Australia

This paper aims to optimize dual-fuel facilitated off-/on-grid multi-energy systems (MESs) for different renewable energy zones (REZs) in Australia. The main objective is to develop a novel MES with the main feature of green hydrogen production and blended natural gas utilization for remote households. The proposed optimal system produces green hydrogen of 5343 kg/yr via proton exchange membrane (PEM) electrolyzer and blends it with natural gas. It involves 20 % hydrogen and 80 % natural gas in the overall volume of the blending process. This study contributes by performing optimal sizing of the components economic-energy-environmental and performance analyses to examine the most feasible solution for each REZ. The results indicate that the optimal system in North Queensland REZ has the lowest levelized cost of energy (LCE) of 1.28 A$/kWh and 0.1003 A $/kWh and the net present cost (NPC) of A$0.311 million and A$0.219 million for off-grid and on-grid configurations. The optimal on-grid system has 95.27 % less carbon emissions than the natural gas-fueled combustion energy system.

The abundant plastic wastes become an imperative global issue and how to handle these organic wastes gains growing scientific and industrial interest. Recently converting plastic wastes into hydrogen fuel has been investigated and the “waste-to-value” practice accelerates the circular economy. To accelerate the development of plastic-to-hydrogen conversion in this review recent advances in plastic-to-hydrogen conversion via thermochemical photocatalytic and electrocatalytic routes are analyzed. All of the thermo- photo- and electrochemical processes can transform different plastic wastes into hydrogen and the hydrogen production efficiency depends heavily on the selected techniques operating parameters and applied catalysts. The application of rational-designed catalysts can promote the selective production of hydrogen from plastic feedstocks. Further studies on process optimization cost-effective catalyst design and mechanism investigation are needed.

A 3.5 tonne forklift containing proton exchange membrane fuel cells (PEMFCs) and lithium-ion batteries was manufactured and tested in a real factory. The work efficiency and economic applicability of the PEMFC forklift were compared with that of a lithium-ion battery-powered forklift. The results showed that the back-pressure of air was closely related to the power density of the stack whose stability could be improved by a reasonable control strategy and membrane electrode assemblies (MEAs) with high consistency. The PEMFC powered forklift displayed 40.6% higher work efficiency than the lithium-ion battery-powered forklift. Its lower use-cost compared to internal engine-powered forklifts is beneficial to the commercialization of this product.

Hydrogen is gaining prominence as a sustainable energy source in the UK aligning with the country’s commitment to advancing sustainable development across diverse sectors. However a rigorous examination of the interplay between the hydrogen economy and the Sustainable Development Goals (SDGs) is imperative. This study addresses this imperative by comprehensively assessing the risks associated with hydrogen production storage transportation and utilization. The overarching aim is to establish a robust framework that ensures the secure deployment and operation of hydrogen-based technologies within the UK’s sustainable development trajectory. Considering the unique characteristics of the UK’s energy landscape infrastructure and policy framework this paper presents practical and viable recommendations to facilitate the safe and effective integration of hydrogen energy into the UK’s SDGs. To facilitate sophisticated decision making it proposes using an advanced Decision-Making Trial and Evaluation Laboratory (DEMATEL) tool incorporating regret theory and a 2-tuple spherical linguistic environment. This tool enables a nuanced decision-making process yielding actionable insights. The analysis reveals that Incident Reporting and Learning Robust Regulatory Framework Safety Standards and Codes are pivotal safety factors. At the same time Clean Energy Access Climate Action and Industry Innovation and Infrastructure are identified as the most influential SDGs. This information provides valuable guidance for policymakers industry stakeholders and regulators. It empowers them to make well-informed strategic decisions and prioritize actions that bolster safety and sustainable development as the UK transitions towards a hydrogen-based energy system. Moreover the findings underscore the varying degrees of prominence among different SDGs. Notably SDG 13 (Climate Action) exhibits relatively lower overall distinction at 0.0066 and a Relation value of 0.0512 albeit with a substantial impact. In contrast SDG 7 (Clean Energy Access) and SDG 9 (Industry Innovation and Infrastructure) demonstrate moderate prominence levels (0.0559 and 0.0498 respectively) each with its unique influence emphasizing their critical roles in the UK’s pursuit of a sustainable hydrogen-based energy future.

