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Operating conditions in a naval facility are very different from those of industrial electric installations. The size of the compartments require that the electrical installations to have small sizes, low weight and to be reliable in operation. Reduced staff size, climatic and technical heavier conditions besides the fact that the naval facility becomes an isolated system, are leading to failure the troubleshoot of the major damages in electrical systems. For these reasons the electrical equipment needs to be achieved and built with first class constructive elements. [ABSTRACT FROM AUTHOR]

The use of inlet air fogging installation to boost the power for gas turbine engines is widely applied in the power generation sector. The application of fogging to mechanical drive is rarely considered in literature [1]. This paper will cover some considerations relating to its application for gas turbines in ship drive. There is an important evaporative cooling potential throughout the world, when the dynamic data is evaluated, based on an analysis of coincident wet and dry bulb information. This data will allow ships' gas turbine operators to make an assessment of the economics of evaporative fogging. The paper represents an introduction to the methodology and data analysis to derive the direct evaporative cooling potential to be used in marine gas turbine power output loss compensation. [ABSTRACT FROM AUTHOR]

The path planning of unmanned ships at the lowest energy consumption is of great significance for energy savings. At present, the path planning of unmanned ships based on the idea of energy savings is usually oriented toward a single navigation state, and there are few research projects on the path planning of ships that sail across multiple navigation states. The navigation states of submersible unmanned ships of path planning in this paper involves underwater navigation states with various diving depths and water's surface navigation state. The improved genetic algorithm is applied to carry out the path planning for a single navigation state and task-driven multi-navigation states of the submersible unmanned ship at energy-saving velocity and non-energy-saving velocity, respectively. The energy-saving velocities are obtained by establishing optimization models. The results show that, at energy-saving velocity, the energy consumption of the same type of navigation paths increase with the diving depth. There is an obvious velocity demarcation point at non-energy-saving velocity range, which makes the sequence of energy consumption of the three types of paths classed by navigation tasks reversed before and after that point. The research can provide technical support for path planning of cross-domain unmanned ships. • The path planning of submersible unmanned ship with multiple navigation states aims to explore the path energy consumption. • Establish a velocity optimization model for each working condition, and apply the optimised velocity to the energy-saving-velocity path planning part. • Comparing the energy consumption of a single navigation state and various task-driven cross-domain paths. • It is believed that the speed, diving depth and path length of various navigation states all have an impact on the path energy consumptio. [ABSTRACT FROM AUTHOR]

In light of the International Maritime Organization guidelines, the new Regulation of the European Union urges shipping companies to set up a system for monitoring, reporting and verification of CO2 emissions based on ship fuel consumption. However, in nowadays market, there is a lack of techniques for fuel consumption monitoring that can be adopted in a real environment. The proposed procedure overcomes the use of Speed-Power curves, which are commonly utilized in the Naval Architecture, by means of a multiple linear regression model that exploits the navigation information usually available in modern ships. This procedure can be used both to alert technical management of a shipping company for anomalous fuel consumption and to quantify the fuel consumption reduction connected with any specific policy adopted to improve energy efficiency. Therefore, this can be particularly profitable for shipping companies and operators in order to claim for carbon credits. The proposed approach is currently implemented by the Energy Saving Technical Department of the Grimaldi Group on a Ro-Ro Pax ship. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we study a comprehensive model that addresses fleet deployment, speed optimization, and cargo allocation jointly, so as to maximize total profits at the strategic level. Our model considers a general fuel consumption function that depends on speed and load. To overcome intractability caused by nonlinear terms, we further separate fuel cost into two terms associated with ship speed and load to obtain a mixed integer linear programming formulation for approximation. Based on column generation techniques, we develop an iterative search algorithm that adaptively reorganizes the approximated formulation. We conduct extensive experiments using generated data sets from actual liner shipping services in different regions of the world to show the effectiveness of our approach as well as the significant impact of speed-load factors on fuel consumptions. Managerial insights are obtained by testing the model under different scenarios, which may greatly assist decision makers in the liner shipping industry. [ABSTRACT FROM AUTHOR]

Shipboard integrated power systems, the key enablers of ship electrification, call for effective power management control (PMC) to achieve optimal and reliable operation in dynamic environments under hardware limitations and operational constraints. The design of PMC can be treated naturally in a model predictive control (MPC) framework, where a cost function is minimized over a prediction horizon subject to constraints. The real-time implementation of MPC-based PMC, however, is challenging due to computational complexity of the numerical optimization. In this paper, an MPC-based PMC for a shipboard power system is developed and its real-time implementation is investigated. To meet the requirements for real-time computation, an integrated perturbation analysis and sequential quadratic programming (IPA-SQP) algorithm is applied to solve a constrained MPC optimization problem. Several operational scenarios are considered to evaluate the performance of the proposed PMC solution. Simulations and experiments show that real-time optimization, constraint enforcement, and fast load following can be achieved with the IPA-SQP algorithm. Different performance attributes and their tradeoffs can be coordinated through proper tuning of the design parameters. [ABSTRACT FROM AUTHOR]

