Australia

Energy storage is essential to address the intermittent issues of renewable energy systems thereby enhancing system stability and reliability. This paper presents the design and operation optimisation of hydrogen/battery/ hybrid energy storage systems considering component degradation and energy cost volatility. The study ex amines a real-world case study which is a grid-connected warehouse located in a tropical climate zone with a photovoltaic solar system. An accurate and robust Multi-Objective Modified Firefly Algorithm (MOMFA) is proposed for the optimal design and operation of the energy storage systems of the case study. To further demonstrate the robustness and versatility of the optimisation method another synthetic case is tested for a location in a temperate climate zone that has a high seasonal mismatch. The modelling results show that the system in the tropical zone always provides a superior return when compared to a similar system in the temperate zone due to abundant solar resources. When comparing battery-only and hydrogen-only systems battery systems perform better than hydrogen systems in many situations with a higher self-sufficient ratio and net present value. However if there is high seasonal variation and a high requirement for using renewable energy (the penetration of renewable energy is >80 %) using hydrogen for energy storage is more beneficial. Furthermore the hybrid system (i.e. combining battery and hydrogen) outperforms battery-only and hydrogenonly systems. This is attributed to the complementary combination of hydrogen which can be used as a longterm energy storage option and battery which is utilised as a short-term option. This study also shows that storing hydrogen in a long-term strategy can lower component degradation enhance efficiency and increase the total economic performance of hydrogen and hybrid storage systems. The developed optimisation method and findings of this study can support the implementation of energy storage systems for renewable energy.

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.

The pressure to move to sustainable energy sources is obvious in today's fast changing energy environment. In this context green hydrogen appears as a beacon of hope with the potential to reinvent the paradigms of energy consumption particularly in the transportation and aviation sectors. Hydrogen has long been intriguing owing to its unique characteristics. It is not only an energy transporter; it has the power to alter the game. Its growing significance is due to its capacity to decarbonize energy generation. Traditional hydrogen generation techniques have contributed considerably to world CO2 emissions accounting for over 2% of total emissions. This environmental problem is successfully addressed by the development of green hydrogen which is created from renewable energy sources. The International Energy Agency (IEA) predicts a 25 to 30 percent increase in global energy consumption by 2040 which is a very grim scenario. If continue to rely on coal and oil this growing demand will result in greater CO2 emissions exacerbating climate change's consequences. In this situation green hydrogen is not only an option but a need. Because green hydrogen has properties with conventional fuels it can be simply integrated into current infrastructure. This harmonic integration ensures that the shift to hydrogen-based solutions in these sectors would not demand a complete redesign of the present systems assuring cost-effectiveness and practicality. However like with any energy source green hydrogen has obstacles. Its combustibility and probable explosiveness have been cited as causes for concern. However developments in safety measures have successfully mitigated these dangers ensuring that hydrogen may be used safely and efficiently across various applications. A further difficulty is its energy density particularly in comparison to conventional fuels. While its energy-to-weight ratio may be good its bulk poses challenges particularly in the aviation industry where space is at a premium. Beyond its direct use as a fuel green hydrogen has potential in auxiliary capacities. It may be used as a dependable backup energy source during power outages as well as in a variety of different sectors and uses ranging from manufacturing to residential. Green hydrogen's adaptability demonstrates its potential to infiltrate all sectors of our economy. Storage is an important enabler for broad hydrogen use. Effective hydrogen storage technologies guarantee not only its availability but also its viability as a source of energy. Current research and advancements in this field are encouraging which strengthens the argument for green hydrogen. At conclusion green hydrogen is in the vanguard of sustainable energy solutions particularly for the transportation and aviation industries. In our collaborative quest of a sustainable future its unique features and environmental advantages make it a vital asset. As we explore further into the complexities of green hydrogen in this publication we want to shed light on its potential obstacles and future route.

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.

