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BACKGROUND: The steam processing characteristics of chicken are a key factor in the simplicity and versatility of steamed chicken dishes. The aim of this study was to investigate in depth the changes in tenderness and water retention of marinated chicken at different slow steaming endpoint temperatures, and to further explore the effect of the evolution of protein conformations on the water status. RESULTS: The results showed that chicken samples' shear force peaked at 80 °C and decreased rapidly at 90 °C. As the steaming endpoint temperature increased between 50 and 90 °C, T21, T22, moisture content and centrifugal loss decreased, but P21, P22 and myofibril water‐holding capacity showed regular changes. The electrophoretic bands and protein conformation changes showed that protein in marinated chicken underwent different degrees of denaturation, degradation and aggregation. And at 70 °C, with an increase of hydrophobic groups and crosslinking of disulfide bonds as well as an increase in the number of denatured sarcoplasmic proteins, the intermolecular network was enhanced, thus affecting the water retention. CONCLUSION: Water status of chicken meat heated at different steaming temperatures is closely related to the evolution of protein conformations. The present study serves as a robust theoretical foundation for enhancing the quality of steamed chicken products at an industrial scale. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A comprehensive thermodynamic model of the marine diesel engine in combination with the operating cost assessment is used in the decision-making process regarding the selection of the most favorable slow steaming speed. The influence of the number of cylinders and sailing speed on exhaust emissions, fuel consumption and operating costs is analyzed for the case of a containership sailing on a Trans-Pacific route. The engine simulation model was used for the calculation of engine fuel consumption, NOX and soot emissions. The operating costs and annual income were calculated through a fuel consumption correlation. The benefit of slow steaming is shown through the comparison of calculated data with the data calculated for the six-cylinder engine and the design speed of 23 knots. The highest reduction of 67.2% in CO2 and 93.3% in NOX emissions is achieved with the seven-cylinder engine at 15 knots, but the six-cylinder engine yields the highest increase in income per route of 6.2%. To comply with the proposed regulations for GHG emissions, the sailing speed should be reduced by at least 26%, which results in a decrease in the annual income by 24% compared to the design speed. [ABSTRACT FROM AUTHOR]

The sustainability of maritime activities is increasingly gaining interest, with the shipping sector actively focusing on decarbonization efforts. Throughout the years, researchers have considered slow steaming for improving the environmental footprint of maritime networks. In order to assess such strategies' effectiveness on existing emissions, research also focuses on the accurate estimation of emission inventories. However, there is a significant gap concerning both fields when considering short-sea shipping, especially passenger shipping. Furthermore, while emissions are characterized by spatial aspects in several studies, there is an apparent gap in considering such aspects for detailed analysis purposes rather than only for visualization purposes. In this study, the Greek Coastal Shipping Network (GCSN) is considered, with its emissions estimated using a top-down method, creating a spatial emission inventory used for further spatial analysis for accurate identification of highly polluted areas. Results indicate that ship emissions do not spread homogeneously throughout the GCSN and that targeted interventions are necessary in several areas of the network. The effectiveness of spatially related slow steaming implementations is evaluated and compared with their implementation on the whole network. The study highlights the need for additional future emission mitigation strategies, such as service optimization, network restructuring, continuous emission monitoring, and fleet renewal with more environmentally efficient ships. The study's aim is to fill the research gap regarding the environmental assessment of passenger shipping and the effects of slow steaming on such networks while presenting an adaptable GIS-based decision support system for enhanced decision-making regarding the environmental efficiency of maritime networks. [ABSTRACT FROM AUTHOR]

A comprehensive thermodynamic model of the marine diesel engine in combination with the operating cost assessment is used in the decision-making process regarding the selection of the most favorable slow steaming speed. The influence of the number of cylinders and sailing speed on exhaust emissions, fuel consumption and operating costs is analyzed for the case of a containership sailing on a Trans-Pacific route. The engine simulation model was used for the calculation of engine fuel consumption, NOX and soot emissions. The operating costs and annual income were calculated through a fuel consumption correlation. The benefit of slow steaming is shown through the comparison of calculated data with the data calculated for the six-cylinder engine and the design speed of 23 knots. The highest reduction of 67.2% in CO2 and 93.3% in NOX emissions is achieved with the seven-cylinder engine at 15 knots, but the six-cylinder engine yields the highest increase in income per route of 6.2%. To comply with the proposed regulations for GHG emissions, the sailing speed should be reduced by at least 26%, which results in a decrease in the annual income by 24% compared to the design speed.

Maritime transportation is the prevalent mode of transport for overseas freight, and it is frequently recognised as a relatively environmentally sustainable means of transport. However, shipping is still a substantial source of greenhouse gas emissions. We investigate the effect on fuel consumption and emissions when container ships are sailing below the design speed (i.e., slow steaming) as a strategy to minimise fuel consumption and costs. The estimation of ship fuel oil consumption is commonly based on the cubic speed‒power relation as a bottom-up approach. Nevertheless, the cubic relation could overestimate the impact of slow steaming on fuel consumption reduction and the emissions assessment. We compare real fuel consumption data and the consequent emissions with the results of assessing these parameters with the mentioned bottom-up approach. The analysis uses a set of container-ship slow steaming voyages, and the assessment is supported by speeds obtained from the Automatic Identification System (AIS). The exponential values obtained for the speed‒power relation range between 3.1 and 3.5, finding an overrating over 20% in all the cases analysed. Finally, we use a weather ship routing optimisation software to investigate additional emissions savings in the framework of ship-specific measures when weather ship routing and slow steaming are applied simultaneously. [ABSTRACT FROM AUTHOR]

