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Hydrogen is viewed as a potential energy solution for the 21st century, with capabilities to tackle issues relating to environmental emissions, sustainability, energy shortages and security. Even though there are potential benefits of renewable hydrogen towards transitioning to net-zero emissions, there is a limited study on the current use, ongoing development and future directions of renewable hydrogen in Australia. Thus, this study conducts a systematic review of studies for exploring Australia's renewable hydrogen energy transition, current trends, strategies, developments and future directions. By using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, earlier studies from 2005 to 2024 from two major databases such as ProQuest and Web of Science are gathered and analyzed. The study highlights significant issues relating to hydrogen energy technologies and opportunities/challenges in production, storage, distribution, utilization, and environmental impacts. The study found that Australia's ambition for a strong hydrogen economy is made apparent with its clear strategic actions to develop a clean technology-based hydrogen production, storage and distribution system. This study provides several practical insights on Australia's hydrogen energy transition, hydrogen energy technologies, investments and innovation as well as strategies/recommendations for achieving a more environment friendly, secure, affordable and sustainable energy future. • A systematic review of research studies published between 2005 and 2024 are gathered and analyzed. • There are potential benefits of renewable hydrogen towards transitioning to net-zero emissions. • There is a limited study on the current use, ongoing development and future directions of renewable hydrogen in Australia. • Australia has clear strategic actions for hydrogen production, storage and distribution system. • Future expectations for renewable hydrogen to be guided by national, regional and local government policies and strategies. [ABSTRACT FROM AUTHOR]

Purpose. To develop a maneuverable power plant (MPP) based on the NuScale small modular reactor (SMR) by selecting a thermal scheme structure for a steam turbine installation using minimal additional equipment and ensuring its operation in both nominal and peak modes with maximum efficiency. This also includes ensuring its maneuverability through the use of hydrogen technologies for generating, storing, and returning energy to the steam turbine cycle. Methodology. The study employed the method of mathematical modeling of thermodynamic cycles of thermal schemes of steam turbine installations (STI) with concentrated parameters, which makes it possible to describe the dynamics of systems consisting of discrete elements that are thermodynamic systems. Findings. Various structural options for the thermal scheme of the MPP based on the NuScale SMR for nominal operation were developed and mathematically modeled, followed by a comparative analysis of their energy efficiency. As a result, a scheme and operational parameters were selected with the highest electrical efficiency (net), which allows increasing the net efficiency of the NuScale SMR-based power plant from the developers’ announced 28 to 32.8 %. A thermal scheme for the MPP based on the SMR with an energy storage system was proposed. Applying this scheme allows increasing the net efficiency of a power plant based on NuScale SMR in peak mode to 34.8 %. Originality. A concept for creation and schematic solution for a prospective MPP based on an SMR capable of accumulating electrical energy was proposed. The main innovative solution regarding the structure of the technological scheme of the MPP based on the SMR is the organization of its operation in nominal and peak modes, which fundamentally differ in the thermodynamic cycle. In the nominal mode, the steam turbine installation operates on a thermodynamic cycle with steam separation, and in the peak mode without it, by increasing the temperature of fresh steam as a result of burning hydrogen and oxygen. Hydrogen and oxygen are produced in an electrolyzer during the power plant’s operation in the nominal mode by using the generated electricity “excess”. Practical value. Small modular reactors are currently mainly in the development stage. Additionally, the non-nuclear part of the SMR-based power plant, namely the STI, has not received sufficient attention, as evidenced by the literature. However, it plays a crucial role in the overall efficiency of the installation. The study focuses on the highly relevant issue of improving the efficiency of an SMR-based power plant by developing the structure of the STI thermal scheme involving hydrogen technologies. This will help reduce dependence on fossil hydrocarbons in the total volume of primary fuel and enable sustainable functioning of the Ukrainian energy system, as well as contribute to the preservation and improvement of the environmental state. [ABSTRACT FROM AUTHOR]

Purpose: The concept of smart specialization refers to the identification of specializations in areas of potential competitive advantages, for which it is necessary to link the scientific and research spheres with the economy and properly focus processes and resources on building the innovative potential of enterprises. The purpose of this study is to assess the importance of human resource potential in the development of innovation of enterprises implementing hydrogen technologies within selected specialized economic areas of so-called smart specializations. In the search and identification of the research gap, it was assumed that the implementation of hydrogen technologies, can certainly be counted among the activities covered by the support of regions interested in innovation, since these technologies are or are now becoming priorities of EU energy policies. Hydrogen technologies are considered to be technologies of the future, forward-looking and strongly innovative, making them perfectly compatible with the concept of smart specializations. Filling the research gap in current research on smart specializations, which includes an analysis of human resource capacity building in the face of the remaining challenges facing hydrogen technology companies, therefore seems to be a particularly interesting issue. Design/methodology/approach: An analysis based on a quantitative survey conducted on a sample of 150 companies in the energy sector related to the development and deployment of hydrogen technologies was used to achieve the research objective. The study used logistic regression, which is a statistical method of analysis used to model the probability of a binary event. The purpose of using this type of regression was to identify and assess the significance of the determinants of the performance of the companies studied. Findings: The study found that the approach to human resource capacity building for the implementation of smart specialization strategies is changing. The results indicate that human resources and human resource potential of enterprises are crucial for the development of innovation, and this is one of the most important challenges of the future for the surveyed enterprises. Originality/value: The analyses carried out within the framework of the work clearly confirm the direction of activity of hydrogen technology companies within the framework of smart specialization strategies and at the same time indicate that the topic is a niche one, entering a phase of intensive development. [ABSTRACT FROM AUTHOR]

Direct reduced iron (DRI) and hot briquetted iron (HBI) are essential feedstocks for tramp element control in the electric arc furnace (EAF). Due to greenhouse gas (GHG) concerns related to CO2 emissions, hydrogen as a substitute for natural gas and a reductant in DRI production is being widely explored to reduce GHG emissions in ironmaking. This study examines the melting behavior of hydrogen DRI (H-DRI) pellets in the EAF containing low-carbon (0.1 wt.%) molten steel and molten slag. A computational heat transfer model was developed to predict the melting behavior of H-DRI pellets. To validate the model, a set of experimental laboratory simulations was conducted by immersing H-DRI in a molten steel bath and slag. The temperature history at the center of the pellet during melting and the shell thickness at different melting stages were utilized to validate the model. The simulation results agree with the experimental measurements of steel balls and H-DRI in different metallic molten steel and slag baths. [ABSTRACT FROM AUTHOR]

