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Given the rapidly increasing concern of the climate change, this paper is aimed to answer whether hydrogen fuel cells can truly be a green solution in the shipping sector from a life cycle perspective. To achieve this goal, the parametric trend life cycle assessment which is LCA-based methodology was applied for around 2000 ships presently engaged in international and domestic services. The lifecycle environmental impacts of various hydrogen production methods were evaluated, including steam methane reforming, coal gasification, methanol cracking, and electrolysis via wind energy. The performance of three representative types of fuel cell systems, proton exchange membrane fuel, molten carbonate fuel cell, and solid oxide fuel cell were taken into account. The steam methane reforming and coal gasification processes were found to have the greatest environmental potentials across their lifetime. However, this paper points out that steam methane reforming could make better lifecycle merits than conventional diesel or LNG products, if production pathways are properly proposed. Additionally, when using LNG as the primary fuel source for fuel cells, it was found that the LNG upstream phase would produce about 100 times more emissions than the downstream phase. The research findings were summarized and condensed into a form of lifetime environmental indicators which enable us to understand/evaluate the quantified correlations between holistic environmental impacts of fuel cells and ship characteristics. The research findings are expected to assist stakeholders in making informed decisions, while also providing an insight into near-future regulatory frameworks and policy making for a green hydrogen maritime economy.

Purpose This study aimed to determine whether ammonia can genuinely help to reduce the carbon footprint of maritime activities. Given this, it was decided to investigate the life cycle of ammonia and its impact on the environment regarding the global warming potential. Methods To achieve this goal, the parametric trend life cycle assessment was applied to yield a general and reliable observation. The research was combined with a comprehensive dataset of over 2061 bulk carriers and eight different ammonia production methods: steam methane reforming, photovoltaics, electrolysis via wind, biomass downdraft gasifier, biomass circulating fluidized bed gasifier (CFBG) system, underground coal gasification (UCG) with carbon capture and storage (CCS), UCG without CCS, and 3-step Cu-Cl cycle. In addition, an existing ME-LGI (ME-liquid gas injection) engine was selected as the propulsion system. Results The results from PT-LCA revealed that for estimating the carbon impact of ammonia as marine fuel from a well-to-wake (WTW) perspective, it is mandatory to focus on the well-to-tank (WTT) phase. The lowest carbon production pathway for the global warming potential (GWP) is the 3-step Cu-Cl cycle and eventually is the most potential route for using ammonia as fuel in the maritime industry. Finally, this study concludes with some formulas, based on regression analysis, which serves as rapid indications for comparing the overall carbon impact of thousands of bulk carriers equipped with the ME-LGI engine, carrying ammonia as fuel from different production methods. Conclusions Given these fuel production routes, the research has also demonstrated that ME-LGI engines can be a groundbreaking way to reduce the carbon footprint of ships. Additionally, the research findings showed that the environmental indicators proposed in this article have the potential to make a significant contribution to the industry. They are anticipated to assist stakeholders in overcoming the discrepancy problem generated by past studies that were so dissimilar from case to case that the scope, boundary of analysis, data, and assumptions they employed were far from current standards and rules. In addition, the GWP according to the ship power was compared and reviewed in terms of the well-to-wake (WTW). Thus, the proposed methodology for developing ammonia ship environmental indicators is to provide valuable insight into environmental policy and decision-making processes.

This paper was to establish a practical approach to evaluating economic and ecofriendly designs for cable arrangement on the deck-side of offshore vessels. Three credible options were identified: acableway arrangement on the main deck alone; the arrangement using both the main deck and passageways; and the arrangement using passageway alone. Each design option was investigated, and their economic and environmental impacts were quantified in aholistic view by Life Cycle and Cost Assessment. The economic and environmental impacts were normalized into monetary values to evaluate the best design option overall. Results revealed that the cableway arrangement using only passageways was the best solution, showing that the total cost of the design was estimated at 308,573 USD, which was 130,010 USD less than the cost of the worst option using only the main deck. The case study proved the effectiveness of the proposed approach to determine an optimal design from avariety of choices, which offers insight into current problems that have underestimated the influence of ship designs on environmental impact. In order to enhance the cleaner production, the proposed approach can be widely applied to every part of shipbuilding such as designing of hull, piping and outfitting.