Abstract The International Maritime Organisation (IMO) has adopted the Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII) as short term measures for decarbonisation of the shipping industry; the IMO also made the collection of relevant data and associated reporting of the indicator mandatory from January 2023. However, many existing ships do not meet the EEXI and CII “targets” and cannot invest in other technologies to meet the relevant requirements. Given the various barriers to energy efficiency, the application of slow steaming may be a measure to effectively meet EEXI and CII requirements. A qualitative systematic literature review was conducted on the potential macroeconomic and social impacts of slow steaming on states, with a special focus on Small Island Development States and Least Developed Countries, when used as the primary modality of reducing GHG emissions from shipping. This effort includes peer-reviewed studies and studies from the gray literature, many of which include examples that borrow data from the aftermath of the economic crisis that was manifested in 2008. The vast majority of those studies is focused on the economic cost-effectiveness or impact on transportation costs when using slow-steaming as a means of reducing marine fuel consumption. Moreover, a number of these studies were relying on modeling techniques, by using a limited number of ships and associated routes to determine the effects of slow-steaming. A reasonable degree of agreement emerged from the literature that a reduction in transportation costs results from a reduction in speed, being attributed primarily to reduced fuel costs, with which it is associated. Other cost-increasing factors, such as vessel operating costs, had a less dominant effect. The literature often pointed out that the cost reduction resulting from the application of slow-steaming was unevenly distributed among maritime stakeholders. Shipping companies were the main beneficiaries of significant cost savings, but these "savings" were not always passed on to shippers.

Inland waterways vessels (IWV) have no mandatory regulations regarding their energy efficiency, as sea-going ships have. So far, there are just two proposed design energy efficiency evaluation methods, both based on IMO EEDI approach and data on EU inland navigation. Operational indicators and real-time navigation measurements from available literature do not exist. Therefore, this paper aims to introduce the energy efficiency in operation (EEO), assessed for the typical Danube cargo vessel. Firstly, an operational profile is acquired by tracking the vessel's voyages, and by identifying actual constraints of each sector the vessel has sailed during the designated time. Secondly, EEO is incorporated within two available methods and calculated based on acquired operational data considering different navigational conditions. The paper shows how the energy efficiency vastly depends on variables such as water depth, current speed, draught, deadweight, river constraints. Analysis is performed for the most employed month of the vessel navigation, and annually. Depending on water level scenarios and during the selected month of sailing, the total amount of CO2 emitted is estimated to be between 22.7 t and 29.9 t, while the necessary average speed reduction (i.e., slow steaming) per sectoral voyage for the requirement compliance is calculated to be in between 4.8%-26%. Slow steaming is assessed to extend the time of voyage for 6.1-10.7 hours on monthly basis and 49-87 hours annually. [ABSTRACT FROM AUTHOR]

Slow steaming is an effective operational measure that reduces fuel consumption and thus emissions on board. With the Carbon Intensity Indicator (CII) regulation coming into force in 2023 from the International Maritime Organization (IMO), ships will have to reduce their CO2 emissions even more. The practice of slow steaming is an important measure to comply with this regulation. In this study, real voyage data of a general cargo ship was used. The changes in fuel consumption, CO2, CH4, N2O, and BC emissions, 20-year global warming potential (GWP20), and 100-year global warming potential (GWP100) of the ship were analysed under different scenarios (75%, 38%, 27%, and 19% main engine load), and the voyage expenses and cost-benefit ratio were calculated. At 38% main engine load, 31.5% less emissions were released than at 75% main engine load. At 27% and 19% main engine load, the emission reduction was 40.6% and 50.1%, respectively. The CO2 reduction target of 40% by 2030 and 50% by 2050 compared to 2008 levels in the IMO Initial GHG Strategy was achieved with slow steaming. As CO2 emissions decreased due to the application of slow steaming, this had a positive impact on the ship's CII rating and it remained at the A rating without further action. Nevertheless, it remains at the A rating with slow steaming, the amount of emissions varies depending on the rate of application of slow steaming in three different scenarios, and this shows that the environmental impact of each A rating is not the same. The results of the economic analysis show that operating costs increase and fuel costs decrease when the travel time is extended with slow steaming. As a result, the total voyage expenses decreased by up to 23.3%.

Slow steaming is an effective operational measure that reduces fuel consumption and thus emissions on board. With the Carbon Intensity Indicator (CII) regulation coming into force in 2023 from the International Maritime Organization (IMO), ships will have to reduce their CO2 emissions even more. The practice of slow steaming is an important measure to comply with this regulation. In this study, real voyage data of a general cargo ship was used. The changes in fuel consumption, CO2, CH4, N2O, and BC emissions, 20-year global warming potential (GWP20), and 100-year global warming potential (GWP100) of the ship were analysed under different scenarios (75%, 38%, 27%, and 19% main engine load), and the voyage expenses and cost-benefit ratio were calculated. At 38% main engine load, 31.5% less emissions were released than at 75% main engine load. At 27% and 19% main engine load, the emission reduction was 40.6% and 50.1%, respectively. The CO2 reduction target of 40% by 2030 and 50% by 2050 compared to 2008 levels in the IMO Initial GHG Strategy was achieved with slow steaming. As CO2 emissions decreased due to the application of slow steaming, this had a positive impact on the ship's CII rating and it remained at the A rating without further action. Nevertheless, it remains at the A rating with slow steaming, the amount of emissions varies depending on the rate of application of slow steaming in three different scenarios, and this shows that the environmental impact of each A rating is not the same. The results of the economic analysis show that operating costs increase and fuel costs decrease when the travel time is extended with slow steaming. As a result, the total voyage expenses decreased by up to 23.3%. [ABSTRACT FROM AUTHOR]

