Fleet Replacement Research Articles

Electric bus fleet transition: assessment approach considering economic and environmental impacts, and its application

In our society, global warming is considered one of the most serious problems. According to scientists, the world has been warmed by 3 degrees per year, which will be catastrophic to our world. To reduce CO2 emission, an electric bus is one way to solve the problem. In this article, we use four different models: Multiple Linear Regression (MLR), Autoregressive Integrated Moving Average Model (ARIMA), Ecological Assessment Model, Bus Fleet Replacement Financial Model, and Integer Programming Model to determine the number of carbon emissions, the least money that government need to spend on transitions, and future blueprint; these help to predict the overall benefits for countries turn into absolutely electric bus society. Our research stands from the sustainable point of view; we view better environment as the goal. By applying these models to three different countries: London, and Toronto, and Philadelphia which is our main focus, we find out that the air quality will be increased by reducing different kinds of pollution. Moreover, by constructing a ten-year blueprint, we find out the best way to spend least money and make the environment gradually become better.

Modeling cost-optimal fuel choices for truck, ship, and airplane fleets: The impact of sustainability commitments

For the next 25 years, numerous transport operators have introduced sustainability commitments to mitigate carbon emissions. However, static goals to reduce fossil fuel usage and adopt renewable fuel technologies pose economic risk. This study analyzes the costs of strategic fleet replacement through a mixed integer linear program. Comparing three Norwegian transport operators, we determine cost-optimal investments in fossil and renewable fuel technologies for two approaches: One integrating and the other neglecting sustainability commitments. Our findings reveal that the truck operator’s sustainability commitments incur minimal additional costs, with battery-electric trucks proving cost-effectiveness early. In contrast, ship and airplane operators exhibit significant differences in fleet replacement decisions, resulting in additional costs ranging from +6% to +31% for ships and +4% to +11% for airplanes, across fuel cost and carbon price scenarios. Norwegian carbon price regulations fall short in incentivizing a cost-competitive technology transition for ships and airplanes. Additional policies are needed to encourage gradual fleet replacement.

Bus fleet decarbonization under macroeconomic and technological uncertainties: A real options approach to support decision-making

Fleet owners deal with various and critical uncertainties while planning bus fleet replacement, encompassing macroeconomic and technological factors, such as fuel and electricity prices, energy consumption, purchasing costs of electric batteries and powertrains, and bus salvage value upon resale. This paper proposes a Real Option-based framework to evaluate investment choices in different bus technologies over time (diesel, hybrid electric, compressed natural gas, and full-electric), where the proposed options usually involve replacing existing diesel fleets with alternatively powered buses. In particular, we provide a multi-option least squares Monte Carlo simulation to help fleet owners in making cost-effective investment decisions, resulting in potential cost savings of up to 10% of the annual total cost of ownership. By applying the proposed approach to different bus route types (inner-city, urban, suburban, commuter), the results show how the optimal investment choices for fleet replacement change over time. Initially, diesel buses or, at most, compressed natural gas buses are more cost-effective compared to electric technology. However, as electric technology becomes increasingly competitive, internal combustion buses are phased out. Inner-city and urban routes are better suited for the electric transition, whereas the transition may progress more slowly on other route types.Finally, we show that, under technological and macroeconomic uncertainties, the duration of contracts can strongly affect the investment decisions, in absence of specific guarantees on the new fleet.

A Model‐Based Systems Engineering Approach for Trucking Fleet Replacement

AbstractHeavy vehicles operating for less than truckload (LTL) carriers are utilized to the maximum extent possible for the operator to maximize vehicle return on investment. However, the decision to purchase new vehicles, reallocate the vehicle, or retire the vehicle is based on complex and interacting factors like performance degradation, total cost of ownership, new regulatory pressures, and maintenance costs. The problem of optimizing fleet capacity is well suited to a model‐based systems engineering approach. Using SysML as the language and MagicGrid as the method, a model for fleet vehicle replacement and utilization was built to understand the best way to maximize and grow shipping capacity. The process started with identifying stakeholders and their needs and ended with system parametric models capable of computing costs. This model has the potential to optimize operating costs for fleets and maximize the use of the vehicle assets. Not only do these optimizations improve company financial performance, they reduce the need to unnecessarily replace expensive equipment, which is a more sustainable business practice.

