Christos A. Kontovas
National Technical University of Athens
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Featured researches published by Christos A. Kontovas.
WMU journal of maritime affairs | 2009
Harilaos N. Psaraftis; Christos A. Kontovas
The purpose of this paper is to present an analysis of carbon dioxide (CO2) emissions of the world commercial fleet. The analysis is based on the Lloyds-Fairplay world ship database for 2007 and produces various emissions statistics of the following major ship types: bulk carriers, crude oil tankers, container vessels, product/chemical carriers, LNG carriers, LPG carriers, reefer vessels, Ro-Ro vessels and general cargo ships. A separate analysis is carried out for small vessels under 400 GRT and for passenger vessels. The main outputs from this analysis for each ship type-size bracket are the emitted grams of CO2 per tonne-km and an estimate of the total CO2 produced in a year. The methodology for estimating these statistics is described, and a comparison with other studies is made.
Maritime Policy & Management | 2011
Christos A. Kontovas; Harilaos N. Psaraftis
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.
Marine Pollution Bulletin | 2010
Christos A. Kontovas; Harilaos N. Psaraftis; Nikolaos P. Ventikos
This paper reports on recent analysis of oil spill cost data assembled by the International Oil Pollution Compensation Fund (IOPCF). Regression analyses of clean-up costs and total costs have been carried out, after taking care to convert to current prices and remove outliers. In the first place, the results of this analysis have been useful in the context of the ongoing discussion within the International Maritime Organization (IMO) on environmental risk evaluation criteria. Furthermore, these results can be useful in estimating the benefit of regulations that deal with the protection of marine environment and oil pollution prevention.
Networks | 2016
Harilaos N. Psaraftis; Min Wen; Christos A. Kontovas
Since the late 70s, much research activity has taken place on the class of dynamic vehicle routing problems DVRP, with the time period after year 2000 witnessing a real explosion in related papers. Our paper sheds more light into work in this area over more than 3 decades by developing a taxonomy of DVRP papers according to 11 criteria. These are 1 type of problem, 2 logistical context, 3 transportation mode, 4 objective function, 5 fleet size, 6 time constraints, 7 vehicle capacity constraints, 8 the ability to reject customers, 9 the nature of the dynamic element, 10 the nature of the stochasticity if any, and 11 the solution method. We comment on technological vis-i-vis methodological advances for this class of problems and suggest directions for further research. The latter include alternative objective functions, vehicle speed as decision variable, more explicit linkages of methodology to technological advances and analysis of worst case or average case performance of heuristics.
Archive | 2015
Harilaos N. Psaraftis; Christos A. Kontovas
Slow steaming is being practised in many sectors of the shipping industry. It is induced principally by depressed shipping markets and/or high fuel prices. In recent years the environmental dimension of slow steaming has also become important, as ship emissions are directly proportional to fuel burned. The purpose of this chapter is to examine the practice of slow steaming from various angles. In that context, a taxonomy of models is presented, some fundamentals are outlined, the main trade-offs are analysed, and some decision models are presented. Some examples are finally presented so as to highlight the main issues that are at play.
Archive | 2016
Christos A. Kontovas; Harilaos N. Psaraftis
Transportation is the backbone of international trade and a key engine driving globalization. However, there is growing concern that the Earth’s atmospheric composition is being altered by human activities, including transportation, which can lead to climate change. Air pollution from transportation and especially carbon dioxide emissions are at the center stage of discussion by the world community through various international treaties, such as the Kyoto Protocol. The transportation sector also emits non-CO2 pollutants that have important effects on air quality, climate, and public health. The main purpose of this chapter is to introduce some basic concepts that are relevant in the quest of green transportation logistics. First, we present the basics of estimating emissions from transportation activities, the current statistics and future trends, as well as the total impact of air emissions and its contribution to climate change. In addition, this chapter presents the basics of environmental policy measures. In that context, we describe a way to measure the cost-effectiveness of various measures through the so-called Marginal Abatement Cost (MAC). Finally, the chapter deals with the topic of the energy efficiency gap and examines why governments and companies may forego cost-effective investments in energy efficiency, even though they could significantly reduce energy consumption at a lower cost.
Archive | 2016
Harilaos N. Psaraftis; Christos A. Kontovas
Among the spectrum of logistics-based measures for green maritime transportation, this chapter focuses on speed optimization. This involves the selection of an appropriate speed by the vessel, so as to optimize a certain objective. As ship speed is not fixed, depressed shipping markets and/or high fuel prices induce slow steaming which is being practised in many sectors of the shipping industry. In recent years the environmental dimension of slow steaming has also become important, as ship emissions are directly proportional to fuel burned. Win-win solutions are sought, but they will not necessarily be possible. The chapter presents some basics, discusses the main trade-offs and also examines combined speed and route optimization problems. Some examples are finally presented so as to highlight the main issues that are at play.
Archive | 2016
Christos A. Kontovas; George Panagakos; Harilaos N. Psaraftis; Eirini V. Stamatopoulou
Green House Gas (GHG) emissions are not the only emissions of concern to the international transport community. SOx emissions are non-GHG emissions that are caused by the presence of sulphur in the fuel. As the maximum percentage of sulphur in automotive and aviation fuels is strictly regulated in most countries around the world, much of the attention in recent years has focused on maritime transport. The attention mainly stems from the fact that in marine fuels the percentage of sulphur can be very high: it can be as high as 4.5 % in Heavy Fuel Oil (HFO), which is the fuel typically used in all deep-sea trades. Even though the amounts of SOx produced by ships are substantially lower than CO2, SOx emissions are highly undesirable as they cause acid rain and undesirable health effects in humans and animals. To mitigate these adverse environmental effects, the international shipping community has taken substantial policy measures. With the introduction of new limits for the content of sulphur in marine fuels in Northern European and North American sea areas, short-sea companies operating in these areas will face substantial additional cost. As of 1/1/2015, international regulations stipulate, among other things, a 0.1 % limit in the sulphur content of marine fuels, or equivalent measures limiting the percent of SOx emissions to the same amount. As low-sulphur fuel is substantially more expensive than HFO, there is little or no room within these companies current margins to absorb such additional cost, and thus significant price increases must be expected. Unlike its deep-sea counterpart, in short-sea shipping such a freight rate increase may induce shippers to use land-based alternatives (mainly road). A reverse shift of cargo would go against the EU policy to shift traffic from land to sea to reduce congestion, and might ultimately (under certain circumstances) increase the overall level of CO2 emissions along the entire supply chain. The purpose of this chapter is to investigate the potential effect of sulphur regulations on the share of cargo transported by the waterborne mode vis-a-vis land-based alternatives.
International Journal of Ocean Systems Management | 2009
Harilaos N. Psaraftis; Christos A. Kontovas
Many organisations and governmental agencies offer online calculators to calculate the carbon footprint of industrial activities. Furthermore, airline companies offer online tools to estimate carbon footprint and promote the purchase of carbon offsets in order to make the trip carbon neutral. This paper presents a free online emissions calculator that computes various emissions-related statistics for a given ship and operational scenario. This web tool is the first publicly available calculator for the shipping industry.
international conference on computational logistics | 2017
Philip Dithmer; Line Blander Reinhardt; Christos A. Kontovas
This paper deals with the Liner Shipping Routing and Scheduling Problem (LSRSP), which consists of designing the time schedule for a vessel to visit a fixed set of ports while minimizing costs. We extend the classical problem to include the external cost of ship air emissions and we present some results of our work investigating the impact of Emission Control Areas in the routing and scheduling of liner vessels.