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Evaluating the integrity of liquefied natural gas (LNG) storage tanks is essential for safety and environmental conservation. In this study, which centered on an LNG storage tank on a specific island, we utilized 37 interferometric wide (IW) swath mode VV polarization Sentinel-1 images from the European Space Agency (August 2020-December 2023). Deformation data were obtained using persistent scatterer synthetic aperture radar (SAR) interferometry (PSInSAR) and small-baseline subset SAR interferometry (SBAS-InSAR) techniques, supplemented by dense point cloud data for 3D and 2D analyses. Results showed consistent deformation rates in the tank, with peaks between October 2021 and August 2022. Point cloud analysis revealed millimeter-level localized deformations (0.1 to 2.6 mm), corroborating InSAR findings. This underscores the importance of PS-InSAR, SBAS-InSAR, and point cloud modeling in monitoring LNG tank deformations, and offers insights into managing the impact of climate change on LNG storage stability. [ABSTRACT FROM AUTHOR]

Liquid hydrogen represents a potential candidate for a climate neutral fuel for shipping. The utilization of this fuel necessitates the implementation of safe and reliable bunkering operations. This paper employs a quantitative risk assessment to compare the safety of bunkering liquid hydrogen with the safety of bunkering LNG. Initially, a frequency analysis is conducted using an event tree. It can be demonstrated, that the occurrence of the hazardous events, pool fire, flash fire and explosion, is more frequent with liquid hydrogen than with LNG. In the second step, the consequence analysis determines necessary safety distances for the hazardous events under consideration. For the events of pool fire and explosion, LNG-bunkering requires higher safety distances. Liquid hydrogen-bunkering requires higher distances for flash fire event. Since the safety distances for flash fire events are largest, they define the distances for the system. However, the consequences of flash fire events are subject to greater uncertainties and require further investigation. Overall, hazardous events occur more often with liquid hydrogen-bunkering, but LNG-bunkering requires in two out of three cases larger safety distances. • A quantitative risk assessment of liquid hydrogen and LNG bunkering is performed. • Leaks will occur more frequently when bunkering liquid hydrogen. • LNG-bunkering requires larger safety distances in two out of three cases. • Flash fire events drive the safety distances of bunkering systems. • However, the consequences of flash fire events still need to be investigated further. [ABSTRACT FROM AUTHOR]

In order to integrate the design of harbor basin water area with digitalization, optimize the habor basin water areaplane design scheme, and improve the safety of LNG ships entering and exiting the port, a design optimization scheme based ondigital twin technology for LNG terminals was studied. Based on the physical characteristics of LNG ships and harbor tugs,geometric features and hydrodynamic parameters were extracted to construct a digital twin model. By applying perception datatechnology, a virtual-real mapping correlation model was established, accurately integrating the actual movement status of LNGships and harbor tugs with intelligent digital technology. The virtual environment was used to conduct docking and departuretests, and based on the test results, a design scheme for the optimization of the layout of the terminal and the docking channelwas developed. The application of digital twin technology in the design process of LNG terminals was thus realized. [ABSTRACT FROM AUTHOR]

Air separation processes are time‐consuming and energy‐intensive. Most of the energy used in air separation unit (ASU) is used for air compression. During the air compression process, some energy is lost, which is converted into waste heat. This wasted energy is used to warm liquefied natural gas (LNG). At some point, LNG ships will dock at an LNG regasification facility. Here, LNG is converted back to gas and supplied to the distribution and transmission systems. During the regasification process, cryogenic LNG has a huge opportunity for cold energy recovery. An innovative air separation process that is integrated with the cold utilization of LNG is presented in this study along with a thorough conceptual design and analysis. The results of this study show that producing high‐purity oxygen and nitrogen, respectively, requires 0.28 kWh kg−1 and 0.06 kWh kg−1 of specific energies. Prior to integration with cold utilization of natural gas, 25 141.6 kW is needed for air compression. However, following integration, 10 554.6 kW of energy is needed, resulting in a 58.01 % energy savings. Exergy destruction as well as efficiency have been calculated for the primary components of the system. Sensitivity analysis is carried out to examine the effects of LNG streams on important parameters. In conclusion, a cryogenic ASU is integrated with an LNG‐direct expansion cycle‐organic Rankine cycle power cycle to supply the necessary power for operation and reduce extraneous power inputs. Overall, this integrated approach increases efficiency, lowers costs, benefits the environment, allows for flexibility and adaptability, and raises system dependability. [ABSTRACT FROM AUTHOR]

Despite being stored at 113 K and at atmospheric pressure, LNG cold potential is not exploited to reduce green ships' energy needs. An innovative system based on three organic Rankine cycles integrated into the regasification equipment is proposed to produce additional power and recover cooling energy from condensers. A first-law analysis identified ethylene and ethane as suitable working fluids for the first and the second ORC, making freshwater and ice available. Propane, ammonia and propylene could be arbitrarily employed in the third ORC for air conditioning. An environmental analysis that combines exergy efficiency, ecological indices and hazard aspects for the marine environment and ship passengers indicated propylene as safer and more environmentally friendly. Exergy analysis confirmed that more than 20% of the LNG potential can be recovered from every cycle to produce a net clean power of 76 kW, whereas 270 kW can be saved by recovering condensers' cooling power to satisfy some ship needs. Assuming the sailing mode, a limitation of 162 kg in LNG consumptions was determined, avoiding the emission of 1584 kg of CO2 per day. Marine thermal pollution is reduced by 3.5 times by recovering the working fluids' condensation heat for the LNG pre-heating. [ABSTRACT FROM AUTHOR]

Since the early 2000s, China has been putting consistent efforts to push its way into the Arctic and secure a position as an equal participant in international political and economic processes in the region. The relevance of this research lies in the crucial importance of the Arctic for the Russian Federation and, consequently, the necessity of developing a balanced foreign policy approach based on an objective assessment of the strategies of major “players” in the region, including China, which is gradually expanding its presence in the Far North. Despite the considerable number of studies conducted by Russian and foreign scientists on various aspects of China’s Arctic policy, the long-term goals of Beijing in the Arctic in the context of its strategy to transform the global governance system remain insufficiently researched. This study aims to identify the key drivers of China’s Arctic policy and to assess the way the implementation of China’s approaches to the core issues of the future development of the region could pose a threat to Russia’s interests. The study is based on the theory of offensive realism, which allows to justify the high degree of competition between the world powers in the geopolitical space of the Arctic and to explain the significant offensive potential of China’s foreign policy, including its northern dimension. The author employed a combination of institutional, logical, and expert assessment methods. The cornerstone of the methodological framework of the research is the systematic approach, through which the Arctic policy of the People’s Republic of China (PRC) is analyzed in a variety of its components with respect to the changing international environment, as well as in the broader context of Beijing’s global foreign policy strategy. Based on the analysis of China’s Arctic policy over the past decades, the author identifies the risks associated with the increased involvement of Chinese capital in the infrastructure projects in the High North and the integration of Russia’s northern logistic route into China’s Belt and Road Initiative (BRI), which aims to transform the global economic system and the structure of international relations to China’s advantage.