Modern marine propulsion systems must be reliable, energy efficient, environmentally friendly, and economical. Efforts to reduce fuel costs and carbon dioxide (CO2) emissions per nautical mile have a significant impact on the choice of propulsion system. Considering that there is no alternative for maritime transport, various technical and technological solutions are being considered that aim to improve efficiency and reduce the negative impact on the environment. One of the ways to achieve this goal is slow steaming, which reduces fuel consumption and CO2 emissions. The designed speed of the vessel has a significant impact on the efficiency of slow steaming. Slow steaming is particularly suitable for large container ships with a design speed of more than 20 knots. In this paper, the effects of slow steaming are analyzed using the example of a container ship with diesel-engine propulsion. Propulsion systems with low-speed and medium-speed marine diesel engines with mechanical power transmission are investigated. Data on the required engine power and propeller speed were used for the study, obtained from calculations during testing of the ship's hull model. The effects of speed reduction on specific fuel consumption and emission reduction were analyzed using numerical models of two-stroke and four-stroke diesel engines. The models were calibrated and validated using data provided by the engine manufacturers. The paper analyses four different cases where one or two low-speed diesel engines, or three or four medium-speed diesel engines, are used for propulsion. The analysis concludes that slow steaming can effectively reduce fuel consumption and CO2 emissions, but the choice of the optimal propulsion system is highly dependent on maritime market conditions in maritime transportation. The choice of propulsion system affects the potential of slow steaming. [ABSTRACT FROM AUTHOR]

The International Maritime Organisation (IMO) has adopted the Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII) as short term measures for decarbonisation of the shipping industry; the IMO also made the collection of relevant data and associated reporting of the indicator mandatory from January 2023. However, many existing ships do not meet the EEXI and CII "targets" and cannot invest in other technologies to meet the relevant requirements. Given the various barriers to energy efficiency, the application of slow steaming may be a measure to effectively meet EEXI and CII requirements. A qualitative systematic literature review was conducted on the potential macroeconomic and social impacts of slow steaming on states, with a special focus on Small Island Development States and Least Developed Countries, when used as the primary modality of reducing GHG emissions from shipping. This effort includes peer-reviewed studies and studies from the gray literature, many of which include examples that borrow data from the aftermath of the economic crisis that was manifested in 2008. The vast majority of those studies is focused on the economic cost-effectiveness or impact on transportation costs when using slow-steaming as a means of reducing marine fuel consumption. Moreover, a number of these studies were relying on modeling techniques, by using a limited number of ships and associated routes to determine the effects of slow-steaming. A reasonable degree of agreement emerged from the literature that a reduction in transportation costs results from a reduction in speed, being attributed primarily to reduced fuel costs, with which it is associated. Other cost-increasing factors, such as vessel operating costs, had a less dominant effect. The literature often pointed out that the cost reduction resulting from the application of slow-steaming was unevenly distributed among maritime stakeholders. Shipping companies were the main beneficiaries of significant cost savings, but these "savings" were not always passed on to shippers. [ABSTRACT FROM AUTHOR]

Maritime transportation is the prevalent mode of transport for overseas freight, and it is frequently recognised as a relatively environmentally sustainable means of transport. However, shipping is still a substantial source of greenhouse gas emissions. We investigate the effect on fuel consumption and emissions when container ships are sailing below the design speed (i.e., slow steaming) as a strategy to minimise fuel consumption and costs. The estimation of ship fuel oil consumption is commonly based on the cubic speed‒power relation as a bottom-up approach. Nevertheless, the cubic relation could overestimate the impact of slow steaming on fuel consumption reduction and the emissions assessment. We compare real fuel consumption data and the consequent emissions with the results of assessing these parameters with the mentioned bottom-up approach. The analysis uses a set of container-ship slow steaming voyages, and the assessment is supported by speeds obtained from the Automatic Identification System (AIS). The exponential values obtained for the speed‒power relation range between 3.1 and 3.5, finding an overrating over 20% in all the cases analysed. Finally, we use a weather ship routing optimisation software to investigate additional emissions savings in the framework of ship-specific measures when weather ship routing and slow steaming are applied simultaneously.

One of the short-term operational measures for fuel savings and reducing CO2 emissions from ships at sea is sailing at reduced speed, i.e., slow steaming, while the gasification of the ship represents an important mid-term technical measure. In this study, the energetic and ecological benefits of slow steaming and gasification are studied for a container ship sailing between Shanghai and Hamburg. Resistance and propulsion characteristics in calm water are calculated using computational fluid dynamics based on the viscous flow theory for a full-scale ship, while the added resistance in waves is calculated by applying potential flow theory. The propeller operating point is determined for the design and slow steaming speeds at sea states with the highest probability of occurrence through the investigated sailing route. Thereafter, the fuel consumption and CO2 emissions are calculated for a selected dual fuel engine in fuel oil- and gas-supplying modes complying with IMO Tier II and Tier III requirements. The results demonstrate a significant reduction in fuel consumption and CO2 emissions for various slow steaming speeds compared to the design speed at different sea states, and for the gasification of a container ship. For realistic weather conditions through the investigated route, the potential reduction in CO2 emissions per year could be up to 11.66 kt/year for fuel oil mode and 8.53 kt/year for gas-operating mode. CO2 emission reduction per year due to gasification under realistic weather conditions could be up to 22 kt/year. [ABSTRACT FROM AUTHOR]

