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Transitioning to electrification: Optimal strategies for ship fleet replacement

TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES 2025年 174卷

作者： Cui, Ziyu Fu, Xiaowen Jin, Huan Chen, Anthony Wang, Kun Hong Kong Polytech Univ Dept Ind & Syst Engn Kowloon Hong Kong Peoples R China Univ Nottingham Dept Comp Sci Ningbo Peoples R China Hong Kong Polytech Univ Dept Civil & Environm Engn Kowloon Hong Kong Peoples R China

To reduce carbon emissions, some shipping companies are strategically transitioning their fleets from diesel-powered ships to electric ones. However, the question of how to cost-effectively design this fleet conversion and the construction of charging stations for electric ships remains a critical issue. In this paper, we present a Mixed-Integer Nonlinear Programming (MINLP) model to minimize the total cost of designing the ship fleet replacement plan within a given planning horizon. At the planning level, the yearly strategic transition schedules for purchasing and salvaging ships are obtained, while the optimal strategy for charging station construction is also determined to satisfy annual cargo demand and charging demand. Then, our model integrates the operational level to determine optimal fleet deployment strategies and operational decisions. Meanwhile, the impact of real-world factors such as waterway depth and emission cost are discussed, respectively. Moreover, we introduce two subsidy schemes and compare their effectiveness on the fleet electrification process. Finally, the proposed model is applied to the Yangtze River shipping network in China using real data. The results show that the shipping company will initially invest in lower-cost electric ships with a limited budget, followed by the acquisition of larger ships. The charging stations are strategically established in the downstream areas, coinciding with the initial deployment of electric ships. Moreover, the impacts of fuel prices and emission cost of diesel-powered ships on the electrification process are compared, with the results indicating that the increase in emission cost has a more pronounced effect on the total cost compared to the rise in fuel prices. Additionally, the subsidy schemes' effect is explored, revealing that financial incentives markedly accelerate the fleet electrification process.

关键词： Electrification Electric ships fleet replacement Charging stations Mixed-integer nonlinear programming

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fleet replacement decisions under demand and fuel price uncertainties

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TRANSPORTATION RESEARCH PART D-TRANSPORT AND ENVIRONMENT 2018年第May期60卷 153-173页

作者： Zheng, Shiyuan Chen, Shun Shanghai Maritime Univ Sch Transportat Shanghai Peoples R China

This paper proposes a real option model to investigate the fleet replacement timing decisions when a shipowner faces uncertain demand on various routes and uncertain fuel prices (both MGO and LNG prices). A multi-option least squares Monte Carlo simulation algorithm is utilized to find the replacement probabilities in future years and the expected NPVs of the cost savings after the replacement. The proposed model is applied to a chemical tanker shipping company. The case results indicate that the shipowner should replace all of his diesel-fuelled vessels with dual-fuelled vessels at one time, rather than replacing them one-by-one. Moreover, we compare the performance of two possible government policies, the vessel subsidy policy and the fuel subsidy policy. The sensitivity analysis indicates that in our case, the shipowner prefers the vessel subsidy policy, which brings him more cost-savings and allows him to make the earlier replacement decision. Alternately, the fuel subsidy policy is suitable for routes with a larger turnover volume if governments wish to see the more obvious policy feedbacks. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： fleet replacement Demand MGO LNG Uncertainty Real options

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A risk management system for sustainable fleet replacement

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2014年第2期237卷 701-712页

作者： Ansaripoor, Amir H. Oliveira, Fernando S. Liret, Anne ESSEC Business Sch Operat Management Dept Singapore 188064 Singapore BT France Res & Technol BT Grp F-75013 Paris France

This article analyzes the fleet management problem faced by a firm when deciding which vehicles to add to its fleet. Such a decision depends not only on the expected mileage and tasks to be assigned to the vehicle but also on the evolution of fuel and CO2 emission prices and on fuel efficiency. This article contributes to the literature on fleet replacement and sustainable operations by proposing a general decision support system for the fleet replacement problem using stochastic programming and conditional value at risk (CVaR) to account for uncertainty in the decision process. The article analyzes how the CVaR associated with different types of vehicle is affected by the parameters in the model by reporting on the results of a real-world case study. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Decision support systems fleet replacement Risk management Stochastic programming Sustainable operations Conditional value at risk (CVaR)

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Integrating fleet replacement and pilot training schedules for airborne service helicopters

