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This study addresses the pressing need for the Norwegian fishery sector to align with national reduction targets and mitigate its environmental impact. Norway has committed to reducing GHG emissions from the fishery sector by at least 40% by 2030 and 95% by 2050. We propose a mathematical model designed for the strategic renewal of the Norwegian fishing fleet by introducing low- and zero-emission propulsion systems. This model generates fleet renewal schedules that minimize the total operational and renewal costs while ensuring compliance with emission targets. We apply our model to a case study based on the Norwegian fishing fleet and determine the optimal decarbonization strategy. We then analyze the impact of changes in energy costs and emission taxes on this strategy through a sensitivity analysis Our results indicate that (1) fleet renewal is mainly driven by the emission reduction targets, rather than economic benefits, and (2) zero-emission propulsion systems are preferable to low-emission propulsion systems when decarbonizing the fleet.

• The Low Emission Zone can reduce pollutant emissions within the regulated area. • A spillover effect might occur outside the Low Emission Zone. • The Low Emission Zone can contribute to promote sustainable travel habits. • Awareness of the benefits of the Low Emission Zone can increase modal shifts. • Behavioral changes after Low Emission Zone enforcement affect environmental impacts. Exposure of the population living in urban areas to an increasing level of air pollution has led local authorities to implement vehicle access restrictions to limit the circulation of pollutant vehicles and foster sustainable travel habits. With these aims, Low Emission Zones (LEZs) have been introduced in several European cities. Many previous works have evaluated the impacts of such regulation; however, they adopted pre-defined assumptions about new travels to access the regulated area and neglected potential behavioral changes induced by the measure. The aim of this paper is to quantify the effects of a LEZ on vehicle pollutant emissions, considering potential short-term variations of travel habits after its introduction (i.e., vehicle replacement, modal shift and destination change), and the associated uncertainty. The study area was the Municipality of Padova (Italy), where a LEZ is likely to be enforced. A holistic evaluation framework was applied combining a behavioral model and a traffic simulation model, calibrated using responses from a mobility survey administered to local stakeholders and traffic counts. The results highlighted the measure could contribute to induce fleet renewal and modal shift toward sustainable transportation means, that could be furtherly fostered by increasing the awareness of the benefits of the LEZ. Furthermore, the outcomes confirmed that the intervention could significantly reduce vehicle pollutant emissions within the area. Nevertheless, a spillover effect could occur outside the LEZ, due to the long detours that travelers deciding to avoid entering the zone have to perform. [ABSTRACT FROM AUTHOR]

Airline fuel consumption is costly for the firms and for society as well due to a climate-change externality. We study how fuel-price changes affect cost-minimizing choices by airlines that have implications for the extent of this externality. The airline industry's capital stock can be easily inventoried as a set of long-lived, durable aircraft. This portfolio approach allows us to study the utilization and composition of the capital stock at a highly disaggregated level. Changes in airline operations directed toward conserving fuel can be an important path toward lower emissions. • This paper studies airline responses to higher fuel prices and low aircraft fuel efficiency. • Both factors lead to slower flying speeds and lower aircraft utilization. • Higher fuel prices tend to raise (lower) the average fuel efficiency (age) of airline fleets. • Higher fuel prices hasten the retirement (acquisition) of aircraft with low (high) efficiency. [ABSTRACT FROM AUTHOR]

• We analyse fleet renewal decisions, taking into account ship scrapping subsidies. • We present a fleet renewal decision model which maximizes firm profit given market demand and a scrapping subsidy. • We compare the optimal fleet renewal schemes with and without the subsidy. • We apply the model to China COSCO Shipping. We introduce a novel dimension to the fleet renewal decisions of a shipping company, taking into account the effects of ship scrapping subsidies. The fleet renewal behavior of a company is analyzed with focus on early scrapping decisions prompted by the subsidy. We present a fleet renewal decision model which maximizes firm profit given market demand and the features of a scrapping subsidy. To assess the effects of a potential subsidy on corporate decisions, we compare the optimal fleet renewal schemes with and without the subsidy. We calculate the outcome of such a policy measure for China COSCO Shipping. [ABSTRACT FROM AUTHOR]

Faced with simultaneous demand and charter cost uncertainty, an industrial shipping company must determine a suitable fleet size, mix, and deployment strategy to satisfy demand. It acquires vessels by time chartering and voyage chartering. Time chartered vessels are acquired for different durations, a decision made before stochastic parameters are known. Voyage charters are procured for a single voyage after uncertain parameters are realized. We introduce the first multi-stage stochastic programming model for the bulk ship fleet renewal problem and solve it in a rolling horizon fashion. Computational results indicate that our approach outperforms traditional methods relying on expected value forecasts. [ABSTRACT FROM AUTHOR]