Feasibility of zero emission freight zones: scenario analysis and risk assessment

To further incentivize the adoption of zero-emission trucks (ZETs), Chinese cities would need more proactive policies like zero-emission freight zones (ZEFZs). However, the design of the policy should avoid the disruption of goods supply, increase of logistic costs, and ensure inclusive transition of small carriers and financial sustainability for city governments. To this end, this study employs Beijing as a case: Based on ZEFZ case studies, policy document and literature review, and data analysis of freight demand distribution and truck movements in Beijing, this study constructs four scenarios with different spatial coverages, restricted truck segments, and roll-out years of ZEFZs. The impacts of different ZEFZ scenarios on emissions reduction potentials, goods supply and vehicle fleet replacement, and public and private expenditure are evaluated. The most cost-efficient and easy-to-implement scenario is recommended as the initial phase of the ZEFZ scheme, with risk assessment and risk mitigation measures.

Environmental Benefits of Pollution and Carbon Reduction by Bus Fleet Electrification in Zhengzhou

Electrification of bus fleets is an effective approach to reducing transportation-related pollution and carbon emissions. Evaluating the impact of electrification on existing bus fleets can provide valuable insights for promoting full electrification of public transportation in large cities. Utilizing the fuel life cycle method, we analyzed the CO2 and pollutant emissions of Zhengzhou's bus fleet before and after electrification and evaluated emissions under different electrification scenarios. Our results indicated that after electrification, the fuel life cycle CO2 and PM2.5 emissions increased by 32.6% and 42.6%, respectively, whereas CO, NOx, and VOC emissions decreased by 28%, 34%, and 25%, respectively. Optimizing the power generation structure is a critical factor in reducing CO2 and PM2.5 emissions during the electrification process. The best scenario for comprehensive electrification and power generation structure optimization could result in a 38.7% reduction in CO2, as well as reductions of 80.1% in CO, 84.4% in NOx, 92.2% in VOC, and 30.2% in PM2.5. Prioritizing electrification on long-distance routes is recommended during the replacement process. Additionally, replacing plug-in hybrid natural gas vehicles with pure electric vehicles has both advantages and disadvantages in terms of emission reduction. Achieving pollution reduction and carbon synergies requires advancing fleet replacement and power structure adjustments simultaneously.

Integrated Sustainability Assessment of Electric Bus Adoption: A Comprehensive Model for Ecological, Economic, and Operational Impact

The spread of electric stations in cities around the world is an important step towards sustainable urban transportation. In Task 1,We developed the FE-VC model to determine carbon emission indicators based on the BWM approach, and demonstrated the ecological consequences over the life cycle through quantitative models. In the quantitative calculation of urban data, compared with diesel buses, the carbon emission reduction rate of pure electric buses is 28.68%, mainly from the fuel cycle, in which the carbon emission reduction rate of the fuel cycle stage is as high as 40.11%, and it takes about 3.5 years to achieve the relative carbon emission reduction. In Task 2, we construct an economic impact consequence model based on the time value of capital with the theory of time value of money as the core, consider the full life cycle of acquisition, operation and vehicle maintenance, quantify and visualize the impact mechanism of electric buses on the economy, and provide a method to understand the economic impact for metropolitan areas. For task 3, based on the optimal enterprise operating cost and the optimized economic impact model, we construct the initial replacement model of the electric bus. The initial replacement model was optimized by simplifying the social cost of carbon emission, and an electric bus replacement model based on the optimal enterprise operating cost was obtained. In city-specific applications, we find that vehicle choice has a significant impact on fleet replacement plans and operating costs, and that using multiple vehicles can significantly reduce operating costs as electrification rates increase.