Energy requirements push the shipping industry towards more energy-efficient ships, while environmental regulations influence the development of environmentally friendly ships by replacing fossil fuels with alternatives. Current mathematical models for ship energy efficiency, which set the analysis boundaries at the level of the ship power system, are not able to consider alternative fuels as a powering option. In this paper, the energy efficiency and emissions index are formulated for ships with alternative power systems, considering three different impacts on the environment (global warming, acidification, and eutrophication) and realistic fuel pathways and workloads. Besides diesel, applications of alternative powering options such as electricity, methanol, liquefied natural gas, hydrogen, and ammonia are considered. By extending the analysis boundaries from the ship power system to the complete fuel cycle, it is possible to compare different ships within the considered fleet, or a whole shipping sector, from the viewpoint of energy efficiency and environmental friendliness. The applicability of the model is illustrated on the Croatian ro-ro passenger fleet. A technical measure of implementation of alternative fuels in combination with an operational measure of speed reduction results in an even greater emissions reduction and an increase in energy efficiency. Analysis of the impact of voluntary speed reduction for ships with different power systems resulted in the identification of the optimal combination of alternative fuel and speed reduction by a specific percentage from the ship design speed. [ABSTRACT FROM AUTHOR]

Modern marine propulsion systems must be reliable, energy efficient, environmentally friendly, and economical. Efforts to reduce fuel costs and carbon dioxide (CO2) emissions per nautical mile have a significant impact on the choice of propulsion system. Considering that there is no alternative for maritime transport, various technical and technological solutions are being considered that aim to improve efficiency and reduce the negative impact on the environment. One of the ways to achieve this goal is slow steaming, which reduces fuel consumption and CO2 emissions. The designed speed of the vessel has a significant impact on the efficiency of slow steaming. Slow steaming is particularly suitable for large container ships with a design speed of more than 20 knots. In this paper, the effects of slow steaming are analyzed using the example of a container ship with diesel-engine propulsion. Propulsion systems with low-speed and medium-speed marine diesel engines with mechanical power transmission are investigated. Data on the required engine power and propeller speed were used for the study, obtained from calculations during testing of the ship’s hull model. The effects of speed reduction on specific fuel consumption and emission reduction were analyzed using numerical models of two-stroke and four-stroke diesel engines. The models were calibrated and validated using data provided by the engine manufacturers. The paper analyses four different cases where one or two low-speed diesel engines, or three or four medium-speed diesel engines, are used for propulsion. The analysis concludes that slow steaming can effectively reduce fuel consumption and CO2 emissions, but the choice of the optimal propulsion system is highly dependent on maritime market conditions in maritime transportation. The choice of propulsion system affects the potential of slow steaming.

This paper analyses the operator's risk-based decision (RBD) company for slow steaming, and creates a sailing speed optimization model for slow steaming (SSOM-SS), aiming to balance the expected utility-based objectives (EUO) of fuel consumption, SOx emissions and delivery delay. Considering the limitations of existing theoretical fuel consumption functions under uncertainties in voyages, the authors applies big data analytics (BDA) techniques like data fusion and feature selection to provide the SSOM-SS with accurate and suitable data on fuel consumption. In addition, a solver is built based on the genetic algorithm (GA) to solve the SSOM-SS. The effectiveness of the SSOM-SS is verified through a case study on the RBD for slow steaming of an Orient Overseas Container Line (OOCL) containership sailing across the sulphur emission control areas (SECAs) in Chinese coastal regions. The results show that the SSOM-SS can facilitate the RBD for slow steaming, and provide a novel tool for sailing speed optimization.

CO2 emissions during ship building, maintenance, and scrapping are not be involved when defining Energy Efficiency Operational Indicator (EEOI). However, these CO2 emissions can only show its value during operation phase of ship life. In order to evaluate the effect of CO2 emissions during ship building, maintenance, and scrapping on energy efficiency, a real time EEOI definition was put forward, a life cycle assessment (LCA) calculation framework was established, and a ship propulsion model with main diesel engine was built. A bulker carrier YUMING was taken as the case ship. CO2 emissions during ship building, maintenance, and scrapping were calculated. Main engine revolution and real time EEOI value with other parameters were obtained by simulating in different ship draft. The results show that life cycle assessment result will explicitly increase the real time EEOI value especially in lower engine speed and lower ship draft. The engine revolution at the lowest EEOI value will increase explicitly by life cycle assessment result. It means that the lower limit of ship speed should increase during slow steaming. Therefore, slow steaming may bring less environmental benefit if the life cycle assessment result is involved. [ABSTRACT FROM AUTHOR]

Yin, X.; Huang, L.; Lu, Y.; Zou, J., and Wan, L., 2021. Experimental investigation on resistance reduction for multiple service conditions of container ship bulbous bow optimization. Journal of Coastal Research, 37(3), 634–643. Coconut Creek (Florida), ISSN 0749-0208. In this article, the main objective is to implement an experimental investigation on resistance reduction within a hydrodynamic container ship design procedure for bulbous bow form optimization under multiple service conditions. One container ship was used as a parent ship, and using different bulb characteristic parameters as design variables, a new hull form with an optimized bulbous bow was developed to satisfy the economical requirement of slow steaming for the modern container vessel. Through the conduction of ship-model resistance tests in both design and scantling drafts covering a wide speed range, the experimental results of various resistance component values were monitored and compared between the original and optimized ship. The results show that the hydrodynamic performance of the optimized hull form is improved, especially at lower speeds, and the total resistance reduction per unit displacement in full scale reaches 30%∼40% and then decreases gradually with the increase of Froude number under design draft conditions in contrast to the original hull, suggesting the evolved hull form optimization method is valuable. In addition, the bulbous bow optimization method is proved more practical and effective than the traditional optimization process, which is only based on a contractually specified design condition. On the basis of the comparison and analysis of test results, the influence of the bulbous bow characteristic parameters on the resistance performance is further studied. The presented work is of high reference value for the hydrodynamic optimization design of modern container vessels. [ABSTRACT FROM AUTHOR]