Stimulating fleet renewal and attaching a price to carbon dioxide emissions have both been suggested as ways of reducing aviation׳s environmental impact. One potential route for emissions reduction is to combine these policy options, by applying a carbon tax which is used to subsidize fleet renewal. Such a policy would have impacts on many aspects of the aviation system, including demand, fleet composition, traffic delays, and airfares. Therefore, its impacts need to be considered holistically, taking into account likely interaction and feedback effects. In this paper, we apply a model of the global aviation system, the Aviation Integrated Model (AIM), to assess the demand and emissions response from passenger aviation following the application of such an aviation sector policy. We find that by 2050, aviation lifecycle carbon dioxide emissions may be reduced by up to 34% compared to the no-policy case for a policy aimed at retiring aircraft over 20 years old. [ABSTRACT FROM AUTHOR]

A methodology was developed to project total vehicular emissions from different emission reduction policies for the light-duty vehicles in the roads network of Tehran, Iran. A road-link-based model was constructed based on a bottom-up approach by coupling COPERT emission functions with the travel demand model of EMME/2. Results showed total emission from the studied network was largely impacted by vehicles' technology and age, speeds in the links, and fuel type. The proper transportation management to reduce the part of passenger cars and improve traffic flow also leads to a significant drop in the emission, e.g., emission decreased by 43% from 20% traffic volume reduction. Results indicated the importance of concurrent implementation of practices for effective emission reduction. Enforcing proper emission standards, expanding public transportation, and vehicles' fleet renewal can potentially reduce more than 90% of current CO emission. [ABSTRACT FROM AUTHOR]

With more stringent requirements for efficient utilisation of energy resources within the transport industry a need for implementation of sustainable development principles has appeared. Such action will be one of competitive advantages in the future. This is especially confirmed within the road transport sector. A methodology implemented in public procurement procedures for fleet renewal regarding the calculation of road vehicles' operational lifecycle costs has been analysed in detail in this paper. Afore mentioned calculation comprises the costs for: vehicle ownership, energy, carbon dioxide, and pollutants emissions. Implementation of this methodology allows making the choice of energy efficient vehicles and vehicles with notable positive environmental effects. The objective of the research is to assess the influence of specific parameters of vehicle operational lifecycle costs, especially energy costs and estimated vehicle energy consumption, on vehicle choice in the procurement procedure. The case of urban bus fleet in Serbia was analysed. Their operational lifecycle costs were calculated and differently powered vehicles were assessed. Energy consumption input values were defined. It was proved that defined fleet renewal scenarios could influence unquestionable decrease in energy consumption. [ABSTRACT FROM AUTHOR]

• A stochastic naval fleet renewal problem is modeled and solved. • The life-cycle of a fleet is simulated by a hybrid simulation model. • The simulation model is coupled with an enhanced genetic algorithm. • Robust renewal strategies are identified by the proposed approach. • The scenario discovery analysis helps examine extreme scenarios. In this paper, we model and solve a strategic problem of fleet renewal to meet future operational needs under uncertain conditions. The fleet renewal problem focuses on mainly strategic decisions involving from fleet size, fleet mix and timing of replacement, yet it is essential to consider a significant amount of detail regarding short-term decisions to prevent inferior or infeasible strategies. In this direction, we develop a hybrid simulation model by combining system dynamics (SD) and discrete event simulation (DES) approaches. The standalone use of this model enables the decision maker to analyze the effects of both short- and long-term decisions on availability by simulating the processes that the fleet undertakes through its life-cycle from asset acquisition to retirement. Nevertheless, the simulation neither suggests nor seeks the best renewal strategy(ies). To alleviate this difficulty, we propose a simulation-based optimization that uses a genetic algorithm (GA) to effectively search a very large set of feasible fleet renewal strategies and uses the developed hybrid simulation model to evaluate candidate strategies found by GA. To provide a decision context where the approach has been developed and applied, we use a naval fleet renewal application. The extensive numerical experiments show that the proposed approach not only finds good and robust renewal strategies but also identify critical resources that influence the fleet's availability. Finally, the robustness of optimized strategies under uncertainty is tested by sensitivity analysis, and mappings between implemented strategies and the fleet performance are constructed by scenario discovery analysis to provide insights for decision makers. [ABSTRACT FROM AUTHOR]