This article is devoted to identifying the features of the еastern liquefied natural gas (hereinafter referred to as LNG) markets and new opportunities for entering them. The purpose of this article is to study the problems of LNG producing companies entering the еastern markets and ways to overcome them. The work analyses the current state of the еastern LNG markets and their development prospects, existing barriers, including those caused by the conflict in the Middle East, and possible consequences of the escalation of the conflict. The authors consider the issues of developing localised infrastructure and technological solutions that increase the efficiency of supply chains, meet specific market needs and provide a competitive advantage in the еastern markets. Logframe and comparative analysis, systems approach, and modelling have been used in the research process. As a result, the study has identified a number of challenges for LNG producers, primarily related to geopolitical complexities, regulatory environment, and market development dynamics, to innovations, ecological norms, and understanding regional tensions that may impact supply chains and trade agreements. The findings of the article can be used when domestic companies develop strategies to enter the еastern LNG markets with existing contracts or expand them.

Despite being stored at 113 K and at atmospheric pressure, LNG cold potential is not exploited to reduce green ships’ energy needs. An innovative system based on three organic Rankine cycles integrated into the regasification equipment is proposed to produce additional power and recover cooling energy from condensers. A first-law analysis identified ethylene and ethane as suitable working fluids for the first and the second ORC, making freshwater and ice available. Propane, ammonia and propylene could be arbitrarily employed in the third ORC for air conditioning. An environmental analysis that combines exergy efficiency, ecological indices and hazard aspects for the marine environment and ship passengers indicated propylene as safer and more environmentally friendly. Exergy analysis confirmed that more than 20% of the LNG potential can be recovered from every cycle to produce a net clean power of 76 kW, whereas 270 kW can be saved by recovering condensers’ cooling power to satisfy some ship needs. Assuming the sailing mode, a limitation of 162 kg in LNG consumptions was determined, avoiding the emission of 1584 kg of CO2 per day. Marine thermal pollution is reduced by 3.5 times by recovering the working fluids’ condensation heat for the LNG pre-heating.

Abstract Floating Production Storage and Offloading (FPSO) unit being an offshore vessel, storing and producing crude oil, prior to crude oil being transported by accompanying shuttle tanker. Critical mooring/hawser strains during offloading operation have to be accurately predicted, in order to maintain operational safety and reliability. During certain types of offloading, excessive hawser tensions may occur, causing operational risks. Current study examines FPSO vessel’s dynamic reactions to hydrodynamic wave-induced loads, given realistic in situ environmental conditions, utilizing the AQWA software package. Current study advocates novel multi-dimensional spatiotemporal risks assessment approach, that is particularly well suited for large dataset analysis, based on numerical simulations (or measurements). Advocated multivariate reliability methodology may be useful for a variety of marine and offshore systems that must endure severe environmental stressors during their intended operational lifespan. Methodology, presented in this study provides advanced capability to efficiently, yet accurately evaluate dynamic system failure, hazard and damage risks, given representative dynamic record of multidimensional system’s inter-correlated critical components. Gaidai risk assessment method being novel dynamic multidimensional system’s lifetime assessment methodology. In order to validate and benchmark Gaidai risk assessment method, in this study it was applied to FPSO and potentially LNG (i.e., Liquid Natural Gas) vessels dynamics. Major advantage of the advocated approach is that there are no existing alternative risk assessment methods, able to tackle unlimited number of system’s dimensions. Accurate multi-dimensional risk assessment had been carried out, based on numerically simulated data, partially verified by available laboratory experiments. Confidence intervals had been given for predicted dynamic high-dimensional system risk levels.

This study presents a comprehensive three-dimensional Computational Fluid Dynamics (CFD) analysis of the pre-cooling process of a Type B LNG tank using various refrigerants, including liquid nitrogen (LN), nitrogen gas (NG), liquefied natural gas (LNG), boil-off gas (BOG), and their combinations. The simulation model accounts for phase change (through the mixture multiphase model), convective heat transfer, and conjugate heat exchange between the fluid and the tank structure. The results indicate that liquid nitrogen is the most efficient refrigerant, achieving the highest cooling rate through both latent and sensible heat. LNG also demonstrated a relatively high cooling rate, 79% of that of liquid nitrogen. Gas-only pre-cooling schemes relying solely on sensible heat exhibited slower cooling rates, with BOG achieved 79.4% of the cooling rate of NG. Mixed refrigerants such as NG + LN and BOG + LNG can achieve comparable, while slightly slower, cooling than the pure liquid refrigerants, outperforming gas-only strategies. A further assessment of the heat transfer coefficient suggests the mixed cooling schemes have almost identical heat transfer coefficient on the inner tank surface to the liquid cooling scheme, over 5% higher than the gas refrigerants. The study also highlighted the uneven temperature distribution within the tank due to the bulkhead's blockage effect, which can induce significant thermal stress and potentially compromise structural integrity. Mixed schemes exhibit thermal gradients higher than those of gas schemes but lower than those of liquid schemes, while achieving cooling speeds comparable to liquid schemes if the inlet velocity of the refrigerants is properly configured. These findings offer valuable insights for developing safer and more efficient pre-cooling procedures for Type B LNG tanks and similar cryogenic storage tanks. [ABSTRACT FROM AUTHOR]

