membrane. The established waterhydrogen balance model can be applied to design modular FO and AWE units to meet demands at various scales from households to cities and from different water sources. The FOWSAWE system is a sustainable and an economical approach for producing hydrogen at a record-high rate directly from wastewater marking a significant leap in P2H practice.

Reducing greenhouse gas emissions in the transport sector is known to be an important contribution to climate change mitigation. Some parts of the transport sector are particularly difficult to decarbonize; this includes the heavy-duty vehicle sector which is considered one of the “hardto-abate” sectors of the economy. Transitioning from diesel trucks to hydrogen fuel cell trucks has been identified as a potential way to decarbonize the sector. However the current and future costs and efficiencies of the enabling technologies remain unclear. In light of these uncertainties this paper investigates the investments required to decarbonize New Zealand’s heavy-duty vehicle sector with green hydrogen. By combining system dynamics modelling literature and hydrogen transition modelling literature a customized methodology is developed for modelling hydrogen transitions with system dynamics modelling. Results are presented in terms of the investments required to purchase the hydrogen production capacity and the investments required to supply electricity to the hydrogen production systems. Production capacity investments are found to range between 1.59 and 2.58 billion New Zealand Dollars and marginal electricity investments are found to range between 4.14 and 7.65 billion New Zealand Dollars. These investments represent scenarios in which 71% to 90% of the heavy-duty vehicle fleet are replaced with fuel cell trucks by 2050. The wide range of these findings reflects the large uncertainties in estimates of how hydrogen technologies will develop over the course of the next thirty years. Policy recommendations are drawn from these results and a clear opportunity for future work is outlined. Most notably the results from this study should be compared with research investigating the investments required to decarbonize the heavy-duty vehicle sectors with alternative technologies such as battery-electric trucks biodiesel and catenary systems. Such a comparison would ensure that the most cost effective decarbonization strategy is employed.

Proton exchange membrane electrolyzers are an attractive technology for hydrogen production due to their high efficiency low maintenance cost and scalability. To receive these benefits however electrolyzers require high power reliability and have relatively high demand. Due to their intermittent nature integrating renewable energy sources like solar and wind has traditionally resulted in a supply too sporadic to consistently power a proton exchange membrane electrolyzer. This study develops an electrolyzer model operating with renewable energy sources at a highly instrumented university site. The simulation uses dynamic models of photovoltaic solar and wind systems to develop models capable of responding to changing climatic and seasonal conditions. The aim therefore is to observe the feasibility of operating a proton exchange membrane system fuel cell yearround at optimal efficiency. To address the problem of feasibility with dynamic renewable generation a case study demonstrates the proposed energy management system. A site with a river onsite is chosen to ensure sufficient wind resources. Aside from assessing the feasibility of pairing renewable generation with proton exchange membrane systems this project shows a reduction in the intermittency plaguing previous designs. Finally the study quantifies the performance and effectiveness of the PEM energy management system design. Overall this study highlights the potential of proton exchange membrane electrolysis as a critical technology for sustainable hydrogen production and the importance of modeling and simulation techniques in achieving its full potential.

Ammonia a molecule that is gaining more interest as a fueling vector has been considered as a candidate to power transport produce energy and support heating applications for decades. However the particular characteristics of the molecule always made it a chemical with low if any benefit once compared to conventional fossil fuels. Still the current need to decarbonize our economy makes the search of new methods crucial to use chemicals such as ammonia that can be produced and employed without incurring in the emission of carbon oxides. Therefore current efforts in this field are leading scientists industries and governments to seriously invest efforts in the development of holistic solutions capable of making ammonia a viable fuel for the transition toward a clean future. On that basis this review has approached the subject gathering inputs from scientists actively working on the topic. The review starts from the importance of ammonia as an energy vector moving through all of the steps in the production distribution utilization safety legal considerations and economic aspects of the use of such a molecule to support the future energy mix. Fundamentals of combustion and practical cases for the recovery of energy of ammonia are also addressed thus providing a complete view of what potentially could become a vector of crucial importance to the mitigation of carbon emissions. Different from other works this review seeks to provide a holistic perspective of ammonia as a chemical that presents benefits and constraints for storing energy from sustainable sources. State-of-the-art knowledge provided by academics actively engaged with the topic at various fronts also enables a clear vision of the progress in each of the branches of ammonia as an energy carrier. Further the fundamental boundaries of the use of the molecule are expanded to real technical issues for all potential technologies capable of using it for energy purposes legal barriers that will be faced to achieve its deployment safety and environmental considerations that impose a critical aspect for acceptance and wellbeing and economic implications for the use of ammonia across all aspects approached for the production and implementation of this chemical as a fueling source. Herein this work sets the principles research practicalities and future views of a transition toward a future where ammonia will be a major energy player.