The concept of energy efficiency (or energy optimization) has become, today, one of the main concerns of humanity to the whole world. In recent decades, the maritime industry, has strived to optimize the fuel consumption of ships through the development of engines and propulsion systems, improved hull design, or using alternative energies, this way making a reduction in the amount of CO2 released to the atmosphere. Main ideea of this paper is to improve the energy performance of a crude oil super tanker ship of 305000 dwt, by studying the possibility of introducing alternative energy sources onboard. [ABSTRACT FROM AUTHOR]

Main ideea of this paper is not only the study of the Energy Efficiency Design Index for a crude oil super tanker ship, witch is a mandatory technical measure for the new ships, but also the study of Energy Efficiency Operational Indicator whitch is a voluntary mesurement for ships in service. [ABSTRACT FROM AUTHOR]

This paper presents the actual method for the calculation of Energy Efficiency Deign Index and analyses the influence of particular variables on the resulted EEDI. Perceived inconsistencies of the actual method of calculation of the attained EEDI are presented with explanation of the influence that the actual calculation has on the design of new ships. Objections are clearly demonstrated on the example of conceptual design of Handy Bulk Carrier. Alternative proposals for improvement of calculation of attained EEDI are introduced. Suggested alterations eliminate observed deficiencies of the existing calculation. [ABSTRACT FROM AUTHOR]

The need for green energy sources without or with low emissions in addition to improve the using efficiency of current fossil fuels in the marine field makes it important to replace or improve current fossil-fuelled engines. The replacement process should work on narrowing the gap between the most scientific innovative clean energy technologies and the concepts of feasibility and cost-effective solutions. Early expectations of very low emissions and relatively high efficiencies have been met in marine power plants using fuel cell. In this study, steam and SOFC based reforming options of natural gas for PEM fuel cells are proposed as an attractive option to limit the environmental impact of the marine sector. The benefits of these two different reforming options can be assessed using computer predictions incorporating chemical flow sheeting software. It is found that a high overall efficiency approaching 60% may be achieved using SOFC based reforming systems which are significantly better than a reformed PEM system or an SOFC only system. [ABSTRACT FROM AUTHOR]

The use of photovoltaic systems on board of ocean-going ships is a goal, which has to be achieved forthcoming years, as an option for decreasing the vessel's greenhouse gas emissions, by reducing the fossil fuels consumption. As per IMO (International Maritime Organization) 2014 Study, the international shipping emitted 796 million tons of carbon dioxide (CO2) in 2012, representing 2.2% of the global emissions of CO2. This paper is dealing with the technical specifications of the PV plants, in order to be compatible with the specific marine environmental conditions, as strong winds, high humidity, storms, salt, corrosion, shading and limited installation area. A brief description of the ship's basic electrical grid sketch and of its main components is presented and the PV systems and solar cells technologies are described, highlighting the advantages and the disadvantages of each for on board of oceangoing vessels implementation. [ABSTRACT FROM AUTHOR]

The shipping sector is today facing challenges which require a larger focus on energy efficiency and fuel consumption. In this article, a methodology for performing a feasibility analysis of the installation of a WHR (waste heat recovery) system on a vessel is described and applied to a case study vessel. The method proposes to calculate the amount of energy and exergy available for the WHR systems and to compare it with the propulsion and auxiliary power needs based on available data for ship operational profile. The expected exergy efficiency of the WHR system is used as an independent variable, thus allowing estimating the expected fuel savings when a detailed design of the WHR system is not yet available. The use of the proposed method can guide in the choice of the installation depending on the requirements of the owner in terms of payback time and capital investment. The results of the application of this method to the case study ship suggest that fuel savings of 5%–15% can realistically be expected, depending on the sources of waste heat used and on the expected efficiency of the WHR system. [ABSTRACT FROM AUTHOR]

The international regulations on fuel efficiency and NO x emissions of commercial ships motivate the investigation of new system layouts, which can comply with the regulations. In combustion engines, measures to reduce the fuel consumption often lead to increased NO x emissions and careful consideration of this trade-off mechanism is required in the design of marine propulsion systems. This study investigates five different configurations of two-stroke diesel-based machinery systems for large ships and their influence on the mentioned trade-off. Numerical models of a low-speed two-stroke diesel engine, turbochargers and an ORC (organic Rankine cycle), are used for the optimisation of the NO x and fuel consumption at design and part-load conditions, using a multi-objective genetic algorithm. Moreover, the effects of engine tuning and exhaust gas recirculation are investigated. The results suggest that increased system complexity can lead to lower fuel consumption and NO x . Fuel consumption reductions of up to 9% with a 6.5% NO x reduction were achieved using a hybrid turbocharger and organic Rankine cycle waste heat recovery system. [ABSTRACT FROM AUTHOR]

The energetic crisis within the context of maritime transport is to be approached with in the economic crisis that exists on a global scale. The oil crisis, triggered periodically, in the years 1973, 2000, 2008 and accentuated as the years go by, has led to spectacular increases in the prices of the crude oil fuels. The problems concerning energetic savings with in transportation have appeared immediately after the beginning of the energetic crisis. Starting with the year 1975, the freighters, the navigation companies and most of the states which own fleets have started a large program of studies and research in order to find the most efficient ways which should lead to energy savings on board ships, with preponderance on the grounds of the savings of crude oil fuels, and implicitly the reduction of the exploitation costs. [ABSTRACT FROM AUTHOR]