This study evaluates the engine performance and life-cycle emissions of hydrogen enriched LNG as a pragmatic solution to more rapidly introducing hydrogen as marine fuel, while waiting for pure hydrogen fuel infrastructure to be built. Engine experiments in a 4-stroke marine diesel engine operating with a spark-ignited pre-chamber ignition system were conducted, and a wide range of engine exhaust emissions measurements including CH 4 , N 2 O, H 2 , and particulate matter (black carbon emission evaluation) were recorded at varying engine loads. The fuel compositions ranged from pure LNG operation to pure hydrogen operation and also included pure conventional diesel fuel oil for comparison. The research methodology integrates engine tests with a full well-to-wake life-cycle assessment (LCA). The impact of using 39.6% hydrogen by energy fraction in natural gas reduced GHG emission by 37.8% on a life-cycle basis at 50% engine load, which could mean a significant reduction of GHG emissions. • Analysis of Hydrogen enriched LNG GHG impact through LCA approach (Well-to-Wake). • A mid-term solution to introduce Hydrogen as maritime fuel. • Experiment of Hydrogen enriched LNG on maritime scale test engine laboratory. • GHG analysis of measured emission data for CO, CO 2 , N 2 O, NO X , PM, CH 4 , H 2. • Detailed climate impact of CH 4 , N 2 O and Black Carbon (BC). [ABSTRACT FROM AUTHOR]

One of the most important issues in the maritime industry is controlling and reducing the amount of emissions caused by marine vessels. In this respect, the International Maritime Organization sets some air pollution-related regulations and encourages maritime companies to utilise current and innovative emission abatement methods on their ships. The application of these approaches to ships not only provides environmental benefits but also creates additional financial costs for the company. In this study, operational data of a container ship has been acquired and examined. Methods such as ammonia, LNG, scrubber, low sulphur fuel use, and selective catalytic reduction have been considered to determine the most appropriate emission reduction approach. Nine different scenarios have been created with the use of stated methods and each scenario is analysed both environmentally and economically and compared to each other. Finally, the most suitable scenario has been determined by calculating the payback period of each investment. Since there is a relatively longer period of redemption, using a dual-fuel engine could be more suitable for long-lasting and newly built ships. For the currently cruising ships, the use of scrubber systems with selective catalytic reduction is an effective solution to reduce the number of emissions. [ABSTRACT FROM AUTHOR]

In today's era of heightened environmental awareness, industries and means of transport are under increasing pressure to minimize their ecological footprint. In particular, small-scale power plants for the marine sector pose environmental challenges due to their pollutant emissions. One promising technology to address this purpose is represented by small-scale gas turbines. In this work, the design of a radial turbine and a centrifugal compressor for a 5 MW engine to be employed onboard ships is developed. After a one-dimensional design, the project involves the aerodynamic and structural design optimization of the two machines using fluid dynamic and structural simulation software. The final configuration obtained by the optimization process and its performance are analyzed, demonstrating that the use of a radial architecture for the construction of a 5 MW small gas-turbine assembly for marine propulsion is feasible. Both the compressor and the turbine optimization procedures led to final values of polytropic efficiencies that were three percentage points larger than the first-guess design machine values, simultaneously allowing for reductions in stress usage factors by more than 38% and 32% for the compressor and the turbine, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Science Research & Application is the property of Omniscient Pte. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper explores the temporalities behind resource nationalism and the liquefied natural gas project (LNG) in Tanzania. At a cost of $42 billion, the LNG project would be one of the most capital-intensive projects in Africa and would allow for export of Tanzanian gas. Focusing on the LNG negotiations during the rule of John Pombe Magufuli, this paper uses interviews with key stakeholders involved in the negotiation and planning of the LNG project, both from the government and the hydrocarbon sector. It argues that competing imaginaries of the future of the gas sector in Tanzania has led to friction between actors and has resulted in slow progression for the project. Central to this has been competing short-, medium-, and long-term time horizons, contrasting market and electoral cycles, and differing imaginaries of what the future of LNG holds for the country. This paper's core argument is that competing perceptions of the future between different actors involved in the project, have allowed for friction between actors. At its core, this is through how the future was constructed for actors, be it through development strategies, price forecasts, or different imagined futures. [ABSTRACT FROM AUTHOR]

In this study, a novel TIP–TIG (TT) automatic welding method was used to weld the girth seams of liquefied natural gas (LNG) tanks composed of 9% nickel steel. The microstructure of the joints was characterized via electron microscopy and x-ray diffraction. The tensile strength and ductility of the joints were evaluated via tensile testing. The low-temperature toughness of the joints was investigated via low-temperature impact testing at - 196 °C. This increased the toughness and strength of the TT-welded joint compared to the corresponding values of joints welded using conventional submerged arc welding (SAW). A comparison with the SAW-welded joints revealed that the TT-welded joint presented high strength and excellent low-temperature toughness, which can be primarily attributed to the low heat input. Compared with SAW, TT welding resulted in a lower joint dilution ratio, smaller heat-affected zone, and lower degree of grain coarsening. In addition to fine austenite, as the joint microstructure and several uniformly distributed carbides in the weld seam. These properties hindered the dislocation slip. However, they promoted precipitation strengthening and grain refinement and provided excellent low-temperature toughness to the TT-welded joints. Notably, TT welding does not require weld-bead cleaning between passes. Additionally, owing to improvements in the degree of automation for TT welding, the welding time can be further matched with that of SAW. TT welding with narrow-gap grooves reduces the required amount of filler metal by more than 50%. Therefore, the TT welding process is significantly advantageous and can replace SAW for girth–seam welding of LNG storage tanks. [ABSTRACT FROM AUTHOR]

Due to the extensive utilization of liquid nature gas (abbreviated as LNG) resources and a multitude of considerations, LNG storage tanks are gradually transitioning towards smaller footprints and heightened safety standards. Consequently, underground LNG storage tanks are being designed and constructed. However, underground LNG storage tanks release a considerable quantity of cold into the ground under both accidental and normal conditions. The influence of cold results in the ground freezing, which further compromises the safety of the structure. Existing research has neglected to consider the effects of this. This oversight could potentially lead to serious safety accidents. In this work, a complete set of experiments using a novel LNG underground storage tank fluid-solid-thermal coupled cryogenic leakage scale model were conducted for the first time to simulate the effect of the tank on the soil temperature field, stress field, and displacement field and to analyze the development of the three fields and the results of the effect. This research helps the related personnel to better design, construct, and evaluate the LNG underground storage tanks to avoid the catastrophic engineering risks associated with cryogenic leakage and helps to improve the design process of LNG underground storage tanks. [ABSTRACT FROM AUTHOR]