The introduction of the maritime autonomous surface ships (MASS) accompanied by alternative fuels to the maritime industry is about to open a new era and lead to a new paradigm shift in terms of sa...

This paper was born to introduce a novel methodology termed Live-Life Cycle Assessment using a simulation-based data generation technique that can remedy the inherent shortcomings of conventional practices of lifecycle assessment. To demonstrate its excellence, the proposed method was applied to one of the most challenging topics in the marine industry. That was to tackle the fundamental doubt of whether solar-electric propulsion ships could truly be the future energy solution of maritime transports by fulfilling new environmental conventions and goals around the world. The case study began with an existing hybrid short route ferry running on diesel and plug-in battery power. Credible PV systems for the case ship was modelled to produce ship performance data under various operational/environmental circumstances of the coastal zones across 29 countries in the platform of MATLAB/Simulink. As a key functionality of Live-Life Cycle Assessment, the produced data was directly fed, as inputs, into life cycle assessment to avoid conventional practices that heavily rely on outdated data libraries. Results of the case study clearly revealed and quantified the correlations of the performance of PV-battery systems with climate parameters such as temperature and irradiance of subject areas as well as national power production methods. For example, in terms of Global Warming Potential, the case ship with the PV system was estimated to reduce 40,812 kg CO2 eq. per year in Brazil (average temp.: 27.4 ℃, major energy source: hydro). Interestingly, the same vessel was found to achieve greater reductions in India (average temp.: 27.5 ℃, major energy source: coal) or Australia (average temp.: 20.1 ℃, major energy source: coal) where are overly laden with coal-based power plants. Therefore, their reduction levels were estimated at 152,887 kg CO2 eq. per year and 141,517 kg CO2 eq. per year respectively. This paper clearly shows the excellence of the proposed method to demystify/quantify the impacts of parametric variables on the performance of the PV-electric ship. Moreover, it highly suggests the Live-Life Cycle Assessment could be a solution as a new standard to respond to strong demand to obtain general observation of lifecycle benefits/harms of new technologies across all industries, not necessarily limited to the maritime sector.

In this article, we present research results on the structure and properties of new self-lubricating antifriction composites based on 4H4VMFS tool steel grinding waste with solid lubricant additives. The new composites are designed to work in the friction units of offset cylinders in printing machines at rotation speeds up to 7000 rpm and increased loads up to 5.0 MPa. The developed technology formed composites with a fine-grained heterophase structure with a metal matrix base of tool steel 4H4VMFS regenerated grinding waste, consisting of high-alloy α−solid solution and hard grains of alloying element carbides, as well as evenly distributed CaF2 antiseizure solid lubricant. This structure ensured the formation of composites with favorable functional properties. During the friction process, antiseizure films were formed on the contact surfaces, resulting in a self-lubrication mode. Comparative tests for friction and wear showed significant advantages of the new waste composite compared to cast bronze parts, which are traditionally used in the friction units of offset cylinders of rolled newspaper printing machines. The stable operation of the new composite made it possible to ensure a “wear-free” effect. Studies have shown the importance and prospects of using the wide range of valuable grinding waste in the reproduction cycle to manufacture quality composites. Reuse of such waste would significantly protect the environment from pollution connected with human activity industrial and mitigate negative impacts on ecosystems and the biosphere.

