Australia

The MultHyFuel project aims to develop evidence-based guidelines for the safe implementation of Hydrogen Refueling Stations (HRS) in a multi-fuel context. As a part of the generation of good practice guidelines for HRS Hazardous Area Classification (HAC) methodologies were analyzed and applied to case studies representing example configurations of HRS. It has been anticipated that Negligible Extent (NE) classifications might be applicable for sections of the HRS for instance a hydrogen generator. A NE zone requires that an ignition of a flammable cloud would result in negligible consequences. In addition depending on the pressure of the system IEC 60079-10-1:2020 establishes specific requirements in order to classify the hazardous area as being of NE. One such requirement is that a zone of NE shall not be applied for releases from flammable gas systems at pressures above 2000 kPag (20 barg) unless a specific detailed risk assessment is documented. However there is no definition within the standard as to the requirements of the specific detailed risk assessment. In this work an example for a specific detailed risk assessment for the NE classification is presented:<br/>• Firstly the requirements of cloud volume dilution and background concentration for a zone of NE classification from IEC 60079-10-1:2020 are analyzed for hydrogen releases from equipment placed in a mechanically ventilated enclosure.<br/>• Secondly the consequences arising from the ignition of the localized cloud are estimated and compared to acceptable harm criteria in order to assess if negligible consequences are obtained from the scenario.<br/>• In addition a specific qualitative risk assessment for the ignition of the cloud in the enclosure was considered incorporating the estimated consequences and analyzing the available safeguards in the example system.<br/>Recommendations for the specific detailed risk assessment are proposed for this scenario with the intention to support improved definition of the requirement in future revisions of IEC 60079-10-1.

Environmental emissions global warming and energy-related concerns have accelerated the advancements in conventional vehicles that primarily use internal combustion engines. Among the existing technologies hydrogen fuel cell electric vehicles and fuel cell hybrid electric vehicles may have minimal contributions to greenhouse gas emissions and thus are the prime choices for environmental concerns. However energy management in fuel cell electric vehicles and fuel cell hybrid electric vehicles is a major challenge. Appropriate control strategies should be used for effective energy management in these vehicles. On the other hand there has been significant progress in artificial intelligence machine learning and designing data-driven intelligent controllers. These techniques have found much attention within the community and state-of-the-art energy management technologies have been developed based on them. This manuscript reviews the application of machine learning and intelligent controllers for prediction control energy management and vehicle to everything (V2X) in hydrogen fuel cell vehicles. The effectiveness of data-driven control and optimization systems are investigated to evolve classify and compare and future trends and directions for sustainability are discussed.

Global warming is an accepted fact of life on Earth posing grave consequences in the form of weather patterns with life-threatening outcomes for inhabitants and their cultures especially those of island countries. These wild and unpredictable weather patterns have persuaded authorities governments and industrial leaders to adapt a range of solutions to combat the temperature rise on Earth. One such solution is to abandon fossil fuels (hydrocarbons) for energy generation and employ renewable energy sources or at least use energy sources that do not generate greenhouse gases. One such energy carrier is hydrogen which is expected to slowly replace natural gas and will soon be pumped into the energy distribution pipeline network. Since the current energy distribution network was designed for hydrocarbons its use for hydrogen may pose some threat to the safety of urban society. This is the first time an overview article has examined the replacement of hydrocarbons by hydrogen from a totally different angle by incorporating material science viewpoints. This article discusses hydrogen properties and warns about the issue of hydrogen embrittlement in the current pipeline network if hydrogen is to be pumped through the current energy distribution network i.e. pipelines. It is recommended that sufficient study and research be planned and carried out to ensure the safety of using the current energy distribution network for hydrogen distribution and to set the necessary standards and procedures for future design and construction.