Floating Production Storage and Offloading (FPSO) unit being an offshore vessel, storing and producing crude oil, prior to crude oil being transported by accompanying shuttle tanker. Critical mooring/hawser strains during offloading operation have to be accurately predicted, in order to maintain operational safety and reliability. During certain types of offloading, excessive hawser tensions may occur, causing operational risks. Current study examines FPSO vessel's dynamic reactions to hydrodynamic wave-induced loads, given realistic in situ environmental conditions, utilizing the AQWA software package. Current study advocates novel multi-dimensional spatiotemporal risks assessment approach, that is particularly well suited for large dataset analysis, based on numerical simulations (or measurements). Advocated multivariate reliability methodology may be useful for a variety of marine and offshore systems that must endure severe environmental stressors during their intended operational lifespan. Methodology, presented in this study provides advanced capability to efficiently, yet accurately evaluate dynamic system failure, hazard and damage risks, given representative dynamic record of multidimensional system's inter-correlated critical components. Gaidai risk assessment method being novel dynamic multidimensional system's lifetime assessment methodology. In order to validate and benchmark Gaidai risk assessment method, in this study it was applied to FPSO and potentially LNG (i.e., Liquid Natural Gas) vessels dynamics. Major advantage of the advocated approach is that there are no existing alternative risk assessment methods, able to tackle unlimited number of system's dimensions. Accurate multi-dimensional risk assessment had been carried out, based on numerically simulated data, partially verified by available laboratory experiments. Confidence intervals had been given for predicted dynamic high-dimensional system risk levels. [ABSTRACT FROM AUTHOR]

As global environmental issues become increasingly prominent, the maritime industry faces an urgent imperative to curtail carbon emissions and mitigate environmental impact. Green marine alternative fuels are actively addressing these challenges. Global patent data are collected, and four sub-technologies of green fuel technologies in the maritime field are extracted based on Natural Language Processing. To evaluate the innovation trends and evolutionary paths of these technologies, the Main Path Analysis is employed to identify the evolution path of technologies and the evolution situation of major innovative entities, while the Social Network Analysis was used to present the results visually. These four sub-technologies (Hydrogen & Fuel Cell, Methanol & Ethanol, Ammonia, and LNG & LPG) have occupied the mainstream of fuel technology in maritime over the past five years, with 34.6% of patents, 38.3% of patent citations, and 93.9% of technological influence, accounting for 27.4%, 20.5%, 16.7% and 44.3%, respectively. Ammonia, and Hydrogen & Fuel Cell are springing up like mushrooms after rain, while the development of LNG & LPG, Methanol & Ethanol is relatively mature. Each of these technologies showcases distinct developmental paradigms. We elaborated on developmental paradigms and future research priorities of each technology in the conclusion. In addition, new technological opportunities are also created through the cross-fertilization of technologies. In particular, integrated systems for hydrogen production, storage, and combustion on LNG ships, and maritime hybrid power systems driven by ammonia and hydrogen have opened a new window for the green development of maritime fuels. • Four green fuel technologies account for 93.9% of maritime fuel technological influence in the past five years. • Hydrogen & Fuel Cell and Ammonia rapidly expand, while LNG & LPG and Methanol & Ethanol are relatively mature. • This study details the unique development paradigms and future research priorities for each technology. • Hydrogen systems on LNG ships and hybrid ammonia-hydrogen maritime power open new avenues for green fuel development. [ABSTRACT FROM AUTHOR]

In the global push to cut carbon emissions, liquefied natural gas (LNG) is increasingly valued as a clean and efficient energy source. Maritime transport is crucial for LNG trade. This study utilizes AIS data and complex network analysis to discover:(1) Overall, maritime LNG trade has consistently grown, showing regional concentration of supply and demand. Despite uneven node degree distribution, the network remains stable. (2) Regionally, trade is becoming more diverse, with multiple subgroups indicating strengthening multilateral trade relationships. Port cooperation is expected to densify, diversify, and embrace multilateralism. (3) Individually, there's significant growth in LNG transshipment ports, especially in Asia and Europe, with Asian ports playing a crucial role alongside emerging ports in Western countries and the United States. [ABSTRACT FROM AUTHOR]

The operation of liquefied natural gas (LNG) marine loading arms plays a pivotal role in the efficient transfer of LNG from maritime vessels to downstream facilities, underpinning the global LNG supply chain. Despite their criticality, these systems frequently encounter operational challenges, notably slow coupling speeds and increased downtimes driven by maintenance demands. Addressing these challenges, Physical Asset Management principles advocate for maximizing process availability by minimizing both planned and unplanned outages. Recognizing maintainability as a key equipment attribute, this document proposes a procedure that extends the use of the UNE 151001 standard to evaluate the maintainability of physical assets. This proposal incorporates into traditional RCM a step for the selection of maintenance levels proposed in the standard, as well as the use of the AHP technique for selecting the weights used during the analysis process. Finally, an aggregated maintainability indicator is presented, which will allow for better evaluation, comparison, and monitoring of this characteristic in one or more industrial assets. To demonstrate its feasibility and utility, the proposed procedure is applied to a set of LNG marine unloading arms. This study identifies pivotal areas for improvement and devises strategic action plans aimed at enhancing asset's maintainability. The outcomes of this analysis not only provide a roadmap for augmenting operational efficiency but also furnish empirical justification for the requisite investments in maintainability enhancements, thereby contributing to the resilience and sustainability of LNG logistics infrastructure. [ABSTRACT FROM AUTHOR]

High-manganese austenitic steel represents an innovative variety of low-temperature steel used in the construction of liquefied natural gas (LNG) storage tanks. This steel boasts remarkable characteristics such as exceptional plasticity, superior toughness at cryogenic temperatures, and robust fatigue resistance, all while providing significant cost benefits. By utilizing high-manganese steel, the material manufacturing costs can be considerably lowered, simultaneously ensuring the long-term stability and safety of LNG storage tanks. The alloying design is pivotal in attaining superior performance in high-manganese steel. Choosing the right chemical components to control the stacked fault energy (SFE) of high-manganese steel and fine-tuning its structure can further improve the balance between strength and plasticity. Summarizing the advancements in alloying design for high-manganese steel is of great importance, as it offers a foundational dataset for correlating the chemical composition with the performance. Therefore, this paper outlines the deformation mechanisms and the principles of low-temperature brittleness in high-manganese austenitic steel, and from this foundation, it explicates the precise functions of alloying elements within it. This aims to provide a reference for future alloying designs and the industrial deployment of high-manganese steel in LNG storage tanks. [ABSTRACT FROM AUTHOR]