In the present work, a comprehensive numerical model was developed to predict the levelised cost of energy (LCOE) for offshore wind farms. A case study is further performed based on the potential developments at the offshore area of the New York State. In the present work, some specific local limitations in the United States are considered by following in line with the present European development experience. A ten-year historical wind data set is used to evaluate the wind farm energy production. The effects of distance to shore, rated power, life span, operation height, farm capacity and seasonal operation plan on LCOE are evaluated. An optimal site giving an LCOE of 123.4 $2018/MWh is found in this paper. In addition, a novel factor named as wind farm energy density (WFED) is suggested in the present study. It shows that when considering the limited coastal area as an issue, a large capacity wind farm may not have good performance compared with a lower capacity wind farm in terms of energy production. The 508 MW wind farm has a better WFED compared with either a 330 MW wind farm or an 800 MW wind farm under the current investigation.

This study aimed to reduce the holistic environmental impacts of insulation materials proposed for the accommodation of a marine cargo ship, and suggest the optimal option for cleaner ship production, using life cycle assessment. With a commercial bulk carrier as a case ship, three major insulations were assessed, which were wool-based material (mineral wool or glass wool), expanded polystyrene, and polyurethane foam. The analysis was scoped based on ‘from cradle to grave’, while focusing on the following five representative environmental indicators: global warming potential100years, acidification potential, eutrophication potential, ozone depletion potential, and human toxicity potential. The assessment was performed in the platform of the GaBi software. The results showed that polyurethane foam would have the greatest impacts, especially in regard to global warming, eutrophication, and human toxicity. On the other hand, expanded polystyrene and wool-based material showed better environmental performance than polyurethane foam. For example, wool-based insulation was found, in terms of GWP and HTP, to produce 2.1 × 104 kg CO2-eq and 760.1 kg DCB-eq, respectively, and expanded polystyrene had similar results with respect to GWP, AP, and EP as 2.1 × 104 kg CO2-eq, 23.3 kg SO2-eq, and 2.7 kg Phosphate-eq, respectively. In fact, the research findings point out the shortcomings of current design practices in selecting insulation materials for marine vessels, while providing meaningful insights into the importance of the selection of appropriate insulation materials for marine vessels for cleaner shipping. Therefore, it is believed that this paper will make a sound contribution to enhancing future design practice and regulatory frameworks in response to environmental issues in the marine industry.

This paper was to investigate the potential benefits of solar panel systems if applied for obtaining propulsion power of a short route ferry operating in the Marmara Sea. The life cycle assessment was applied to evaluate the long-term environmental impact of the solar power systems on-board in replace of conventional diesel engine systems. The cost and benefit of such systems were evaluated through the economic assessment where the life cycle cost relative to installation, operation and recycling of the solar panels, fuel savings and payback time were considered. Research findings revealed the payback time would be around three years, whereas the accumulative fuel cost saving would be over $300,000 by the end of vessel life. The sensitivity analysis using two varying parameters - energy efficiency and investment cost - implied, that the longer payback time would be positively associated with lower energy efficiencies and higher investment costs. It was also suggested that the marginal cost of the carbon credit should be $ 190 per tonne or higher to make the shipping business successful.

This paper is to provide a guidance as to which scrubber system is applied for marine vessels in both environmental and economic perspectives. It performs a comparative analysis for two different types of wet scrubber systems: they are generally referred as "open loop" and "closed loop" systems. Those systems are evaluated via life cycle assessment technique, which is further used for evaluating the global warming, acidification and eutrophication potentials. The economic aspect of the scrubber installation will be estimated by establishing the payback time of the installation costs. Sensitivity analysis is performed to determine the effect of various economic scenarios on payback times. Research results reveal that the environmental impacts are higher for the closed loop scrubber than open loop scrubber. The open loop scrubber has a marginally shorter payback time under different scenarios; for No EGCS (MGO) case, it was revealed 3.2 years (with open loop) and 3.6 years (with closed loop), and for No EGCS (VLSFO + MGO) case, 5.4 years (with open loop) and 5.9 years (with closed loop).

