Australia

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 %.

Large-scale hydrogen storage at scales ranging from gigawatt-hours (GWh) to terawatt-hours (TWh) is currently projected to be an important component of the lowest cost options for a 100% variable renewable energy system driven partly by benefits to the grid from converting variable renewable electricity into hydrogen and partly by the anticipated growing role of hydrogen in a future net-zero energy system. Lined engineered cavities (LEC)s are among the prospective types of underground storage technology because they enable hydrogen storage at highpressure in the gaseous form and are expected to not rely on specific types of rock mass. They fill a niche in moderate storage capacity and cost because of their complementary advantages. An overview of various possible configurations and materials suitable for LECs for storing hydrogen is first reviewed to identify potential cost savings and performance improvements. Amongst the various LEC configurations lined engineered shafts (LES) are identified as having the greatest potential for cost reduction in softer rock masses such as sedimentary formations due to reduced excavation and construction complexity. Despite these advantages significant gaps remain in understanding the long-term behaviour of LES under cyclical loading as revealed through a review of the theoretical and experimental techniques used to study similar LEC configurations. This review paper con cludes with several recommendations for future research in numerical model formulation and material advancement with strong potential to increase the feasibility of LESs for hydrogen storage.

Hydrogen energy has been proposed as a reliable and sustainable source of energy which could play an integral part in demand for foreseeable environmentally friendly energy. Biomass fossil fuels waste products and clean energy sources like solar and wind power can all be employed for producing hydrogen. This comprehensive review paper provides a thorough overview of various hydrogen storage technologies available today along with the benefits and drawbacks of each technology in context with storage capacity efficiency safety and cost. Since safety concerns are among the major barriers to the broad application of H2 as a fuel source special attention has been paid to the safety implications of various H2 storage techniques. In addition this paper highlights the key challenges and opportunities facing the development and commercialization of hydrogen storage technologies including the need for improved materials enhanced system integration increased awareness and acceptance. Finally recommendations for future research and development with a particular focus on advancing these technologies towards commercial viability.

The shift to renewable energy sources requires systems that are not only environmentally sustainable but also cost-effective and reliable. Mitigating the inherent intermittency of renewable energy optimally managing the hybrid energy storage efficiently integrating the microgrid with the power grid and maximizing the lifespan of system components are the significant challenges that need to be addressed. With this aim the paper proposes an economic viability assessment framework with an optimized dynamic operation approach to determine the most stable cost-effective and environmentally sound system for a specific location and demand. The green integrated hybrid microgrid combines photovoltaic (PV) generation battery storage an electrolyzer a hydrogen tank and a fuel cell tailored for deployment in remote areas with limited access to conventional infrastructure. The study’s control strategy focuses on managing energy flows between the renewable energy resources battery and hydrogen storage systems to maximize autonomy considering real-time changes in weather conditions load variations and the state of charge of both the battery and hydrogen storage units. The core system’s components include the interlinking converter which transfers power between AC and DC grids and the decentralized droop control approach which adjusts the converter’s output to ensure balanced and efficient power sharing particularly during overload conditions. A cloud-based Internet of Things (IoT) platform has been employed allowing continuous monitoring and data analysis of the green integrated microgrid to provide insights into the system's health and performance during the dynamic operation. The results presented in this paper confirmed that the proposed framework enabled the strategic use of energy storage particularly hydrogen systems. The optimal operational control of green hydrogen-integrated microgrid can indeed mitigate voltage and frequency fluctuations caused by variable solar input ensuring stable power delivery without reliance on the main grid or fossil fuel backups.

Temporal decomposition methods aim to solve optimisation problems by converting one problem over a large time series into a series of subproblems over shorter time series. This paper introduces one such method where subproblems are defined over a window that moves back and forth repeatedly over the length of the large time series creating a convergent sequence of solutions and mitigating some of the boundary considerations prevalent in other temporal decomposition methods. To illustrate this moving window method it is applied to two models: an energy storage facility trading electricity in a market; and a hydrogen electrolyser powered by renewable electricity produced and potentially stored onsite. The method is simple to implement and it is found that for large optimisation problems it consistently requires less computation time than the base optimisation algorithm used in this study (by factors up to 100 times). In addition it is analytically demonstrated that decomposition methods in which a minimum is attained for each subproblem need not attain a minimum for the overall problem.

The global resurgence of hydrogen as a clean energy source particularly green hydrogen derived from renewable energy is pivotal for achieving a carbon-neutral future. However scalability poses a significant challenge. This research proposes innovative business models leveraging the low-emission property of green hydrogen to reduce its financial costs thereby fostering its widespread adoption. Key components of the business workflow are elaborated mathematical formulations of market parameters are derived and case studies are presented to demonstrate the feasibility and efficiency of these models. Results demonstrate that the substantial costs associated with the current hydrogen industry can be effectively subsidized via the implementation of proposed business models. When the carbon emission price falls within the range of approximately 86–105 USD/ton free access to hydrogen becomes a viable option for end-users. This highlights the significance and promising potential of the proposed business models within the green hydrogen credit framework.