RELEVANCE. In the modern world, on the verge of global climate change, the search and implementation of alternative energy sources become particularly significant. Hydrogen energy is one of the most promising directions, offering a revolutionary approach to the decarbonization of various industrial sectors. The development of technologies related to the production, storage, and use of hydrogen opens new horizons for creating a sustainable and environmentally friendly energy infrastructure.OBJECTIVE. To review the technological state of hydrogen refueling stations (HRS), analyze the latest global trends and developments in this area, identify factors contributing to the efficiency of HRS components, and present thermodynamic principles of hydrogen fuel use. To outline the main problems associated with the need for widespread implementation of hydrogen infrastructure and to identify potential directions for their resolution. To develop suggestions for creating a modular layout of a container-type hydrogen station, which will allow a flexible approach to organizing hydrogen infrastructure with the possibility of rapid scaling and adaptation under various operating conditions.METHODS. Based on the use of literature data. The method of prototyping an autonomous hydrogen refueling station was used, and mathematical calculations of thermodynamic processes occurring in the components of HRS were conducted.RESULTS. Studies in the field of technological state of stations have been examined and systematized, and development trends have been identified. The main components involved in the operation of a hydrogen station are described. Thermodynamic processes of hydrogen fuel use that contribute to a significant reduction in energy consumption of hydrogen stations have been investigated.CONCLUSION. The hydrogen station combines efficient conversion of hydrogen into electricity, minimization of emissions, energy independence, and flexibility in energy storage. Determining the optimal operating parameters of HRS equipment based on the thermodynamics of processes, considering the specifics of temperature regimes of Russian regions, is important for reducing costs and increasing the energy efficiency of hydrogen fuel systems. The proposed structure of the container-type HRS is an optimal platform for subsequent modernizations and innovations in the field of hydrogen technologies.

Hydrogen has recently attracted considerable attention as a promising alternative for addressing energy and environmental issues. Hydrogen is a flexible and clean energy carrier that can be used in various industries, including transportation, manufacturing, and power generation, without emitting harmful emissions. This study provides a detailed review of hydrogen technologies and policies in the context of a hydrogen economy. Hydrogen production is examined with its cost analysis and current technological challenges, in addition to the key aspects of hydrogen storage, transportation and applications. This review also provides a critical discussion of global policies and roadmaps that have been proposed or implemented to achieve a hydrogen-based future economy. These policies include funding for R&D, financial incentives, tax credits, and frameworks. Finally, two key areas that can be exploited to expedite global hydrogen adoption are proposed. First, technological challenges can be addressed by employing an integrated system approach to produce hydrogen for various applications, along with vigorous investment in research on material development in handling/storing hydrogen. Second, policies to accelerate hydrogen adoption should focus on public–private partnerships, media awareness campaigns, and the introduction of green credit scores. [ABSTRACT FROM AUTHOR]

The utilisation of hydrogen is being explored as a viable solution for reducing carbon emissions in port operations, with potential applications in cargo handling, transportation, and shipping vessel operations. To comprehensively list the decarbonisation options in ports, this study conducted a Systematic Literature Review to identify and then survey twelve highly cited review papers. Initially, a typology approach was used to categorise the decarbonisation options by activities and technologies. Subsequently, the study introduced a novel Port Energy Map to reveal the energy system pathways and their interconnections. Each pathway was then converted into a simpler linear sequence of activities, shown as a Port Energy System Taxonomy, which outlines the energy supply and energy-using activities. By utilising this taxonomy and map, the study identified opportunities and research gaps for integrating hydrogen technologies into port energy systems, which serves as a valuable tool for assessing port decarbonisation options. [ABSTRACT FROM AUTHOR]

The purpose of the present work is to design an extended decision support system (DSS), namely the CRITIC (combining criteria interaction through inter-criteria correlation) & CRADIS (compromise ranking of alternatives from distance to ideal solution) model under the single-valued neutrosophic set. Its notable advantages are that it renders a more robust expression of uncertainty and the decision-making process is more closely managed. Also, it allows the DM to evaluate on a broader area and avoid data and conflict among the decision-making team. Therefore, the proposed extended DSS is implemented to help the strategic decision on the hydrogen technologies prioritization for decarbonization considering the sustainability and reliability principles in the oil refining industry. The results indicate that the alternative of green hydrogen from low-temperature electrolysis using solar renewable energy is the most suitable scenario for the decarbonization in the oil refineries located in south Iran, in particular the Abadan's oil refinery. [Display omitted] • An energy transition for the oil refining industry is defined. • A DSS (the CRITIC and CRADIS model) under single-valued neutrosophic set is implemented. • Decision-making criteria are sustainability and reliability principles. • For the decarbonization, five alternatives are introduced. • Solar renewable energy with the average deviation of 0.9180 is selected. [ABSTRACT FROM AUTHOR]

Given the current maturity of hydrogen technologies, accurate and computationally efficient numerical models are crucial for improving their understanding and development. Traditional models are either computationally prohibitive or lack the capacity to assess the spatial distribution of critical variables. The present paper suggests a hybrid numerical model for Fuel Cells (FCs) and electrolysers, articulating the coupling between a 1D analytical model and a Computational Fluid Dynamics (CFD) model via a nonlinear regression. Results present an initial validation of the 1D analytical model and the CFD model, and, once the validation is proven successful, the hybrid model is evaluated with a relatively long and highly varying loading profile that covers a wide range of the potential operational points of a FC. The hybrid model shows promising results, showing fidelity levels similar to CFD models, including the capacity to assess the spatial distribution, and a low computational cost. Hence, this hybrid model is demonstrated to be an attractive tool for the design of FCs and electrolysers, optimisation of thermal management and control strategies, degradation analysis, and techno-economic analysis. [ABSTRACT FROM AUTHOR]

The connection of Ti–H by ATAT, USPEX codes with QE and VASP interfaces is investigated in the work. Predictive estimates revealed a number of stable and geometrically optimized hydrides with different atomic compositions: Ti 6 H 2 , Ti 5 H 3 , Ti 5 H 2 , Ti 4 H 3 , Ti 3 H 5 of a simple triclinic group and highly symmetrical TiH 2 , Ti 2 H 2 , Ti 6 H 2 , Ti 3 H 5 alloys. The stability of hydrides was evaluated by first principles calculations and by the convex hull method. Model estimates of mechanical characteristics have shown that hydrides with low mass density are high-strength compounds. The detected hydrides can be included in the reference database of Ti–H compounds. The possibility of obtaining alloys based on Ti–Al with additions of Sc, Y, Dy, Ho by "Hydride technologyˮ is considered. The formation of a lamellar structure upon the introduction of 2 at.% Sc, Y into Ti–50Al (at.%) was found. When 2 at.% Dy, Ho is added to Ti–50Al (at.%), isotype compounds Y 6 Ti 4 Al 43 , Dy 6 Ti 4 Al 43 , Ho 6 Ti 4 Al 43 are formed. The values of microhardness and electrical resistance are given. [ABSTRACT FROM AUTHOR]

