Australia

Metal hydride-based hydrogen storage (MHHS) has been used for several purposes including mobile and stationary applications. In general the overall MHHS performance for both applications depends on three main factors which are the appropriate selection of metal hydride material uses design configurations of the MHHS based on the heat exchanger and overall operating conditions. However there are different specific requirements for the two applications. The weight of the overall MHHS is the key requirement for mobile applications while hydrogen storage capacity is the key requirement for stationary applications. Based on these requirements several techniques have been recently used to enhance MHHS performance by mostly considering the faster hydrogen absorption/desorption reaction. Considering metal hydride (MH) materials their low thermal conductivity significantly impacts the hydrogen absorption/desorption reaction. For this purpose a comprehensive understanding of these three main factors and the hydrogen absorption/desorption reaction is critical and it should be up to date to obtain the suitable MHHS performance for all related applications. Therefore this article reviews the key techniques which have recently been applied for the enhancement of MHHS performance. In the review it is demonstrated that the design and layout of the heat exchanger greatly affect the performance of the internal heat exchanger. The initial temperature of the heat transfer fluid and hydrogen supply pressure are the main parameters to increase the hydrogen sorption rate and specific heating power. The higher supply pressure results in the improvement in specific heating power. For the metal hydride material selection under the consideration of mobile applications and stationary applications it is important to strike trade-offs between hydrogen storage capacity weight material cost and effective thermal conductivity.

The use of alternative fuels is a primary means for decarbonising the maritime industry. Liquefied natural gas (LNG) liquid hydrogen (LH2) and liquid ammonia (LNH3) are liquified gases among the alternative fuels. The safety risks associated with these fuels differ from traditional fuels. In addition to their low-temperature hazards the flammability of LNG and LH2 and the high toxicity of LNH3 present challenges in fuel handlings due to their high likelihood of fuel release during bunkering. This study aims at drawing extensive comparisons of the evaporation and vapour dispersion behaviours for the three fuels after release accidents during bunkering and discuss their safety issues. The study involved the release event of the three fuels on the main deck area of a reference bulk carrier with a deadweight of 208000 tonnes. Two release scenarios were considered: Scenario 1 involved a release of 0.3 m3 of fuel and Scenario 2 involved a release of 100 kg of fuel. An empirical equation was used to calculate the fuel evaporation process and the Computational Fluid Dynamic (CFD) code FDS was employed to simulate the dispersion of vapour clouds. The obtained results reveal that LH2 has the highest evaporation rate followed by LNG and LNH3. The vapour clouds of LNG and LNH3 spread along the main deck surface while the LH2 vapour cloud exhibits upward dispersion. The flammable vapour clouds of LNG and LH2 remain within the main deck area whereas the toxic gas cloud of LNH3 disperses towards the shore and spreads near the ground on the shore side. Based on the dispersion behaviours the hazards of LNG and LH2 are com parable while LNH3 poses significantly higher hazards. In terms of hazard mitigations effective water curtain systems can suppress the vapour dispersion.

Hydrogen flight is one important part of the way to net zero aviation. However safety challenges around refuelling are not well understood but are paramount to enable airports to be more comfortable with using hydrogen in the airport environment. This study investigates safety considerations of hydrogen aircraft refuelling at airports. Technical and human factor risks are explored as well as risk assessment models. Two focus groups were conducted in 2022. Data was analysed using NVivo revealing major themes including the mental and physical performance of refuellers technical aspects of refuelling stations environmental factors and the use of risk assessment models. These findings contribute significantly to an understanding of hydrogen refuelling challenges in busy airport environments. Recommendations help airports preparing for hydrogen as a fuel source further supporting the transition towards net zero aviation. Future research could focus on carrying out experiments analysing chemical reactions between kerosene and hydrogen vapours and testing the identified risk assessment tools in different airport environments.