Coupling agent-based modelling and life cycle assessment for a behaviour-driven evaluation of SAEVs

ABSTRACT Shared Automated Electric Vehicles (SAEVs) are poised to revolutionize future transportation. However, potential drawbacks, including increased vehicle usage and the projected shorter vehicle lifespan, introduce critical factors that may impact efficiency and environmental benefits. This research introduces a framework that integrates Agent-Based Modelling (ABM) with Life Cycle Assessment (LCA) for a behaviour-driven SAEV assessment. The ABM simulates regional SAEV operations, informing the LCA of pre- and post-integration scenarios. Sensitivity analysis on fleet sizes, system performance metrics, and Global Warming Potential (GWP) reference values are performed. Findings demonstrate that SAEVs significantly decrease the fleet size and total travel distance by raising the average travel per vehicle. SAEVs integration yields a 75–86% daily GWP reduction without significantly compromising user experience. Over 30 years, fleet replacement needs due to inadequate fleet sizing raised GWP by 170%. Balancing short and long-term environmental impact requires optimizing fleet size to achieve sustainable and efficient service delivery.

Electric mobility toward sustainable cities and road-freight logistics: A systematic review and future research directions

The importance of electric vehicles (EVs) lies in the fact that they are seen as a key solution to the climate change problem. In the last decade, this topic has received significant interest from the scientific community, contributing to publications in different areas. However, the existing literature is fragmented, and efforts have not been made to categorize and analyze it from a freight logistics perspective. This work aims to fill this gap by presenting a systematic literature review (SLR) of the potential impacts of EVs on sustainable road-freight transport operations, including in urban areas. We reviewed 237 peer-reviewed articles for bibliometric and literature classification analysis, whereby 119 articles were subsequently studied for content analysis and research gaps related to sustainability approaches. The bibliometric analysis showed significant growth in the body of research in the past two years, reflected in the number of journal papers, authors, and references. In the literature and keywords analysis, we identified five main categories and research areas: economic and competitive aspects, city logistics, environmental sustainability, vehicle fleet operations, and infrastructure and technology. In addition, this paper revealed eight key research gaps for future research: multimodal integration, long-haul and heavy-duty truck approaches, emerging economies, business models, social factors, charging infrastructure inclusion, and fleet replacement policies. These findings can enlighten researchers and practitioners toward sustainable research and real-life applications of electromobility in freight logistics.

A short Literature Review on Sawlog and Pulpwood Transport Efficiency and Fuel Consumption

Timber transport is one of the main components of woody supply chain, which causes high costs and considerable emissions depending on truck size, type, transport distance, and payload. A cradle-to-gate life cycle assessment of Softwood plantations and regrowth hardwood native forests estimated that the most significant contributor to total greenhouse emissions per unit of wood production in softwood plantation was log haulage at 37%. For regrowth native hardwood forests, log transportation contributed 23% of greenhouse gas emissions. This research, built on existing literature, focused on how timber harvesting transportation costs and emissions to the environment can be reduced, specifically, the transport of the industrial timber logs from the Forest Stockpile to the processing facility or unloading points. The review summarized the data and highlighted that the efficiency and emissions data could be categorized into five themes: Higher Capacity Transportation (HCT), Road Networks & Surfaces, Logistics and Planning, Fleet Replacement, and Fuel efficiency technologies. Fuel efficiency improvements across these themes ranged from 3% to 43% within the reviewed case studies. Several studies researched the fuel efficiency of High Capacity Transport indicated that the fuel consumption in liters per ton kilometer was 8-11% lower in the 92-tonne combination HCT compared to a 72-tonne combination HCT due to the increased payload for High Capacity Transport. Road networks and the composition of the surfaces have been shown to have a strong correlation to emissions. Studies have shown a 16.7% increase in emissions from a network of predominantly highways to a higher proportion of Forrest and Gravel roads. Studies that included data on vehicle age found efficiency improvements of up to 26% when new vehicles’ fuel consumption was compared to older vehicles. Newer truck fleets incorporate newer technologies, with reports showing fuel consumption improvements of up to 43% with less than a two-year payback period.