Achieving carbon neutrality in the future involves the use of low-carbon hydrogen as an energy source - in the power industry and heat supply of isolated areas - as a carbon-neutral fuel for generation and a secondary source of energy. In the transport sector, the prospects for the use of hydrogen extend to almost all types of vehicles - from cars, trains and ships to special-purpose equipment, air transport, both in fuel cells and in internal combustion engines. Rosatom State Corporation has developed a technology for producing hydrogen by water electrolysis using an anion-conducting matrix. The matrix is an inorganic fibrous material, and anionic conductivity is achieved as a result of the introduction of potassium cations during impregnation with a KOH solution. A wide range of productivity up to 115 % and the possibility of its dynamic change make it possible to effectively combine these electrolyzers with renewable energy sources. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this research is to carry out a literature review on the use of life-cycle cost (LCC) approaches for hydrogen technologies, by analysing its evolution over a decade (2012–2021). Methods: The SCOPUS database has been used to select relevant literature on the subject. After adoption of inclusion/exclusion criteria, a total of 67 papers were selected for our review. Then, we analysed these studies in terms of hydrogen technologies (fuel cells, electrolysers, hydrogen storage approach, etc.) covered by the LCC approaches. In addition, we also performed an analysis of the LCC features — type of LCC (conventional, environmental, social), integration with LCA/S-LCA, guidelines followed, system boundaries (cradle-to-farm gate, cradle-to-consumer, cradle-to-grave, cradle-to-cradle), functional units, financial tools (NPV, BEP, etc.), type of costs included, and life span — to provide a comprehensive view of LCC studies applied to hydrogen technologies. We also discussed and interpreted the most significant findings. Results and discussion: Our main results can be summarised as follows: (i) the number of LCC studies for application to hydrogen technologies has increased in the decade 2012–2021; (ii) China is the leading country for number of publications on the subject (15 papers), even if the most prolific author and institution are Iranians; (iii) a large number of studies performed LCC analysis including fuel cells and/or electrolysers based on proton exchange membranes; (iv) the most widely used LCC approach is a cradle-to-consumer (37 papers); (vi) almost all the studies on LCC of hydrogen technologies included initial, operation and maintenance costs; while other costs — replacement, external, end-of-life — are included in a limited number of papers; (vii) the net present value (NPV) is the most used financial tool. Conclusions: LCC analysis for application to hydrogen technologies has gained interest in recent years. However, the number of studies that explicitly follow LCC or LCA guidelines is very limited (only 7). The life-cycle cost analyses performed are quite incomplete in terms of costs included in the life-cycle stages. Besides, there is a lack of information and uniformity in the use of functional units and financial tools. [ABSTRACT FROM AUTHOR]

The integration of water electrolyzers and photovoltaic (PV) solar technology is a potential development in renewable energy systems, offering new avenues for sustainable energy generation and storage. This coupling consists of using PV-generated electricity to power water electrolysis, breaking down water molecules into hydrogen and oxygen. While oxygen is a useful byproduct, the created hydrogen is used as a clean, storable energy carrier or feedstock for numerous businesses. It is possible to operate the device with or without battery storage. When solar energy is combined with batteries, excess solar energy may be stored for later use, maximizing energy efficiency and guaranteeing a steady supply of electricity even in the absence of direct sunlight. On the other hand, battery-free systems depend on the electrolyzer’s continuous power generation to convert solar energy into hydrogen during the day. In addition to allowing for the production of renewable hydrogen,this hybrid PV-solar and water electrolyzer setup contributes to grid stability by offering demand-side flexibility. Moreover, the modularity of these systems enables scalability to meet diverse energy requirements, spanning from residential to industrial applications, thereby fostering a cleaner and more sustainable energy landscape. This review delves into various topologies for PV-driven electrolysis and conducts a thorough exploration of the dynamics of low-temperature water electrolyzers. Specifically, it examines their integration with three primary technologies: Proton Exchange Membrane, Alkaline, and Anion Exchange Membrane, shedding light on their implications for the broader integration landscape. Through detailed analysis and insights, this study enriches the understanding of the potential and challenges inherent in the convergence of PV solar, water electrolysis, and renewable energy systems.

Direct reduced iron (DRI) and hot briquetted iron (HBI) are essential feedstocks for tramp element control in the electric arc furnace (EAF). Due to greenhouse gas (GHG) concerns related to CO2 emissions, hydrogen as a substitute for natural gas and a reductant in DRI production is being widely explored to reduce GHG emissions in ironmaking. This study examines the melting behavior of hydrogen DRI (H-DRI) pellets in the EAF containing low-carbon (0.1 wt.%) molten steel and molten slag. A computational heat transfer model was developed to predict the melting behavior of H-DRI pellets. To validate the model, a set of experimental laboratory simulations was conducted by immersing H-DRI in a molten steel bath and slag. The temperature history at the center of the pellet during melting and the shell thickness at different melting stages were utilized to validate the model. The simulation results agree with the experimental measurements of steel balls and H-DRI in different metallic molten steel and slag baths.

This article presents a concept of establishing a network of energy self-sufficient nodes in Slovenia and the EU, within the Defence RESilience Hub Network in Europe project initiated by the Ministry of Defence of Slovenia (MORS). The goal is to reduce the energy dependence of military facilities on external suppliers. A mathematical model of a military site's micro-grid incorporates multiple energy vectors and their conversion and storage, with a focus on hydrogen technologies. A case study of a military site in Belgium shows that an energy system with solar and wind power can provide sufficient hydrogen for transportation needs and operate the site autonomously for up to 30 days. Additionally, the carbon footprint of the military base as an energy system was calculated, indicating potential reductions in environmental impacts. [ABSTRACT FROM AUTHOR]

The relevance. The paper presents a technical and economic model of a liquefied hydrogen production complex supplied only by renewable energy. The model compares technical and economic indicators of «green» liquefied hydrogen production in different locations subject to their climate, technical and economic conditions. The unique characteristic of the proposed model is that it considers the main technological processes for hydrogen production, conversion and storage, taking into account the annual hourly profile of possible renewable energy generation and shipping schedule of liquefied hydrogen as a commercial output. Employing the model will be relevant at the stage of pre-feasibility studies devoted to the creation of hydrogen energy productions in regions with high renewable energy potentials and remote from power infrastructure and allow enhancing reasonableness of estimations when taking investment decisions. The main aim: to develop a technical and economic model of such a complex and to test it by estimating the levelized cost of «green» liquid hydrogen for selected locations in Mongolia and Japan. Object: the autonomous complex for production of «green» hydrogen. Methods. The model is based on an optimization problem that determines the level and structure of costs born to produce liquefied hydrogen using solar and wind energy. Results. For verification of the model the comparative estimations for production of 10000 tonnes per year of the liquefied «green» hydrogen were calculated. The costs for locations in Mongolia (east coast of Lake Hubsugul) and Japan (coastal areas of Yamagata Prefecture) amount to $10,8 per kg and $13,4 per kg, respectively.