One of the short-term operational measures for fuel savings and reducing CO2 emissions from ships at sea is sailing at reduced speed, i.e., slow steaming, while the gasification of the ship represents an important mid-term technical measure. In this study, the energetic and ecological benefits of slow steaming and gasification are studied for a container ship sailing between Shanghai and Hamburg. Resistance and propulsion characteristics in calm water are calculated using computational fluid dynamics based on the viscous flow theory for a full-scale ship, while the added resistance in waves is calculated by applying potential flow theory. The propeller operating point is determined for the design and slow steaming speeds at sea states with the highest probability of occurrence through the investigated sailing route. Thereafter, the fuel consumption and CO2 emissions are calculated for a selected dual fuel engine in fuel oil- and gas-supplying modes complying with IMO Tier II and Tier III requirements. The results demonstrate a significant reduction in fuel consumption and CO2 emissions for various slow steaming speeds compared to the design speed at different sea states, and for the gasification of a container ship. For realistic weather conditions through the investigated route, the potential reduction in CO2 emissions per year could be up to 11.66 kt/year for fuel oil mode and 8.53 kt/year for gas-operating mode. CO2 emission reduction per year due to gasification under realistic weather conditions could be up to 22 kt/year.

Energy requirements push the shipping industry towards more energy-efficient ships, while environmental regulations influence the development of environmentally friendly ships by replacing fossil fuels with alternatives. Current mathematical models for ship energy efficiency, which set the analysis boundaries at the level of the ship power system, are not able to consider alternative fuels as a powering option. In this paper, the energy efficiency and emissions index are formulated for ships with alternative power systems, considering three different impacts on the environment (global warming, acidification, and eutrophication) and realistic fuel pathways and workloads. Besides diesel, applications of alternative powering options such as electricity, methanol, liquefied natural gas, hydrogen, and ammonia are considered. By extending the analysis boundaries from the ship power system to the complete fuel cycle, it is possible to compare different ships within the considered fleet, or a whole shipping sector, from the viewpoint of energy efficiency and environmental friendliness. The applicability of the model is illustrated on the Croatian ro-ro passenger fleet. A technical measure of implementation of alternative fuels in combination with an operational measure of speed reduction results in an even greater emissions reduction and an increase in energy efficiency. Analysis of the impact of voluntary speed reduction for ships with different power systems resulted in the identification of the optimal combination of alternative fuel and speed reduction by a specific percentage from the ship design speed.

Slow steaming is an operational measure in ocean-going vessels sailing at slow speeds. It can help climate mitigation efforts by cutting down marine fuel consumption and consequently reducing CO2 and other Greenhouse Gas Emissions (GHG). Due to climate change both the European Union (EU) and the International Maritime Organization (IMO) are analysing the inclusion of international shipping in the EU Emissions Trading System (ETS) in the near future or alternatively implementing a carbon tax. The paper proposes a methodology to decide the optimal speed of a vessel taking into account its characteristics and the factors that determine its economic results. The calculated cash flow can be used in valuation models. The methodology is applied for a case study for any container ship in a range from 2000 to 20,000 Twenty-foot Equivalent Units (TEU) on a leg of a round trip from Shanghai to Rotterdam. We calculate how speed reduction, CO2 emissions and ship owner’s earnings per year may vary between a business-as-usual scenario and a scenario in which shipping is included in the ETS. The analysis reveals that the optimal speed varies with the size of the vessel and depends on several variables such as marine fuel prices, cargo freight rates and other voyage costs. Results show that the highest optimal speed is in the range of 5500–13,000 TEUs whether or not the ETS is applied. As the number of TEUs transported in a vessel increases emissions per TEU decrease. In an established freight rate market, the optimal speed fluctuates by 1.8 knots. Finally, the medium- and long-term expectations for slow steaming are analysed based on future market prices.

Trans-ocean liner shipping companies adopt slow steaming during periods when the market is characterised by low demand, high fuel prices, low freight rates and overcapacity. The most recent instance in which this occurred was the period following the 2008/2009 global financial crises, and the speeds have not yet rebounded to the pre-crisis levels. Most of the existing research regarding slow steaming takes environmental, economic and maritime engineering perspectives, meaning that the phenomenon is studied from the viewpoint of ship owners. The purpose of this paper is to explore the effects of slow steaming from the shipper's perspective. • This paper explores the effects of slow steaming from the shipper's perspective. • Six Swedish companies acting globally were studied; the data from the case companies have been collected through face-to-face interviews. • The results of the study show that reliability has been regarded as more important than the sailing time itself. [ABSTRACT FROM AUTHOR]

Environmental pollution is increasingly becoming a major global problem. Consequently, companies and policy makers are facing mounting pressure to reduce their impacts of logistics activities and make transport greener. The challenge to reduce the carbon intensity of maritime transport is even more important when we take into equation the fact that carries about 90% of the world trade. While car industry has already taken actions to greener cars, maritime industry is subject to fewer regulations and slower progress. This article overviews upcoming trends of green intermodal chains, initiatives in green maritime transport and how noteworthy is share of their impact in the transport chain as a whole. Speed reduction is one of most important measures which can be implemented right away with win-win impacting on environment and fuel cost. The study analysis environmental impacts of different services to eastern Adriatic ports, with special emphasis of slow steaming impacts on pollution level. The paper exposes that direct lines with bigger ships cause lower emissions of CO2, NOx and SOx and that with decisions of slow steaming the pollution level decreases significantly. [ABSTRACT FROM AUTHOR]

In this article, an innovative hydrodynamic optimization design of bulbous bow hull-form under various service conditions resulting from the slow steaming of container vessel is presented, improving the overall performances for the real multi-variant usage situations more practical than the single specification of design, which includes both numerical computation and experimental validation. Effects of slow steaming–based statistical analysis of the actual operative occurrence during the lifetime is conducted, obtaining a combined probability density distribution of speed and displacement ushering in the evaluation of objective function. Three main component elements of the hydrodynamic optimization procedure that comprises parametric design of bulbous bow hull-form variation part, hydrodynamic numerical solver part, and optimization technique part are established and integrated. The proposed optimization process is subsequently applied to find the optimal bulbous bow of a container carrier for the hipping demand of different speeds and displacement distributed utilization, reducing significantly total conditions resistance of the hull, on a higher level decreasing the operative cost as well as gas emissions of the ship. Finally, there is an experimental campaign carried out between the optimal and original models to validate the numerical optimization computations. The compared investigation has provided a good agreement from the perspective of both numerical and experimental studies, as a result confirming the success of the present optimization framework and the utility value of the proposed optimization consideration on various service conditions during ship design stage. [ABSTRACT FROM AUTHOR]