Time-dependent electric bus and charging station deployment problem

Battery electric buses (BEBs) have gained popularity due to their emission-free and energy-efficient features. Many transit authorities worldwide have set goals to gradually replace their bus fleets with BEBs. Considering the potential decline in BEB battery and charger prices, this study proposes a time-dependent bus fleet transition model to determine the optimal bus fleet transition plan, which includes selecting the bus lines to be electrified, determining the timing and type of BEBs to be purchased, and deploying on-route fast chargers and depot chargers. The model is a bi-objective integer linear program that considers the trade-off between electrified transit mileages and bus electrification costs. A normalized normal constraint method is applied to solve the bi-objective optimization model. The effectiveness of the proposed model is tested using a real-world bus network. Additionally, sensitivity analyses are conducted to better understand the impact of different parameter values on the optimal solutions. Our proposed model can provide transit authorities with a powerful tool to make informed decisions about their BEB fleet replacement plans.

Optimal fleet replacement management under cap-and-trade system with government subsidy uncertainty

Optimal fleet replacement management under cap-and-trade system with government subsidy uncertainty

Using this DEMATEL Corporate social responsibility CSR

When discussing Corporate Social Responsibility (CSR) in developing nations, academics and policymakers frequently ignore the perspectives of local producers. This paper fills a void in the literature by explicitly adopting a phenomenological approach and mapping the justifications offered by regional manufacturers to CSR programs in the West. To investigate this topic, data from two qualitative studies on CSR programs in Sialkot, Pakistan’s soccer ball industry were used. Previous research has presented technologies related to managing a green aircraft fleet, including retrofits, fleet renewal, and alternative biofuels, as well as opportunities to carry out retrofits and value emissions. An alternative integer program model has also been developed to optimize fleet replacement strategies within budgets. The Intergovernmental Panel on Climate Change has noted the ineffectiveness of airplane operations. Since 2005, IATA’s Green Teams have been working with airlines to reduce this inefficiency. Improved operational practices are expected to reduce emissions by 2020. Thus, more efficient operations can reduce CO2 emissions and conserve fuel. Any financial benefits from an international plan to cut airplane emissions should be set aside for environmental causes, and these profits must be partially reinvested. Only a few of the additional measures being taken to lower the emissions profile of the global aviation industry include supporting the development and use of more fuel-efficient aircraft and low-carbon, sustainable jet fuels. The Program in Science and Human Affairs at the Battelle Memorial Institute in Geneva was established between 1972 and 1976 to conduct research and address complex and interrelated problem groups using the DEMATEL (Decision-making Testing and Evaluation Laboratory) system. DEMATEL is one of the decision-making tools that employs several criteria to extract the complex structure of a problem. The DEMATEL method is widely used to identify the cause-and-effect relationships among different elements of a complex problem. The objective of DEMATEL is to scale from a complex system and the relationship between causal dimensions it is to model the understandable structure of that system. When measuring complexity, the cause-and-effect relationship of the criteria can be clearly seen. From the result it is seen that Technology (TE) the first rank where as is the infrastructure (IN) is having the lowest rank. Resulting in Technology (TE) ranked first, There Infrastructure (IN) has low rank.

Long term lithium availability and electric mobility: What can we learn from resource assessment?

A more sustainable global mobility system in which Internal Combustion Engine (ICE) vehicles are replaced by electric vehicles (EVs) powered by lithium-ion batteries (LiBs), taking into account the existing, or inferred, resource, is still possible? The present study aims at providing an answer to this question, through the design of an innovative compartmental model. Model scenarios have been considered accounting for three different estimates of the resource, i.e. the declared reserves, the hypothesized resources, and the full beneficiation of dissolved Li in the oceans. Input data were provided from the historical data of Li primary production, EVs production and recycling rates.The replacement of the ICE vehicles fleet appears possible only under extreme, unrealistic situations, unless the Li “stored” in the oceans is considered exploitable. The main viable policies, i.e. the optimisation of the resource share (almost entirely devoted to mobility issues) and of recycling strategies (pushed up to >90 %) have a modest effect on the achievement of fleet replacement. The total amount of geological lithium resources results as the main limiting factor for the complete transition to EVs. According to the developed model, the peak of production would occur between 2078 and 2130, unless seawater Li is accounted for.The future of the global mobility in a resource-constrained world should be driven toward a model based on the service rather than the individual property of vehicles. Planning a total number of electric vehicles able to assure long term sustainability will be also highly relevant.