The steel industry is one of the major sources of greenhouse gas emissions with significant energy demand. Currently 73% of the world’s steel is manufactured through the coal-coke-based blast furnace-basic oxygen furnace route (BF-BOF) emitting about two tonnes of CO2 per tonne of steel produced. This review reports the major technologies recent developments challenges and technoeconomic comparison of steelmaking technol ogies emphasising the integration of hydrogen in emerging and established ironmaking and steelmaking pro cesses. Significant trials are underway especially in Germany to replace coal injected in the tuyeres of the blast furnace with hydrogen. However it is not clear that this approach can be extended beyond 30% replacement of coke because of the associated technical challenges. Direct smelting and fluidised bed technologies can emit 20%–30% less CO2 without carbon capture and storage utilisation. The implications of hydrogen energy in these technologies as a substitute for natural gas and coal are yet to be fully explored. A hydrogen-based direct reduction of iron ore (DRI) and steel scrap melting in an electric arc furnace (EAF) appeared to be the most mature technological routes to date capable of reducing CO2 emission by 95% but rely on the availability of rich iron concentrates as feed materials. Shaft furnace technologies are the common DRI-making process with a share of over 72% of the total production. The technology has been developed with natural gas as the main fuel and reductant. However it is now being adapted to operate predominantly on hydrogen to produce a low-carbon DRI product. Plasma and electrolysis-based iron and steelmaking are some of the other potential technologies for the application of hydrogen with a CO2 reduction potential of over 95%. However these technologies are in the preliminary stage of development with a technology readiness level of below 6. There are many technological challenges for the application of hydrogen in steel manufacturing such as challenges in distributing heat due to the endothermic H2 reduction process balancing carbon content in the product steel (particularly using zerocarbon DRI) removal of gangue materials and sourcing of cost-competitive renewable hydrogen and highquality iron ore (65>Fe). As iron ore quality degrades worldwide several companies are considering melting DRI before steelmaking possibly using submerged arc technology to eliminate gangue materials. Hence sig nificant laboratory and pilot-scale demonstrations are required to test process parameters and product qualities. Our analysis anticipates that hydrogen will play an instrumental role in decarbonising steel industries by 2035.

H2 geo-storage has been suggested as a key technology with which large quantities of H2 can be stored and withdrawn again rapidly. One option which is currently explored is H2 storage in sedimentary geologic for mations which are geographically widespread and potentially provide large storage space. The mechanism which keeps the buoyant H2 in the subsurface is structural trapping where a caprock prevents the H2 from rising by capillary forces. It is therefore important to assess how much H2 can be stored via structural trapping under given geo-thermal conditions. This structural trapping capacity is thus assessed here and it is demonstrated that an optimum storage depth for H2 exists at a depth of 1100 m at which a maximum amount of H2 can be stored. This work therefore aids in the industrial-scale implementation of a hydrogen economy.

Mobility has been a prominent target for proponents of the hydrogen economy. Given the complexities involved in the mobility value chain actors hoping to participate in this nascent market must overcome a range of challenges relating to the availability of vehicles the co-procurement of supporting infrastructure a favourable regulatory environment and a supportive community among others. In this paper we present a state-of-play account of the nascent hydrogen mobility market in Victoria Australia drawing on data from a workshop (N ¼ 15) and follow-up interviews (n ¼ 10). We interpret findings through a socio-technical framework to understand the ways in which fuel cell electric vehicles (FCEVs)dand hydrogen technologies more generallydare conceptualised by different stakeholder groups and how these conceptualisations mediate engagement in this unfolding market. Findings reveal prevailing efforts to make sense of the FCEV market during a period of considerable institutional ambiguity. Discourses embed particular worldviews of FCEV technologies themselves in addition to the envisioned roles the resultant products and services will play in broader environmental and energy transition narratives. Efforts to bring together stakeholders representing different areas of the FCEV market should be seen as important enablers of success for market participants.