Hydrogen has emerged as a promising alternative to meet the growing demand for sustainable and renewable energy sources. Underground hydrogen storage (UHS) in depleted gas reservoirs holds significant potential for large-scale energy storage and the seamless integration of intermittent renewable energy sources due to its capacity to address challenges associated with the intermittent nature of renewable energy sources ensuring a steady and reliable energy supply. Leveraging the existing infrastructure and well-characterized geological formations depleted gas reservoirs offer an attractive option for large-scale hydrogen storage implementation. However significant knowledge gaps regarding storage performance hinder the commercialization of UHS operation. Hydrogen deliverability hydrogen trapping and the equation of state are key areas with limited understanding. This literature review critically analyzes and synthesizes existing research on hydrogen storage performance during underground storage in depleted gas reservoirs; it then provides a high-level risk assessment and an overview of the techno-economics of UHS. The significance of this review lies in its consolidation of current knowledge highlighting unresolved issues and proposing areas for future research. Addressing these gaps will advance hydrogen-based energy systems and support the transition to a sustainable energy landscape. Facilitating efficient and safe deployment of UHS in depleted gas reservoirs will assist in unlocking hydrogen’s full potential as a clean and renewable energy carrier. In addition this review aids policymakers and the scientific community in making informed decisions regarding hydrogen storage technologies.

The addition of small amounts of certain gases such as O2 CO and SO2 may mitigate hydrogen embrittlement in high-pressure gas transmission pipelines that transport hydrogen. To practically implement such inhibition in gas transmission pipelines a comprehensive understanding and quantification of this effect are essential. This review examines the impact of various added gases to hydrogen including typical odorants on gaseous hydrogen embrittlement of steels and evaluates their inhibition effectiveness. O2 CO and SO2 were found to be effective inhibitors of hydrogen embrittlement. Yet the results in the literature have not always been consistent partly because of the diverse range of mechanical tests and their parameters. The absence of systematic studies hinders the evaluation of the feasibility of using gas phase inhibitors for controlling gaseous hydrogen embrittlement. A method to quantify the effectiveness of gas phase inhibition is proposed using gas phase permeation studies.

The transition from fossil fuels to renewable energy sources particularly hydrogen has emerged as a central strategy for decarbonization and the pursuit of net-zero carbon emissions. Meeting the demand for large-scale hydrogen storage a crucial component of the hydrogen supply chain has led to the exploration of underground hydrogen storage as an economically viable solution to global energy needs. In contrast to other subsurface storage options such as salt caverns and aquifers which are geographically limited depleted gas reservoirs have garnered increasing attention due to their broader distribution and higher storage capacity. However the safe storage and cycling of hydrogen in depleted gas reservoirs require the preservation of high stability and integrity in the caprock reservoir and wellbore. Nevertheless there exists a significant gap in the current research concerning storage integrity in underground hydrogen storage within depleted gas reservoirs and a systematic approach is lacking. This paper aims to address this gap by reviewing the primary challenges associated with storage integrity including geochemical reactions microbial activities faults and fractures and perspectives on hydrogen cycling. The study comprehensively reviews the processes and impacts such as abiotic and biotic mineral dissolution/precipitation reactivation and propagation of faults and fractures in caprock and host-rock wellbore instability due to cement degradation and casing corrosion and stress changes during hydrogen cycling. To provide a practical solution a technical screening tool has been developed considering controlling variables risks and consequences affecting storage integrity. Finally this paper highlights knowledge gaps and suggests feasible methods and pathways to mitigate these risks facilitating the development of large-scale underground hydrogen storage in depleted gas reservoirs.

Hydrogen is the gas of the moment: an abundant element that can be created using renewable energy transported in gaseous or liquid form and offering the ability to provide energy with only water vapour as an emission. Hydrogen can also be used in a fuel blend in electricity generation gas turbines providing a low carbon option for providing the peak electricity to cover high demand and firming.<br/>While the electricity grid is itself transforming to decarbonising hard-to-abate industries such as cement and bauxite refineries are slower to reduce emissions constrained by their high temperature process requirements. Hydrogen offers a solution allowing onsite production process heat with waste heat recovery supporting blended gas turbine generation for onsite electricity supply.<br/>This article builds on decarbonisation pathway simulation results from an ANEM model of the electricity grid identifying the amount of peak demand energy required from gas turbines. The research then examines the quantity flow rate storage requirements and emissions reduction if this peak generation were supplied by open cycle hydrogen capable gas turbines.