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The use of hydrogen as a clean fuel has drawn the attention of many scientists due to the problem of energy and environmental pollution caused by fossil fuels. One of the important requirements for expanding the use of hydrogen is the investigation and thermodynamic analysis of liquefaction cycle; this includes the thermodynamic investigation of different cycles of hydrogen liquefaction in pre-cooling and cryogenic cooling. Thermodynamic analysis comprises an examination of the cycle's energy and exergy, as well as the equipment employed. In this research, three liquefaction cycles with different pre-cooling cycle and cryo-cooling cycle have been evaluated. The use of organic Rankine cycle (ORC) and liquefied natural gas (LNG) has also been applied in the cycles and the arrangement of the equipment. Simulations and analyzes have been done in Aspen HYSYS V12. The results show that in the pre-cooling process of cycles 1, 2, and 3, the amount of useful exergy is 49.87 %, 58.87 %, and 61.21 %, respectively, which means that the third cycle uses the input exergy better. Also, in the pre-cooling process of cycles 1, 2, and 3, the amount of exergy loss is 33.86 %, 26.77 %, and 19.73 %, respectively, which means that the third cycle has less exergy loss in the pre-cooling process. The findings indicate that in each of the three cycles, over 50 % of the input exergy is wasted in the cryo-cooling process. Value of specific energy consumption (SEC) for cycle 1,2, and 3 is equal to 6.605 kWh/kgLH2 , 6.601 kWh/kgLH2 and 6.618 kWh/kgLH2, respectively. The three cycles under examination had COP values of 0.19945, 0.19936, and 0.19884, in that order. Also, the values for EXE cycles 1, 2, and 3 are 45.816 %, 45.883 %, and 45.797 %, respectively. Analyzing the energy and exergy of liquefaction cycles is a good step toward increasing cycle efficiency, identifying weak places, and altering cycles to improve efficiency.

Bu çalışmada, ağır ticari araç sınıfında yer alan bir çekicinin performansı dizel ve sıvılaştırılmış doğal gaz (LNG) yakıtlı bir motora sahip olması durumunda deneysel olarak incelenmiştir. Testler sırasında her iki çekicide Euro VI normlarına sahip 338 kW gücünde motor kullanılmıştır. Araçlar toplam 41000 kg ağırlıkta eğimsiz düz bir yolda kullanılarak 85 km/h hızdan 20 km/h hıza serbest yavaşlama ve kalkıştan 85 km/h hıza ulaşana kadar hızlanma testlerine tabi tutulmuştur. Ayrıca 164,3 km’si otoyol, 44,4 km’si kırsal yol ve 54,7 km’si şehir içi yol olmak üzere toplam 263,4 km’den oluşan bir güzergâhta kullanılan araçların ortalama yakıt tüketim maliyetleri hesaplanmıştır. Sonuçlara göre, LNG yakıtlı aracın 100 km için yakıt maliyeti 1003,58 TL dizel aracın ise 1359,32 TL olarak hesaplanmıştır. LNG yakıtlı aracın ilk satış maliyetinin %30 daha pahalı olacağı öngörüldüğünde bile elde edilmiş olan %27 oranındaki yakıt tasarrufunun uzun yol kullanılan bir araç için kayda değer bir sonuç olduğu anlaşılmaktadır.

The global narrative around domestic energy security is dominated by the paradigm of import-dependent countries, and as a result the interactions of energy export activities with domestic energy systems are not generally considered. In this paper, we apply a systems approach to establish two potential blind spots in evaluating the whole-of-system energy security of energy resource exporters (actual primary energy self-sufficiency and export exposure of the domestic energy system), and examine some case studies, primarily in the Australian context, to validate the existence of these blind spots. The commencement of LNG exports from the state of Queensland is examined in detail. Furthermore, we propose two novel quantitative indicators to mitigate the blind spots established. First, a revised method is proposed to calculate energy self-sufficiency, showing for the exporters studied a less secure position than shown by the traditional method. Second, an indicator is proposed to quantify the extent of exposure of the domestic energy system to international markets through export linkages, which we have applied to Australia’s domestic energy system, showing the extent of the increase in international exposure since LNG exports from Queensland commenced in 2015–2016. Conclusions of this paper include the realization that domestic energy security for energy exporters, such as Australia and the other countries examined, is more complex and, in the cases examined, less secure than importer-oriented energy security frameworks have previously recognized. A further conclusion is established that the decoupling of energy resource exports from the domestic energy system through transition to a zero-carbon energy system based on domestic renewable energy sources can be an effective means of improving Australia’s energy security.

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The use of alternative fuels is a primary means for decarbonising the maritime industry. Liquefied natural gas (LNG), liquid hydrogen (LH2), and liquid ammonia (LNH3) are liquified gases among the alternative fuels. The safety risks associated with these fuels differ from traditional fuels. In addition to their low-temperature hazards, the flammability of LNG and LH2 and the high toxicity of LNH3 present challenges in fuel handlings due to their high likelihood of fuel release during bunkering. This study aims at drawing extensive comparisons of the evaporation and vapour dispersion behaviours for the three fuels after release accidents during bunkering and discuss their safety issues. The study involved the release event of the three fuels on the main deck area of a reference bulk carrier with a deadweight of 208,000 tonnes. Two release scenarios were considered: Scenario 1 involved a release of 0.3 m3 of fuel, and Scenario 2 involved a release of 100 kg of fuel. An empirical equation was used to calculate the fuel evaporation process, and the Computational Fluid Dynamic (CFD) code FDS was employed to simulate the dispersion of vapour clouds. The obtained results reveal that LH2 has the highest evaporation rate, followed by LNG and LNH3. The vapour clouds of LNG and LNH3 spread along the main deck surface, while the LH2 vapour cloud exhibits upward dispersion. The flammable vapour clouds of LNG and LH2 remain within the main deck area, whereas the toxic gas cloud of LNH3 disperses towards the shore and spreads near the ground on the shore side. Based on the dispersion behaviours, the hazards of LNG and LH2 are comparable, while LNH3 poses significantly higher hazards. In terms of hazard mitigations, effective water curtain systems can suppress the vapour dispersion. • The LNG, LH2, and LNH3 vapour dispersions are compared under identical release scenarios. • LH2 exhibits the highest evaporation rate, followed by LNG and LNH3. • The hazards associated with LNG and LH2 are comparable. • LNH3 poses greater hazards when compared to LH2 and LNG. [ABSTRACT FROM AUTHOR]