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JOURNAL OF THE CHINESE INSTITUTE OF ENGINEERS 2016年第6期39卷 653-665页

作者： Tang, Ching-Hui Huang, Hsin-Ta Natl Taiwan Ocean Univ Dept Transportat Sci Keelung Taiwan Kainan Univ Dept Air Transportat Taoyuan Taiwan

In this study, we examine an integrated problem involving fleet replacement and pilot training scheduling for airborne service helicopters. Two objectives, minimizing the total cost and the number of batches of pilot training, are considered based on the practical requirements. Multi-objective programming combined with a time-space network technique is applied to solve the problem. Numerical tests, in reference to the operations of a Taiwanese organization, are carried out to demonstrate the performance of the proposed model. A comparison of the proposed model and two single-objective models corresponding to the two objectives is also presented.

关键词： fleet replacement pilot training schedule multi-objective programming network model

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Optimal fleet replacement: A case study on a Spanish urban transport fleet

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JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY 2017年第8期68卷 886-894页

作者： Riechi, J. Macian, V. Tormos, B. Avila, C. Fed Technol Univ Parana Curitiba Parana Brazil Univ Politecn Valencia Valencia Spain

Optimizing the average annual cost of a bus fleet has become an increasing concern in transport companies management around the world. Nowadays, there are many tools available to assist managerial decisions, and one of the most used is the cost analysis of the life cycle of an asset, known as "life cycle cost''. Characterized by performing deterministic analysis of the situation, it allows the administration to evaluate the process of fleet replacement but is limited by not contemplating certain intrinsic variations related to vehicles and for disregarding variables related to exigencies of fleet use. The main purpose of this study is to develop a combined model of support to asset management based in the association of the life cycle cost tool and the mathematical model of Monte Carlo simulation, by performing a stochastic analysis considering both age and average annual mileage for optimum vehicle replacement. The utilized method was applied in a Spanish urban transport fleet, and the results indicate that the use of the stochastic model was more effective than the use of the deterministic model.

关键词： fleet replacement optimization operation and maintenance costs transport life cycle cost analysis Monte Carlo simulation

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Flexible lease contracts in the fleet replacement problem with alternative fuel vehicles: A real-options approach

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2018年第1期266卷 316-327页

作者： Ansaripoor, Amir H. Oliveira, Fernando S. Curtin Business Sch Sch Informat Syst Kent St Bentley WA 6102 Australia NUS Business Sch Dept Analyt & Operat Mochtar Riady BldgB1Z17-3615 Kent Ridge Dr Singapore 119245 Singapore

We study the use of flexible lease contacts in the fleet portfolio management problem of a firm that aims to minimize its cost and risk (Recursive Expected Conditional Value at Risk), simultaneously, in a stochastic multi-period setting by deciding which technologies to use in its fleet. We propose a model using real options (return and swap) to model contract flexibility and to account for different uncertainties (CO2 prices, fuel prices, mileage covered by a vehicle, fuel consumption, and technological). We analyse how fuel price uncertainty and technological progress influence the value of the options. We validate the results using a real-world case study conducted in the UK. (C) 2017 Elsevier B.V. All rights reserved.

关键词： Transportation fleet replacement Real options Risk management Sustainability

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Electric vehicle type selection for single-line transit fleet replacement

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JOURNAL OF PUBLIC TRANSPORTATION 2023年 25卷

作者： Tang, Chunyan Zhao, Ailing Liu, Tao Zhang, Jiyu Dalian Maritime Univ Coll Transportat Engn Dalian 116026 Peoples R China Southwest Jiaotong Univ Inst Syst Sci & Engn Sch Transportat & Logist Natl Engn Lab Integrated Transportat Big Data Appl Chengdu 611756 Peoples R China Changan Univ Coll Transportat Engn Xian Shaanxi Peoples R China

