Neural network-based fuel consumption estimation for container ships in Korea

ABSTRACT

Due to the outstanding strength of advanced machine-learning techniques, they have become increasingly common in predictive studies in recent years, particularly in predicting ship energy performance. In constructing predictive models, prior studies have mostly employed vessels’ technical parameters to establish machine-learning algorithms. To bridge this research gap and enable wider applications, this paper presents the design of a multilayer perceptron artificial neural network (MLP ANN) as a machine-learning technique to estimate ship fuel consumption. We utilized the real operational data from 100–143 container ships to estimate fuel consumption for five different container ships grouped by size. We compared the performance of two ANN models and two multiple-regression models. Four input parameters (sailing time, speed, cargo weight, and capacity) were included in the first ANN and the first regression model, while the other two models only consider two inputs from physical function. The mean absolute percentage error of the ANN models with four inputs was the smallest and less than those in extended statistical models, demonstrating the MLP’s superiority over the statistical model. The MLP ANN model can thus be applied to confirm the effectiveness of the slow-steaming method for achieving energy efficiency.     

基于ARM和μC/OS-II的船用柴油机最低油耗航速控制系统设计与实现

介绍一种船舶柴油机最低油耗航速控制系统.利用这套系统可以在不影响船舶航行安全和航运周期的前提下,通过实时检测的方式,控制主机运行于最低油耗航速,从而大大降低船舶航行时的主机燃油消耗.     

Optimal container ship size: a global cost minimization approach

ABSTRACT

Currently, the best container ship size in a service is determined mainly by the liner operator, considering only the economies of scale of ships. Its external diseconomies to the ports and shippers are usually not considered in the decision-making process, which may reduce the overall efficiency and lead to global nonoptimality. This study incorporates the cost to the shipping companies at the main lines, ports, and feeder services, as well as the external costs to shippers and ports in a hub-and-spoke network, and determines the best ship size and the number of weekly services to minimize the overall costs. The external cost to the shippers in the feeder ports is assumed to be proportional to the feeder cost, and a sensitivity analysis is provided. The maximum container ship size is estimated according to different levels of freight demand. A numerical analysis shows that the optimal size should be smaller than the current biggest container ships in service.     

集装箱船舶大型化对中国班轮运输的影响

通过竞争情报分析提供了各班轮公司未来船队结构和运力的变化趋势,由此观察到各班轮公司为了降低自身的营运成本,在最近几年大量订购超巴拿马型甚至更大型的集装箱船舶参与运输,但是却不能达到其预期的规模效应。原因就在于相当一部分成本随着船型的增大而线性增加,规模不经济。我们探讨了中国的班轮运输市场的几个重要特点:中外贸易的不平衡导致了货源的不平衡;未来贸易结构的调整会影响航线的布局和调派;贸易上的不稳定因素使班轮公司遇到外在的风险。这些特点会深远地影响集装箱船舶大型化的经济受益,相反的,集装箱船舶大型化的趋势也会加剧这些负面的影响,危及整个班轮运输市场。     

The impact of port operations on efficient ship operation from both economic and environmental perspectives

Recently, shipping lines have focused on efficient ship operation, which relates to energy efficiency issues in shipping and, particularly, to operational issues such that the minimisation of fuel consumption and resulting greenhouse gas emissions. Efficient ship operation in container lines is closely related to the ship’s time at sea and ship’s time in port. Reduction in port time, thanks to high-quality port operations, allows improvement in the operational efficiency of a liner service by reducing the fuel consumption of a ship at sea and its resulting CO₂ emissions. The main goal of this article is to investigate how time in port affects efficient ship operation in terms of operating costs, CO₂ emissions and externalities. For this, as a methodology, a simulation based upon system dynamics is introduced. Major finding is that less time in port resulting from the improvement of port operations contributes to efficient ship operation in terms of operating costs, amount of CO₂ emissions and external effects in the liner shipping industry. In particular, a sensitivity analysis on efficient ship operation vis-à-vis the quality of port operation shows that bigger ships need to select highly productive calling ports that provide less time in port.     