This paper was to conduct a comparative analysis between two credible marine fuels: LNG and hydrogen from safety perspective. As the first step, a bulk carrier 80,000 DWT Kamsarmax was selected as the case ship, whereas the conceptual design of retrofitting the bunkering system was implemented. In order to gain important insights into risk levels of those fuels associated with bunkering, accidental fire/explosion scenarios were developed, and the potential risks of those adverse situations were quantified. The results were interpreted as a form of the levels of safety zones applicable for bunkering. As the first attempt to compare the risk of two promising marine fuels, this paper is highly believed to give some meaningful insights into proper understanding of risk levels, thereby establishing safety practices and conducting future regulatory frameworks to mitigate those risks accordingly.

This paper is to evaluate the LNG bunkering safety for a 50,000 dead weight tonnage bulk carrier renowned as the world first LNG fueled bulk carrier. To establish a proper level of the safety zone against the potential risk of gas release from the LNG bunkering systems encompassing from truck to ship, it introduces an enhanced quantitative risk assessment process with two key ideas: firstly, the integration of the population-independent analysis with the population-dependent analysis, and secondly, the combination between the probabilistic analysis and CFD simulation for gas dispersion. Research results reveal that the appropriate levels of the safe zone can be set at 28.8 m in 1E-4/year criterion that concerns the individual risk of a fatality at the given distance to the risk source of 1 in 10,000 years, whereas at 46.6 m (in 1E-5/year criterion) and at 213.3 m (in 1E-6/year criterion) when the area within 5% and higher gas concentration in air is regarded the critical zone. On the other hand, in case of the critical area considered to be within 2.5% and higher gas concentration in air, the safety zone will much expand to 34.9 m (in 1E-4/year criterion), 80.4 m (in 1E-5/year criterion) and 541.8 m (in 1E-6/year criterion). These dissimilarities suggest that LNG bunkering ports pay attention to selecting appropriate safety criteria which would considerably change the range of safety zones. The case study also demonstrates the effectiveness of the proposed approach that can remedy the shortcomings/shortfalls of existing technical and regulatory guidance on establishing the zones. It is, therefore, believed that the risk assessment approach proposed in this paper can contribute to determining the appropriate level of safety zones whereas providing practical insight into port authorities and flag states.

Over the last few decades, oil tankers and bulk carriers, which preferably adopting the concept of a single stern tube bearing, have been subjected to the mechanical damages on propulsion shaft bearings since such a concept overly requires a single bearing to support the full load of the propulsion shaft. This paper was to fundamentally address the problem of current practices of aligning a single stern tube bearing for commercial ships by determining the effective supporting point to balance the load of the propulsion shaft properly. Since selecting a case ship subjected to the damage on the stern tube bearing, it investigated the actual cause of the damage, thereby finding a practical way to enhance the sustainability of the propulsion shaft system using the single stern tube bearing. Computer-aided simulations using the finite element analysis as well as on-site measurements were carried out. Research findings revealed that the ignorance of the relative slope angle between the propulsion shaft and the aft stern tube bearing had led to misalignment, which resulted in adverse effects on the stability of the shaft system, and consequently damaged the stern tube bearing. Results of the analysis suggested that the degree of slope be taken into account when estimating the effective supporting point of the bearing. Finally, this paper pointed out that the establishment of a shaft installation guideline considering the effect of the shaft slope, thereby preventing wiping damage of the aft stern tube bearing would be an urgent task.

This paper was inspired to answer the fundamental question on whether electric battery powered ships can ultimately be a promising solution for future maritime environmental protection. The overall process was designed to demystify the holistic environmental benefits and harms of 14 primary energy sources for electricity production in consideration of the national-specific cases of 33 countries. A series of comparative analyses between the diesel as the reference fuel and the battery-electric propulsions were conducted with 27 short-route ferries engaged in Scotland coastal areas. A key message obtained from the analysis results were that the impact of battery application was far from the zero-emission shipping in the lifecycle perspective. Moreover, the same vessels were found to yield completely different environmental performances, depending on how those countries produce electricity. In some Asian countries heavily relying on fossil-based power generation, the environmental impact of battery operation was estimated far greater than that of diesel operation in the UK. Case studies were, then, scaled-up to about 5500 marine vessels presently engaged in international voyages. In general, consistent results were found. Research findings distinctively demonstrated the misguidance of current maritime policies for encouraging battery-powered ships and identified that these shortcomings would stem from the limitations of current practices of maritime environmental assessment. Lastly, it strongly suggested to the marine industry and stakeholders that the environmental protection from shipping activities would be not only a matter of ships but also a matter of how the national power grid develops.