Hydrogen delivery at elevated pressures is often required for fuel cell and combustion applications to improve volumetric energy density. Catalytic membrane reformers (CMRs) integrate hydrogen production and purification from reforming liquid hydrogen carriers such as ammonia enabling direct recovery of pressurized purified hydrogen. In this study high-pressure ammonia is supplied to a catalytic membrane reformer (CMR) to enhance both performance and hydrogen recovery pressures. Increasing operating pressure in the CMR resulted in nearly doubling the hydrogen flux from 17.2 to 34 sccm cm− 2 compared to our previous work. However as the recovery pressure of the permeate increased the performance notably decreased with hydrogen recovery dropping from 98 % at atmospheric pressure to 44 % at 10 bar. Nevertheless the system demonstrated rates of ammonia conversion hydrogen flux and hydrogen recovery comparable to leading literature reports when supplying ammonia at 20 bar and recovering the permeate up to 10 bar. Additionally by using ammonia as both a feed and sweep gas we demonstrate the direct production of high-pressure NH3/H2 fuel blends including a 70:30 mixture representative of natural gas without loss in CMR performance. These results highlight the potential of CMR technology to reduce hydrogen compression costs and enable on-demand generation of ammonia-derived fuel blends.

Historically it has been a challenge to simulate the experimentally observed cellular structures and marginal behavior of multidimensional hydrogen-oxygen detonations in the presence of losses even with detailed chemistry models. Very recently a quasi-two-dimensional inviscid approach was pursued where losses due to viscous boundary layers were modeled by the inclusion of an equivalent mass divergence in the lateral direction using Fay’s source term formulation with Mirels’ compressible boundary layer solutions. The same approach was used for this study along with the inclusion of thermally perfect detailed chemistry in order to capture the correct ignition sensitivity of the gas to dynamic changes in the thermodynamic state behind the detonation front. In addition the strength of transverse waves and their impact on the detonation front was investigated. Here the detailed San Diego mechanism was applied and it has been found that the detonation cell sizes can be accurately predicted without the need to prescribe specific parameters for the combustion model. For marginal cases where the detonation waves approach their failure limit quasi-stable mode behavior was observed where the number of transverse waves monotonically decreased to a single strong wave over a long enough distance. The strong transverse waves were also found to be slightly weaker than the detonation front indicating that they are not overdriven in agreement with recent studies.

Russia’s invasion of Ukraine has reaffirmed the importance of scaling up renewable energy to decarbonise Europe’s economy while rapidly reducing its exposure to foreign fossil fuel suppliers. Therefore the question of sources of flexibility to support a fully decarbonised European energy system is becoming even more critical in light of a renewable-dominated energy system. We developed and used a Pan-European energy system model to systematically assess and quantify sources of flexibility to meet deep decarbonisation targets. The electricity supply sector and electricity-based end-use technologies are crucial in achieving deep decarbonisation. Other low-carbon energy sources like biomethane hydrogen synthetic e-fuels and bioenergy with carbon capture and storage will also play a role. To support a fully decarbonised European energy system by 2050 both temporal and spatial flexibility will be needed. Spatial flexibility achieved through investments in national electricity networks and cross-border interconnections is crucial to support the aggressive roll-out of variable renewable energy sources. Cross-border trade in electricity is expected to increase and in deep decarbonisation scenarios the electricity transmission capacity will be larger than that of natural gas. Hydrogen storage and green hydrogen production will play a key role in providing traditional inter-seasonal flexibility and intraday flexibility will be provided by a combination of electrical energy storage hydrogen-based storage solutions (e.g. liquid H2 and pressurised storage) and hybrid heat pumps. Hydrogen networks and storage will become more critical as we move towards the highest decarbonisation scenario. Still the need for natural gas networks and storage will decrease substantially.

The PRHYDE project (PRotocol for heavy duty HYDrogEn refueling) funded by the Clean Hydrogen partnership aims at developing recommendations for heavy-duty refueling protocols used for future standardization activities for trucks and other heavy duty transport systems applying hydrogen technologies. Development of a protocol requires a validated approach. Due to the limited time and budget the experimental data cannot cover the whole possible ranges of protocol parameters such as initial vehicle pressure and temperature ambient and precooling temperatures pressure ramp refueling time hardware specifications etc. Hence a validated numerical tool is essential for a safe and efficient protocol development. For this purpose engineering tools are used. They give good results in a very reasonable computation time of several seconds or minutes. These tools provide the heat parameters estimation in the gas (volume average temperature) and 1D temperature distribution in the tank wall. The following models were used SOFIL (Air Liquide tool) HyFill (by ENGIE) and H2Fills (open access code by NREL). The comparison of modelling results and experimental data demonstrated a good capability of codes to predict the evolution of average gas temperature in function of time. Some recommendations on model validation for the future protocol development are given.