fleet replacement is an important decision-making activity in public transit planning and operations. Recently, with the goal of reducing carbon dioxide emissions and achieving carbon neutrality, diesel buses are being replaced with new electric buses (EBs) in many cities around the world. The study proposes a methodology to analyze and compare the life-cycle cost and passenger waiting time of multi-type EBs, so as to assist transit agencies in determining the optimum EB type to replace existing diesel buses. The proposed methodology is applied to a real-life case study of a bus line in Dandong, China. The case study includes six types of EBs categorized by their charging technologies and passenger capacities, including three slow-charging EBs with capacities of 40, 60, and 76 passengers, as well as three fast-charging EBs with capacities of 50, 65, and 75 passengers. The results show that no matter which charging technology is considered, the life-cycle cost of largesize EBs is the lowest. From the perspective of passengers, small-size EBs resulting in shorter waiting time are more favorable. When passenger demands on all route segments change with the same rate, the total passenger waiting time for each vehicle type will not change. But, with the increase of passenger demand, the average passenger waiting time decreases for all vehicle types. The results also indicate that the bus line length does not have a significant impact on EB vehicle selection. In addition, the phase-out of the vehicle purchase subsidy policy will have no impact on EB type selection due to the current low-level purchase subsides.

关键词： Pubic transit fleet replacement Electric bus Life-cycle cost Waiting time

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Parallel machine replacement with shipping decisions

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INTERNATIONAL JOURNAL OF PRODUCTION ECONOMICS 2019年 218卷 62-71页

作者： Shields, Brett A. Seif, Javad Yu, Andrew Junfang Francis Marion Univ Dept Phys & Engn Florence SC 29502 USA Univ Tennessee Dept Ind & Syst Engn Knoxville TN 37996 USA

In this research, the Parallel Machine replacement Problem is adapted to include shipping decisions between demand sites. The formulation arises from an application in the construction industry, where the shipping of assets is vital. The benefit of including shipping decisions with replacement analysis is presented in a numerical example where heavy machinery is considered. The formulation is shown to significantly increase in computational complexity as the number of demand sites increases, and therefore an efficient heuristic algorithm is presented to solve large-size problems. Managerial implications are derived from sensitivity analysis on the shipping cost-per-mile, and economic impact is discussed. It is shown that the optimal solution does not change even when shipping cost inflates significantly.

关键词： Parallel machine replacement Physical asset management Logistics Project management fleet replacement

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Genetic Algorithm for Optimization of the replacement Schedules for Major Surface Combatants 8th

Genetic Algorithm for Optimization of the Replacement Schedu...

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8th International Conference on the Theory and Practice of Natural Computing (TPNC)

作者： Fee, Michele van Oers, Bart Logtmeijer, Richard Caron, Jean-Denis Fong, Van Def Res & Dev Canada Maritime Operat Res Team Ottawa ON Canada Def Mat Org Bur Life Cycle Anal Utrecht Netherlands

ISBN: (纸本)9783030345006;9783030344993

The replacement of aging naval fleets is a multi-faceted problem with many important factors and scheduling constraints, where the development of a sound transition plan relies on leveraging flexibilities. A successful fleet schedule should aim to balance operational requirements, fleet maintenance facility workloads and the availability of ready personnel (operators and maintainers) while conforming to shipbuilding schedules and service life limitations. To evaluate different transition strategies, optimized fleet schedules are generated using a Genetic algorithm with limited-range integer codons. This approach is illustrated with the analysis of five transition scenarios for the replacement of a nine ship frigate class.

关键词： Optimization Planning and scheduling Genetic algorithm fleet replacement Navy

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An integrated model and solution approach for fleet sizing with heterogeneous assets

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TRANSPORTATION SCIENCE 2005年第1期39卷 87-103页

作者： Wu, PL Hartman, JC Wilson, GR Lehigh Univ Dept Ind & Syst Engn Moher Lab Bethlehem PA 18015 USA

This paper addresses a fleet-sizing problem in the context of the truck-rental industry. Specifically, trucks that vary in capacity and age are utilized over space and time to meet customer demand. Operational decisions (including demand allocation and empty truck repositioning) and tactical decisions (including asset procurements and sales) are explicitly examined in a linear programming model to determine the optimal fleet size and mix. The method uses a time-space network, common to fleet-management problems, but also includes capital cost decisions, wherein assets of different ages carry different costs, as is common to replacement analysis problems. A two-phase solution approach is developed to solve large-scale instances of the problem. Phase I allocates customer demand among assets through Benders decomposition with a demand-shifting algorithm assuring feasibility in each subproblem. Phase 11 uses the initial bounds and dual variables from Phase I and further improves the solution convergence without increasing computer memory requirements through the use of Lagrangian relaxation. Computational studies are presented to show the effectiveness of the approach for solving large problems within reasonable solution gaps.

关键词： fleet size and mix fleet replacement benders decomposition

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