This review paper examines the possible pathways and possible technologies available that will help the shipping sector achieve the International Maritime Organization’s (IMO) deep decarbonization targets by 2050. There has been increased interest from important stakeholders regarding deep decarbonization, evidenced by market surveys conducted by Shell and Deloitte. However, deep decarbonization will require financial incentives and policies at an international and regional level given the maritime sector’s ~3% contribution to green house gas (GHG) emissions. The review paper, based on research articles and grey literature, discusses technoeconomic problems and/or benefits for technologies that will help the shipping sector achieve the IMO’s targets. The review presents a discussion on the recent literature regarding alternative fuels (nuclear, hydrogen, ammonia, methanol), renewable energy sources (biofuels, wind, solar), the maturity of technologies (fuel cells, internal combustion engines) as well as technical and operational strategies to reduce fuel consumption for new and existing ships (slow steaming, cleaning and coating, waste heat recovery, hull and propeller design). The IMO’s 2050 targets will be achieved via radical technology shift together with the aid of social pressure, financial incentives, regulatory and legislative reforms at the local, regional and international level.

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This article describes the basics of power plant construction comprising waste heat recovery system and shaft generator-motor on a large container vessel. Two experiments enclosing fuel consumption and electric load monitoring during vessel acceleration and slowing down in a range of slow steaming speed were presented. Using collected data, approximating functions for relation fuel consumption, main engine speed in vicinity of shaft generator-motor minimum permissible speed, were described. Based on the experimental data, a simulation for hypothetical 4000 NM voyage was carried out. Ship's total fuel consumption per voyage, for different engine speeds—below and above shaft generator-motor minimum cut-in speed—was elaborated. It was found that during slow steaming, fuel consumed by auxiliary boiler has much higher impact on the total fuel cost per voyage than fuel consumed by diesel generators when shaft generator-motor minimum permissible speed is not reached. Existence of a non-economical speed range just below shaft generator-motor minimum permissible speed was exposed. Evaluation of non-fuel cost of voyage was carried out. The amount of non-fuel cost was estimated to approximately 3.5% of overall variable cost of voyage. The influence of voyage speed on CO2 and NOX emission was elaborated. Ranges of most economical and most ecological (in terms of CO2 and NOX emission) speeds for simulated voyage were determined. [ABSTRACT FROM AUTHOR]

Abstract The implementation of International Maritime Organization regulations for CO 2 emission reduction has oriented ships to sail at lower speeds. Speed reduction reduces fuel consumption of ships significantly. In order to perform efficient ship operation, energy demand throughout the whole engine room has to be decreased. The goal of the study is to minimize electrical power consumption during slow steaming operation, hence equivalent fuel consumption and emissions could be decreased. A computational study was carried out in order to clarify potential savings with respect to main engine load. The study quantifies the energy savings in main engine cooling system which has significant potential to reduce electrical power consumption in slow steaming operations. Operational requirements are determined with the help of realistic engine room simulator of a container ship which has waste heat recovery system. The values, obtained from the simulator were verified using the technical manual of a diesel engine, which have similar output power range. The results of calculations show that there is great potential to improve energy efficiency when variable pumps are used. Based on the results, from the main engine cooling system, 60% of electrical power demand reduction can be achieved. The power reduction saved by pumps, decreases considerable amount of marine diesel oil consumption as 296.2 tons where 367.4 tons of fuel needed by diesel generators or oil fired boiler. The reduction in fuel consumption is 80% that the saving in the central cooling system corresponds 948 tons of CO 2 emission reduction and $207,300 cost saving. Highlights • Slow steaming was investigated with a novel perspective. • Cooling system is analysed for decreased engine loads. • Propose a cooling solution to decrease fuel consumption at marine engine operations. [ABSTRACT FROM AUTHOR]

Highlights • Methanol fuel is proposed as an alternative marine fuel. • Environmental and economic analysis of dual fuel engine is carried out. • As a case study, cellular container ship is investigated. • The results show the environmental and the economic benefits for methanol fuel. Abstract In this study, the use of methanol is proposed as an alternative fuel to comply with the international maritime organization (IMO) emission regulations. Environmental and economic analysis of the methanol-diesel dual fuel engine is carried out. As a case study, cellular container ship is investigated. The results show environmental benefits for reducing NO x , SO x , CO, CO 2 , and PM emissions by 76.78%, 89%, 55%, 18.13%, and 82.56%, respectively. In order to reduce the dual-fuel cost to the cost of the diesel fuel at maximum continuous rating (MCR), the ship speed should be reduced by 28%. In addition, the currently operated diesel engine uses selective catalytic reduction method (SCR) to comply with the IMO emission regulations. Combining the benefits of ship slow steaming and the saved SCR costs, the cost-effectiveness of dual-fuel engine for reducing NO x , CO, and CO 2 emissions will be 385.2 $/ton, 6548 $/ton, and 39.9 $/ton, respectively. [ABSTRACT FROM AUTHOR]