Installing multi-renewable energy (RE) power plants at designated locations known as RE parks is a promising solution to address their intermittent power. This research focuses on optimizing RE parks for three scenarios: photovoltaic (PV)-only wind-only and hybrid PV-wind with the aim of generating green hydrogen in locations with different RE potentials. To ensure rapid response to RE fluctuations a Proton Exchange Membrane (PEM) electrolyzer is employed. Furthermore this research proposes detailed models for manufacturer-provided wind power curves electrolyzer efficiency against its operating power and electrolyzer cost towards its capacity. Two optimization cases are conducted in MATLAB evaluating the optimum sizes of the plants in minimizing levelized cost of hydrogen (LCOH) using classical discrete combinatorial method and determining the ideal PV-to-wind capacity ratio for operating PEM electrolyzer within hybrid PV-wind parks using particle swarm optimization. Numerical simulations show that wind power-based hydrogen production is more cost-effective than PV-only RE parks. The lowest LCOH $4.26/kg H2 and the highest LCOH $14.378/kg H2 are obtained from wind-only and PV-only configurations respectively. Both occurred in Adum-Kirkeby Denmark as it has highest average wind speed and lowest irradiance level. Notably LCOH is reduced with the hybrid PV-wind configuration. The results suggest the optimum PV-to-wind capacity ratio is 65:35 on average and indicate that LCOH is more sensitive to electrolyzer’s cost than to electricity tariff variation. This study highlights two important factors i.e. selecting the suitable location based on the available RE resources and determining the optimum size ratio between the plants within the RE park.

Hydrogen as a primary carbon-free energy carrier is confronted by challenges in storage and transportation. However liquid organic hydrogen carriers (LOHCs) present a promising solution for storing and transporting hydrogen at ambient temperature and atmospheric pressure. Unlike circular energy carriers such as methanol ammonia and synthetic natural gas LOHCs do not produce by-products during hydrogen recovery. LOHCs only act as hydrogen carriers and the carriers can also be recycled for reuse. Although there are considerable advantages to LOHCs there are also some drawbacks especially relative to the energy consumption during the dehydrogenation step of the LOHC recycling. This review summarizes the recent progresses in LOHC technologies focusing on catalyst developments process and reactor designs applications and techno-economic assessments (TEA). LOHC technologies can potentially offer significant benefits to Australia especially in terms of hydrogen as an export commodity. LOHCs can help avoid capital costs associated with infrastructure such as transportation vessels while reducing hydrogen loss during transportation such as in the case of liquid hydrogen (LH2). Additionally it minimises CO2 emissions as observed in methane and methanol reforming. Thus it is essential to dedicate more efforts to explore and develop LOHC technologies in the Australian context.