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

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

Carbon dioxide and hydrogen storage in geological formations at Gt scale are two promising strategies toward net-zero carbon emissions. To date investigations into underground hydrogen storage (UHS) remain relatively limited in comparison to the more established knowledge body of underground carbon dioxide storage (UCS). Despite their analogous physical processes can be used for accelerating the advancements in UHS technology the existing distinctions possibly may hinder direct applicability. This review therefore contributes to advancing our fundamental understanding on the key differences between UCS and UHS through multi-scale comparisons. These comparisons encompass key factors influencing underground gas storage including storage media trapping mechanisms and respective fluid properties geochemical and biochemical reactions and injection scenarios. They provide guidance for the conversion of our existing knowledge from UCS to UHS emphasizing the necessity of incorporating these factors relevant to their trapping and loss mechanisms. The article also outlines future directions to address the crucial knowledge gaps identified aiming to enhance the utilisation of geological formations for hydrogen and carbon dioxide storage.

Cryogenic liquid hydrogen offers a promising solution for achieving high-density hydrogen storage and efficient on-site distribution. However the potential hazards associated with hydrogen leakages necessitate thorough investigations. This research aims to model cryogenic hydrogen release from circular and high aspect ratio (HAR) nozzles tested by Sandia. The test conditions cover reservoir pressures and temperatures corresponding to cryogenic hydrogen storage. The study conducts computational simulations using OpenFOAM to examine hydrogen concentration temperature fields mass fraction and temperature distributions achieving good agreement with the experimental data. To further explore the study of velocity variations shows a consistent decay rate with room-temperature jets. The numerical data reveals comparable inverse centreline hydrogen mass fractions (0.254 for HAR and 0.26 for circular) and normalised centreline temperature decay rates (0.031 for HAR and 0.032 for circular). The present computational model holds the potential for further analysis of cryogenic hydrogen in large-scale facilities.

To combat global temperature rise we need affordable clean and renewable energy that does not add carbon to the atmosphere. Hydrogen is a promising option because it can be used as a carbon-free energy source. However storing and transporting pure hydrogen in liquid or gaseous forms is challenging. To overcome the limitations associated with conventional compressed and liquefied hydrogen or physio-chemical adsorbents for bulk storage and transport hydrogen can be attached to other molecules known as hydrogen carriers. Circular carriers which involve the production of CO2 or nitrogen during the hydrogen recovery process include substances such as methanol ammonia or synthetic natural gas. These carriers possess higher gravimetric and volumetric hydrogen densities (i.e. 12.5 wt% and 11.88 MJ/L for methanol) than cyclic carriers (i.e. 6.1 wt% and 5.66 MJ/L for methylcyclohexane (MCH)) which produce cyclic organic chemicals during dehydrogenation. This makes circular carriers particularly appealing for the Australian energy export market. Furthermore the production-decomposition cycle of circular carriers can be made carbon-neutral if they are derived from renewable H2 sources and combined with atmospheric or biomass-based CO2 or nitrogen. The key parameters are investigated in this study focusing on circular hydrogen carriers relevant to Australia. The parameters are ranked from 0 (worst) to 10 (best) depending on the bandwidth of the parameter in this review. Methanol shows great potential as a cost-effective solution for long-distance transport of renewable energy being a liquid at standard conditions with a boiling point of 64.7 °C. Methane is also an important hydrogen carrier due to the availability of natural gas infrastructure and its role as a significant export product for Australia.

Hydrogen shaft injection into blast furnaces (BFs) has a large potential to eliminate carbon dioxide emissions yet the temporal evolution of thermal and chemical states following shaft-injected hydrogen utilisation has not been reported in the open literature. In this research a recently developed transient-state multifluid BF model is applied to elucidate the temporal evolution of in-furnace phenomena. Besides a domain-average method is adopted to analyse the extensive simulation data to determine the time required to attain the next steady-like state. The results show that the evolution of thermal and chemical conditions varies across different regions with distinct characteristics near the furnace wall. The shifts in iron oxide reduction behaviour are completed within 10 to 20 h after the new operation and the transition time points to the next steady-like states of thermal and chemical conditions are different. As the hydrogen flow rate increases the average transition time decreases. However 2 to 4 days are required for the studied BF to reach a new steady-like state in the considered scenarios. The model offers a cost-effective approach to investigating the transient smelting characteristics of an ironmaking BF with hydrogen injection.