With the significant development of renewable energy sources in recent years, integrating energy storage systems within a renewable energy microgrid is getting more attention as a promising future hybrid energy system configuration. Recently, hydrogen systems are being considered a promising energy storage option that utilised electrolysers to produce and store hydrogen when energy is surplus and re-supply it into microgrids using fuel cells in energy shortage scenarios. To control the energy flow within such hybrid energy systems, designing an energy management system should be considered a critical task, that allows the technical and economic optimal operation of microgrids. This study presents a comprehensive review and analysis of different energy management systems for hydrogen technologies-based microgrids, including the strategies' objectives, constraints and techniques as well as the optimisation methods and simulation tools. In addition, an insightful discussion of the existing challenges and suggestions for the future research direction has been given. • Reviewed current energy management techniques in hydrogen-based microgrids. • Discuss the challenges and future of the energy management system research topic. • Survey experimental platforms, including simulation software and practical systems. [ABSTRACT FROM AUTHOR]

The application of newly available technologies in the green maritime sector is difficult due to conflicting requirements and the inter-relation of different ecological, technological and economical parameters. The governments incentivize radical reductions in harmful emissions as an overall priority. If the politics do not change, the continuous implementation of stricter government regulations for reducing emissions will eventually result in the mandatory use of, what we currently consider, alternative fuels. Immediate application of radically different strategies would significantly increase the economic costs of maritime transport, thus jeopardizing its greatest benefit: the transport of massive quantities of freight at the lowest cost. Increased maritime transport costs would immediately disrupt the global economy, as seen recently during the COVID-19 pandemic. For this reason, the industry has shifted towards a gradual decrease in emissions through the implementation of "better" transitional solutions until alternative fuels eventually become low-cost fuels. Since this topic is very broad and interdisciplinary, our systematic overview gives insight into the state-of-the-art available technologies in green maritime transport with a focus on the following subjects: (i) alternative fuels; (ii) hybrid propulsion systems and hydrogen technologies; (iii) the benefits of digitalization in the maritime sector aimed at increasing vessel efficiency; (iv) hull drag reduction technologies; and (v) carbon capture technologies. This paper outlines the challenges, advantages and disadvantages of their implementation. The results of this analysis elucidate the current technologies' readiness levels and their expected development over the coming years. [ABSTRACT FROM AUTHOR]

The need for decarbonization has become an urgent objective being pursued across borders and sectors. The energy sector is one example to follow, with the penetrations of renewable energy sources increasing year after year and already having an impact on carbon emissions. Despite their benefits, as these penetration levels grow, grid frequency is likely to be affected, namely in small, isolated power systems. Part of this instability is caused by the different types of connections to the grid used by most renewable energy sources. These converter-connected technologies do not contribute to the grid's inertia the same way synchronous generators do, therefore the difficulties in keeping the frequency under control. Focusing on the behaviour of the system's frequency, following some disturbances, a grid model of the Portuguese Terceira Island is created to assess the potential benefits of using hydrogen technologies (electrolysers and fuel cells) to provide grid services. In this paper, two scenarios are analyzed, the system's frequency response to large imbalances and steady-state imbalances stemming from load and wind power forecasting errors. The results reflect how the frequency behaviour is affected by the amount of the system's inertia, synchronous generators characteristics, and the presence of electrolysers and fuel cells. Hydrogen systems impact positively on the frequency containment after large disturbances, the impact related to the response to steady-state imbalances being lesser and prone to affect the stacks lifespan. • A grid model of a Portuguese island is created to assess the benefits of hydrogen to provide frequency control. • Models are developed for electrolysers, fuel cells and synchronous generators. • Two scenarios are analyzed: the response to large imbalances and steady-state imbalances (load and wind forecasting errors). • Hydrogen systems positively impact the frequency containment after large disturbances. • The impact related to the response to steady-state imbalances is lesser and prone to affect the stacks lifespan. [ABSTRACT FROM AUTHOR]

This study examines cost-effective strategies for reducing greenhouse gas (GHG) emissions in Korea's industry sector to achieve the nation's 2050 carbon neutrality goal, using the Global Change Analysis Model (GCAM) integrated assessment modeling (IAM) framework. We find that the iron & steel, cement, and chemical industry segments contribute about 70% of the sector's GHG mitigation efforts to align with 2050 carbon neutrality. Key decarbonization options include electrification of industrial processes, utilization of hydrogen and bioenergy, and adoption of carbon capture and storage (CCS) technologies, although the relative significance of these options varies across the segments. We also demonstrate the dependency of sectoral decarbonization pathways on the availability of CCS and hydrogen technologies, as well as their influence on the development of upstream energy infrastructures, such as electricity and hydrogen production. Our results indicate that limited CCS deployment would necessitate a faster phase-out of fossil fuel-based industrial technologies and quicker decarbonization of the electricity and hydrogen production sectors. Conversely, constrained hydrogen deployment would increase reliance on CCS, placing a greater emission reduction burden on other sectors like electricity generation and buildings. Within the industry sector, limited CCS utilization would force the chemical segment to achieve disproportionately larger negative emissions compared to the constrained hydrogen deployment scenario, as the latter allows for wider adoption of CCS, particularly in the iron & steel segment. Overall, the study emphasizes the need for rapid and extensive transformation of the three key industrial segments to achieve Korea's 2050 carbon neutrality target, with CCS technologies and, to a lesser extent, hydrogen technologies playing a significant role in shaping the industry's decarbonization pathways and the nation's energy systems. [ABSTRACT FROM AUTHOR]