This scientific paper deals with management of all parties of maritime transport services with an emphasis on shipowner management for purposes of optimizing ship voyage costs by applying Virtual Arrival of the vessel to the port. Virtual Arrival is a process involving an agreement to reduce a vessel's speed during voyage due to berth occupancy at ship accommodation at the discharge port. The reduction in speed during voyage will result in reduced fuel consumption, which directly affects shipowner management, namely voyage costs. The proposed algorithm of Virtual Arrival defines interdependence of the parties of the maritime transport process as well as the actions undertaken in the following procedure of the arrival. The algorithm results show the possibility of creating a mutual financial benefit and display profitability of shipowner management and other parties of the Mutual Agreement. Furthermore, the paper analyzes Mutual Effects of the Virtual Arrival to all other represented parties of the maritime transport process. [ABSTRACT FROM AUTHOR]

According to a range of assessments, there exists a large cost-effective potential to increase energy efficiency in shipping through reduced speed at sea enabled by shorter time in port. This means that the energy needed can be reduced whilst maintaining the same transport service. However, the fact that a large cost-effective potential has been identified that is not being harnessed by decision-makers in practice suggests that there is more to this potential to understand. In this paper, the possibilities for increasing energy efficiency by reducing waiting time in port are explored and problematised through a case study of a short sea bulk shipping company transporting dry bulk goods mainly in the North and Baltic seas. Operational data from two ships in the company’s fleet for one year showed that the ships spent more than 40% of their time in ports and that half of the time in port was not productive. The two most important reasons for the large share of unproductive time were that ports were closed on nights and weekends and that ships arrived too early before the stevedores were ready to load or unload the cargo. Reducing all of the unproductive time may be difficult, but the results also show that even a conservative estimate of one to four hours of reduced time per port call would lead to a reduction in energy use of 2–8%. From in-depth interviews with employees of the shipping company, ports and ship agencies, a complex picture is painted when attempting to understand how this potential arises. Aspects such as a lack of effective ship-shore-port communication, little time for ship operators, an absence of means for accurately predicting energy use of voyages as a function of speed, perceived risk of arriving too late, and relationships with third-party technical management may all play a role. [ABSTRACT FROM AUTHOR]

A solid oxide fuel cell (SOFC) and micro gas turbine (MGT) hybrid power system is a newly developed and promising power technology for ship power systems. Compared to conventional power plants on commercial ship, the technology can achieve a high efficiency (up to 80 %) and very low emission (up to zero) []. However, working as a marine power provider onboard ship, the control strategy of the hybrid system is one of the key challenges due to the requirement of balance between power generation from the SOFC's chemical reaction and the MGT's rotation mechanical power generation. In this paper, based on a system model, the control strategy for the hybrid power systems is presented. To get the maximum efficiency, the control of key parameters of the SOFC, such as stack temperature, fuel flow rate, fuel utilization and related power have been investigated and the control of power sharing between the two power sources of SOFC and MGT is proposed. The simulation results demonstrate that the control system can effectively control the SOFC and MGT subsystem and make them undertake their appropriate load separately with the forthcoming load. [ABSTRACT FROM AUTHOR]

Shore power (SP) and emission control area (ECA) have been two of the main polices for a green maritime logistics. However, it is still not clear how the joint impact of these two polices will influence vessels' shipping and energy consumption plan. The influence could be more complicated at the post-pandemic era of COVID-19 when the vessel's refueling could be risky. This paper develops mathematical model of the vessel's routing and fuel inventory decisions by considering both the SP and ECA. Based on the model, we analyze the optimal decision of a vessel under three different policy conditions, which are non-SP, compulsive utilization of SP at all ports, and optional SP utilization by the vessel. The numerical experiments are conducted based on the information of a vessel delivering cargos along the coastline in China. The results uncover a novel phenomenon that the implementation of the SP might incentive the vessel to travel longer distance outside the ECA for a lower total cost that results in more pollutant emissions. We show that the SP policy would influence the vessel's fuel management and refueling times which can change the route of vessel sailing inside and outside ECAs. Sensitivity analysis also shed light on how the government's decision on the SP policy may influence the overall pollutant emissions of the vessel from both berthing at ports and sailing on the sea. We discussed how the fixed cost of refueling, which is affected by the risk of the COVID-19 condition, will influence the vessel's plan under the SP and ECA polices. This study suggests the government to make an integrated policy of both SP and ECA at the post-pandemic era to achieve an overall reduction of the pollutant emission. [ABSTRACT FROM AUTHOR]

A dynamic positioning (DP) system on a diesel-electric ship applies electric power to keep the positioning and heading of the ship subject to dynamic disturbances due to the winds, waves and other external forces using electric thrusters. Vice versa, position and heading errors can be allowed in order to implement energy storage in the kinetic and potential energy of the ship motion using the DP control system to convert between mechanical and electrical power. New simple formulas are derived in order to relate the dynamic energy storage capacity to the maximum allowed ship position deviation, as a function of the frequency of the requested dynamic energy storage. The benefits of DP dynamic energy storage are found to be reduced diesel-generator maintenance need, reduced fuel consumption and emissions, reduced risk for blackout, and increased operational flexibility allowing power-consuming operations such as drilling and lifting to be safely prioritized over DP for short periods of time. [ABSTRACT FROM AUTHOR]

