Browsing by Author "Tanhuanpää, Taru"

The accumulation of biological material, i.e., biofouling, on ship`s hulls is a significant issue both for the shipping companies and the environment. Biofouling on a ship`s hull increases friction, leading to increased fuel consumption and hence, an increase in the fuel costs and emissions from shipping. Furthermore, the EU maritime traffic will be included in the EU Emissions Trading System in 2024, meaning that shipping companies must pay for their carbon dioxide emissions. This creates an additional economic incentive for the companies to prevent biofouling. The main methods for preventing biofouling on a ship`s hull are different coatings and possible in-water cleaning of the coated surfaces. The coating types include biocidal coatings, fouling release coatings, and hard coatings. Despite the notable problems from biofouling, there is currently no international regulation concerning biofouling management of shipping companies. A holistic understanding of this complex issue is needed to develop more sustainable shipping in the future. In this thesis, I analyze this topic by further developing an existing Bayesian network model, which is a decision tool for examining the outcomes from different biofouling management strategies. My focus on the topic is the costs of shipping companies from biofouling and its management. The existing model concerns the costs of coating, in-water cleaning, and fuel consumption. In this thesis, I add emission allowance costs and uncertainty to the fuel prices in the model to study whether these additions would change the profitability of different biofouling management strategies. My hypothesis is that to minimize the costs of biofouling and its management, shipping companies should increase the in-water cleaning times when the emission allowance costs are included in the model. The study revealed that the most cost-effective coating type, for a general cargo ship and a tanker, is a fouling release coating. For a passenger ship, the cost-effectiveness depends on the age of the coating, but a biocidal coating is the most cost-effective option when the age of the coatings is two years. My additions to the existing model did not change the result concerning the cost-effectiveness of the coating types. The results also revealed that the future inclusion of maritime transport to the EU Emissions Trading System will increase the costs of shipping companies from biofouling. Despite this, my hypothesis got rejected since the inclusion of the emission allowance costs did not lead to increased in-water cleaning times. My changes in the fuel prices led to a decrease in the in-water cleaning times, for some ship types, compared to the original model. This is not due to the uncertainty itself but because the fuel price distributions, which I used, led to lower expected fuel costs than in the original model. The study highlights that fuel costs might be one of the most important factors in determining whether enhanced biofouling management will be profitable for shipping companies in the future.