The Organic Rankine Cycle (ORC) is one of the most promising systems to recover the waste heat sourced from internal combustion engines. In this study, thermodynamic, economic and environmental analyses of the scavenge air cooling water-driven Waste Heat Recovery System (WHRS) based on the organic Rankine cycle are conducted for a dual-fuel marine engine integrated with exhaust gas recirculation (EGR) system. Zero ozone-depleting and low global warming potential working fluids; R245fa, R236ea from hydrofluorocarbons, R600a, R601a from hydrocarbons, R1234ze and R1234yf from hydrofluoroolefins are selected for the low-grade WHRS. In addition to the thermal analyses, the mass and volume of the system along with the safety factors of the working fluids are evaluated to judge the physical applicability of the system for ships. Thermo-economic performances of the fluids are analyzed, optimized and compared under various engine loads, Tier II and Tier III modes to reveal the effects of different engine operating conditions on the parameters. According to the results, scavenge air has a significant amount of waste heat at medium and heavy loads and switching the engine mode remarkably affects the performance of the WHRS. R601a shows the best thermo-economic performance, however, considering the applicability of the system R236ea is the most suitable working fluid for the ORC WHRS. The overall thermal efficiency of the power generation system can be increased by about 2.8%. [ABSTRACT FROM AUTHOR]

Pilot-ignition Otto marine engines are known for greatly reduced emissions of air pollutants (sulphur oxides, nitrogen oxide, particulates) compared to marine diesel engines. However, lubricating oil emissions still are about one order of magnitude higher than in land-based systems. To identify reduction potentials, a better understanding of oil emission mechanisms has to be gained. For this purpose, mass spectrometric oil emission measurements and fluorescence lubricating film thickness measurements were performed on a medium-speed marine engine. With the fluorescence measuring system, the varying lubricating oil film on the cylinder wall can be visualised and analysed in sub-crank-angle resolution. By applying the developed calibration method to the measurement data, the oil film thickness can be determined in µm. It is shown that the oil film left by the piston rings on the liner as it moves down is almost halved after ignition compared to during intake stroke. The authors have further been able to detect and time operating point dependent ring rotation and investigations show a connection between ring rotation and cylinder liner temperature distribution. Aligning ring gaps allow blow-by to happen. This and other high intensity events such as engine knock, load shedding or the transition from diesel-mode to gas-mode, heavily disturb the oil layer and cause peaking oil emissions. [ABSTRACT FROM AUTHOR]

This paper presents a theoretical analysis of the selected properties of HCNG fuel calculations and a literature review of the other fuels that allow the storage of ecologically produced hydrogen. Hydrogen has the most significant CO2 reduction potential of all known fuels. However, its transmission in pure form is still problematic, and its use as a component of fuels modified by it has now become an issue of interest for researchers. Many types of hydrogen-enriched fuels have been invented. However, this article will describe the reasons why HCNG may be the hydrogen-enriched fuel of the future and why internal combustion (IC) piston engines working on two types of fuel could be the future method of using it. CO2 emissions are currently a serious problem in protecting the Earth's natural climate. However, secondarily, power grid stabilization with a large share of electricity production from renewable energy sources must be stabilized with very flexible sources—as flexible as multi-fuel IC engines. Their use is becoming an essential element of the electricity power systems of Western countries, and there is a chance to use fuels with zero or close to zero CO2 emissions, like e-fuels and HCNG. Dual-fuel engines have become an effective way of using these types of fuels efficiently; therefore, in this article, the parameters of hydrogen-enriched fuel selected in terms of relevance to the use of IC engines are considered. Inaccuracies found in the literature analysis are discussed, and the essential properties of HCNG and its advantages over other hydrogen-rich fuels are summarized in terms of its use in dual-fuel (DF) IC engines. [ABSTRACT FROM AUTHOR]

• A novel system is proposed to utilize LNG cold energy in cascade. • Thermodynamic and economic analyses are carried out for the proposed system. • The system is compared to other systems in the same field for performance evaluation. • The round-trip efficiency of the proposed energy storage system is 138.81 %. For cutting down the energy consumption and improving the cold energy conversion efficiency of the traditional liquefied air energy storage system (LAES), a novel energy system integration solution is proposed by combining the LAES with liquefied natural gas (LNG) regasification process. In this paper, the principal energy storage and energy release processes are simulated by Aspen Hysys. The influences of air mass flow rate and LNG regasification pressure on the performance are analyzed. The results indicate that the introducted system can attain 137.82 % round-trip efficiency, which is about 20 % higher than the conventional LAES system. Besides, the energy capacity reaches up to 10.87 MW and the exergy efficiency is 39.58 % during long-distance transportation. It's noteworthy that the power output in the liquefied air energy discharging period far exceeds the power generation from the organic Rankine cycle. The higher LNG transport pressure, the worse LNG-LAES system performance. When the air mass flow rate raises from 40,000 kg/h to 64,000 kg/h, the exergy efficiency is 3.4 % higher than the original, while the round-trip efficiency decreases by 29.79 %. Finally, through economic viability calculations, the dynamic recovery period of the LNG-LAES system is 5.41 years. [ABSTRACT FROM AUTHOR]

Liquefied natural gas production plants usually suffer from line blockage, which causes economic, environmental, and safety issues. The blockage, mainly caused by the solidification of heavy hydrocarbons, should be avoided or mitigated by removing the impurities as thoroughly as possible. In this work, we proposed a scheme taking cryogenic liquefied propane as absorbent to absorb heavy hydrocarbons in the liquefied natural gas production process. This paper first investigated freeze-out profiles of liquefied natural gas combined with marginal benzene and toluene by the ThermoFAST simulator, which showed that the precipitated solid tended to form under a low temperature, which posed challenges in purification. Subsequently, the feasibility of using liquefied propane as an absorbent to remove benzene and toluene was studied using Aspen Plus. A cryogenic absorption and regeneration process for liquefied natural gas purification was proposed, and factors influencing the performance were investigated. The results showed that the hydrocarbon impurities are removed more thoroughly at a high flowrate of the recycled absorbent stream. The absorption process exhibited an apparent cooling effect mainly caused by the vaporization of liquefied propane to the gas phase, and the higher operation temperature impedes the vaporization process. For a better purification effect, the system should be operated under a lower pressure or with a higher recycled absorption solution flowrate. Based on the design simulation results, utilizing liquefied propane as an absorbent to remove heavy hydrocarbons is novel and promising for LNG purification. [ABSTRACT FROM AUTHOR]