In this study, electrical machine technologies are compared comprehensively for a hybrid turbocharger used with a high‐power marine engine. It is required for the machine to operate in a thermally aggressive environment, with turbine exhaust temperatures in excess of 600°C. Furthermore, it is required to both generate from the extra exhaust energy (turbo‐compounding) at high‐engine loads as well as a motor for low‐engine loads during slow steaming. The application investigated translates to a machine featuring both high‐power (150 kW) and high speeds (25–50 krpm), together with a considerable constant power–speed region. In this study, induction machines (IM), permanent magnet machines and switched reluctance machines are compared taking into account a number of aspects including the thermal performance, torque ripple, converter volt–ampere rating, and cost. In light of the technical and market requirements, the IM featuring new materials is prototyped and tested for the application in a representative environment. [ABSTRACT FROM AUTHOR]

Abstract It was necessary to determine how to estimate the operational efficiency through an objective evaluation since a ship owner's interest was closely connected to the operating cost. Ship owners demanded that shipyards predicted the most efficient speed based on the evaluated operating cost by considering the hydrodynamic characteristics of a ship, sea route, environmental conditions including wind and waves, equipment features including main engine, and GCU, fuel property, and others. In this paper, we constructed a new approach to estimate the operating cost, by developing direct cost evaluation in consideration of the requested factors. As a result, the observed slow steaming was investigated on the basis of the hydrodynamic characteristics of the vessel and the effect of the activated GCU on the operating cost could be analyzed. Finally, a speed range within which slow steaming was effective was perceived, and the most efficient speed was observed at the lowest speed of that range. Highlights • The operating cost of an LNGC was estimated in consideration of the hydrodynamic characteristics, sea route, environmental conditions, and equipment operation. • The characteristics of the slow steaming was investigated from the estimated operating cost. • The most efficient speed was found in a speed range within which slow steaming is effective. [ABSTRACT FROM AUTHOR]

The International Maritime Organization introduced two energy efficiency indexes to reduce greenhouse gas emissions from ships. One of the short-run solutions is to reduce ship speed. The present research calculates the cost-effectiveness of reducing CO2 emissions and the improved Energy Efficiency Design Index (EEDI) corresponded to the reduced Energy Efficiency Operational Indicator (EEOI) due to slow steaming. As a case study, RO-RO cargo vessel has been investigated. Reducing ship speed by 10% and 40% will reduce CO2 emission by 27.05% and 78.39% with cost-effectiveness of 121.2 $/ton CO2 and 287.6 $/ton CO2, respectively. The attained EEDI values will be improved by 2.04% and 35.81% with the reduced EEOI values by 8.76% and 70.65%, respectively. Although ship slow steaming by 40% would comply with the required EEDI for the first and the second phases, the complied EEDI value needs to be further reduced by 7% in the year 2025. [ABSTRACT FROM AUTHOR]

Abstract Seaborne trade continues to grow and is an important component of the global economy. Threats from shipping to marine ecosystems include oil spills and other water pollution, air pollution, anchor scouring, biological invasions, container loss, chronic noise, and collisions between ships and large whales. Shipping and its associated threats can be influenced by a suite of regulations and economic events. The dynamic nature of ship traffic can be characterized using ship tracking data from automatic identification system (AIS) technology. These data enhance our ability to analyze the ecological threats from commercial shipping as a component of spatially explicit risk assessments. We explore ship traffic variability using a case study in waters off California. AIS data from 2008 to 2015 were used to evaluate the role of vessel emission regulations and economic events on vessel routes and speeds. We document vessels navigating around emission control areas (ECAs) or reducing speed when traveling through them. Large freight vessels decreased speeds from 2008 to 2015 by about 3–6 knots in many areas, with lowered speeds observed in areas of both heavy and sparse vessel use. The timing and location of the speed reductions appear to be most influenced by state and international clean fuel standards, which required the use of more costly fuels. Therefore, the speed reductions may have provided a more cost-effective means of travel. We also found temporary speed increases off southern California when vessels used longer routes to avoid traveling through an ECA. We conclude that the establishment of ECAs had a profound influence on vessel routes and speeds, likely due to the higher costs of clean fuels. Proposals have come before the International Maritime Organization (IMO) to establish clean fuel requirements in various locations around the world to reduce air-borne emissions from vessels. Our research suggests such proposals, or other events that may affect marine fuel prices, can have key impacts on vessel behavior. Consequently, it is important to consider this variability when designing strategies to minimize threats from shipping to vulnerable biophysical systems. Highlights • Maritime shipping is dynamic and poses threats to cetaceans and ecosystems. • Fuel regulations trigger vessel traffic changes (routing and speed changes). • Economic events and regulations at various scales influence vessel behavior. • Emission control areas and fuel prices can be important drivers of ecological risk. • Results show import of shipping variability in spatially explicit risk assessments. [ABSTRACT FROM AUTHOR]

Dynamic speed choice in real-life seaway and market conditions, when subject to technical and contractual constraints, is a highly complex problem. In this paper, we investigate dynamic speed choice using a large dataset of average sailing speeds for nearly 18,000 individual voyages as calculated from Automated Identification System (AIS) data. Using a set of multiple regression models, we expand the traditional analysis of speed determinants, from only macroeconomic variables to also include proxies for organizational constraints, operator quality, trading pattern, loading conditions, technical constraints and ship-specific variables. We find that owners do not appear to adjust vessel speeds based on freight market conditions and fuel prices, as argued in classical maritime economic theory. Instead, vessel-specific variables such as age and design speed, as well as operational factors such as loading conditions, show some explanatory power. The poor model fit may be due to factors outside our model, such as weather conditions and contractual limitations. From a policy point of view, the results actually suggest that higher fuel prices do not contribute to a reduction in vessel speeds and emissions. [ABSTRACT FROM AUTHOR]