Increasing the energy efficiency in high energy demand sectors such as industry with a high reliance on coal, oil and natural gas is considered a pivotal step towards reducing greenhouse gas emissions and meeting the Paris Agreement targets. The European Commission published final energy demand projections for industry capturing current policies and market trends up to 2050. This Reference scenario for industry in 2050, however, does not give insights into the extent to which energy efficiency potentials are already implemented, in which sectors further efficiency can be achieved, to what extent or with which technologies. In this paper, the EU Reference scenario is broken down and compared to a Frozen Efficiency scenario with similar GDP developments but without energy efficiency. Through bottom-up analyses, it is found that with energy efficiency technologies alone, this Reference scenario for industry energy demands (10.6 EJ in 2050) cannot be achieved. That means that the EU Reference assumes higher energy efficiency than possible and too high an effect of current policies. In the Frozen Efficiency scenario, the energy demand reaches 14.2 EJ in 2050 due to the GDP development; 22% higher than 2015. Energy efficiency improvements and increased recycling can decrease industrial energy demand by 23% (11.3 EJ in 2050). In order to further reduce the energy demand, our analyses shows that the wide implementation of innovative in combination with electrification or hydrogen technologies can further decrease the 2050 energy demand to 9.7 EJ or 10.3 EJ, respectively. [ABSTRACT FROM AUTHOR]

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Hydrogen is the most abundant chemical element on the Earth, and it has really a wide variety of applications, starting from use in refining, petrochemical industry, steel manufacturing, and ending with use in energy production and renewable gas (hereinafter – RG) blending for gradual replacement of natural gas in all sectors of the national economy. Being practically emission-free, if produced in sustainable way or from renewable energy sources (hereinafter – RES), hydrogen is regarded as one of the most promising energy sources for decarbonisation of practically the entire segment of industrial and energy production. Growing pressure of the European climate neutrality targets has triggered special interest in production, use, storage and transportation of hydrogen – especially the green one, which can be used in at least four fundamental ways: as a basic material, a fuel, an energy carrier and an energy storage medium. In the context of sector coupling, however, hydrogen facilitates decarbonisation of those industrial processes and economic sectors in which carbon dioxide (hereinafter – CO2) emissions can either not be reduced by electrification or this reduction would be minimal and linked to very high implementation costs. At the same time, development of an extensive hydrogen economy is the key to the achievement of the European climate protection targets, with the European Commission's (hereinafter – EC) Hydrogen Strategy, a framework created in 2020 to develop and promote sustainable hydrogen economy in the European Union (hereinafter – EU), in its centre. Green hydrogen also will take its legitimate place in the gaseous fuel diversification risk management strategy, as this gaseous fuel is not only one of the most perspective future energy sources, but also one of the most volatile and demanding sources. In the process of gaseous fuel diversification in the EU and worldwide, new logistical chains and supply – demand networks of green hydrogen will emerge. Therefore, adequate addressing of potential challenges of this new regional and global production, delivery and consumption framework will be of utmost importance for secure, safe and predictable functioning of future energy systems. [ABSTRACT FROM AUTHOR]

The world is currently facing a power shortage due to the inadequacy of conventional energy sources and increased energy requirements in almost all sectors of human life. To mitigate this issue, the researchers have taken the considerable interest of researchers over the past decade in enhancing energy efficiency and viability. A hybrid renewable energy system (HRES) can efficiently produce clean energy to meet energy demand. Thus, it is extensively employed to improve power system quality, reliability, and economy, rather than solely relying on non-renewable energy sources. Nevertheless, RE sources' uncertain and intermittent nature, like wind speed and solar radiation, is associated with HRES. This problem can be solved with proper optimization by coupling HRES with energy conversion and storage devices, e.g., electrolyzer, fuel cell, and hydrogen tank, which can admirably balance power generation and energy demand. The literature is rich in employing optimization techniques on HRES with hydrogen technologies (HRES-H 2). However, a gap is found in the overall research progress of optimization approaches, considering HRES coupled with H 2 equipment. Therefore, the current study comprehensively reviews all the optimization approaches applied in this field worldwide. Further, a text mining-based software VOSviewer is used to investigate the scientific landscape of the literature body to figure out the current trends and future scope of HRES-H 2. It has been investigated that the researchers are focusing on: techno-economic optimization of HRES-H 2 , developing sophisticated hydrogen infrastructure to reduce the overall cost of hydrogen fuel, introducing AI-based multi-objective optimization techniques to make the HRES-H 2 system more reliable and economically viable, and the impact of renewable and hydrogen technologies on the reduction of global warming. Lastly, an insightful of the current review highlighting the present shortcomings and opportunities of clean energy and hydrogen has been discussed, and suggestions are provided. • A text mining-based software called VOSviewer has been adopted to analyze the scientific landscape of the literature body. • Critically reviewed existing optimization techniques and software tools utilized for the optimization of HRES-H 2. • Bibliometric analysis has been conducted to investigate the current trends and potential future research topics. • An insightful discussion has presented enlightening shortcomings and opportunities of clean energy and hydrogen globally. [ABSTRACT FROM AUTHOR]

Hydrogen and hydrogen-related technologies will have an important role in world energy projection in the near future. Interest in hydrogen technologies will also increase, especially due to the smart cities concept and the increase in renewable energy supply. In addition to being a clean energy source, the tendency of hydrogen to 100% renewable energy supply makes it ahead of other alternative fuels. The share of hydrogen and related energy technologies in reducing global warming and emissions will continue to increase day by day. For this reason, projections and investment opportunities should be determined for the coming years. In energy projections, the evaluation of hydrogen in terms of energy diversity until 2030 is carried out with EnergyPlan software. Accordingly, the reduction in the amount of emissions and costs were determined by mixing hydrogen into the natural gas pipelines by 5–10, and 20% by volume by producing electrolyzers with photovoltaic systems and according to the number of vehicles with fuel cells in the transportation sector until 2030. • The importance of hydrogen in the 2030 energy projection was examined. • The concept of smart cities and the use of renewable energy and energy projection were discussed. • The reduction in CO2 emissions was calculated by mixing hydrogen with natural gas. • The importance of hydrogen for a sustainable future was emphasized. [ABSTRACT FROM AUTHOR]

The International Maritime Organization (IMO) established new strategies that could lead to a significant reduction in the carbon footprint of the shipping sector to address global warming. A major factor in achieving this goal is transitioning to renewable fuels. This implies a challenge, as not only ship-innovative solutions but also a complete low-carbon fuel supply chain must be implemented. This work provides a method enabling the exploration of the potential of low-carbon fuel technologies for specific shipping routes up to larger sea regions. Several aspects including vessel sizes, impact of weather and shipping routes, emissions savings and costs are considered. The local energy use is determined with proven bottom-up prediction methods based on ship positioning data from the Automatic Identification System (AIS) in combination with weather and ship technical data. This methodology was extended by an approach to the generation of a basic low-carbon fuel system topology that enables the consideration of local demand profiles. The applicability of the proposed approach is discussed at hand via a case study on Roll-on/Roll-off passenger and cargo (RoPax) ferries transitioning from conventional fuels to a compressed hydrogen fuel system. The results indicate a potential reduction in emissions by up to 95% and possible system sizes and costs. [ABSTRACT FROM AUTHOR]