This paper presents the first analysis on how financial savings arising from energy efficient ships are allocated between owners and those hiring the ships. This as an important undertaking as allocation of financial savings is expected to have an impact on the incentives faced by ship owners to invest in more energy efficient vessels. We focus on the dry bulk Panamax segment as it contributes to around 50Mt (5%) of total CO2 emissions from shipping in 2007 and therefore its importance in terms of environmental impact should not be neglected. The time charter market represents a classical example of the principal-agent problem similar to the tenant-landlord problem in the buildings sector. We discovered that on average only 40% of the financial savings delivered by energy efficiency accrue to ship owner for the period 2008-2012. The finding that only part of the savings are recouped by shipowners affecting their incentives towards energy efficiency could consequently have implications on the type of emission reduction policies opted at both, global and regional levels. [ABSTRACT FROM AUTHOR]

The closed-loop thermosyphon (CLT) has advantages of simple structure and reliability for transporting heat in long distances with small decrease in temperature. It is considered a promising cooling device for power electronics onboard ships. In this research, CLT for cooling of power electronics onboard ship was developed, and the performance was experimentally examined using a CLT apparatus. The performance was investigated for steady-state heat transfer under a wide range of pressures and heat loads from 18.3 kPa to 35.3 kPa and from 88.9 W to 616.2 W, respectively. The fill charge rates were 27% and 45%. The circulation coolant temperature at the condenser was set to 15°C. The measured data for each rated heat input were registered by a data logger in every 5-s increment of sampling data for a 30-min period. During the steady-state operation, CLT could maintain the system pressure and produced the vapor bulk temperature at around saturation boiling regime. The temperature distributions of the system were measured from each probed thermocouple along the loop. It is understood that higher heat inputs around above 349 W could keep the bulk vapor in an almost constant temperature from evaporation process up to the inlet position of the condenser. The condenser of the direct hull cooling method could also maintain the condensation process with a temperature decrease of around 30°C from the inlet vapor temperature of the condenser. It was clarified that the CLT has good thermal performance in the higher heat loads with low thermal resistance and provides a steady circulation loop from each two-phase process of heating in the evaporator and cooling during condensation. [ABSTRACT FROM AUTHOR]

Abstract: Increased energy efficiency will be paramount in mitigating CO2 emissions from shipping. Paradoxically, previous research has shown that a substantial amount of measures that typically increase energy efficiency, should be cost-efficient to implement. This is often explained in literature in terms of barriers in markets, institutions and organizations. This article is the first of a series of articles from a joint industry project aiming at understanding good energy management practices in shipping companies. It explores barriers to energy efficiency in shipping through a case study of a short sea shipping company in their process to implement an energy management system. An action research design was chosen to contribute to better practice as well as knowledge in the research community. The study shows that work with energy efficiency was not straightforward, and several challenge areas could be discerned: project management capabilities, ship-shore communication, division of responsibilities, access to performance measurements, and competence in energy efficiency. It is proposed that interpretative research methodologies such as action research could contribute to new perspectives on the traditional barrier discourse. [Copyright &y& Elsevier]

The extensive electrification of ship power systems has become a very appealing option for the development of more efficient and environmentally friendly ships. Optimal power management and energy storage systems will have a key role in such systems as they can lead to fuel consumption reduction and increase overall ship efficiency. However, technical difficulties arising from the inherent complexity of such systems should be overcome. In this paper, the optimal operation of a ship electric power system comprising full electric propulsion and energy storage system is analyzed. An optimal power management method is proposed so that the operation cost is minimized, greenhouse gas emissions are limited and, at the same time, the associated technical and operational constraints are not violated. [ABSTRACT FROM PUBLISHER]

Wing-diesel engine-powered hybrid ships can effectively reduce fuel consumption and CO 2 emissions by using wind energy as the auxiliary driving power. The energy optimization management of the hybrid system can further improve the ship's energy efficiency. To achieve this purpose, it is significant to establish an effective energy consumption model for the energy optimization management of the hybrid system. Therefore, an energy consumption model is established based on the energy conversion analysis of the hybrid power system in this paper. This model can effectively describe the energy consumption of the hybrid ship under different navigational environmental conditions. Then, a joint optimization method of the wing attack angle and of the sailing speed for the hybrid ship is proposed by adopting a swarm intelligence optimization algorithm, in order to reduce energy consumption and CO 2 emissions of the hybrid ship under different navigational environmental conditions. Finally, the energy consumption optimization potentials by adopting the hybrid power system and the proposed joint optimization method are analyzed. The results show that the energy consumption and CO 2 emissions along a typical route can be reduced by about 4.5%. This study provides an important basis for future practical operations of wing-diesel engine-powered hybrid ships. • An energy consumption model of wing-diesel engine-powered hybrid ships is established. • The wind energy resources analysis and the sailing route division are achieved. • A joint optimization method of energy consumption for wing-diesel engine-powered hybrid ships is proposed. • The proposed method can reduce ship energy consumption and CO 2 emission by about 4.5%. [ABSTRACT FROM AUTHOR]