The shift from fossil fuels to clean energy carriers such as renewable H2 is imminent. Consequently a global H2 market is taking shape involving countries with limited or insufficient energy resources importing from renewable-rich countries. This study evaluates the techno-economics of renewable hydrogen (H2) export in a globally significant scenario in which Australia exports to Japan. To gain insight into the immediate realisable future the base year was selected as 2030 with a consequently small (in export terms) hydrogen production rate of 100 t/day landed capacity. Electricity was generated by photovoltaic arrays (PV) connected directly to proton exchange membrane (PEM) electrolyser plant allowing for flexible gaseous hydrogen (GH2) production. To enhance the fidelity of the technoeconomic model we incorporated rarely applied but impactful parameters including dynamic efficiency and the overload capacity of PEM electrolysers. The GH2 produced was assumed to be converted into condensed forms suitable for export by sea: liquid hydrogen (LH2) and the chemical carriers liquid ammonia (LNH3) methanol (MeOH) methylcyclohexane (MCH). These were assumed to be reconverted to GH2 at the destination. LNH3 and MCH emerged as promising carriers for export yielding the lowest landed levelised cost of hydrogen (LCOH). LH2 yielded the highest LCOH unless boiloff gas could be managed effectively and cheaply. A sensitivity analysis showed that a lower weighted average cost of capital (WACC) and scale-up can significantly reduce the landed LCOH. Increasing the production rate to 1000 t/day landed capacity very significantly lowered the landed LCOH providing a strong incentive to scale up and optimise the entire supply chain as fast as possible.

Concerning the transition from a carbon-based energy economy to a renewable energy economy hydrogen is considered an essential energy carrier for efficient and broad energy systems in China in the near future. China aims to gradually replace fossil fuel-based power generation with renewable energy technologies to achieve carbon neutrality by 2060. This ambitious undertaking will involve building an industrial production chain spanning the production storage transportation and utilisation of hydrogen energy by 2030 (when China’s carbon peak will be reached). This review analyses the current status of technological R&D in China’s hydrogen energy industry. Based on published data in the open literature we compared the costs and carbon emissions for grey blue and green hydrogen production. The primary challenges concerning hydrogen transportation and storage are highlighted in this study. Given that primary carbon emissions in China are a result of power generation using fossil fuels we provide an overview of the advances in hydrogen-to-power industry technology R&D including hydrogen-related power generation technology hydrogen fuel cells hydrogen internal combustion engines hydrogen gas turbines and catalytic hydrogen combustion using liquid hydrogen carriers (e.g. ammonia methanol and ethanol).

Blending hydrogen to existing fuel mix represents a major opportunity for decarbonisation. One important consideration for this application is the chemical interaction between hydrogen and hydrocarbon fuels arising from their different combustion chemistries and varying considerably with combustion processes. This paper conducted an exploratory study of hydrogen’s impact on autoignition in several combustion processes where hydrogen is used as a blending component or the main fuel. Case studies are presented for spark ignition engines (H2/natural gas) compression ignition engines (H2/diesel) moderate or intense low-oxygen dilution (MILD) combustors (H2/natural gas) and rotational detonation engines (H2/natural gas). Autoignition reactivity as a function of the hydrogen blending level is investigated numerically using the ignition delay iso-contours and state-of-the-art kinetic models at time scales representative of each application. The results revealed drastically different impact of hydrogen blending on autoignition due to different reaction temperature pressure and time scale involved in these applications leaving hydrocarbon interacting with hydrogen at different ignition branches where the negative pressure/temperature dependency of oxidation kinetics could take place. The resulted non-linear and at times non-monotonic behaviours indicate a rich topic for combustion chemistry and also demonstrates ignition delay iso-contour as a useful tool to scope autoignition reactivity for a wide range of applications.

Supporters of hydrogen energy urge scaling up technology and reducing costs for competitiveness. This paper explores how hydrogen energy technologies (HET) are perceived by Australia’s general population and considers the way members of the public imagine their role in the implementation of hydrogen energy now and into the future. The study combines a nationally representative survey (n = 403) and semi-structured interviews (n = 30). Results show age and gender relationships with self-reported hydrogen knowledge. Half of the participants obtained hydrogen information from televised media. Strong support was observed for renewable hydrogen while coal (26%) and natural gas (41%) versions had less backing. Participants sought more safety-related information (41% expressed concern). Most felt uncertain about influencing hydrogen decisions and did not necessarily recognise they had agency beyond their front fence. Exploring the link between political identity and agency in energy decision-making is needed with energy democracy a potentially productive direction.

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.