Hydrogen technologies have been rapidly developing in the past few decades, pushed by governments' road maps for sustainability and supported by a widespread need to decarbonize the global energy sector. Recent scientific progress has led to better performances and higher efficiencies of hydrogen-related technologies, so much so that their future economic viability is now rarely called into question. This article intends to study the integration of hydrogen systems in both gas and electric distribution networks. A preliminary analysis of hydrogen's physical storage methods is given, considering both the advantages and disadvantages of each one. After examining the preeminent ways of physically storing hydrogen, this paper then contemplates two primary means of using it: integrating it in Power-to-Gas networks and utilizing it in Power-to-Power smart grids. In the former, the primary objective is the total replacement of natural gas with hydrogen through progressive blending procedures, from the transmission pipeline to the domestic burner; in the latter, the set goal is the expansion of the implementation of hydrogen systems—namely storage—in multi-microgrid networks, thus helping to decarbonize the electricity sector and reducing the impact of renewable energy's intermittence through Demand Side Management strategies. The study concludes that hydrogen is assumed to be an energy vector that is inextricable from the necessary transition to a cleaner, more efficient, and sustainable future. [ABSTRACT FROM AUTHOR]

The article proposes a methodological approach to the development of the tools for studying the international electro-hydrogen system creation in Northeast Asia. The term "hydrogen carrier" was introduced and its definition was given. The resource, economic and technological prerequisites for the development of the unified regional infrastructure to produce, transfer, transform and utilise both electricity and "hydrogen carriers" for consumers of energy services are considered. The author points out the need for a comprehensive consideration of technological, economic, social and political factors when developing such a complex technical system, which affects the diverse actors' interests. In order to create mutual understanding and balance the stakeholders' interests, the tool to evaluate the efficiency of such a system is necessary. The use of mathematical models is becoming one of the most vital and widespread techniques employed for this purpose. Thereby, the article deals with the structure and the development stages of a regional electro-hydrogen model for Northeast Asia. The review of models that address the issues of hydrogen technologies and renewable energy integration into energy supply systems is given. The main types of models used to describe such technical and economic systems are identified and it is concluded that the development of a two-level modelling system is necessary. The production and transport models at the upper (international) level should be the core of the proposed models system. At the lower level (the "green hydrogen carriers" production), the models of optimal resource management are required to determine the composition and parameters of the technological equipment. Step-by-step development of the modelling system is proposed. The first stage is the simplest scenario where only solar and wind energy is considered as an energy source. At this stage, it is possible to weed out inefficient technologies and identify targeted technologies and mechanisms for multilateral regional cooperation. The second stage should balance the interests of the actors and stakeholders. Here, the traditional renewable energy (biomass, hydro and pumped storage) along with carbon (thermal) and nuclear power generation, as well as other ("carbon") hydrogen technologies will become available for consideration. The final, third stage of the research tools development, will require separate accounting of "green" and "carbon" energy to consider certification mechanisms and energy pricing when building the international hydrogen system in Northeast Asia. In conclusion, the structure of the first stage production and transport model is described. This model will allow estimating the comparative effectiveness of different electric and hydrogen technologies to deliver green energy to consumers in the Northeast Asian economies. [ABSTRACT FROM AUTHOR]

The application of newly available technologies in the green maritime sector is difficult due to conflicting requirements and the inter-relation of different ecological, technological and economical parameters. The governments incentivize radical reductions in harmful emissions as an overall priority. If the politics do not change, the continuous implementation of stricter government regulations for reducing emissions will eventually result in the mandatory use of, what we currently consider, alternative fuels. Immediate application of radically different strategies would significantly increase the economic costs of maritime transport, thus jeopardizing its greatest benefit: the transport of massive quantities of freight at the lowest cost. Increased maritime transport costs would immediately disrupt the global economy, as seen recently during the COVID-19 pandemic. For this reason, the industry has shifted towards a gradual decrease in emissions through the implementation of “better” transitional solutions until alternative fuels eventually become low-cost fuels. Since this topic is very broad and interdisciplinary, our systematic overview gives insight into the state-of-the-art available technologies in green maritime transport with a focus on the following subjects: (i) alternative fuels; (ii) hybrid propulsion systems and hydrogen technologies; (iii) the benefits of digitalization in the maritime sector aimed at increasing vessel efficiency; (iv) hull drag reduction technologies; and (v) carbon capture technologies. This paper outlines the challenges, advantages and disadvantages of their implementation. The results of this analysis elucidate the current technologies’ readiness levels and their expected development over the coming years.

The global climate and environmental crisis dictate the need for the development and implementation of environmentally friendly and efficient technical solutions, for example, generation based on renewable energy sources. However, the annually increasing demand for electricity (according to the forecasts of the U.S. Energy Information Administration, the amount of energy consumed for the period 2006–2030 will increase by 44 %) cannot be fully provided by alternative energy. The main reason is not so much the high cost of these technologies, like unstable power generation, which determines the need for an additional reserve of regulated power. The solution to this problem can be the combined use of generation based on renewable energy sources with energy storage units of large capacity. Currently, a promising direction is the use of excess electricity for the production of hydrogen and its further accumulation in hydrogen storage. In this case an additional energy can be generated using industrial fuel cells (electrochemical generators) to compensate for the power shortage. At the same time, the distinctive advantage of hydrogen energy storage systems lies in the ability to accumulate a large amount of energy for long periods of time. This fact makes it possible to increase the reliability of the functioning of the electric power system, to provide power supply with a sufficiently long interruption (in case of faults) or allocation for isolated operation. With an increase in the unit capacity and the share of renewable generation in the total installed capacity, researches that aimed to systematic analysis of the impact of the implemented generation unit and the energy storage system on the parameters of the mode of the electric power system become more relevant. There are a number of tasks can be noted related to determining the optimal location and size of the generation unit and energy storage systems being implemented in terms of reducing power losses and maintaining an appropriate voltage level in the nodes of the electric power system. In this article, a variant of solving the optimization task for a typical 15-bus IEEE scheme is presented by means of software calculation using the bubble sorting method. To achieve this goal, the following tasks were solved: the objective function, which indicates the optimal location and size of the generation unit, and constraints, for example, the available deviation of voltage level, were formed; the software implementation of the algorithm for calculating power flows and power losses using the bubble sorting method was carried out. The results of the work of the program code for two scenarios are presented: for instance, installation of one renewable generation unit with a different range of possible capacities, and are compared with the data obtained in the MATLAB/Simulink software package. [ABSTRACT FROM AUTHOR]