This paper proposes an efficient, objective method of optimizing fuel costs during the sea passage. The presented method based on data collection and calculations can be used in daily practice for masters of vessels and by ship's management divisions. The paper presents not only the use of the method for newly constructed but also for ships already in service. The biggest advantage of this method is that it does not need extra expenses to determine the fuel effectiveness in a changeable marine fuel market. [ABSTRACT FROM AUTHOR]

The International Maritime Organization (IMO) is developing the Energy Efficiency Design Index (EEDI) for new ships, which is a gauge of a ship's CO2 design efficiency. By evaluating the baselines for tankers, LNG carriers, and containerships utilizing the "standard" ships, this study provides the attained EEDI that can be achieved with well-designed newbuildings prior to application of innovative technologies. As such, they serve as an effective metric for validating the proposed EEDI baselines. This paper summaries the findings from this study, which were submitted to SNAME T&R Ad Hoc Panel 18 tasked with investigating the EEDI. This paper, originally presented at SNAME 's symposium on "Climate Change and Ships " in February, 2010, was revised in June of 2011 to reflect changes to the EEDI methodology contained in MEPC 61/5/3 and the baseline calculations contained in MEPC 62/6/4. [ABSTRACT FROM AUTHOR]

Ship efficiency has become an increasingly important subject for ship designers and owners. Both the predicted high cost of fuel in the future and the need to reduce emissions are driving this drive for improved efficiency. The IMO is also seeking measures to reduce the CO2 emissions from ships, and their proposed Energy Efficiency Design Index (EEDI) aims at ensuring that future vessels will be more efficient. Two ship concepts, a large RoRo vessel and a Cruise ferry, have been developed to highlight different technologies that can be used to improve efficiency. The designs show that the power demand can be reduced significantly with existing basic naval architecture methods. Optimization of main dimensions for life cycle cost, rather than building cost alone, can deliver large savings. Also, new propulsion concepts, such as triple shaft lines or Wing thrusters, yield clear propulsion power savings. Other measures to reduce fuel consumption, such as waste heat recovery and wind power, also show large gains. [ABSTRACT FROM AUTHOR]

A generic computer model for systematic investigations of container ship designs is described in this paper. The primary statistical data on container ships used for the model development are also presented. The model can be used to calculate exhaust gas emissions from container ships, including emissions of carbon dioxide (C02>. A calculation procedure to estimate the newly designated Energy Efficiency Design Index (EEDI), which is under development at the International Maritime Organisation (IMO), is included in the model. Different ship design parameters have been varied to see the influence of these parameters on the EEDI. It is found possible to reduce EEDI by roughly 20 % without reducing ship speed, but only by changing some of the design parameters, such as reducing the sea margin by using a derated main engine, increasing the length of the ship by 5 %, and reducing steel weight by 3% via steel weight optimization. [ABSTRACT FROM AUTHOR]

The article presents an overview of a report submitted to the International Maritime Organization (IMO) on marginal abatements costs and cost effectiveness of energy-efficiency measures on ships. The primary objectives of the report are noted, along with an explanation on the approach in the analysis of estimates of carbon dioxide emissions reduction potential and associated marginal abatement costs. Key findings and methodology of the report are given.

Zheng, Z.-H., and Zhou, X.-H., 2019. Design and simulation of ship energy efficiency management system based on data analysis. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 552–556. Coconut Creek (Florida), ISSN 0749-0208. Using the systematic method of modern ship energy efficiency management, strict control and management of ship energy consumption, energy utilization and carbon dioxide emissions will be of great significance for achieving energy conservation and emission reduction of ships and promoting the green development of shipping. On the basis of summarizing the previous research results, this paper designs a ship energy efficiency management model based on data analysis through a large number of current industry data collection, manufacturing and operation data collection, collation and analysis. The model system can monitor and collect various dynamic and static parameters in real time, and calculate the ship energy efficiency design index (EEDI) and the ship energy efficiency operation index (EEOI). Combined with the ship's own and its energy consumption information, such as range, cargo capacity, speed, host power, the system can dynamically analyze the entire production and operation process of the ship. The final simulation experiment shows the feasibility and effectiveness of this model. [ABSTRACT FROM AUTHOR]

The International Maritime Organization adopted a strategy to reduce the total annual GHG emissions from international shipping by at least 50% by 2050, compared to 2008 levels. The European Union proposed an even farther reaching transformation: the European Commission adopted a set of proposals to make the EU's transport policies fit for reducing net greenhouse gas emissions by at least 55% by 2030, compared to 1990 levels. Therefore, all industrial actions in line and consistent with these strategies are essential. One of such activities may be a gradual transition from the most common independent controls of transport ships' thrusters, propellers, and rudders to an integrated, power optimized, 3 degrees of freedom joystick control. In this paper, the full mission bridge simulator (FMBS) research on potential energy savings and, consequently, a GHG emission reduction, while steering a RoPax twin-screw ferry equipped with bow thrusters by a joystick control, is presented. The task of navigators engaged in the research was to steer the vessel either via classic engine, rudder, and thruster levers or via a joystick while (1) following the predefined straight track, (2) rotating at the turning area, and (3), finally, crabbing (moving sideways) until stopping at the quay fenders. The conclusions are that energy savings of approximately 10% can be expected for berthing manoeuvres controlled by a joystick, compared to independent actuators' controls. These conclusions have been drawn from a statistical analysis of the ship's energy consumption during typical manoeuvring phases of 18 berthing operations performed in FMBS. [ABSTRACT FROM AUTHOR]

