The fuel consumption effect of prolonged port stays

Abstract

Optimizing fuel efficiency on marine vessels reduces both the fuel cost and the emission of greenhouse gasses. One way of optimizing fuel efficiency is through periodical hull treatments due to hull deterioration and hull fouling. Hull fouling occurs to a larger extent during idle periods and in tropical waters. This thesis develops a model using differencein- differences to estimate the causal effect of prolonged port stays, and prolonged tropical port stays, on fuel consumption. The estimates of change in fuel consumption after being exposed to prolonged port stays in certain ports can be used by shipowners to optimize the time interval between hull treatments to reduce fuel cost and emission of greenhouse gasses. The data included in this thesis comprises noon report data from eight Panamax vessels from two different vessel classes. The noon reports are supplied with AIS-data, port coordinates data, and third-party weather data. The results correspond with the expectation of prolonged tropical port stays leading to an increase in fuel consumption only for one of the vessel classes, and only when considering prolonged port stays as idle periods of 10 days or more. All other results contradict with the expectations of increased fuel consumption after prolonged port stays and suggest a reduction in fuel consumption after being exposed to prolonged port stays. Finally, ways to improve the method and the design of its covariates are identified.