水流速度对内河船舶营运能效影响分析

本文在能源消耗和环境污染的危机下,致力于内河船舶能源消耗和温室气体排放的研究,分析了水流速度对内河船舶营运能效的影响。本分析是基于一艘客船的数据进行的,分别对不同航段下水流速度,主机转速,燃油消耗进行测量,并计算得到内河船舶营运能效。根据测量结果提出内河船舶营运能效提升策略,为内河航运业的节能减排提供帮助。     

大型船舶蒸汽系统热能计算分析

以大型万箱级集装箱船为研究对象，从船舶蒸汽系统设计的角度出发，结合船舶在降速及燃烧高粘度燃油航行状态下蒸汽耗量的分析，废气锅炉蒸汽产量分析，计算出主机废气排量及温度、锅炉产汽量及船舶设备的耗汽量，最终得出辅锅炉不启动运行前提下的船舶主机最低运行功率，以达到船舶最大节能降耗的效果，对航运企业船队综合节能增效策略最佳实践具有参考价值。     

基于智能控制的船舶辅机节能技术研究

随着船舶燃油价格上涨,船舶节能技术成为国际造船及航运行业的研究热点。文章介绍了一种基于智能控制的船舶辅机节能技术途径,阐述了智能控制的节能原理,提出了智能控制节能技术方案,通过实施变频调速、应用高效永磁电动机、根据全船平台信息进行自适应的辅机控制调节等技术来降低船舶辅机的能耗,达到船舶节能的目的。     

2010年世界船舶市场评述与展望

回顾了2010年世界船舶市场的发展,并对未来船舶市场进行了预测。随着世界经济的复苏,2010年航运市场出现反弹,虽然全年呈现震荡格局,但整体好于2009年,散货船、油船、集装箱船年平均运价均高于上年,特别是集装箱船年平均运价比上年高出一倍多。与此同时,三大船型建造市场出现轮动效应,上半年散货船引导造船市场,下半年行情有所下滑,油船订单则从第二季度开始增加,而沉寂许久的集装箱船建造市场在下半年也开始出现大量新订单。预计2011年的船舶市场将难以维持2010年的繁荣局面,但集装箱船建造市场和海工装备有望延续2010年下半年出现的良好市场行情。     

Hybrid Electric Drive for DDG-51 Class Destroyers

The first of the Arleigh Burke class destroyers is nearing its mid-life. This class of ships was designed during the late 1970s through the 1980s to meet the threats that were prevalent at that time. Since entering service in 1991, these ships have shown themselves to be extremely versatile and the class now consists of nearly 60 ships in service. Their combat systems have been continually upgraded and adapted to meet the new threats the United States faces today. However, in order to keep these platforms viable throughout the first half of the 21st century, their operating costs must be reduced. Manpower, maintenance, and fuel are three of the top operating cost drivers. Most surface combatants spend very little of their underway time operating at full speed or even close to that. Over 1/3 of their underway time is spent at 12 knots and under. This is less than half of their maximum speed and only a fraction of the maximum power owing to the cubic speed–power relationship. Although the existing mechanical drive system is reasonably efficient, the main gas turbines are extremely inefficient at these very low power levels. A shaft-mounted auxiliary electric propulsion system (EPS) can take advantage of excess capacity in the ship service generators to reduce the main engine operating hours. Enabling bi-directional power flow from this auxiliary electric drive will provide additional generation capacity for ship service loads at a modest additional cost. It also provides a "cross-connect" capability from one shaft to the other. This paper will explore one prospect for reducing the operating cost of the DDG-51 class of ships by installing an auxiliary EPS that would powered by the ship service electrical plant. This additional system would serve to reduce both underway fuel usage as well as maintenance on the gas turbine main engines by reducing the number of operating hours on each engine. We will examine the technology trade-offs in this ongoing study.     