Hydrogen recognised as a clean and sustainable energy carrier with excellent transportation fuel properties drives numerous countries towards a hydrogen-based economy due to its high utilisation efficiency and minimal environmental impact. However the gaseous nature of hydrogen necessitates larger storage surface areas. Underground Hydrogen Storage (UHS) has emerged as a promising and efficient method to overcome this challenge. Currently only a handful of UHS locations exist globally due to the novelty of this field. With its abundant depleted hydrocarbon reservoirs boasting significant storage capacity Western Australia presents a suitable region for hydrogen storage. This paper comprehensively analyses petrophysical and petrographic characteristics employing XRD MIP and Micro-CT techniques on sandstone and claystone samples obtained from several fields in Western Australia. The suitability of these samples for hydrogen storage is evaluated based on mineral composition and porosity. The analysis reveals that more than 96% of Quartz is present in the sandstone samples. The claystone samples exhibit a mineral composition comprising Quartz Calcite K-feldspar Kaolinite Pyrite Albite and Muscovite. The study suggests that hydrogen storage in formation rock is favourable due to the low reactivity of hydrogen with silicate minerals but interactions with cap rock minerals should be considered. Micro-CT results indicate the connected porosity in the 17.23–4.67% range. Pore distribution in sandstones ranges from nanometers to millimetres with a substantial proportion of connected pores in the intermediate range which is conducive to hydrogen storage. This is particularly advantageous as the hydrogen-water system is highly water-wet with hydrogen primarily occupying medium and larger pores minimising hydrogen trapping. In claystone most pores were below 3 nm but instrumental constraints limited their quantification. In conclusion the petrophysical and petrographic analysis underscores the potential of Western Australian depleted hydrocarbon reservoirs for hydrogen storage. Understanding the mineralogical reactions with cap rock minerals is crucial while the favourable pore distribution in sandstones further supports the viability of hydrogen storage.

Interest in hydrogen-powered rail vehicles has gradually increased worldwide over recent decades due to the global pressure on reduction in greenhouse gas emissions technology availability and multiple options of power supply. In the past research and development have been primarily focusing on light rail and regional trains but the interest in hydrogen-powered freight and heavy haul trains is also growing. The review shows that some technical feasibility has been demonstrated from the research and experiments on proof-of-concept designs. Several rail vehicles powered by hydrogen either are currently operating or are the subject of experimental programmes. The paper identifies that fuel cell technology is well developed and has obvious application in providing electrical traction power while hydrogen combustion in traditional IC engines and gas turbines is not yet well developed. The need for on-board energy storage is discussed along with the benefits of energy management and control systems.

The necessity of energy solutions that are economically viable ecologically sustainable and environmentally friendly has become fundamental to economic and societal advancement of nations. In this context renewable energy sources emerge as the most vital component. Furthermore hydrogen generation systems based on renewable energies are increasingly recognized as the most crucial strategies to mitigate global warming. In the present study a comparative analysis is conducted from an exergy-economic perspective to find the most efficient configuration among three different systems for renewable-based power to hydrogen production. These renewable sources are wind turbine salinity gradient solar pond (SGSP) and ocean thermal energy conversion (OTEC). SGSP and OTEC are coupled with a hydrogen production unit by a trilateral cycle (TLC) to improve the temperature match of the heating process. The heat waste energy within these systems is recovered by a thermoelectric generator (TEG) and a proton exchange membrane electrolyzer (PEME) is used for hydrogen production. Under base case input conditions the net power input of PEME is estimated to be approximately 327.8 kW across all configurations. Additionally the 3E (energy exergy and exergy-economic) performance of the three systems is evaluated by a parametric study and design optimization. The results of the best performance analysis reveal that the best exergy efficiency is achievable with the wind-based system in the range of 5.8–10.47% and for average wind speed of 8–12 m/s. Correspondingly the most favorable total cost rate is attributed to the wind-based system at a wind speed of 8 m/s equating to 66.08 USD/h. Subsequently the unit cost of hydrogen for the SGSP-based system is estimated to be the most economical ranging from 42.78 to 44.31 USD/GJ.