The road to electrification: Bus fleet replacement strategies

The public transport market in most global cities is dominated by diesel buses, which can have significant adverse impacts on the environment and human health. To reach carbon neutrality, many public transport operators are attempting to replace their existing bus fleets with electric buses (EBs). This paper develops a generic bus replacement model to help public transit (PT) operators progressively renew their existing bus fleets so as to reach particular electrification goals within a given planning horizon. Unlike existing studies, our model more comprehensively considers the external costs, which include external climate costs, external health costs and used battery recycling costs/profits. Furthermore, by incorporating different incentives, variants on the model can be adopted to investigate how different government incentives can affect the replacement behaviors of PT operators. Finally, our proposed approach is applied to real-world data from a bus operator in Singapore which is aiming to achieve a 100% cleaner energy bus fleet within 20 years. The experiments indicate that an EB subsidy can effectively accelerate the electrification process, and a 25% EB subsidy could achieve full electrification eight years earlier than if no EB subsidy were applied. Moreover, we explore how the diesel tax and diesel bus (DB) tax affect EB replacement. Our experiments suggest a 10% diesel tax rate can achieve good results but imposing a DB tax will not encourage PT operators to purchase EBs earlier.

Electric vehicle type selection for single-line transit fleet replacement

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 large-size 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.

Reconstruction mechanism and strategy of global maritime green supply chain against the backdrop of nuclear pollution.

Owing to the nuclear accident at Fukushima, everyone involved in the supply chain began to reflect on the ongoing efforts to minimize the environmental impact. Being part of the green supply chain, it is important for maritime companies to restructure their mechanism and strategy for the future. This study analyzes the framework of the reconstruction mechanism and strategy of the global maritime green supply chain against the backdrop of nuclear pollution in four dimensions, namely, ecology, management, economy, and society. On the basis of these four dimensions, 20 suitable evaluation indicators are constructed to develop an expert questionnaire. These indicators are used to identify the importance of the maritime green supply chain through the fuzzy analytic hierarchy process so that decision makers can discover the intrinsic key competencies. According to the results of the study, the indicators of critical success factors (CSFs) are as follows: 1. "Reduction of waste discharge and pollution treatment"; 2. "Construction of environmentally friendly fleets, desulfurization retrofit, and fleet replacement to comply with the International Maritime Organization's regulations and improve energy efficiency"; 3. " Regular audit, assessment, and review of compliance with environmental laws and regulations"; 4. "Priority access to ports and increased profitability by participating in the Green Ship Incentive Program"; and 5. " Dedicated management units and departments responsible for policies related to green capabilities." The results provide a reference for the decision making of maritime companies to identify the key reconstruction mechanism and CSFs in the maritime green supply chain and explore future service models as a way to build competitive advantage and ensure sustainable operations. This study integrates the ecological theory and concept of the green supply chain management. Furthermore, the results of this study provide policy implications for stakeholders, such as maritime companies and governments, in implementing and promoting green supply chain practices.

Transitioning to sustainable freight transportation by integrating fleet replacement and charging infrastructure decisions

The transportation sector is the largest contributor to global greenhouse gas emissions. Disruptive technological changes in this sector, such as alternative fuel vehicles, are crucial for emission reduction. We show how a cost-minimizing strategic transition plan to adopt electric trucks over time can be developed for a firm that owns and operates a fleet of diesel trucks. We consider the case in which the firm decides to invest in the charging infrastructure required to support this transition, either because the public charging infrastructure is currently inadequate or for strategic reasons. The congestion effect at the charging stations, the charging times, and the potential loss of productive driving time due to detours to reach charging stations are explicitly considered. By developing an independence property, we are able to model this problem as a linear integer program without specifying origins and destinations. We illustrate the resulting transition plan with realistic parameter configurations. Our results indicate that a firm with high transportation demand density over a given service region significantly benefits from adoption of electric trucks, while also enjoying substantial carbon emissions savings. High demand density also favors smaller battery capacity with shorter ranges under the optimized charging network capacity, even though larger battery capacity would increase productivity with extended ranges. Our analysis also offers insights for governments and regulators regarding the impact of several influential factors such as carbon cost, content of renewable energy in electricity mix, diesel engine efficiency, and subsidizing the charging infrastructure. Additionally, we present an extension to the model that allows for different modalities of partnership in the infrastructure investment; notably public-private and private-private partnerships. While in general our results suggest that such partnerships are beneficial to all involved, the amount and relative distribution of the potential gains depend on the topography and on the density of charging infrastructure.