Ship resistance when operating in floating ice floes: Derivation,validation, and application of an empirical equation

With the effects of global warming, the Arctic is presenting a new environment where numerous ice floes are floating on the open sea surface. Whilst this has improved Arctic shipping navigability in an unprecedented way, the interaction of such floes with ships is yet to be understood to aid the designing of ships and route planning for this region. To further explore this topic, the present work develops a procedure to derive an empirical equation that can predict the effects of such floes on ship resistance. Based on a validated computational approach, extensive data are extracted from simulations of three different ships with varying operational and environmental conditions. The ice-floe resistance is shown to strongly correlate with ship beam, ship buttock angle, ship waterline angle, ship speed, ice concentration, ice thickness and floe diameter, and the regression powers of each of the parameters on resistance are ascertained. This leads to a generic empirical equation that can swiftly predict ice-floe resistance for a given ship in a given condition. Subsequently, demonstrations are given on the incorporation of the derived equation into a set of real-time Arctic ship performance model and voyage planning tool, which can predict a ship's fuel consumption in ice-infested seas and dynamically suggest a route with the least safety concern and fuel consumption. Moreover, the equation is validated by providing ice resistance prediction for experimental and full-scale conditions from multiple sources, showing high accuracy. In conclusion, the empirical equation is shown to give valid and rapid estimates for ice-floe resistance, providing valuable insights into ship designs for the region, as well as facilitating practical applications for polar navigation.     

“The Geography of Maritime Transport–Space as a Perspective in Maritime Research and Development”

Emissions from commercial shipping are currently the subject of intense scrutiny. Among the top fuel-consuming categories of ships and hence air polluters are container vessels. The main reason is their high service speed. Lately, speed reduction has become a very popular operational measure to reduce fuel consumption and can obviously be used to curb emissions. This paper examines such an operational scenario. Since time at sea increases with slow steaming, there is a parallel and strong interest to investigate possible ways to decrease time in port. One way to do so is to reduce port service time. Another possible way to minimize disruption and maximize efficiency is the prompt berthing of vessels upon arrival. To that effect, a related berthing policy is investigated as a measure to reduce waiting time. The objective of reducing emissions along the maritime intermodal container chain is investigated vis-à-vis reduction in operational costs and other service attributes. Some illustrative examples are presented.     

Economic feasibility of an NSR/SCR-combined container service on the Asia-Europe lane: a new approach dynamically considering sea ice extent

The trend towards global warming and the rapid decline in the extent of summer Arctic sea ice over recent years has increased the feasibility of international Arctic shipping. In this study we propose a seasonal NSR (North Sea Route)/SCR (Suez Canal Route)-combined shipping service linking Shanghai and Rotterdam, using the Northern Sea Route during the economical navigable window but using the traditional Suez Canal Route at other times. Different from the previous literatures, this paper dynamically considers the sea ice extent in the model, which is more reasonable for the assessment of Arctic container shipping, because fuel consumption is highly related to ship speed, while ship speed is determined by the relative distances of ice-covered and ice-free route stages. A new approach is developed to predict the time points at which the ship enters and exits the ice-covered stage, given that both the ship position and the extent of sea ice are constantly changing. The results show that the NSR/SCR-combined Arctic container service can be more economical than the SCR, given lower NSR tariffs.     

江苏内河集装箱船标准船型设计分析

为提升江苏内河集装箱运输船舶标准化水平,实现船型与船闸、航道等通航基础设施发展相匹配,通过梳理内河标准船型主尺度标准和通航管理规定的修订情况,结合京杭运河江苏段集装箱营运船舶的调研,在船舶主尺度、舱室布置、船体结构和新能源动力的应用等方面分析江苏内河集装箱船标准船型的设计要点,完成48 TEU、64 TEU和96 TEU标准集装箱船设计。虽然受限于内河航运关注船舶成本的现状,标准集装箱船的设计更多采用传统基础船型设计思路,但研发运用先进技术、满足内河EEDI的绿色节能型船舶是标准船型的重要发展方向。     

Methodology for ro-ro ship and fleet sizing with application to short sea shipping

A novel methodology is developed for determining the characteristics of a cargo roll-on/roll-off (ro-ro) ship and the fleet size required for a given short sea shipping route. The ship and required fleet size to satisfy the transportation demand (for each pair of speed and freight rate) are determined using a database of existing cargo ro-ro ships to obtain the main technical characteristics of the most suitable ship. The time charter, voyage costs and revenue are then calculated considering the technical characteristics of each ship. Fuel costs are corrected for the actual ship speed and loading condition. A number of restrictions in the transportation problem are considered leading to the exclusion of unfeasible solutions. The maximum profit over the period of a year is identified among the feasible pairs of speed and freight rate. This general methodology is applied in a case study that considers the route between Leixões (Portugal) and Rotterdam (Netherlands). The study allows the identification of the most suitable ship and fleet sizes for different market penetration levels and quantifies the impact on shipping company profit of changes in parameters such as fuel costs, time charter costs, emission control area, installed propulsion power and stacking factor.     