This article proposes a supply chain-based green hydrogen microgrid modelling for a number of remote Australian communities. Green hydrogen can be used as an emissions-free fuel source for electricity generation in places where large-scale renewable energy production is impossible due to land availability population or government regulations. This research focuses on the Torres Strait Island communities in northern Australia where the transition from diesel to renewable electricity generation is difficult due to very limited land availability on most islands. Due to geographical constraints low population and smaller electrical load the green hydrogen needs to be sourced from somewhere else. This research presents a green hydrogen supply chain model that leverages the land availability of one island to produce hydrogen to supply other island communities. In addition this research presents a model of producing and transporting green hydrogen while supplying cheaper electricity to the communities at focus. The study has used a transitional scenario planning approach and the HOMER simulation platform to find the least-cost solution. Based on the results a levelised cost of energy range of AU$0.42 and AU$0.44 was found. With the help of a green hydrogen supply chain CO2 emissions at the selected sites could be cut by 90 %. This study can be used as a guide for small clustered communities that could not support or justify large-scale renewable generation facilities but need more opportunities to install renewable generation.

Hydrogen-based Power Systems (H2PSs) are gaining accelerating momentum globally to reduce energy costs and dependency on fossil fuels. A H2PS typically comprises three main parts: hydrogen production storage and power generation called packages. A review of the literature and Original Equipment Manufacturers (OEM) datasheets reveals that no single manufacturer supplies all H2PS components posing significant challenges in system design parts integration and safety assurance. Additionally both the literature and H2PS projects’ database highlight a gap in a systematic hydrogen equipment and auxiliary sub-systems technology selection process and how this selection affects the overall H2PS Balance of Plant (BoP). This study addresses that gap by providing a guideline for available technology options and their impact on the H2PS-BoP. The analysis compares packages and auxiliary sub-system technologies to support informed engineering decisions regarding technology and equipment selection. The study finds that each package’s technology influences the selection criteria of the other packages and the associated BoP requirements. Furthermore the choice of technologies across packages significantly affects overall system integrity and BoP. These interdependencies are illustrated using a cause-and-effect matrix. The study’s significance lies in establishing a structured guideline for engineering design and operations enhancing the accuracy of feasibility studies and accelerating the global implementation of H2PS.

Green hydrogen is critical for achieving net-zero emissions with water electrolysis offering a CO2-free solution. This study provides a comprehensive comparative financial and economic assessment of a hybrid PV/wind hydrogen production system using three types of electrolysers including Alkaline Electrolyser (AEL) Proton Exchange Membrane Electrolyser (PEMEL) and Solid Oxide Electrolyser (SOEL). Key performance metrics such as net present value (NPV) Internal Rate of Return (IRR) revenues Earnings Before Interest Tax Depreciation and Amortization (EBITDA) Earning Before Taxes (EBT) Debt Service Coverage Ratio (DSCR) and levelized cost of Hydrogen (LCOH) are evaluated to identify the most cost-effective option. The findings reveal that AEL is the most economical solution achieving a higher NPV (503374 k€) and IRR (16.94 % for project IRR) though PEMEL and SOEL remain competitive. Other metrics such as DSCR show that the hydrogen project generates 30 % more cash flow than is required to cover its debt service. Additionally the results of the LCOH analysis demonstrate that a hybrid plant consisting of 10 % PV and 90 % wind is more cost-effective in the studied region than both solar-based or wind-based hydrogen production plants. AEL and PEMEL are approximately 7–6 €/kg less expensive than SOEL but this gap is expected to be narrowed by 2030. The hybrid renewable energy project reduces CO2 emissions by 6786.6 Mt over its lifetime. These findings guide policymakers and investors toward scalable cost-effective green hydrogen deployment emphasizing the synergy of hybrid renewables and mature electrolysis technologies.