Traditionally, the determination of static load characteristics is one of the main stages in the preparation of a design model of an electric power system. It is especially important to correctly take into account energy-intensive industries, which make a huge contribution to the formation of these characteristics. In particular, the increased interest in hydrogen technologies observed in the world as one of the most promising high-tech areas of energy development, and an increase in the share of the installed capacity of generation units based on renewable energy sources determine the prospects for the development of hydrogen production by water electrolysis. Accordingly, a significant increase in the scale of application of hydrogen technologies, in particular, in accordance with the "Hydrogen Strategy for Climatically Neutral Europe", the European Commission for the production of "green" hydrogen, determines the task of forming correct mathematical models of these devices in terms planning of modes, analyzing their impact on the parameters of electric power systems. Determination of static load characteristics on the basis of a physical experiment will not allow obtaining a characteristic with a significant increase or decrease in voltage in the node of the electric power system, which occur only in emergency modes of operation of the power system. Therefore, it seems relevant to analyze and determine the electrical characteristics of consumers by mathematical modeling of the power circuit. This article presents the results of correcting the static load characteristic of a high-power electrolyzer used in the production of hydrogen. The analysis of these results obtained with the MATLAB software is carried out using least squares regression to procure polynomial functions of the static load characteristics. According to this analysis, the static characteristics of the considered electrolyzer, being close to linear within the control range, outside the control range acquire parabolic dependences of active and reactive power on voltage. The static load characteristics of the installation are determined by the parameters of the power circuit and the current-voltage characteristic of the rectifiers displacing the vertices of the parabolas from the origin, which should be taken into account to increase the reliability of the design scheme. [ABSTRACT FROM AUTHOR]

The International Maritime Organization (IMO) established new strategies that could lead to a significant reduction in the carbon footprint of the shipping sector to address global warming. A major factor in achieving this goal is transitioning to renewable fuels. This implies a challenge, as not only ship-innovative solutions but also a complete low-carbon fuel supply chain must be implemented. This work provides a method enabling the exploration of the potential of low-carbon fuel technologies for specific shipping routes up to larger sea regions. Several aspects including vessel sizes, impact of weather and shipping routes, emissions savings and costs are considered. The local energy use is determined with proven bottom-up prediction methods based on ship positioning data from the Automatic Identification System (AIS) in combination with weather and ship technical data. This methodology was extended by an approach to the generation of a basic low-carbon fuel system topology that enables the consideration of local demand profiles. The applicability of the proposed approach is discussed at hand via a case study on Roll-on/Roll-off passenger and cargo (RoPax) ferries transitioning from conventional fuels to a compressed hydrogen fuel system. The results indicate a potential reduction in emissions by up to 95% and possible system sizes and costs.

Hydrogen technologies have been rapidly developing in the past few decades, pushed by governments’ road maps for sustainability and supported by a widespread need to decarbonize the global energy sector. Recent scientific progress has led to better performances and higher efficiencies of hydrogen-related technologies, so much so that their future economic viability is now rarely called into question. This article intends to study the integration of hydrogen systems in both gas and electric distribution networks. A preliminary analysis of hydrogen’s physical storage methods is given, considering both the advantages and disadvantages of each one. After examining the preeminent ways of physically storing hydrogen, this paper then contemplates two primary means of using it: integrating it in Power-to-Gas networks and utilizing it in Power-to-Power smart grids. In the former, the primary objective is the total replacement of natural gas with hydrogen through progressive blending procedures, from the transmission pipeline to the domestic burner; in the latter, the set goal is the expansion of the implementation of hydrogen systems—namely storage—in multi-microgrid networks, thus helping to decarbonize the electricity sector and reducing the impact of renewable energy’s intermittence through Demand Side Management strategies. The study concludes that hydrogen is assumed to be an energy vector that is inextricable from the necessary transition to a cleaner, more efficient, and sustainable future.

In recent years, there has been considerable interest in the development of zero-emissions, sustainable energy systems utilising the potential of hydrogen energy technologies. However, the improper long-term economic assessment of costs and consequences of such hydrogen-based renewable energy systems has hindered the transition to the so-called hydrogen economy in many cases. One of the main reasons for this is the inefficiency of the optimization techniques employed to estimate the whole-life costs of such systems. Owing to the highly nonlinear and non-convex nature of the life-cycle cost optimization problems of sustainable energy systems using hydrogen as an energy carrier, meta-heuristic optimization techniques must be utilised to solve them. To this end, using a specifically developed artificial intelligence-based micro-grid capacity planning method, this paper examines the performances of twenty meta-heuristics in solving the optimal design problems of three conceptualised hydrogen-based micro-grids, as test-case systems. Accordingly, the obtained numeric simulation results using MATLAB indicate that some of the newly introduced meta-heuristics can play a key role in facilitating the successful, cost-effective development and implementation of hydrogen supply chain models. Notably, the moth-flame optimization algorithm is found capable of reducing the life-cycle costs of micro-grids by up to 6.5% as compared to the dragonfly algorithm. Image 1 • A metaheuristic-driven model is proposed to optimally design H 2 -based microgrids. • An energy management strategy is used to facilitate the uptake of fuel cell vehicles. • The performances of twenty metaheuristics are studied in terms of solution quality. • The moth-flame optimizer outperforms the well-respected algorithms in this area. • Levelized costs of electricity and H 2 are found to be well below the present rates. [ABSTRACT FROM AUTHOR]

Summary: Transition to more renewable energies to render current energy demand and set aside conventional resources for the next generation needs promising strategies. Frame the future energy plan to address the energy crisis requires to have insight and foresight about the hereafter of technologies and their markets. Among different renewable energy resources, hydrogen demonstrates an encouraging future. Therefore, understanding the flexibility and compatibility of hydrogen production technologies is important to pave the way for this transition. One strategy to achieve the mentioned targets is to evaluate different hydrogen technologies based on their life cycle and their acceptance at the commercial scale. For the very first time, various hydrogen production technologies are evaluated in terms of the technology life cycle. A novel approach is employed to find the current state of the hydrogen production technologies market. By applying simple and free tools such as search traffic and patent search, the technology adoption curve and technology life cycle of each hydrogen production technology is assessed. Two criteria are utilized for this matter, patents as a technical indicator and Google trend as a technology interest indicator. For this matter 35 088 patents have been extracted and analysed. Then the data are fitted by logistic function curve to foresight different technologies' life cycle. The technology attractiveness of each hydrogen production technologies is determined by obtaining the ratio of published patents to granted ones. The level of acceptance of each hydrogen technology is assessed by using an adaptation diagram. By the combination of these two diagrams, the current status and future of the technologies are achieved and validated. Findings show that most of the hydrogen production technologies are in the slope of enlightenment and plateau of productivity stages. [ABSTRACT FROM AUTHOR]