This paper provides a general insight into the importance of proper hull maintenance and suggests an optimal maintenance strategy for ship operators from both an economic and environmental point of view. Results of life cycle assessment show that significant cost reductions can be obtained by renewing steels every 10 years within the proposed hull maintenance strategy. The assessment also indicates that annual hull inspections and re-coating can contribute to reducing hull resistance and hence fuel consumption, thereby reducing the overall operating costs and emissions. This paper provides ship owners a direct relationship between effective hull maintenance and the reduction in maintenance cost. It also provides information to inform policy makers of the benefits of following a maintenance optimization strategy. This study shows that life cycle assessment can provide information to shipyards and owners to facilitate reliable long-term maintenance decisions.

The objective of this paper is to examine the characteristics of leaked-gas dispersion in ship-to-ship liquefied natural gas (LNG) bunkering, thereby providing an insight towards determining the appropriate level of safety zones. For this purpose, parametric studies are undertaken in various operational and environmental conditions, with varying geometry of the ships, gas leak rate, wind speed and wind direction. The study applies computational fluid dynamics (CFD) simulations for case-specific scenarios where a hypothetical LNG bunkering ship with a capacity of 5100 m3 in tank space is considered to refuel two typical types of large ocean-going vessels: an 18,000 TEU container ship and a 319,000 DWT very large crude oil carrier. It is found that wind speed, wind direction, ship geometry and loading condition are important parameters affecting the extent of safety zones in addition to gas leak rate and leak duration. Details of the computations and discussions are presented.

This article presents a comprehensive overview of the life cycle environmental and energy assessment for all residential and commercial constructions made of timber walls, globally. The study was carried out based on a systematic literature analysis conducted on the Scopus database. A total of 66 research articles were relevant to timber wall design. Among these, the residential construction sector received more attention than the commercial sector, while the low-rise construction (1–2 stories) gained more attention than high-rise construction (>5 stories). Most of these studies were conducted in Canada, Europe, Malaysia, and the USA. In addition, the end-of-life phase received limited attention compared to upstream phases in most of the studies. We compared all environmental and energy-based life cycle impacts that used “m2” as the functional unit; this group represented 21 research articles. Global warming potential was understandably the most studied life cycle environmental impact category followed by acidification, eutrophication, embodied energy, photochemical oxidation, and abiotic depletion. In terms of global warming impact, the external walls of low-rise buildings emit 18 to 702 kg CO2 kg eq./m2, while the internal walls of the same emit 11 kg CO2 kg eq./m2. In turn, the walls of high-rise buildings carry 114.3 to 227.3 kg CO2 kg eq./m2 in terms of global warming impact. The review highlights variations in timber wall designs and the environmental impact of these variations, together with different system boundaries and varying building lifetimes, as covered in various articles. Finally, a few recommendations have been offered at the end of the article for future researchers of this domain.