This study explores the generation of natural hydrogen through the serpentinization of onshore ultramafic rocks highlighting its potential as a clean energy resource. By investigating critical factors such as mineral composition temperature and pressure the research develops an empirical model using multiple regression analysis to predict hydrogen generation rates under varying geological conditions. A novel five-stage volumetric calculation methodology is introduced to estimate hydrogen production from ultramafic rock bodies. The application of this framework to the Giles Complex an ultramafic-mafic intrusion in Australia suggests a hydrogen generation potential of approximately 2.24 × 1013 kg of hydrogen through partial serpentinization. This estimate is based on the assumed mineral composition depth and temperature conditions within the intrusion which influence the extent of serpentinization reactions. The findings demonstrate the significant potential of ultramafic complexes for natural hydrogen production and provide a foundation for advancing natural hydrogen exploration refining predictive models and supporting sustainable energy development.

This study explores the design and feasibility of a novel fuel cell-powered wind farm for residential electricity hydrogen/oxygen production and cooling/heating via a compression chiller. Wind turbine energy powers Proton Exchange Membrane (PEM) electrolyzers and a compression chiller unit. The proposed system was modeled using EES thermodynamic software and its economic viability was assessed. A case study across seven Italian regions with varying wind potentials evaluated the system’s feasibility in diverse weather conditions. Multi-objective optimization using Response Surface Methodology (RSM) determined the number of wind turbines as optimum number of electrolyzers & fuel cell units. Optimization results indicated that 37 wind turbines 1 fuel cell unit and 2 electrolyzer units yielded an exergy efficiency of 27.98 % and a cost rate of 619.9 $/h. TOPSIS analysis suggested 32 wind turbines 2 electrolyzers and 2 reverse osmosis units as an alternative configuration. Further twelve different scenarios were examined to enhance the distribution of wind farmgenerated electricity among the grid electrolyzers and reverse osmosis systems. revealing that directing 25 % to reverse osmosis 20 % to electrolyzers and 55 % to grid sales was optimal. Performance analysis across seven Italian cities (Turin Bologna Florence Palermo Genoa Milan and Rome) identified Genoa Palermo and Bologna as the most suitable locations due to favorable wind conditions. Implementing the system in Genoa the optimal site could produce 28435 MWh of electricity annually prevent 5801 tons of CO2 emissions (equivalent to 139218 $). Moreover selling this clean electricity to the grid could meet the annual clean electricity needs of approximately 5770 people in Italy

Australia has set a new climate target of reducing emissions by 62–70% below 2005 levels by 2035 with sustainable aviation fuel (SAF) central to achieving this goal. This review critically examines techno-economic analysis (TEA) and life cycle assessment (LCA) of Powerto-Liquid (PtL) electrofuels (e-fuels) which synthesize atmospheric CO2 and renewable hydrogen (H2) via Fischer-Tropsch (FT) synthesis. Present PtL pathways require ~0.8 kg of H2 and 3.1 kg of CO2 per kg SAF with ~75% kerosene yield. While third-generation feedstocks could cut greenhouse gas emissions by up to 93% (as low as 8 gCO2e/MJ) real world reductions have been limited (~1.5%) due to variability in technology rollout and feedstock variability. Integrated TEA–LCA studies demonstrate up to 20% energy efficiency improvements and 40% cost reductions but economic viability demands costs below $3/kg. In Australia abundant solar resources vast transport networks and supportive policy frameworks present both opportunities and challenges. This review provides the first comprehensive assessment of PtL-FT SAF for Australian conditions highlighting that large-scale development will require technological advancement feedstock development infrastructure investment and coordinated policy support.