• The spatial and temporal distribution characteristics of ship energy consumption are analyzed. • A dynamic collaborative optimization model incorporating speed and route is established. • A novel MPC-based dynamic collaborative optimization algorithm is proposed. • The novel dynamic collaborative method can reduce ship energy consumption. It is of significant importance to optimize the energy consumption of ships in order to improve economy and reduce CO 2 emissions. However, the energy use of ships is affected by a series of navigational environmental parameters, which have certain spatial and temporal differences and variability. Therefore, the dynamic collaborative optimization method of sailing route and speed, which fully considers the spatial and temporal distribution characteristics of those factors, is of great importance. In this paper, the spatial and temporal distribution characteristics of the environmental factors and their related ship energy consumption profiles are first analyzed. Subsequently, a ship energy consumption model considering various environmental factors is established to realize the prediction of energy use of ships within the navigation region. Then, a novel dynamic collaborative optimization algorithm, which adopts the Model Predictive Control (MPC) strategy and swarm intelligence algorithm, is proposed, to further improve the ship's energy consumption optimization. Finally, a case study is conducted to demonstrate the effectiveness of the proposed method. The results show that the newly developed dynamic collaborative optimization method, which fully considers the continuously time-varying characteristics of environmental and operational parameters, could effectively reduce the energy consumption in comparison to the original operational mode. In addition, the adoption of the MPC strategy produces better performance results compared to the optimization method without the MPC strategy. [ABSTRACT FROM AUTHOR]

Utilization of coral aggregates (CAs) for concrete production can effectively resolve the shortage of raw materials for construction in remote islands and reduce the energy consumption due to the shipping from the mainland. However, the porous nature of CAs and contained salt will affect the mechanical and durability performance of the concrete. This study aims to first summarize the characteristics of CAs and properties of coral aggregate concrete (CAC) and then propose future research needs based on the identified knowledge gaps. The previous studies indicate that the utilization of CAs in concrete can lead to significant strength loss and the elastic modulus of CAC is generally lower than that of ordinary concrete (OC). The workability of concrete at the fresh stage can also be reduced by the added porous CAs. To resolve these issues, the pre-treatment protocols were proposed to enhance the performance of CAC, including acid washing, surface coating, and utilization of alternative cementitious materials. However, the influence of CAs on the durability performance of concrete has not been fully understood, including drying shrinkage and carbonation resistance. The corrosion issue is also a serious threat to the durability performance of reinforced CAC. It is expected that using the non-corrosive fiber-reinforced polymer (FRP) bars can effectively resolve the corrosion issues, but the related investigations are quite limited. The research needs on the durability performance of CAC and the evaluation of FRP bars reinforced CAC are then proposed for further investigation. This study can serve as a solid base for future investigation on CAC and promote its application in ocean engineering. • The effects of coral aggregates on the properties of concrete are discussed. • Many effective measures to improve the performance of coral aggregate concrete are summarized. • The combination of fiber reinforced polymer bars and coral aggregate concrete is attractive. [ABSTRACT FROM AUTHOR]

In order to reduce fuel consumption and reduce the deviation between the final battery state-of-charge (SOC) value and the target value at the same time, a novel double-layer multi-objective optimization method is proposed, which adopts an improved ant colony optimization (ACO) algorithm and the equivalent fuel consumption minimization strategy (ECMS) considering mode switching. The proposed strategy adopts a two-layer structure. In the inner layer, the ECMS considering mode switching was adopted to optimize the working mode and working point, so as to achieve the goal of reducing fuel consumption. In the outer layer, aiming at the shortcomings of traditional ACO, the heuristic factor and adaptive volatilization factor were introduced. An improved ACO method was proposed to optimize the equivalent factor, so as to achieve the goal of reducing the deviation between the final value of SOC and the target value. In order to verify the effectiveness of the proposed algorithm, it is compared with the traditional ECMS strategy and the rule-based (RB) ECMS strategy. The simulation results show that the proposed energy management strategy combining an improved ACO algorithm with ECMS considering mode switching can reduce the energy consumption of the whole ship and control the battery power. [ABSTRACT FROM AUTHOR]

Navigation challenge corresponding development strategies to overcome the collection and application of the shipbuilding industry due to the control of various data-based energy efficiency measures. Ship performance data collection and navigation of ships navigate this energy efficiency strategy, an integral part of the management plan. The provisions of various navigation strategies in CNNs (Convolutional Neural Network) are believed to play an important role in ship performance in modern integrated bridge systems. Therefore, it realizes a large amount of onboard data to process the process. In general, navigation systems can provide guidance for the transmission in exercise, and provide effective guidance for the navigation information and direction of the ship. It can provide effective information and convenience for the exercise of the ship during the voyage of the ship. This paper mainly studies the methods and ways to provide some solutions through big data. The author suggests using the data flow chart recorded for the ship engine. This can easily monitor the main performance and some data of the ship during navigation, thus improving the guiding effect of navigation. Database image recognition is to monitor possible accidents through sensors, and classify and compress the monitored data. The classified ship dataset is then compressed to reduce the number of parameters passed to the coastal data center. A compressed dataset of ship performance and navigation information is expanded to its original size in the first step of the process. The two steps of data compression and expansion are done with another CNN technology (i.e., deep learning) of the autoencoder. The new dataset contains estimated ship performance parameters and navigation information, even if the compressed dataset has been expanded to its original size. Therefore, comparisons between actual and presumed datasets are made to change. [ABSTRACT FROM AUTHOR]