Hydrogen fuel has shown promise as a clean alternative fuel aiding in the reduction of fossil fuel dependence within the transportation sector. However hydrogen refueling stations and infrastructure remains a barrier and are a prerequisite for consumer adoption of low-cost and low-emission fuel cell electric vehicles (FCEVs). The costs for FCEV fueling include both station capital costs and operation and maintenance (O&M) costs. Contributing to these O&M costs unscheduled maintenance is presently more costly and more frequent than for similar gasoline fueling infrastructure and is asserted to be a limiting factor in achieving FCEV customer acceptance and cost parity. Unscheduled maintenance leads to longer station downtime therefore causing an increase in missed fueling opportunities which forces customers to seek refueling at other operable stations that may be significantly farther away. This research proposes a framework for a hydrogen station prognostics health monitoring (H2S PHM) model that can minimize unexpected downtime by predicting the remaining useful life for primary hydrogen station components within the major station subsystems. The H2S PHM model is a data-driven statistical model based on O&M data collected from 34 retail hydrogen stations located in the U.S. The primary subcomponents studied are the dispenser compressor and chiller. The remaining useful life calculations are used to decide whether or not maintenance should be completed based on the prediction and expected future station use. This paper presents the background method and results for the H2S PHM model as for a means for improving station availability and customer confidence in FCEVs and hydrogen infrastructure

Safety and reliability have long been recognized as key issues for the development commercialization and implementation of new technologies and infrastructure and hydrogen systems are no exception to this rule. Reliability engineering quantitative risk assessment (QRA) and knowledge exchange each play a key role in proactive addressing safety – before problems happen – and help us learn from problems if they happen. Many international research activities are focusing on both reliability and risk assessment for hydrogen systems. However the element of knowledge exchange is sometimes less visible. To support international collaboration and knowledge exchange the International Energy Agency (IEA) convened a new Technology Collaboration Program “Task 43: Safety and Regulatory Aspects of Emerging Large Scale Hydrogen Energy Applications” started in June 2022. Within Task 43 Subtask E focuses on Hydrogen Systems Safety. This paper discusses the structure of the Hydrogen Systems Safety subtask and the aligned activities and introduces opportunities for future work.

Social risk is a comprehensive concept that considers not only internal/external physical risks but also risks (which are multiple varied and diverse) associated with social activity. It should be considered from diverse perspectives and requires a comprehensive evaluation framework that takes into account the synergistic impact of each element on others rather than evaluating each risk individually. Social risk assessment is an approach that is not limited to internal system risk from an engineering perspective but also considers the stakeholders development stage and societal readiness and resilience to change. This study aimed to introduce a social risk approach to assess the public safety of large-scale hydrogen systems. Guidelines for comprehensive social risk assessment were developed to conduct appropriate risk assessments for advanced science and technology activities with high uncertainties to predict major impacts on society before an accident occurs and to take measures to mitigate the damage and to ensure good governance are in place to facilitate emergency response and recovery in addition to preventive measures. In a case study this approach was applied to a hydrogen refueling station in Japan and risk-based multidisciplinary approaches were introduced. These approaches can be an effective supporting tool for social implementation with respect to large-scale hydrogen systems such as liquefied hydrogen storage tanks. The guidelines for social risk assessment of large-scale hydrogen systems are under the International Energy Agency Technology Collaboration Program Hydrogen Safety Task 43. This study presents potential case studies of social risk assessment for large-scale hydrogen systems for future.

The central role of hydrogen in the EU’s decarbonization strategy has increased the importance of critical raw materials. To address this the EU has taken legislative steps including the 2023 Critical Raw Materials Act (CRMA) to ensure a stable supply. Using a leader–follower Stackelberg game framework this study analyzes CRM market dynamics integrating CRMA compliance through rules on sourcing and stockpiling value chain resilience via the inclusion of supply diversification strategies and geopolitical influences by modeling exporter behaviors and trade dependencies. Results highlight the potential for strategic behavior by major exporters stressing the benefits of diversifying export sources and maintaining strategic stockpiles to stabilize supply. The findings provide insights into the EU’s efforts to secure CRM supplies key to achieving decarbonization goals and fostering a sustainable energy transition. Future research should explore alternative cost-reduction strategies mitigate exporter market power and evaluate the implications for pricing mechanisms market outcomes and consumer welfare