We propose an analytical modeling methodology for quantifying the impact of slow steaming on the carrier’s voyage cost and on the shipper’s total landed logistics costs. The developed methodology can be employed by a carrier and a shipper in their contract negotiations, in order for the two parties to determine how they could divide between them the savings resulted from slow steaming. We demonstrate that the impact of slow steaming and speed adjustment policies on the shippers’ total landed logistics costs tend to increase as the vessel travels towards the end of its voyage. [ABSTRACT FROM AUTHOR]

We analyze the efficacy of using dockage-fee discounts as an incentive for oceangoing vessel operators to comply with the Vessel Speed Reduction programs of seaports, such as those implemented at the ports in Long Beach, Los Angeles, San Diego, New York and New Jersey. On the basis of unique data from the Port of Long Beach's program, we find that discounts are indeed effective, and that those effects vary considerably by operator type, suggesting a role for differentiated pricing strategies to better motivate compliance. We also develop a novel method for exploiting those data to estimate the value of time for vessel operators, with estimates ranging from US$268 to $759 per hour. Our findings are obtained from a discrete-choice model for panel data that estimates how the probability of compliance is influenced by potential dockage-fee savings and speed-reduction delays, and by the characteristics of operators and their vessels. That model also reveals the tradeoffs those operators make between time and money, from which we derive our value of time estimates. [ABSTRACT FROM AUTHOR]

Slow steaming, as one of the operational measures for curbing CO 2 emissions in the maritime transport industry, has already begun to be implemented, which is evident from ship operating profiles. While sailing, the ship encounters varying sea states which significantly affect ship fuel consumption and CO 2 emissions and consequently have an impact on the benefits that come from slow steaming. In this study, the benefits of slow steaming in realistic sailing conditions using the example of one Post Panamax Containership and on the four most common containership trading routes are investigated. The results demonstrate that the benefits of slow steaming significantly differ depending on the sailing route as well as on the location along the sailing route and on the month, highlighting the importance of accurate assessment of sea states along the sailing route. • The benefits of slow steaming are quantified for realistic sailing conditions. • The benefits are estimated for the four most common containership trading routes. • The location along the same route and month significantly affects the benefits. • The relationship between fuel consumption and ship speed is given. • The reduction in fuel consumption significantly differs with the sailing route. [ABSTRACT FROM AUTHOR]

To cope with the long term recession in the shipping industry due to oversupply of ships and high oil prices and due to reinforcement of environmental regulations to reduce greenhouse gas emission from ships, large container vessels built recently have ultra-long stroke engines with high propulsion efficiency. For these, de-rated engine and tuning technologies are used to reduce fuel oil consumption. However, previously built vessels were optimized for high ship speed. In these case, lowering ship speed to reduce ship operating cost does not provide similar benefits. Therefore, engine manufacturers have developed a turbocharger cut-out system to reduce fuel oil consumption at low speed. This has the advantage of reducing fuel consumption at low speeds, but also has the characteristic of producing higher torsional exciting force than is typical in existing engines for low load ranges. In this paper, the performance and dynamic characteristics of a marine diesel engine were reviewed after applying a turbocharger cut-out system. Then the effects on the engine body vibration and the torsional vibration were examined for a corresponding propulsion shafting system in a Panamax container-vessel equipped with a turbocharger cut-out system optimized for slow steaming. As a result, the torsional vibratory stress in shafts was increased. This had a larger effect on the X-mode shape of the engine body vibration and on the upper structure vibration, when one of three turbochargers was cut out. [ABSTRACT FROM AUTHOR]

Emissions of GHG from the transport sector and how to reduce them are major challenges for policy makers. The purpose of this paper is to analyse the level of greenhouse gas (GHG) emissions from ships while in port based on annual data from Port of Gothenburg, Port of Long Beach, Port of Osaka and Sydney Ports. Port call statistics including IMO number, ship name, berth number and time spent at berth for each ship call, were provided by each participating port. The IMO numbers were used to match each port call to ship specifications from the IHS database Sea-web. All data were analysed with a model developed by the IVL Swedish Environmental Research Institute for the purpose of quantifying GHG emissions (as CO 2 -equivalent) from ships in the port area. Emissions from five operational modes are summed in order to account for ship operations in the different traffic areas. The model estimates total GHG emissions of 150,000, 240,000, 97,000, and 95,000 tonnes CO 2 equivalents per year for Gothenburg, Long Beach, Osaka, and Sydney, respectively. Four important emission-reduction measures are discussed: reduced speed in fairway channels, on-shore power supply, reduced turnaround time at berth and alternative fuels. It is argued that the potential to reduce emissions in a port area depends on how often a ship revisits a port: there it in general is easier to implement measures for high-frequent liners. Ships that call 10 times or less contribute significantly to emissions in all ports. [ABSTRACT FROM AUTHOR]

Maritime inventory routing problem is addressed in this paper to satisfy the demand at different ports during the planning horizon. It explores the possibilities of integrating slow steaming policy as mentioned in Kontovas et al. (2011) and Norstad et al. (2011) within ship routing. A mixed integer non-linear programming model is presented considering various scheduling and routing constraints, loading/unloading constraints and vessel capacity constraints. Non-linear equation between fuel consumption and vessel speed has been incorporated to capture the sustainability aspects. Several time window constraints are inculcated in the mathematical model to enhance the service level at each port. Penalty costs are incurred if the ship arrives early before the starting of the time window or if it finishes its operation after the ending of the time window. Costs associated with the violation of time window helps in maintaining a proper port discipline. Now, owing to the inherent complexity of the aforementioned problem, an effective search heuristics named Particle Swarm Optimization for Composite Particle (PSO-CP) is employed. Particle Swarm Optimization – Differential Evolution (PSO-DE), Basic PSO and Genetic Algorithm (GA) are used to validate the result obtained from PSO-CP. Computational results provided for different problem instances shows the superiority of PSO-CP over the other algorithms in terms of the solution obtained. [ABSTRACT FROM AUTHOR]