Energy saving and emission reduction have attracted a great deal of attention in the maritime industry. The optimization of a ship's energy efficiency can reduce energy consumption and CO 2 emissions effectively. However, most of the available studies only focus on either the sailing speed or route optimization, and the interaction between speed and route under the influence of multiple environmental factors was not accounted properly. In this paper, a novel joint optimization method of the sailing route and speed, which considers the interaction between route and speed as well as multiple environmental factors, is proposed to fully exploit the energy efficiency's potential. Moreover, a joint optimization model of the sailing route and speed, which is based on an energy consumption model that considers multiple environmental factors, is established. Next, a solution algorithm for the joint optimization model is investigated in order to achieve joint decision-making with regard to the sailing route and speed. Finally, a case study is conducted that demonstrates the effectiveness of the proposed method. The results show that the proposed method can achieve the optimal sailing route and speed under complex environmental conditions, as well as a reduction in fuel consumption and CO 2 emissions of about 4%. A novel joint optimization method of the sailing route and speed, which considers the interaction between route and speed as well as multiple environmental factors, is proposed to fully exploit the energy efficiency's potential. Firstly, the energy efficiency data of a ship and the meteorological information are obtained. Subsequently, a joint optimization model of the sailing route and speed, which is based on an energy consumption model that considers multiple environmental factors, is established, through the analysis of the navigational environment data and the energy efficiency data of the ship. Finally, a novel joint optimization method of the sailing route and speed that considers the multiple environmental factors is proposed. The proposed optimization method can jointly determine the optimal sailing route and speed under various navigational environmental conditions. A case study is carried out to demonstrate the validity of this optimization method. Our results show that the proposed method can achieve the optimal sailing route and speed under complex environmental conditions, as well as a reduction in fuel consumption and CO 2 emissions of about 4%. Image 1 • A joint optimization model of the sailing route and speed is established. • A solution algorithm for the joint optimization model based on the PSO is investigated. • A novel joint optimization method of the sailing speed and route is proposed. • The proposed method can reduce ship energy consumption and CO 2 emissions by 4%. [ABSTRACT FROM AUTHOR]

All-electric ships, and especially the hybrid ones with diesel generators and batteries, have attracted the attention of maritime industry in the last years due to their less emission and higher efficiency. The variant emission policies in different sailing areas and the impact of physical and environmental phenomena on ships energy consumption are two interesting and serious concepts in the maritime issues. In this paper, an efficient energy management strategy is proposed for a hybrid vessel that can effectively consider the emission policies and apply the impacts of ship resistant, wind direction and sea state on the ships propulsion. In addition, the possibility and impact of charging and discharging the carried electrical vehicles' batteries by the ship is investigated. All mentioned matters are mathematically formulated and a general model of the system is extracted. The resulted model and real data are utilized for the proposed energy management strategy. A genetic algorithm is used in MATLAB software to obtain the optimal solution for a specific trip of the ship. Simulation results confirm the effectiveness of the proposed energy management method in economical and reliable operation of the ship considering the different emission control policies and weather condition impacts. [ABSTRACT FROM AUTHOR]

Two main contributions of this paper are 1) the energy consumption of ships (ECS) in port is predicted, 2) reduction strategies for energy consumption of ships in port are discussed by the proposed prediction models considering green port. Firstly, 15 characteristics which have impact on the energy consumption of ships are collected by Jingtang Port in China and analysis is conducted. Then, five machine learning models including Gradient Boosting Regression (GBR), Random Forest Regression (RF), BP Network (BP), Liner Regression (LR) and K-Nearest Neighbor Regression (KNN) are developed and 15 features consisting of inherent property of ship and external features of ports are set as inputs. After then, k-folds cross validation is adopted to verify the effectiveness of models. Finally, the feature importance is calculated and the most important features are selected. Besides, experiments are conducted to find the effect of changing several features on energy consumption of ships, and two consumption reduction strategies are discussed. The results show that net tonnage, deadweight tonnage, actual weight and efficiency of facilities are the top 4 features for predicting the energy consumption of ships. In conclusion, when efficiency of facilities is doubled, the energy consumption of ships is reduced by 34.17% at berth and 8.41% in port. The finding of proposed methods and discussed strategies can give references to green port construction. [ABSTRACT FROM AUTHOR]