Increasing renewable energy technology penetration into electrical grids to meet net zero CO2 emission targets is a key challenge in terms of intermittency; one solution is the provision of sufficient energy storage. In the current study we considered future projections of electrical demand and renewable energy (in 2042) for the Southwest Interconnected System grid in Western Australia. Required energy storage considered is a mixture of battery energy storage systems and underground hydrogen storage in a depleted gas reservoir. The Southwest Interconnected System serves as an excellent case study given that it is a comparatively large isolated grid with substantial potential access to renewable energy resources as well as potential underground hydrogen storage sites. This work utilised a dynamic energy model that summates the wind and solar energy resources on an hourly basis. Excess energy utilised battery energy storage systems capacity first followed by underground hydrogen storage. The relative size of the renewables and the storage options is then optimised in terms of minimising wholesale energy production costs. This unique optimisation analysis across the full integrated system clearly indicated that both battery energy storage systems and underground hydrogen storage are required; underground hydrogen storage is predominately necessary to meet seasonal unmet energy demand that amounts to approximately 6% of total demand. Underground hydrogen storage costs were dominated by the required electrolyser requirements. The optimised levelised cost of electricity was found to be US$106/MWh which is approximately 45% larger than current wholesale electricity prices.

Ports have significant emissions from using carbon-based electricity and fuels. This paper presents a scoping literature review of port energy models providing interpretations of the models capabilities and limitations in representing activities coverages of hydrogen technologies use as decarbonisation prediction tools and to highlight research directions. Three model categories were assessed. The Conceptual-Driven use a top-down analytical structure for objectives optimisation. Recent publications have increasing coverages of port activities by electrical with hydrogen technologies but limited representation of diesel equipment. The Data-Driven represent entire ports as top-down or focus on electrical mobile equipment in bottom-up data-only abstract structures for algorithm analysis. Both model types omit coverage of hydrogen powered mobile equipment at temporal resolutions representing typical duties and measured emissions for weighting predictions. A HybridDriven model is proposed as a decarbonisation assessment tool for improved representation of diesel mobile equipment duty-profiles referenceable baselines and matching with hydrogen technologies characteristics.

Hydrogen injection (HI) is an emerging decarbonisation technology for ironmaking blast furnaces (BFs) yet its impact on the in-furnace phenomenon in the raceway of an industry BF remains unclear. In this study an industrialscale Reactive Computational Fluid Dynamic Discrete Element Method coupling model (rCFD-DEM) is developed to study the impacts of HI on the raceway dynamics and coke combustion inside an industrial-scale BF. To overcome the limit in previous CFD-DEM works this work considers the impact of top loading on the in-raceway reacting flow for the first time. The comparisons show that the raceway size is sensitive to the top loading ratio suggesting that the top loading should be considered in future raceway modelling. Then the quantitative effect of the HI rate is numerically evaluated. It is indicated that when the HI rate increases from zero to 8 kg/tHM the raceway height and depth increase by 95% and 81% respectively under the investigated conditions. The underlying mechanism is explored: the increase in HI rate leads to an increase in inter-phase drag force and interparticle collision and in the convection and radiation heat transfer rates by 33 and 32 times respectively. This study provides a cost-effective tool to understand and optimise HI in industrial-scale BFs for a lower carbon footprint empowering the steel industry with crucial insights.