As the need for alternative energy sources and reduced emissions grows proven technologies are often sidelined in favour of emerging solutions that lack the infrastructure for mass adoption. This study explores a transitional approach by modifying existing compression ignition engines to run on a hydrogen/diesel mixture for performance improvement utilising water injection to mitigate the drawbacks associated with hydrogen combustion. This approach can yield favourable results with current technology. In this modelling study ten hydrogen energy ratios (0–90%) and nine water injection rates (0–700 mg/cycle) were tested in a turbocharged Cummins ISBe 220 31 six-cylinder diesel engine. An engine experiment was conducted to validate the model. Key performance indicators such as power mechanical efficiency thermal efficiency indicated mean effective pressure (IMEP) and brake-specific fuel consumption (BSFC) were measured. Both water injection and hydrogen injection led to slight improvements in all performance metrics except BSFC due to hydrogen’s lower energy density. In terms of emissions CO and CO2 levels significantly decreased as hydrogen content increased with reductions of 94% and 96% respectively at 90% hydrogen compared to the baseline diesel. Water injection at peak rates further reduced CO emissions by approximately 40% though it had minimal effect on CO2 . As expected NOx (which is a typical challenge with hydrogen combustion and also with diesel engines in general) increased with hydrogen fuelling resulting in an approximately 70% increase in total NOx emissions over the range of 0–90% hydrogen energy. Similar increases were observed in NO and NO2 e.g. 90% and 57% increases with 90% hydrogen respectively. However water injection reduced NO and NO2 levels by up to 16% and 83% respectively resulting in a net decrease in NOX emissions in many combined cases not only with hydrogen injection but also when compared to baseline diesel.

Hydrogen is expected to play a critical role in future energy systems projected to have an annual demand of 401–660 Mt by 2050. With large-scale green hydrogen projects advancing in water-scarce regions like Australia Chile and the Middle East and North Africa understanding water requirements for large-scale green hydrogen production is crucial. Meeting this future hydrogen demand will necessitate 4010 to 6600 GL of demineralised water annually for electrolyser feedwater if dry cooling is employed or an additional 6015 to 19800 GL for cooling water per year if evaporative cooling is employed. Using International Panel of Climate Change 2050 climate projections this work evaluated the techno-economic implications of dry vs. evaporative cooling for large-scale electrolyser facilities under anticipated higher ambient temperatures. The study quantifies water demands costs and potential operational constraints showing that evaporative cooling is up to 8 times cheaper to implement than dry cooling meaning that evaporative cooling can be oversized to accommodate increased cooling demand of high temperature events at a lower cost. Furthermore of the nations analysed herein Chile emerged as having the lowest cost of hydrogen owing to the lower projected ambient temperatures and frequency of high temperature events.

Unlocking the potential of offshore renewables for green hydrogen (GH2) production can be a game-changer empowering economies with their visionary clean energy policies amplifying energy security and promoting economic growth. However their novelty entails uncertainty and risk necessitating a robust framework for facility deployment and infrastructure planning. To optimize offshore GH2 infrastructure placement this work proposes a novel and robust GIS-based multi-criteria decision-making (MCDM) framework. Encompassing thirtytwo techno-socio-economic-safety factors and ocean environmental impact analysis this methodology facilitates informed decision-making for sustainable and safe GH2 development. Utilizing the synergies between offshore wind and solar resources this study investigates the potential of hybrid ocean technologies to enhance space utilization and optimize efficiency. To illustrate the practical application of the proposed framework a case study examining a GH2 system in Australia's marine region and its potential nexus with nearby offshore industries has been conducted. The performed life cycle assessment (LCA) explored various configurations of GH2 production storage and transportation technologies. A Bayesian objective weight integrating technique has been introduced and contrasted statistically with the hybrid CRITIC Entropy MEREC and MARCOS-based MCDM approaches. Various locations are ranked based on the net present value of life cycle cost GH2 production capacity risk availability and environment sustainability factors illustrating their compatibility. A sensitivity analysis is conducted to confirm that a Bayesian approach improves the decision-making outcomes through identifying optimal criteria weights and alternative ranks more effectively. Empowering strategic GH2 decisions globally the proposed approach optimizes system performances cost sustainability and safety excelling in harsh environments.