The proposed 'Vertical Gas Corridor' is a project that will directly challenge Russia's last remaining major gas pipeline Bratstvo - Brotherhood (Urengoy-Pomary-Uzhgorod route) into the heart of Europe. Bringing non-Russian gas into southern and central Europe via the Southern Gas Corridor has been a long-standing aim of the EU, regional EU member states, Turkey and gas producers as far afield as Central Asia and the Middle East, albeit with significantly differing agendas. Many projects, often grandiose, have been proposed over the years, often falling foul of the complex political and economic interests which crisscross the region. Russia's invasion of Ukraine in February 2022 provided yet another twist to this Levantine Great Game, creating both new impetus for supply diversification and new infrastructure options as the Kremlin's control over the pipelines originally built to bring gas west and south from Russia weakened. Now, under plans hatched by southeast and central European states, the region's growing gas interconnectivity could take another significant step forward, further weakening Russian gas Monopoly JSC Gazprom. The natural gas has only recently, since the 70s of the last century, turned into one of the main types of fuel. At the beginning of this century, about 88-90% of natural gas was delivered by gas pipelines under long-term economic contracts directly from a specific supplier to a specific customer, the rest - by tankers, in the form of liquefied gas (LNG). In 2021, global LNG imports, according to the report of the International LNG Importers Group (GIIGNL), increased by 4.5% compared to the previous year and reached 513.7 billion cubic meters (372.3 million tons). The group's research notes that in 2021, the LNG already accounts for about 40% of the global gas market, with the rest coming through gas pipelines. In 2021, about 73% of the LNG (375 billion cubic meters, or 271.8 million tons) was imported by Asian countries. In addition, only 36.6% of the world's LNG volume was sold on the spot market, i.e. in small lots, - the rest was sold through long-term contracts, thereby neglecting the market mechanism of free price formation. Due to the Russia-Ukraine war, the European Union's gas supply from Gazprom's pipelines was interrupted and Brussels is desperately looking for alternative routes. For the first time, the idea of such an alternative in the form of the "Trans-Caspian gas pipeline" was put forward by then US President Bill Clinton in 1996. However, due to the uncertainty of the status of the Caspian Sea and the lack of delimitation of its shelf boundaries, due to the conflicting position of Azerbaijan, Iran and Turkmenistan, this project was not implemented yet. After the annexation of Crimea in 2014 by Russia, the construction of one of the components of the "Southern Gas Corridor" (SGC) supported by the European Union - the "White Stream" gas pipeline and the liquefied gas project AGRI(LNG) initiated in 2007 - "Azerbaijan-Georgia-Ukraine-Romania-Hungary Interconnector" was postopned for an indefinite time. It should be noted that these were the most promising projects for Georgia and Azerbaijan, since both of them turned aside not only Russia, but also Turkey and, accordingly, neutralized its transit hegemony. This gas, passing through the SCP, was sent through the Trans-Anatolian gas pipeline and the Trans-Adriatic (TAP), from Turkey to Europe as one EU's South Gas Corridor (SGC). The Russia-Ukraine war has disrupted global supply chains and weakened the world economy, but it provides a new opportunity for Azerbaijan. In particular, as the US and Europe impose sanctions on Russian oil and natural gas, Azerbaijan has a chance to increase gas exports through 2022 and in the coming years via the 3,500-kilometer Southern Gas Corridor (SGC), which runs through seven countries and supplies gas to southern Turkey. Azerbaijan currently supplies 10 billion cubic meters of gas to Europe and 6 billion cubic meters - to Turkey, through the SGC. To meet the growing demand of Europe, Azerbaijan is also developing two new gas fields and is open to investment to expand the capacity of the SGC, in particular, by installing additional compressor stations, it will be possible to double the gas flow. However, according to the Azerbaijani Ministry of Economy, "reduced investment" from Europe may slow down the country's efforts to increase supply. Therefore: -The role of the "Southern Gas Corridor" in the context of the Russia-Ukraine war, and, consequently, the transit importance of Georgia for the EU energy security will increase even more; - The "corridor" will provide the Caspian countries with new, increased opportunities for the export of energy resources to the world market and will have a significant impact on the security and stability of the region; The Vice Prime Minister, Minister of Economy of Georgia, Mr. Levan Davitashvili, stated at a briefing held on November 21, 2022 that the Georgian government is working on a project to supply gas from the Caspian Sea shore of Azerbaijan to Europe through Georgia. According to Mr. L. Davitashvili the project, in which Azerbaijan, Romania and Hungary also participate, already have been started in 2015 and provides for a plan by which "... gas will be liquefied on the territory of Georgia, and then it will be re-gasified in Romania." Unfortunately, this project was stopped and had no further development", he said, adding that "... Europe is especially interested in alternative sources of gas supply, when everyone is talking about diversification of energy supply. This project has gained special relevance this year". Mr. L. Davitashvili noted that the evaluation of the project and the infrastructure in the territory of Georgia-Azerbaijan is underway. "It won't happen in a day or a year," he said, adding that "...first, we need to depict a complete picture...then we need to formulate a detailed action plan...and start implementing this plan step by step, including attracting investments." At the same time Azerbaijan's oil is in decline, but gas is growing. The future of Azerbaijan and Georgia energy cooperation is with natural gas EU's SGC and the Black Sea LNG terminals.Special attention should be paid to the prospects of supplying liquefied natural gas from Azerbaijan via Kulevi, Georgia to Romania from the SOCAR's BST Ltd. [ABSTRACT FROM AUTHOR]

Various combinations of ship propulsion systems have been developed with low-carbon-emission technologies to meet regulations and policies related to climate change, one of which is the combined gas turbine and steam turbine integrated electric drive system (COGES), which is claimed to be a promising ship propulsion system for the future. The objective of this paper is to perform a techno-economic and environmental assessment of the COGES propulsion system applied to liquefied natural gas (LNG) carriers. A propulsion system design for a 7500 m3 LNG carrier was evaluated through the thermodynamics approach of the energy system. Subsequently, carbon emissions and environmental impact analyses were carried out through a life cycle assessment based on the power and fuel input of the system. Afterwards, a techno-economic analysis was carried out by considering the use of boil-off gas for fuel and additional income from carbon emission incentives. The proposed propulsion system design produces 1832 kilowatts of power for a service speed of 12 knots with the total efficiency of the system in the range of 30.1%. The results of the environmental evaluation resulted an overall environmental impact of 10.01 mPts/s. The results of the economic evaluation resulted in a positive net present value and a logical payback period for investment within 8 years of operation. The impact of this result shows that the COGES has a promising technological commercial application as an environmentally friendly propulsion system. Last, for the economy of the propulsion system, the COGES design has a positive net present value, an internal rate return in the range of 12–18%, and a payback period between 6 and 8 years, depending on the charter rate of the LNG carrier. [ABSTRACT FROM AUTHOR]