In response to the surging global demand for clean energy solutions and sustainability hydrogen is increasingly recognized as a key player in the transition towards a low-carbon future necessitating efficient storage and transportation methods. The utilization of natural geological formations for underground storage solutions is gaining prominence ensuring continuous energy supply and enhancing safety measures. However this approach presents challenges in understanding gas-rock interactions. To bridge the gap this study proposes a data-driven strategy for contact angle prediction using machine learning techniques. The research leverages a comprehensive dataset compiled from diverse literature sources comprising 1045 rows and over 5200 data points. Input features such as pressure injection rate temperature salinity rock type and substrate were incorporated. Various artificial intelligence algorithms including Support Vector Machine (SVM) k-Nearest Neighbors (KNN) Feedforward Deep Neural Network (FNN) and Recurrent Deep Neural Network (RNN) were employed to predict contact angle with the FNN algorithm demonstrating superior performance accuracy compared to others. The strengths of the FNN algorithm lie in its ability to model nonlinear relationships scalability to large datasets robustness to noisy inputs generalization to unseen data parallelizable training processes and architectural flexibility. Results show that the FNN algorithm demonstrates higher accuracy (RMSE = 0.9640) than other algorithms (RMSERNN = 1.7452 RMSESVM = 1.8228 RMSEKNN = 1.0582) indicating its efficacy in predicting the contact angle testing subset within the context of underground hydrogen storage. The findings of this research highlight a low-cost and reliable approach with high accuracy for estimating contact angle of water–hydrogen–rock system. This technique also helps determine the contribution and influence of independent factors aiding in the interpretation of absorption tendencies and the ease of hydrogen gas flow through the porous rock space during underground hydrogen storage.

Hydrogen will be an integral component for the transition to sustainable energy generation and storage due to its favourable characteristics and versatility in its application. This research provides a greater understanding of the potential light energy has to increase water electrolysis efficiency by examining the effects that light energy fields have on the molecular and electrochemical dynamics during electrolysis. The results indicate that light energy increased efficiency by ~10% while enhancing the molecular dynamics regardless of application. The application of a line laser generated the highest gains in efficiency with a maximum of ~15%. Furthermore the application of a line laser with a linear magnetic field resulted in a synergistic effect which generated higher increases in molecular dynamics as well as an ~18% increase in efficiency and a ~58% increase in hydrogen gas production. As such the application of light energy fields presents a promising method for enhancing water’s molecular dynamics and electrolysis efficiency.

Hydrogen has become an important component of the global transition to zero-carbon economies. Low-carbon and green hydrogen gas and fuel cell technology for domestic household use will depend on skilled practi tioners particularly gasfitters to convert install and maintain hydrogen-based appliances. Upskilling gasfitters to work with hydrogen is critical to transitioning from natural gas to hydrogen for heating and cooking. Yet limited research exists on training and upskilling trade practitioners in the context of renewable energy and lowcarbon technologies. This paper makes a novel contribution to research on upskilling for renewable and lowcarbon technologies by drawing on the findings from a survey of 1001 plumbers in Australia. The survey designed using the Theory of Planned Behavior aimed to predict behaviors regarding hydrogen training and ascertain social and structural enablers for such behavior. The results show that plumbers have limited awareness of hydrogen yet have positive attitudes towards upskilling to work with the low-carbon fuel. Perceived benefits to business sustainability customer service and safety underpin the positive attitudes. The research shows that while plumbers are enthusiastic about upskilling for hydrogen upskilling policies and programs must ensure key stakeholders who inform plumbers’ ongoing practice are on board and informed about hydrogen training opportunities.