The global population is predicted to increase from ~7.3 billion to over 9 billion people by 2050.Together with rising economic growth this is forecast to result in a 50% increase in fueldemand which will have to be met while reducing carbon dioxide (CO 2 ) emissions by 50–80%to maintain social political energy and climate security. This tension between rising fuel demandand the requirement for rapid global decarbonization highlights the need to fast-track thecoordinated development and deployment of efficient cost-effective renewable technologies forthe production of CO 2 neutral energy. Currently only 20% of global energy is provided aselectricity while 80% is provided as fuel. Hydrogen (H 2) is the most advanced CO 2 -free fuel andprovides a ‘common’ energy currency as it can be produced via a range of renewabletechnologies including photovoltaic (PV) wind wave and biological systems such as microalgaeto power the next generation of H 2 fuel cells. Microalgae production systems for carbon-basedfuel (oil and ethanol) are now at the demonstration scale. This review focuses on evaluating thepotential of microalgal technologies for the commercial production of solar-driven H2 fromwater. It summarizes key global technology drivers the potential and theoretical limits ofmicroalgal H2 production systems emerging strategies to engineer next-generation systems andhow these fit into an evolving H 2 economy.

There is growing interest in using hydrogen (H2) as a marine fuel. Fire and explosion risks depend on hydrogen release and dispersion characteristics. Based on a validated Computational Fluid Dynamics (CFD) model this study performed hydrogen release and dispersion analysis on an under-deck compressed H2 storage system for a Live-Fish Carrier. A realistic under-deck H2 storage room was modelled based on the ship’s main dimensions and operational profile. Det Norske Veritas (DNV) Rules and Regulations for natural gas storage as a marine fuel were employed as base design guidelines. Case studies were developed to study the effect of two ceiling types (flat and slanted) in terms of flammable cloud formation and dissipation. During the leak’s duration it was found that the recommended ventilation rate was insufficient to dilute the average H2 concentration below 25% of the flammable range as required by DNV (1.2% required against 1.3% slanted and 1.4% flat). However after 35 s of gas extraction the H2 concentration was reduced to 0.5% and 0.6% in the slanted and flat cases respectively. The proposed methodology remains valid to improve the ventilation system and assess mitigation alternatives or other leakage scenarios in confined or semi-confined spaces containing compressed hydrogen gas.

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.

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.

Hydrogen is emerging as a promising future energy medium in a wide range of industries. For mobile applica tions it is commonly stored in a gaseous state within high-pressure composite overwrapped pressure vessels (COPVs). The current state of the art pressure vessel technology known as Type V eliminates the internal polymer gas barrier used in Type IV vessels and instead relies on carbon fibre laminate to provide structural properties and prevent gas leakage. Achieving this functionality at high pressure poses several engineering challenges that have thus far prohibited commercial application. Additionally the traditional manufacturing process for COPVs filament winding has several constraints that limit the design space. Automated fibre placement (AFP) a highly flexible robotic composites manufacturing technique has the potential to replace filament winding for composite pressure vessel manufacturing and provide pathways for further vessel optimi sation. A combination of both AFP and Type V technology could provide an avenue for a new generation of highperformance composite pressure vessels. This critical review presents key work on industry-standard Type IV vessels alongside the current state of Type V CPV technology including manufacturing developments challenges cost relevance to commercial standards and future fabrication solutions using AFP. Additionally a novel Type V CPV design concept for a two-piece AFP produced vessel is presented.