Replacing the energy density and convenience of diesel fuel for all forms of fossil fuel-powered trains presents significant challenges. Unlike the traditional evolutions of rail which has largely self-optimised to different fuels and cost structures over 150 years the challenges now present with a timeline of just a few decades. Fortunately unlike the mid-1800s simulation and modelling tools are now quite advanced and a full range of scenarios of operations and train trips can be simulated before new traction systems are designed. Full trip simulations of large heavy haul trains or high speed passenger trains are routinely completed controlled by emulations of human drivers or automated control systems providing controls of the “virtual train”. Recent developments in digital twins can be used to develop flexible and dynamic models of passenger and freight rail systems to support the new complexities of decarbonisation efforts. Interactions between many different traction components and the train multibody system can be considered as a system of systems. Adopting this multi-modelling paradigm enables the secure and integrated interfacing of diverse models. This paper demonstrates the application of the multi-modelling approach to develop digital twins for rail decarbonisation traction and it presents physics-based multi-models that include key components required for studying rail decarbonisation problems. Specifically the challenge of evaluating zero-emission options is addressed by adding further layers of modelling to the existing fully detailed multibody dynamics simulations. The additional layers detail control options energy storage the alternate traction system components and energy management systems. These traction system components may include both electrical system and inertia dynamics models to accurately represent the driveline and control systems. This paper presents case study examples of full trip scenarios of both long haul freight trains and higher speed passenger trains. These results demonstrate the many complex scenarios that are difficult to anticipate. Flowing on from this risks can be assessed and practical designs of zero-emission systems can be proposed along with the required recharging or refuelling systems.

The experimental performance of an autothermal hydrogen release unit comprising a perhydro benzyltoluene (H12-BT) dehydrogenation chamber and a catalytic hydrogen combustion (CHC) chamber in thermal contact is discussed. In detail the applied set-up comprised a multi-tubular CHC heating based on seven parallel tubes with the reactor shell containing a commercial dehydrogenation catalyst. In this way the CHC heated the endothermal LOHC dehydrogenation using a part of the hydrogen generated in the dehydrogenation. The proposed heating concept for autothermal LOHC dehydrogenation offers several advantages over state-of-the-art heating concepts including minimized space consumption high efficiency and zero NOx emissions. During performance tests the process reached a minimum hydrogen combustion fraction of 37 % while the minimum heat requirement for the dehydrogenation reaction for industrial scale plants is 33 %. The reactor orientation (vertical vs horizontal) and the flow configuration (counter-current vs. co-current) showed very little influence on the performance demonstrating the robustness of the proposed reactor design.

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

The global energy sector is aiming to substantially reduce CO2 emissions to meet the UN climate goals. Among the proposed strategies underground storage solutions such as radioactive disposal CO2 NH3 and underground H2 storage (UHS) have emerged as promising options for mitigating anthropogenic emissions. These approaches require rigorous research and development (R&D) often involving laboratory-scale experiments to establish their feasibility before being scaled up to pilot plant operations. Microorganisms which are ubiquitous in laboratory environments can significantly influence geochemical reactions under variable experimental conditions of porous media and a salt cavern. We have selected a consortium composed of Bacillus sp. Enterobacter sp. and Cronobacter sp. bacteria which are typically present in the laboratory environment. These microorganisms can contaminate the rock sample and develop experimental artifacts in UHS experiments. Hence it is pivotal to sterilize the rock prior to conduct experimental research related to effects of microorganisms in the porous media and the salt cavern for the investigation of UHS. This study investigated the efficacy of various disinfection and sterilization methods including ultraviolet irradiation autoclaving oven heating ethanol treatments and gamma irradiation in removing the microorganisms from silica sand. Additionally the consideration of their effects on mineral properties are reviewed. A total of 567 vials each filled with 9 mL of acid-producing bacteria (APB) media were used to test killing efficacy of the cleaning methods. We conducted serial dilutions up to 10−8 and repeated them three times to determine whether any deviation occurred. Our findings revealed that gamma irradiation and autoclaving were the most effective techniques for eradicating microbial contaminants achieving sterilization without significantly altering the mineral characteristics. These findings underscore the necessity of robust cleaning protocols in hydrogeochemical research to ensure reliable reproducible data particularly in future studies where microbial contamination could induce artifacts in laboratory research.