Solid oxide fuel cells (SOFCs) have garnered significant attention as a promising technology for clean and efficient power generation due to their ability to utilise renewable fuels such as hydrogen and ammonia. As carbon-free energy carriers hydrogen and ammonia are expected to play a pivotal role in achieving net-zero emissions. However a critical research question remains: how does the electrochemical performance of SOFCs compare when fuelled by hydrogen vs. ammonia and what are the implications for their practical application in power generation? This mini-review paper is premised on the hypothesis that while hydrogen-fuelled SOFCs currently demonstrate superior stability and performance at low and high temperatures ammonia-fuelled SOFCs offer unique advantages such as higher electrical efficiencies and improved fuel utilisation. These benefits make ammonia a viable alternative fuel source for SOFCs particularly at elevated temperatures. To address this the mini-review paper provides a comprehensive comparative analysis of the electrochemical performance of SOFCs under direct hydrogen and ammonia fuels focusing on key parameters such as open-circuit voltage (OCV) power density electrochemical impedance spectroscopy fuel utilisation stability and electrical efficiency. Recent advances in electrode materials electrolytes fabrication techniques and cell structures are also highlighted. Through an extensive literature survey it is found that hydrogen-fuelled SOFCs exhibit higher stability and are less affected by temperature cycling. In contrast ammonia-fuelled SOFCs achieve higher OCVs (by 7%) and power densities (1880 mW/cm2 vs. 1330 mW/cm2 for hydrogen) at 650 °C along with 6% higher electrical efficiency. Despite these advantages ammonia-fuelled SOFCs face challenges such as NOx emissions nitride formation environmental impact and OCV stabilisation which are discussed alongside potential solutions. This mini review aims to provide insights into the future direction of SOFC research emphasising the need for further exploration of ammonia as a sustainable fuel alternative.

We report on the first stage of an energy systems integration project to develop hybrid renewable energy generation and storage of hydrogen for subsequent use via research-based low regret system testbeds. This study details the design and construction of a flexible plug-and-play hybrid renewable power and hydrogen system testbed with up to 50 kW capacity aimed at addressing and benchmarking the operational parameters of the system as well as key components when commissioned. The system testbed configuration includes three different solar technologies three different battery technologies two different electrolyser technologies hydrogen storage and a fuel cell for regenerative renewable power. Design constraints include the current limit of an AC microgrid regulations for grid-connected inverters power connection inefficiencies and regulated hazardous area approval. We identify and show the resolution of systems integration challenges encountered during construction that may benefit planning for the emerging pilot or testbed configurations at other sites. These testbed systems offer the opportunity for informed decisions on economic viability for commercial-scale industry applications.

The increasing adoption of liquid hydrogen (LH2) as a clean energy carrier presents significant safety challenges particularly in confined underground spaces like tunnels. LH2′s unique properties including high energy density and cryogenic temperatures amplify the risks of leaks and explosions which can lead to catastrophic overpressures and extreme temperatures. This study addresses these challenges by investigating the diffusion and explosion behaviour of LH2 leaks in tunnels providing critical insights into disaster prevention and structural resilience for underground infrastructure. Using advanced numerical simulations validated through theoretical calculations and experimental analogies the study analyses hydrogen diffusion patterns overpressure dynamics and thermal impacts following an LH2 tank rupture. Results show that LH2 explosions generate overpressures exceeding 50 bar and temperatures surpassing 2500 ◦C far exceeding the hazards posed by gaseous hydrogen leaks. Mitigation measures such as suction ventilation and high humidity significantly reduce explosion impacts underscoring their value for tunnel safety. This research advances understanding of hydrogen safety in confined spaces demonstrating the importance of integrating mitigation measures into tunnel design. The findings contribute to disaster prevention strategies offer insights into optimizing safety protocols and support the development of resilient infrastructure capable of accommodating hydrogen technologies in a rapidly evolving energy landscape.