We perform a simulation study of hydrogen injection in a depleted gas reservoir to assess the geomechanical impact of hydrogen storage relative to other commonly injected gases (methane CO2). A key finding is that the differences in hydrogen density compressibility viscosity and thermal properties compared to the other gases result in significantly less thermal perturbation at reservoir level. The risks of fault reactivation and wellbore fractures due to thermally-induced stress changes are significantly lower when storing hydrogen compared to results observed in CO2 scenarios. This implies that hydrogen injection and production has a much smaller geomechanical footprint with benefits for operational safety. We also find that use of nitrogen cushion gas ensures efficient deliverability and phase separation in the reservoir. However in this study a large fraction of cushion gas was back-produced in each cycle demonstrating the need for further studies of the surface processing requirements and economic implications.

Introduction: An online deliberative engagement process was undertaken with members of the general public to understand what they value or would like to change about the energy system within the broader context of decarbonizing Australia's energy networks identifying a role for future fuels (hydrogen and biogas). Citizens developed a set of principles that could guide Australia's path toward a low-carbon energy future reflecting on expectations they place upon energy transition. Next citizens' principles were shared with policy-makers in government and policy-influencers from the energy industry using an online interactive workshop.<br/>Methods: This study analyses policy-makers and -influencers response to citizens' guiding principles using the 'diamond of participatory decision-making' framework for analysis. Convergence and divergence in diverse complex and rich views across cohorts and implications thereupon energy policy were identified.<br/>Results: Although considerable alignment between multi-stakeholders' views was noted key areas of divergence or what is called the “groan zone” were easily identified in relation to social and environmental justice issues. This groan zone highlights the struggles that energy policy-makers face -the need to listen and respond to citizens' voices vs. the need for practical and workable policies that also support overarching government or industry objectives.<br/>Discussion: Policy making when the views of different stakeholders align is relatively straightforward. However this is not the case where the expectations diverge. More creative measures will be needed to address divergent views and expectations whilst maintaining procedural fairness in this case using democratic deliberative engagement processes. While the use of deliberative processes is gaining momentum worldwide particularly concerning climate change and energy transition policies this paper also highlights the benefits of conducting a robust post facto analysis of the content of the processes. Areas of alignment where policy can be made and implemented relatively easily without contention are identified. Other areas (such as making electrification mandatory) might be more complex or have unwanted negative social and environmental justice effects. Overall this paper bridges an analytical gap between “expectation studies” and participatory research. By borrowing terminology from a participatory research framework we sharpen the concepts in “expectation studies” from a consensus inclusion and diversity standpoint.

In today’s world the need for sustainable energy solutions is paramount to address the ongoing crisis of increasing greenhouse gas emissions and global warming. Industries heavily reliant on fossil fuels must explore alternative energy sources. Hydrogen with its high heating value and zero direct emissions has emerged as a promising fuel for the future. Electrolytic hydrogen production has gained significance as it enables demand-side response grid stabilization using excess energy and the mitigation of curtailment from intermittent renewable energy sources (RES) such as solar and wind. Advanced combined heat and power (CHP) systems comprise of Solid oxide fuel cell (SOFC) module and a coupled reforming reactor to capture energy contained in the SOFC exhaust gases from SOFC. In present work 3D CFD model of an experimental coupled reactor used for onsite hydrogen production is developed and implemented into ANSYS Fluent® software. The study is aimed at opti mizing the reactor performance by identifying appropriate kinetic models for reforming and combustion re actions. SOFC anode off-gas (AOG) comprising mainly of unconverted hydrogen is combined with methane combustion to enhance thermal efficiency of the reactor and hence the CHP system. Kinetic models for catalytic reforming and combustion are implemented into ANSYS Fluent® through custom-built user defined functions (UDFs) written in C programming language. Simulation results are validated with experimental data and found in good agreement. AOG assisted combustion of methane shows a substantial improvement in thermal efficiency of the system. Improvement in thermal efficiency and reduction in carbon-based fuel demand AOG utilization contributes to sustainable hydrogen production and curtailment of greenhouse gas emissions.