Major objectives of this study were to produce low-emitting wood pellet biofuel from selected agro-forest tree species, i.e., Kikar (Acacia nilotica), Oak (Quercus semicarpifolia), and Mesquite (Prosopis juliflora), grown in the southern part of the Khyber Pakhtunkhwa (KP) province of Pakistan using indigenously developed technology (pelletizer machine). Primary raw material, such as sawdust of the selected agro-forest tree species, was obtained from sawmills located in southern part of KP. Life cycle inventory (LCI) was sourced for entire production chain of the wood pellet biofuel by measuring quantities of various inputs consumed and output produced. In addition, the wood pellets were characterized to examine diameter, length, moisture content, ash content, bulk density, high heating value (HHV), low heating value (LHV), as well as nitrogen and sulphur contents. A comprehensive life cycle assessment was performed for wood pellet biofuel production chain using SimaPro v9.1 software. A functional unit of one (01) kilogram (kg) wood pellet biofuel was applied following a gate-to-gate approach. The results of the present study were in accordance with the recommended Italian standard CTI-R 04/5 except for pellet bulk density and nitrogen content. The bulk density for all wood pellets, manufactured from the saw dust of three different agro-forest tree species, were lower than the recommended Italian standard, while for nitrogen content, the results were higher than the recommended Italian standard. Among the environmental impacts, Kikar (Acacia nilotica) wood pellets were the major contributor to fossil fuel depletion, followed by ecotoxicity, mineral depletion and acidification/eutrophication. This was primarily due to lubricating oil and urea-formaldehyde (UF) resin used as inputs in the wood pellets biofuel manufacture. Likewise, human health and ecosystem quality was also affected by lubricating oil, UF resin, and saw dust, respectively. In cumulative exergy demand of 1 kg wood pellets biofuel, the highest impact was from Kikar wood pellets for non-renewable fossils, mainly due to lubricating oil used. Difference in environmental impacts, damage assessment, and exergy were examined in three different scenarios for major hotspot inputs by reducing 20% lubricating oil in case 1, 20% UF resin in case 2, and without usage of UF resin in case 3, while marked reduction was observed in ecotoxicity, fossil fuel, and mineral depletion, as well as acidification/eutrophication impact category. Moreover, a pronounced reduction was also noted in the non-renewable fossil fuel category of cumulative exergy demand of one kg of wood pellets biofuel produced.

Ships encounter different wave heights in real sea states. Various wave heights can lead to substantial changes in the behaviour of a ship during manoeuvring, and hence a ship's manoeuvrability in waves should be accurately evaluated to ensure navigational safety at sea. The aim of this study is to estimate wave height effects on the manoeuvring behaviour of the benchmarking KRISO Container Ship (KCS) model by performing a fully nonlinear unsteady RANS simulation. Three types of manoeuvres were simulated with the free-running KCS model appended with an actuator disk and a moving semi-balanced horn rudder using a dynamic overset technique: self-propulsion, course keeping control, and turning circle manoeuvres. Manoeuvring analyses were carried out in the bow quartering waves of a range of wave heights for constant wave length, as coupled with the fifth-order Stokes wave model. In order to control the rudder deflection based on manoeuvre mechanisms, a feedback controller was embedded in the present CFD model. The results clearly revealed that wave heights have a strong effect on the manoeuvring behaviour of the KCS, including ship's speeds, seakeeping behaviour, and critical turning indices through comparative analyses under different wave height conditions. One important finding is the standard manoeuvring parameters in waves, which would help navigation officers in decision-making for manoeuvring actions in waves.

It is critical to estimate the manoeuvring behaviours of ships in waves since it is closely associated with navigation safety at sea. This study aims to predict the wavelength effects on the ship manoeuvring behaviours using a Computational Fluid Dynamics (CFD) based technique which enables resolving the complex interactions between hull, rudder, and propeller in waves. An Unsteady Reynolds-Averaged Navier-Stokes (URANS) model of the well-known benchmarking KRISO Container Ship (KCS) was developed using the dynamic overset grid technique to simulate the ship motions and rudder deflection. To represent the effects of the propeller, the body force method using an infinite-blade actuator disk was used. The manoeuvring analyses were carried out in bow waves of wavelength-to-ship-length ratios varying between 0.7 and 2.0 for constant wave height. Two representative free-running manoeuvres were conducted, namely, course keeping control, and standard turning circle manoeuvres. The analyses revealed that the wavelength has a significant influence on the manoeuvring performance, especially for the approach speeds, ship motions, and manoeuvring indices. The key findings of this research will increase the understanding of ship manoeuvrability in waves and therefore help to enhance navigation safety at sea.