N-type sulfide semiconductors are promising photocatalysts due to their broad visible-light absorption facile synthesis and chemical diversity. However photocorrosion and limited electron transport in one-step excitation and solid-state Z-scheme systems hinder efficient overall water splitting. Liquidphase Z-schemes offer a viable alternative but sluggish mediator kinetics and interfacial side reactions impede their construction. Here we report a stable Z-scheme system integrating n-type CdS and BiVO₄ with a [Fe(CN)₆]³⁻/[Fe(CN)₆]⁴⁻ mediator achieving 10.2% apparent quantum yield at 450 nm with stoichiometric H₂/O₂ evolution. High activity reflects synergies between Pt@CrOx and Co3O4 cocatalysts on CdS and cobalt-directed facet asymmetry in BiVO₄ resulting in matched kinetics for hydrogen and oxygen evolution in a reversible mediator solution. Stability is dramatically improved through coating CdS and BiVO4 with different oxides to inhibit Fe4[Fe(CN)6]3 precipitation and deactivation by a hitherto unrecognized mechanism. Separate hydrogen and oxygen production is also demonstrated in a twocompartment reactor under visible light and ambient conditions. This work unlocks the long-sought potential of n-type sulfides for efficient durable and safe solar-driven hydrogen production.

Biohydrogen is known for its clean fuel properties with zero emissions. It serves as a reliable alternative to fossil fuel. This paper analyses the status of bio-hydrogen production in Malaysia and the on-going efforts on its advancement. Critical discussions were put forward on biohydrogen production from thermochemical and biological technologies governing associated technological issues and development. Moreover a comprehensive and vital overview has been made on Malaysian and global polices with road maps for the development of biohydrogen and its application in different sectors. This review article provides a framework for researchers on bio-hydrogen production technologies investors and the government to align policies for the biohydrogen based economy. Current biohydrogen energy outlook for production installation units and storage capacity are the key points to be highlighted from global and Malaysia’s perspectives. This critical and comprehensive review provides a strategic route for the researcher to research towards sustainable technology. Current policies related to hydrogen as fuel infrastructure in Malaysia and commercialization are highlighted. Malaysia is also gearing towards clean and decarbonization planning.

Photocatalysis offers an attractive strategy to upgrade H2O to renewable fuel H2. However current photocatalytic hydrogen production technology often relies on additional sacrificial agents and noble metal cocatalysts and there are limited photocatalysts possessing overall water splitting performance on their own. Here we successfully construct an efficient catalytic system to realize overall water splitting where hole-rich nickel phosphides (Ni2P) with polymeric carbon-oxygen semiconductor (PCOS) is the site for oxygen generation and electron-rich Ni2P with nickel sulfide (NiS) serves as the other site for producing H2. The electron-hole rich Ni2P based photocatalyst exhibits fast kinetics and a low thermodynamic energy barrier for overall water splitting with stoichiometric 2:1 hydrogen to oxygen ratio (150.7 μmol h−1 H2 and 70.2 μmol h−1 O2 produced per 100 mg photocatalyst) in a neutral solution. Density functional theory calculations show that the co-loading in Ni2P and its hybridization with PCOS or NiS can effectively regulate the electronic structures of the surface active sites alter the reaction pathway reduce the reaction energy barrier boost the overall water splitting activity. In comparison with reported literatures such photocatalyst represents the excellent performance among all reported transition-metal oxides and/or transition-metal sulfides and is even superior to noble metal catalyst.

This paper investigates the circularity of green hydrogen and resource recovery from brine using an integrated approach based on alkaline water electrolysis (AWE). Traditional AWE employs highly alkaline electrolytes which can lead to electrode corrosion undesirable side reactions and gas cross-over issues. Conversely indirect brine electrolysis requires pre-treatment steps which negatively impact both techno-economics and environmental sustainability. In response this study proposes an innovative brine electrolysis process utilizing solid electrolytes (SELs). The process includes an on-site brine treatment facility leveraging a self-driven phase transition technique and incorporates a hydrophobic membrane as part of a membrane distillation (MD) system to facilitate the gas pathway. Polyvinyl alcohol (PVA) and tetraethylammonium hydroxide (TEAOH)-based electrolytes combined with potassium hydroxide (KOH) at various concentrations function as a self-wetted electrolyte (SWE). This design partially disperses water vapor while effectively preventing the intrusion of contaminated ions into the SWE and electrode-catalyst interfaces. PVA-TEAOH-KOH-30 wt% SWE demonstrated the highest ion conductivity (112.4 mScm−1) and excellent performance with a current density of 375 mAcm−2. Long-term electrolysis confirmed with a nine-fold brine in volume concentration factor (VCF) demonstrated stable performance without MD membrane wetting. The Cl−/ClO− and Br− concentrations in the SWE were reduced by five orders of magnitude compared to the original brine. This electrolyzer supports the circular use of resources with hydrogen as an energy carrier and concentrated brine and oxygen as valuable by-products aligning with the sustainable development goals (SDGs) and net-zero emissions by 2050.