The optimization of ship energy consumption is attracting a great deal of attention, as societies seek to save energy and reduce emissions. Shipping companies are more concerned with the energy consumption of a ship fleet, as opposed to that of a single ship. Because the energy consumption of a fleet is influenced by multiple factors including environmental factors, port operations and transport demands, an improvement in a single ship's energy consumption does not necessarily mean that the overall energy consumption of a fleet is good. In addition, those factors are usually varying over time, making it hard to optimize the fleet's energy consumption by methods that do not consider these time-varying factors. Therefore, a bi-level distributed dynamic optimization method based on distributed model predictive control is proposed. Moreover, an upper-level optimization model for fleet operational decision-making and a lower-level dynamic optimization model of fleet energy consumption are established. Based on these, a control algorithm for the dynamic optimization of fleet energy consumption is developed. Finally, a case study is carried out to demonstrate the effectiveness of the method. It can further reduce the energy consumption of each ship by at least 1.1% and about 6.8% for the whole fleet. A bi-level distributed dynamic optimization method adopting distributed model predictive control (DMPC) strategy is proposed to optimize fleet energy efficiency. It mainly includes an upper-level optimization model for the fleet operational decision-making, and a lower-level dynamic optimization model for the fleet energy consumption considering multiple time-varying influencing factors. Based on these, a control algorithm for the dynamic optimization of fleet energy efficiency (DOFEE) is developed. A case study is carried out to demonstrate the validity of this optimization method. Our results show that this method can reduce energy consumption of ship fleets effectively.The bi-level distributed dynamic optimization for the fleet energy consumption. Image 1 • A fleet energy efficiency model considering multiple influencing factors is established. • A bi-level distributed dynamic optimization method adopting DMPC strategy is proposed. • A control algorithm for the dynamic optimization of fleet energy efficiency is developed. • The proposed method can reduce fleet energy consumption and CO 2 emissions by about 6.8%. [ABSTRACT FROM AUTHOR]

A large number of mitigation strategies including both technical and operational measures have been proposed to reduce ship energy consumption and hence carbon emissions. Under cost and other practical constraints, when prioritizing among mitigation measures, different data sources such as observed data from physical systems and simulated data from simulation models may be used. Data obtained from different sources have different characteristics in terms of accuracy and data volume. Therefore, it is important to integrate different data sources when evaluating alternative mitigation measures in a systematic and systemic manner. In response, a Gaussian process metamodel based method is proposed to evaluate energy saving measures when different data sources are combined synergistically. In addition, a cost-effectiveness analysis is used to prioritize the mitigation strategies based on cost considerations. A case study is developed to demonstrate the advantages of the proposed method in terms of accuracy and efficiency. All mitigation measures selected in the case study are found to have a negative cost which can translate to both energy and cost savings. Among the evaluated measures, speed reduction has shown to be the most plausible measure in terms of energy savings and marginal cost-effectiveness. • A robust and efficient Gaussian process metamodel is developed in this study. • The method can simultaneously handle data from multiple sources. • Cost-effectiveness criteria are applied to evaluate ship energy saving measures. • The method can help prioritize mitigation strategies from a system perspective. [ABSTRACT FROM AUTHOR]

The papers in this special section focus on energy conversion in next generation electric ships. These papers bring together papers focused on the recent advancements in energy conversion techniques used in electric ship technologies. [ABSTRACT FROM PUBLISHER]

Interest in hybrid propulsion systems that can be used on small vessels has increased significantly in recent years. They can replace inefficient and environmentally burdensome conventional systems based on diesel engines. Hybrid propulsion has many advantages such as high energy efficiency and virtually noiseless operation, and therefore it fits well with the current trends of "green shipping" and "zero emission". The aim of the research conducted was to examine and analyse the varied energy demand of a small inland ferry with electric propulsion depending on the navigation strategy. The work included tests carried out on a model of the vessel. Conventional resistance tests involving towing the model at a constant speed proved to be of no use for the unit, which, during a short voyage, moves with variable speeds and manoeuvres. Therefore, atypical and unique tests were performed to determine the energy consumption during the acceleration of the unit and the parameters of navigation with the propulsion turned off. The work resulted in calculated forecasts of energy consumption by the ship depending on the adopted cruising style and a proposal of the most energy-efficient way to cross the shipping route connecting the two banks of the Motława River in the city of Gdańsk. [ABSTRACT FROM AUTHOR]

Energy management strategy is a key technology of hybrid power ships. In recent years, renewable energy ship technologies have become a popular research field and one promising development direction to realize reasonable utilization of energy resource, as well as energy conservation and emission reduction. Among these technologies, the solar energy hybrid ship technology is currently attracting attention all over the word. In this paper, a 5000-car space solar energy hybrid ship is used as the research objective, and an energy management strategy that is based on fuzzy logic is proposed to distribute the ship power generation, solar energy, and battery output power according to the ship's electrical load demand, and the fuzzification and stochasticity of solar energy. By comparing the simulation results with real ship testing results, it is identified that the proposed fuzzy logic energy management strategy can optimize the operation conditions of individual power generation sources, improve the overall performance of power system, and reduce the ship's overall fuel consumption. [ABSTRACT FROM AUTHOR]

In this paper, a hybrid ship powered by diesel generator sets and power batteries in series is considered. By analyzing the characteristics of hybrid ship cycle operating conditions, the load power of the hybrid ship under load uncertainty is firstly predicted. Then, considering the economy, emissions and continuous navigation time (endurance) of the hybrid ship, an energy optimization strategy based on the predicted load power is proposed to achieve the goal of minimum fuel consumption, minimum emissions and maximum endurance of ship operation. The experimental results show that, compared with the fuzzy logic rules based strategy, the fuel economy of the ship is increased by 9.6% and the ship’s endurance is increased by 24% for the proposed strategy. [ABSTRACT FROM AUTHOR]