This paper presents a thorough critical literature review aimed at understanding the challenges associated with freshwater supply associated with rapidly growing global hydrogen economies. The review has been prompted by the fact that the hydrogen production projected for 2030 will create at least an additional demand of 2.1 billion cubic meters for freshwater which needs to be addressed to support sustainable development of emerging hydrogen economies. The key solutions explored by this study include seawater and wastewater treatment methods for large-scale freshwater generation along with the newly introduced technique of direct seawater-fed electrolysis. Prior research indicates that desalination technologies including reverse osmosis and membrane distillation also offer promising avenues for large-scale freshwater production at costs comparable to other desalination techniques. Additionally low-temperature desalination methods such as membrane distillation could play a significant role in freshwater production for electrolysis underscoring the importance of exploring waste recovery opportunities within the system (e.g. fuel cell heat recovery). This review also identifies research gaps that need to be addressed to overcome freshwater supply challenges and enhance the sustainability and techno-economic viability of large-scale hydrogen energy systems.

Integrated energy systems (IESs) are essential for enabling the energy transition in communities and reducing CO2 emissions. This paper proposes a novel IES that combines photovoltaic (PV) and solar thermal energy with coordinated electrical and thermal energy storage to meet the energy demands of residential communities. The system also incorporates hydrogen production for fuel cell vehicles. A dual-objective optimization model was developed minimizing both economic costs and CO2 emissions. The system’s performance was evaluated using data from a case study in Dalian which showed that the IES successfully reduced the annual total cost and CO2 emissions compared to conventional systems. The key findings showed that PV electrolysis for hydrogen production provides both economic and environmental advantages. The system’s integration of solar thermal energy offers higher economic efficiency while PV energy supplies enhance coordination. Additionally carbon trading prices effectively reduce emissions but excessively high prices do not always lead to better emission outcomes. This study introduces a comprehensive multi-energy approach for optimizing the energy supply contributing novel insights to the field of sustainable energy systems.

This paper uses established and recently introduced methods from the applied mathematics and statistics literature to study trends in the end-use sector and the capacity of low-carbon hydrogen projects in recent and upcoming decades. First we examine distributions in plants over time for various end-use sectors and classify them according to metric discrepancy observing clear similarity across all industry sectors. Next we compare the distribution of usage sectors between different continents and examine the changes in sector distribution over time. Finally we judiciously apply several regression models to analyse the association between various predictors and the capacity of global hydrogen projects. Across our experiments we see a welcome exponential growth in the capacity of zero-carbon hydrogen plants and significant growth of new and planned hydrogen plants in the 2020’s across every sector.

Hydrogen-diesel dual direct-injection (H2DDI) engines present a promising pathway towards cleaner and more efficient transportation. In this study hydrogen split injection strategies were explored in an automotive-size single-cylinder compression ignition (CI) engine with a focus on varying the injection timings and energy fractions. The engine was operated at an intermediate load with fixed combustion phasing through adjustments of pilot diesel injection timing. An energy substitution principle guided the variation in energy fraction between the two hydrogen injections and then diesel injection while keeping the total energy input constant. The findings demonstrate that early first hydrogen injection timings lead to characteristics indicative of premixed combustion reflecting a high homogeneity of the hydrogen-air mixture. In contrast hydrogen stratification levels were predominantly influenced by later second injection timings with mixing-controlled combustion behaviour apparent for very late injections near top dead centre or when the second hydrogen injection held high energy fractions which led to decreased nitrogen oxides (NOx: NO and NO2) emissions. The carbon dioxide (CO2) emissions did not show high sensitivity to the hydrogen split injection strategies exhibiting about 77 % reduction compared to the diesel baseline due primarily to increased hydrogen energy fraction of up to 90 %

Considerable progress has been made recently in the use of nanoporous materials for hydrogen storage. In this article the current status of the field and future challenges are discussed ranging from important open fundamental questions such as the density and volume of the adsorbed phase and its relationship to overall storage capacity to the development of new functional materials and complete storage system design. With regard to fundamentals the use of neutron scattering to study adsorbed H2 suitable adsorption isotherm equations and the accurate computational modelling and simulation of H2 adsorption are discussed. The new materials covered include flexible metal–organic frameworks core–shell materials and porous organic cage compounds. The article concludes with a discussion of the experimental investigation of real adsorptive hydrogen storage tanks the improvement in the thermal conductivity of storage beds and new storage system concepts and designs.

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.