As the world shifts towards renewable energy sources the need for reliable large-scale energy storage solutions becomes increasingly critical. Underground Hydrogen Storage (UHS) emerges as a promising option to bridge this gap. However the success of UHS heavily depends on the durability of infrastructure materials particularly cement in wellbores and in unlined rock caverns (URCs) where it serves a dual role in grouting and sealing. This study explores the chemical interactions between hydrogen and cement in these environments exploring how hydrogen might compromise cement integrity over time. We employed advanced thermodynamic analyses kinetic batch tests and 1D reactive transport models to simulate the behaviour of cement when exposed to hydrogen under conditions found in two potential UHS sites: the Haje URC in the Czech Republic and a depleted gas field in the Perth Basin Western Australia. Our results reveal that while certain cement phases are vulnerable to dissolution the overall increase in porosity is minimal suggesting a lower risk of significant degradation. Notably hydrogen was found to penetrate 5 cm of cement within just 4–5 days at both sites. These insights are crucial for enhancing the design and maintenance strategies of UHS facilities. Moreover this study not only advances our understanding of material sciences in the context of hydrogen energy storage but also underscores the importance of sustainable infrastructure in the transition away from fossil fuels.

The present study explores the potential of integrating the NET Zero Cycle (NZC) with hydrogen production by alkaline electrolyzers. To achieve this an Aspen Plus model was developed for the NZC and its accuracy was first confirmed by comparing it with literature data. The creation of a model for an alkaline electrolyzer was achieved using Aspen Custom Modeler and later imported into Aspen Plus. A comprehensive simulation was conducted in Aspen Plus to examine the synergies between the NZC and the alkaline electrolyzer. In this integration the oxygen demand of the NZC is met by a combination of an air separation unit (ASU) and the electrolyzer. The electrolyzer not only partially fulfills the oxygen requirements but also acts as an external heat supplier for the regenerator. Additionally the NZC supplies deionized water to the electrolyzer. A thermodynamic analysis in dicates that the integration of the NZC and alkaline electrolyzers results in a higher efficiency of 56.5 % compared to the stand-alone NZC an improvement of 2.3 %. Assuming that the NZC and alkaline electrolyzer operate at the same power production and input levels the alkaline electrolyzer can generate substantial oxygen to reduce the energy consumption of the ASU significantly. This aspect represents one of the primary reasons for the enhanced efficiency observed in this study. However the ASU still needs to be operated to provide the full oxygen demands of the process. To identify the key parameters influencing the integration of the NZC and alkaline electrolyzers a sensitivity analysis was performed. To enhance the system efficiency a comprehensive investigation was conducted to analyze the influence of key parameters such as combustor outlet temperature (COT) turbine outlet pressure (TOP) and combustor outlet pressure (COP) on the thermodynamic first law efficiency of the cycle. An increase in electrolyzer input power and a reduction in electrolyzer inlet feed were associated with a higher cycle effi ciency. The results also highlight that the TOP COT and the electrolyzer input power have a more significant impact on the cycle thermodynamic first law efficiency within the range of 5.7 4.0 and 2.6 % respectively while COP only causes a 0.4 % change in cycle efficiency. The integrated system demonstrates an impressive system first law thermodynamic efficiency of 62.5 % and exergy efficiency of 60.6 %.