The industrial sector is the world's second largest emitter of greenhouse gases, hence a methodology for decarbonizing factory systems is crucial for achieving global climate goals. Hydrogen is an important medium for the transition towards carbon neutral factories due to its broad applicability within the factory, including its use in electricity and heat generation and as a process gas or fuel. One of the main challenges is the identification of economically and environmentally suitable design scenarios, such as for the entire value chain for hydrogen generation and application. For example, the infrastructure for renewable electricity, hydrogen generation, hydrogen conversion (e.g. into synthetic fuels), storage and transport systems as well as application in the factory. Due to the high volatility of energy generation and the related dynamic interdependencies within a factory system, a valid technical, economic and environmental evaluation of benefits induced by hydrogen technologies can only be achieved using digital factory models. In this paper, we present a framework to integrate hydrogen technologies into factory systems. This enables decision makers to identify promising measures according to their expected impact and collect data for appropriate factory modelling. Furthermore, a concept for factory modelling and simulation is presented and demonstrated in a case study from the electronics industry, assessing the use of hydrogen for decentralized power and heat generation. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable energy solutions, the integration of renewable energy sources and hydrogen technologies has emerged as a promising avenue. This paper introduces the Integrated Renewable Energy-Driven Hydrogen System as a holistic approach to achieve energy independence and self-sufficiency. Seamlessly integrating renewable energy sources, hydrogen production, storage, and utilization, this system enables diverse applications across various sectors. By harnessing solar and/or wind energy, the Integrated Renewable Energy-Driven Hydrogen System optimizes energy generation, distribution, and storage. Employing a systematic methodology, the paper thoroughly examines the advantages of this integrated system over other alternatives, emphasizing its zero greenhouse gas emissions, versatility, energy resilience, and potential for large-scale hydrogen production. Thus, the proposed system sets our study apart, offering a distinct and efficient alternative compared to conventional approaches. Recent advancements and challenges in hydrogen energy are also discussed, highlighting increasing public awareness and technological progress. Findings reveal a payback period ranging from 2.8 to 6.7 years, depending on the renewable energy configuration, emphasizing the economic attractiveness and potential return on investment. This research significantly contributes to the ongoing discourse on renewable energy integration and underscores the viability of the Integrated Renewable Energy-Driven Hydrogen System as a transformative solution for achieving energy independence. The employed model is innovative and transferable to other contexts. [Display omitted] • Integrating renewable energy and hydrogen for energy independence. • Advantages of Integrated Renewable Energy-Driven Hydrogen System: Zero emissions, resilient energy. • Economic viability: Payback period of 2.8–6.7 years. • Technological progress in hydrogen energy. • A novel and transferable system dynamics model for sustainable solutions is proposed. [ABSTRACT FROM AUTHOR]

The "Green Deal", that most of the countries all of around the world are planning for the near future, represents the biggest challenge and opportunity of this century to change the approach of producing energy for promoting ever more the sustainable development, the environmental friendly processes and renewable sources exploitation. Hydrogen will be part of this revolution and it is expected that it will represent, together with electricity from renewable energy sources, the green energy carrier of the future. Currently, the role and the perspectives of the hydrogen utilization as energy vector may be resumed by the concepts of the so-called "hydrogen economy", which is driving the creation of new energy infrastructures, able to exploit renewable feedstocks instead of the derived of the fossil fuels. The aforementioned scopes seem to be particularly ambitious, especially in the countries in which the utilization of derived of fossil fuels is quite impressive. Nevertheless, the transition from a fossil fuel-based to a sustainable and green society is already started and it will allow safer and cleaner industrial processes and improve the quality of the human life as well. [ABSTRACT FROM AUTHOR]

Highlights • Zero-emissions transportation fueling is the most cost-effective use of excess renewable energy. • Energy storage provides limited emission reduction benefits on already low-carbon grids. • Renewable gas production provides limited emissions reduction but significant cost benefits. • Load flexibility is critical for maximizing the cost-effectiveness of emissions reduction options. Abstract Preventing the curtailment of excess renewable generation, caused by mismatches between variable renewable electricity generation and the electric load, is a key strategy for maximizing greenhouse gas emissions reductions by integrating renewable resources into the electric grid. Strategies to harness excess renewable generation for useful purposes exist, but it is unclear which of these end uses provides the most effective use of available excess generation to maximize greenhouse gas emissions reductions in a cost-effective manner. This study investigates and compares three end-use strategies for utilizing excess renewable generation – storage in electrical energy storage systems, production of transportation fuel or vehicle charging, or production of renewable gas – and their diverse technology pathways on the bases of their greenhouse gas emissions reduction potential and the impacts of their implementation on the cost of energy services. This is accomplished by modeling the integration of 46 different technology pathways for using excess renewable generation in a 70% renewable and an 80% renewable electric grid configuration during the year 2050 in California using the Holistic Grid Resource Integration and Deployment (HiGRID) platform, which is a temporally-resolved resource dispatch model of the electricity system. Technology and cost characteristics for batteries, hydrogen energy storage systems, vehicle fueling or charging, and renewable gas production technologies are collected from multiple sources and their effect on reducing greenhouse gas emissions and affecting the Levelized Cost of Energy (LCOE) services in the HiGRID platform are examined. It was discovered that using excess renewable generation to produce transportation fuel for hydrogen vehicles or to charge electric vehicles provided the largest total greenhouse gas emissions reductions and lowest per-ton cost of greenhouse gas reduction. Use in grid energy storage and production of renewable gas provided similar but relatively lower total greenhouse gas reductions than transportation, with the latter imposing lower per-ton costs of greenhouse gas reduction. More generally, greenhouse gas reduction potential of these end uses depended on the intensity of the fuel being displaced by renewables, while LCOE effects depended on the temporal flexibility of the technologies associated with this end use. Overall, this study provides insight into a priority order for directing the use of excess renewable generation towards end uses to achieve greenhouse gas reduction goals such as those in California in a cost-minimal manner, and investigates the sensitivities that influence the effectiveness of these end uses. [ABSTRACT FROM AUTHOR]