Air pollution scenario analyses of fleet replacement strategies to accomplish reductions in criteria air pollutants and 74 VOCs over India

Traffic emissions are a major source of air pollution and associated damage to human health in India. Many of the Indian metro cities urgently require cleaner transportation technologies to ensure cleaner air. Here, using newly compiled spatially disaggregated, gridded, high-resolution (0.1° × 0.1°) road transport emission inventory for India for 2030 (RTEII) of 74 speciated VOCs, CO, SO 2 , NOx, NH 3 , CH 4 , CO 2, BC, OC and PM 2.5 from varied fuels and vehicle technologies that are currently in use in India, we investigated changes in emission in response to substitution of the existing vehicular fleet by cleaner alternatives. Three “what-if” intervention scenarios were considered to assess the extent in improvement of air quality due to the reduction in the primary emission of air pollutants. The results show that significant reductions in direct emission of pollutants (Non-Methane VOCs, −91%; CO, −80%; PM 2.5 , 44%) including toxic VOCs (e.g., isocyanic acid, −76%; BTEX, −93%; as well as individual VOC classes (e.g., sum of OVOCs, −61% and sum of alkenes, −80%) can likely be achieved in 2030 by shifting from highly polluting Internal Combustion Engine (ICE) based 2 and 3-wheeled vehicles to Electric Vehicles (EVs) under scenario 1. The amount of secondary pollutants such as SOA and O 3 that can potentially be formed from traffic also showed significant reduction of 94% and 84%, respectively, under scenario 1. Conversion of diesel fuelled vehicles to CNG under scenario 2 can lead to a larger reduction in black carbon emissions (−50%). Scenario 3, in which the benefits of scenarios 1 and 2 are combined, represents the best long-term strategy moving forward, which can result in massive emission reductions of pollutants through existing technologies of greener transport fleets over India. Large scale conversion of the vehicle fleets as explored here can lead to a substantial reduction of air pollution and fewer lives lost. • Study examines 2030 road-transport emission reductions for India. • Three “what-if” intervention scenarios with electric vehicles and greener fuels. • 2&3-wheeler vehicles replacement by EVs reduced NMVOC emissions by 91%. • Conversion of diesel fuelled vehicles to CNG reduced primary BC by 50%. • Combining EVs and diesel to CNG for HDVs can improve air quality over India greatly.

Public Transport Fleet Replacement Optimization Using Multi-Type Battery-Powered Electric Buses

To achieve a green and sustainable public transit system, most transit agencies plan to completely replace current diesel and hybrid buses with battery-powered electric buses (EBs) in the decades ahead. Based on performances of EBs in practical operations, this study develops a transit fleet replacement model using multi-type EBs to determine an optimal fleet replacement plan in a cost-effective manner, considering associated diesel–electric replacement rates and in-vehicle crowd costs for passengers. Multi-type EBs include small EBs with fast charging technique, and large EBs with fast and slow charging techniques. The proposed model is applied to a real-life case study of the transit system in Qingdao, China. The results obtained indicate that large EBs with a high price tag are preferentially purchased in the first few years of the analysis period, whereas small EBs with a low price tag are favored in the latter years. The use of multi-type EBs results in a significant saving of the total cost, compared with the use of single-type EBs. Interestingly, with the increase of passenger demand, a large EB with a fast charging method presents more benefits than others. In contrast, a small EB has more advantages in a transit system with low demand.