Virtual power plants (VPPs) are gaining significance in the energy sector due to their capacity to aggregate distributed energy resources (DERs) and optimize energy trading. However their effectiveness largely depends on accurately modeling the uncertain parameters influencing optimal bidding strategies. This paper proposes a deep learning-based forecasting method to predict these uncertain parameters including solar irradiation temperature wind speed market prices and load demand. A stochastic programming approach is introduced to mitigate forecasting errors and enhance accuracy. Additionally this research assesses the flexibility of VPPs by mapping the flexible regions to determine their operational capabilities in response to market dynamics. The study also incorporates power-to‑hydrogen (P2H) and hydrogen-to-power (H2P) conversion processes to facilitate the integration of hydrogen fuel cell vehicles (HFCVs) into VPPs enhancing both technical and economic aspects. A network-aware VPP connected to generation resources storage facilities demand response programming (DRP) vehicle-to-grid technology (V2G) P2H and H2P is used to evaluate the proposed method. The problem is formulated as a convex model and solved using the GUROBI optimizer. Results indicate that a hydrogen refueling station can increase profits by approximately 49 % compared to the base case of directly selling surplus generation from renewable energy sources (RESs) to the market and profits can further increase to roughly 86 % when other DERs are incorporated alongside the hydrogen refueling station.

Hydrogen is increasingly recognized as a key energy vector for achieving deep decarbonization across urban and industrial sectors. Supporting global efforts to reduce greenhouse gas (GHG) emissions and achieve the Sustainable Development Goals (SDGs) it is essential to understand the multi-sectoral role of the hydrogen value chain spanning production storage and end-use applications with particular emphasis on smart city systems and industrial processes. Green hydrogen production technologies including alkaline water electrolysis (AWE) proton exchange membrane (PEM) electrolysis anion exchange membrane (AEM) electrolysis and solid oxide electrolysis cells (SOECs) are evaluated in terms of efficiency scalability and integration potential. Storage pathways are examined across physical storage (compressed gas cryo-compressed and liquid hydrogen) material-based storage (solid-state absorption in metal hydrides and chemical carriers such as LOHCs and ammonia) and geological storage (salt caverns depleted gas reservoirs and deep saline aquifers) highlighting their suitability for urban and industrial contexts. In the smart city domain hydrogen is analyzed as an enabler of zero-emission transportation low-carbon residential and commercial heating and renewable-integrated smart grids with long-duration storage capabilities. System-level studies demonstrate that coordinated integration of these applications can deliver higher overall energy efficiency deeper reductions in life-cycle GHG emissions and improved resilience of urban energy systems compared with sector-specific approaches. Policy frameworks safety standards and digitalization strategies are reviewed to illustrate how hydrogen infrastructure can be embedded into interconnected urban energy systems. Furthermore industrial applications focus on hydrogen’s potential to decarbonize energy-intensive processes and enable sector coupling between electricity heat and manufacturing. The environmental implications of hydrogen deployment are also considered including resource efficiency life-cycle emissions and ecosystem impacts. In contrast to reviews addressing isolated aspects of hydrogen technologies this study synthesizes technological infrastructural and policy dimensions integrating insights from over 400 studies to highlight the multifaceted role of hydrogen in sustainable urban development and industrial decarbonization and the added benefits achievable through coordinated cross-sector deployment strategies.