This paper systematically investigates the safety of fuel preparation room containing high pressure fuel gas supply systems in order to identify shortcomings and practical gaps of the current regulations. A very large ore carrier of 300,000 DWT was taken as an example and the LNG fuel system was designed for it. An event tree analysis was conducted on the fuel system to identify events that can lead to an explosion. Along with a fault tree analysis model, generic failure data from various sources were used to estimate frequency of potential explosion. For the consequence analysis computational fluid dynamics and finite element analysis software were used to estimate the impact of explosions on the boundary structure of the fuel preparation room. Research findings show that the current rules and regulations concerning the safety of fuel preparation rooms and that the high pressure fuel gas supply system is subject to an unacceptably high level of explosion risk with the frequency of explosion as high as 3.13E-04 per year. The impact of an explosion within the fuel preparation rooms can cause stresses in excess of allowable stress in the bottom structure if not being strengthened. It is proposed that special attention is given to the structural design and/or enhanced safe measures for the FPRs and the relevant regulations updated to account for this.

The use of liquefied natural gas (LNG) has been recognized as an effective alternative fuel for marine propulsion, evidently, a growing number of vessels, including passenger ships, is already running on such a fuel. While LNG bunkering can be performed in several ways, depending on transferred volumes and managerial considerations, the time spent for LNG bunkering is regarded to be a key factor to ensure the cost-effectiveness of such operation, since a minimization of bunkering duration at the berth will make port infrastructures available for more vessels. As a result, passenger embarkment is simultaneously conducted with ship bunkering, which may increase the potential risk to individuals both onboard and nearby. Given this background, this paper is to investigate the potential risk of passenger vessels with the identification of credible scenarios for port operations that can be carried out simultaneously with LNG bunkering. An approach of quantitative risk assessment is applied to determine the risk levels pertinent to proposed scenarios. For frequency analysis, the technique of the fault tree analysis is adopted to integrate the influence of human error and management policy to the likelihood of unwanted events. Consequence analysis is conducted in aids of a commercial software to simulate the impact of LNG dispersion and fires. Research findings have shown that simultaneous operations have a negative impact both on frequency and consequence of accidental scenarios arising from LNG bunkering, taking the risk beyond lower acceptance criteria. Finally, a quantification of the risk increase is proposed to help stakeholders identify criticalities and reduce the risk contributions of simultaneous operations.

This research was focused on a comparative analysis of using LNG as a marine fuel with a conventional marine gas oil (MGO) from an environmental point of view. A case study was performed using a 50K bulk carrier engaged in domestic services in South Korea. Considering the energy exporting market for South Korea, the fuel supply chain was designed with the two largest suppliers: Middle East (LNG-Qatar/MGO-Saudi Arabia) and U.S. The life cycle of each fuel type was categorized into three stages: Well-to-Tank (WtT), Tank-to-Wake (TtW), and Well-to-Wake (WtW). With the process modelling, the environmental impact of each stage was analyzed based on the five environmental impact categorizes: Global Warming Potential (GWP), Acidification Potential (AP), Photochemical Potential (POCP), Eutrophication Potential (EP) and Particulate Matter (PM). Analysis results reveal that emission levels for the LNG cases are significantly lower than the MGO cases in all potential impact categories. Particularly, Case 1 (LNG import to Korea from Qatar) is identified as the best option as producing the lowest emission levels per 1.0 &times, 107 MJ of fuel consumption: 977 tonnages of CO2 equivalent (for GWP), 1.76 tonnages of SO2 equivalent (for AP), 1.18 tonnages of N equivalent (for EP), 4.28 tonnages of NMVOC equivalent (for POCP) and 26 kg of PM 2.5 equivalent (for PM). On the other hand, the results also point out that the selection of the fuel supply routes could be an important factor contributing to emission levels since longer distances for freight transportation result in more emissions. It is worth noting that the life cycle assessment can offer us better understanding of holistic emission levels contributed by marine fuels from the cradle to the grave, which are highly believed to remedy the shortcomings of current marine emission indicators.