The research provides a comparative theoretical investigation of the operational characteristics of an electric semi-truck and vehicles powered by conventional combustion engines using diesel fuel, hydrotreated vegetable oil (HVO), and methane (including biomethane) in the dual fuel configuration. The Volvo tractor units that are offered for retail in 2024, namely the Volvo FH Electric, Volvo FH500 in dual fuel configuration, and Volvo FH500TC Diesel Euro VI, were chosen for comparison. The considerations encompassed include the road tractor's mass, energy usage, power-to-weight ratio, dynamics, ability to recharge or refuel, payload restrictions, impact on logistics expenses, compliance with regulations on drivers' working hours, and a report on carbon dioxide emissions. The study concludes by discussing and drawing conclusions on the competitiveness of different drive types in truck tractors, specifically in relation to identifying the most suitable areas of application. Synthetic conclusions demonstrate the high effectiveness of the electric drive in urban and suburban conditions. However, vehicles equipped with internal combustion engines using renewable fuels fill the gap in energy-intensive drives in long-distance transport. [ABSTRACT FROM AUTHOR]

With the rapid development of the world's natural gas industry, LNG (Liquefied Natural Gas) has received widespread attention as a clean energy source. However, the leakage accidents of LNG are usually accompanied by safety hazards such as explosions, low temperatures, and phase transitions. In this study, the field experiment is carried out to cover LNG leakage pool with HEF (High-Expansion Foam). In the process of LNG leakage, when the ambient temperature at the bottom of the reservoir drops to about − 82.3 °C (the critical temperature of LNG), the ambient temperature would rise briefly due to the effect of phase transition. Meanwhile, the temperature distribution of different vertical and horizontal positions in the reservoir during the process of leakage is analyzed. Besides, it is also found that the density of the spilled vapor is much lower than that of the air, but the water in the surrounding air encounters the cryogenic vapor to condense into small droplets, the small droplets entrap part of the flammable gas during the process of settling to the ground, therefore, the flammable vapor still shows a heavy gas effect. During the initial period of HEF coverage, evaporation from the liquid pools accelerates, resulting in a 386% increase in peak concentration of methane above the reservoir. Nevertheless, when HEF application is maintained an effective thickness, it can effectively reduce the methane vapor concentration downstream of the reservoir near the surface to less than 1/2 LFL (1/2 of the Lower Flammability Limit). In general, the large-scale field experiments have far-reaching engineering significance and reference value for the occurrence and emergency treatment of LNG leakage accidents under actual working conditions. [ABSTRACT FROM AUTHOR]

Over the past few decades, the liquefied natural gas (LNG) business has experienced astounding expansion and gained global relevance. LNG has emerged as a key element in meeting the world's rising energy demand while working to cut carbon emissions, since it is a cleaner and more adaptable energy source. The entire process from natural gas extraction to consumption is covered in the presented analysis of the LNG value chain, starting out by looking at the discovery and production of natural gas reserves, highlighting important innovations and methods used during the extraction stage. The procedures used to treat and purify natural gas in order to meet the strict standards for liquefaction are detailed. Analysis of the liquefaction process reveals numerous liquefaction technologies, e.g. the well‐known conventional liquefaction and the cutting‐edge floating LNG and small‐scale LNG facilities. LNG storage and transportation, as critical components in the value chain, are examined in great detail. When the LNG reaches its destination, regasification plays a crucial role in repurposing it as a gas for distribution and consumption. Regasification technologies, such as conventional onshore terminals, floating storage and regasification units, and land‐based regasification facilities, are covered. Concerns regarding methane emissions and the carbon footprint, the potential for reducing greenhouse gas emissions through new technology, the environmental impact of LNG, and the economics of LNG are also considered across its value chain. [ABSTRACT FROM AUTHOR]

India, the world's most populous country, is the world's third-largest emitter of greenhouse gases (GHGs). Despite employing several energy sources, it still relies heavily on coal, its primary energy source. Given India's swiftly rising energy demand, this challenges meeting emission reduction targets. In recent years, India has significantly increased investments in renewables like solar and hydrogen. While commendable, these initiatives alone cannot meet the country's expanding energy demands. In the short term, India must rely on both domestic and imported fossil fuels, with natural gas being the most environmentally friendly option. In this context, this paper attempts to forecast energy consumption, natural gas production, and consumption in India until 2050, using both univariate and multivariate forecasting methods. For multivariate forecasting, we have assumed two alternative possibilities for GDP growth: the business-as-usual and the high-growth scenarios. Each of our forecasts indicates a notable shortfall in the projected production of natural gas compared to the expected demand, implying our results are robust. Our model predicts that nearly 30–50 percent of India's natural gas consumption will be met by imports, mainly in the form of LNG. Based on these findings, this paper recommends that Indian government policies emphasize increasing domestic natural gas production, importing LNG, and expanding renewable energy resources. [ABSTRACT FROM AUTHOR]

The global narrative around domestic energy security is dominated by the paradigm of import-dependent countries, and as a result the interactions of energy export activities with domestic energy systems are not generally considered. In this paper, we apply a systems approach to establish two potential blind spots in evaluating the whole-of-system energy security of energy resource exporters (actual primary energy self-sufficiency and export exposure of the domestic energy system), and examine some case studies, primarily in the Australian context, to validate the existence of these blind spots. The commencement of LNG exports from the state of Queensland is examined in detail. Furthermore, we propose two novel quantitative indicators to mitigate the blind spots established. First, a revised method is proposed to calculate energy self-sufficiency, showing for the exporters studied a less secure position than shown by the traditional method. Second, an indicator is proposed to quantify the extent of exposure of the domestic energy system to international markets through export linkages, which we have applied to Australia's domestic energy system, showing the extent of the increase in international exposure since LNG exports from Queensland commenced in 2015–2016. Conclusions of this paper include the realization that domestic energy security for energy exporters, such as Australia and the other countries examined, is more complex and, in the cases examined, less secure than importer-oriented energy security frameworks have previously recognized. A further conclusion is established that the decoupling of energy resource exports from the domestic energy system through transition to a zero-carbon energy system based on domestic renewable energy sources can be an effective means of improving Australia's energy security. [ABSTRACT FROM AUTHOR]