Hydrogen plays a key role in decarbonising hard-to-abate sectors like aviation steel and shipping. However producing pure hydrogen requires significant energy to break chemical bonds from its sources such as gas and water. Ideally the energy used for this process should match the energy output from hydrogen but in reality energy losses occur at various stages of the hydrogen economy—production packaging delivery and use. This results in needing more energy to operate the hydrogen economy than it can ultimately provide. To address this passive power sources like latent thermal energy storage systems can help reduce costs and improve efficiency. These systems can enable passive cooling or electricity generation from waste heat cutting down on the extra energy needed for compression liquefaction and distribution. This study explores integrating latent thermal energy storage into all stages of the hydrogen economy offering a cost and sizing approach for such systems. The integration could reduce costs close the waste-heat recycling loop and support green hydrogen production for achieving NetZero by 2050.

The rapid growth of Australia’s hydrogen economy highlights the pressing need for innovative regulatory strategies that address the distinct characteristics of hydrogen supply chains. This study focuses on the supply-side dynamics of the hydrogen energy sector emphasizing the importance of tailored frameworks to ensure the safe efficient and reliable movement of hydrogen across the supply chain. Key areas of analysis include the regulatory challenges associated with various transportation and storage methods particularly during long-distance transport and extended storage periods. The research identifies notable gaps and inconsistencies within the current regulatory systems across Australian states which inhibit the development of a unified hydrogen economy. To address these challenges the concept of Proactive Regulation for Hydrogen Supply (PRHS) is introduced. PRHS emphasizes anticipatory governance that adapts alongside technological advancements to effectively manage hydrogen transportation and storage. The study advocates for harmonizing fragmented state frameworks into a cohesive national regulatory system to support the sustainable and scalable expansion of hydrogen logistics. Furthermore the paper examines the potential of blockchain technology to enhance safety accountability and traceability across the hydrogen supply chain offering practical solutions to current regulatory and operational barriers.

Decarbonising aquaculture support vessels is pivotal to reducing greenhouse gas (GHG) emissions across both the aquaculture and maritime sectors. This study evaluates the technical and economic feasibility of deploying hydrogen as a marine fuel for a 14.95 m net cleaning vessel (NCV) operating in Tasmania Australia. The analysis retains the vessel’s original layout and subdivision to enable a like-for-like comparison between conventional diesel and hydrogen-based systems. Two options are evaluated: (i) replacing both the main propulsion engines and auxiliary generator sets with hydrogen-based systems— either proton exchange membrane fuel cells (PEMFCs) or internal combustion engines (ICEs); and (ii) replacing only the diesel generator sets with hydrogen power systems. The assessment covers system sizing onboard hydrogen storage integration operational constraints lifecycle cost and GHG abatement. Option (i) is constrained by the sizes and weights of PEMFC systems and hydrogen-fuelled ICEs rendering full conversion unfeasible within current spatial and technological limits. Option (ii) is technically feasible: sixteen 700 bar cylinders (131.2 kg H2 total) meet one day of onboard power demand for net-cleaning operations with bunkering via swap-and-go skids at the berth. The annualised total cost of ownership for the PEMFC systems is 1.98 times that of diesel generator sets while enabling annual CO2 reductions of 433 t. The findings provide a practical decarbonisation pathway for small- to medium-sized service vessels in niche maritime sectors such as aquaculture while clarifying near-term trade-offs between cost and emissions.

Hydrogen is the key to decarbonising heavy-duty transport. Understanding the distribution of hydrogen demand is crucial for effective planning and development of infrastructure. However current data on future hydrogen demand is often coarse and aggregated limiting its utility for detailed analysis and decision-making. This study developed a spatial disaggregation approach to estimating hydrogen demand for heavy-duty trucks and mapping the spatial distribution of hydrogen demand across multiple scales in Australia. By integrating spatial datasets with economic factors market penetration rates and technical specifications of hydrogen fuel cell vehicles the approach disaggregates the projected demand into specific demand centres allowing for the mapping of regional hydrogen demand patterns and the identification of key centres of hydrogen demand based on heavy-duty truck traffic flow projections under different scenarios. This approach was applied to Australia and the findings offered valuable insights that can help policymakers and stakeholders plan and develop hydrogen infrastructure such as optimising hydrogen refuelling station locations and support the transition to a low-carbon heavy-duty transport sector.