Energy savings potential of hull cleaning in a shipping industry

Abstract

The operational performance of ships, which is reflected through fuel consumption and carbon dioxide emission, is affected by various influential parameters. One of the important parameters is biofouling, which occurs at the immersed surfaces in between maintenance periods. Containerships are usually fouled with biofilm, which is commonly neglected during ship operation, as it is considered that biofilm does not affect ship performance significantly. This study investigates the potential energy savings of cleaning the biofilm for Post Panamax and Post Panamax Plus class of containerships, which are estimated for calm water condition, under weather and oceanographic conditions and for various draughts. The method for the estimation of the detrimental effects of biofilm using actual ship operating profiles and engine loads is proposed, and the potential fuel consumption and carbon dioxide emission reduction with hull cleaning is estimated and discussed. For the investigated containership fleets, an annual increase in fuel oil consumption for sailing in calm water is up to 153,689.9 t/year, while in CO2 emission is up to 478,590.5 t/year for Post Panamax containerships, while for Post Panamax Plus containerships these increases are up to 157,650.7 t/year and 490,924.1 t/year, respectively. The annual costs related to the increased fuel costs due to biofilm presence for the investigated fleets are therefore up to 64 M$/year for Post Panamax fleet and 66.6 M$/year for Post Panamax Plus fleet. The obtained results highlight the importance of keeping the hull clean from both an environmental and economic point of view and indicate the detrimental effects of biofilm.