Application of fuel-saving strategies onboard high-speed passenger ships

Strategies of fuel consumption onboard ships are of one of the crucial issues in marine shipping industry. Many of the relevant authorities maritime domain gave great interesting to that issue, either through research that discussed the impact of marine fuel consumption on the environment and economy of ships or through practical experiments’ that are made by marine engine manufacturers. Over the years, many solutions have been put forward to overcome this problem while maintaining the amount of goods transported globally at the same transfer rate and ship speed. The present paper sheds light on many of the methods used currently to reach this purpose. It is explained that applying a certain fuel-saving strategy will rely on some of the factors, especially the type of ship. Mainly two methods including: shore-side power and cold out of heat strategies have been investigated regarding adaption, economic, and environmental issues in case of applying onboard high-speed passenger ships.     

Energy efficiency optimization analysis of fuel cell/lithium battery hybrid ship based on whale optimization algorithm北大核心CSCD

[目的]为提升船舶的能源利用率,对多因素影响下的燃料电池/锂电池混合动力船舶能效优化方法进行分析。[方法]基于Matlab/Simulink仿真建模软件,建立对象船舶的能效仿真模型,研究通航环境要素对船舶能效的影响。考虑动力源特性和船舶功率需求,提出基于模糊逻辑的功率分配策略,以优化系统能量流动。然后在此基础上,以系统总能耗最低为优化目标,建立考虑多因素的船舶航速非线性优化模型,采用鲸鱼优化算法开展优化模型动态寻优,并进行不同航行方法和航行时间约束下的能效优化分析。[结果]结果显示,在总航行时间不变的情况下,采用所提的考虑多因素的船舶能效优化方法可以降低船舶5.04%的总能耗和13.16%的燃料电池氢气总消耗。[结论]所述方法对船舶节能减排具有积极的作用,同时对提高船舶续航力和经济性具有重要意义。     

舰载网络化监控系统

船舶监测、报警装置是现代船舶必不可少的设备之一，现代舰艇也采用了一些对主机系统的监控装置，随着电子信息技术和自动控制技术的不断发展，现代化船舶和舰艇的信息处理能力、作战系统网络化、控制自动化程度越来越高，舰艇指挥员需要扩大对舰艇各部分状态的感知。鉴于这种情况，建立基于现行全舰网络的舰载网络化监控系统是必须的。根据这一发展趋势对舰载网络化监控相关技术进行了研究。     

近海石油平台支援船主机油耗优化模型的建立

针对近海石油平台支援船进行研究,建立了近海石油平台支援船关于风、浪、潮汐的船舶数学运动模型并计算了目标船裸船体阻力和附体阻力；根据主机功率的传递过程以及船舶有效功率的估算方法,建立船舶主机油耗优化模型；之后运用基于遗传算法的多目标优化方法对主机油耗优化模型进行计算与验证,结果表明优化后的主机油耗模型具有良好的节能效果。     

Green shipping management capability and firm performance in the container shipping industry

This study empirically identifies crucial green shipping management capability and examines its impact on firm performance using survey data collected from container shipping firms, including shipping companies and agencies. Exploratory and confirmatory factor analysis is performed to identify three critical green shipping management capability dimensions, namely, greener policy, greener ships, and greener suppliers. In this study, firm performance is categorized into environmental performance and financial performance. The results indicate that a greener policy has a direct and positive influence on both the greener ships and the greener suppliers factors. Greener ships and greener suppliers are found to have an indirect and positive influence on financial performance through environmental performance. Accordingly, this study suggests that container shipping managers could focus on organizational green shipping management capability, specifically regarding policies, ships, and suppliers, to improve their environmental and financial performance. The theoretical and practical implications of the findings for container shipping firms have been discussed.