FEASIBILITY ANALYSIS OF THE DRIVE TRAIN ELECTRIFICATION FOR A RESCUE BOAT

Sammanfattning: Progressing constraints on green house gas emissions lead to a sustainability trend,which greatly a↵ects the transport sector. Nowadays, companies show increasing interest indeveloping sustainable solutions.This thesis has been started thanks to a project given by Sj¨or¨addningss¨allskapet, themost relevant association that performs sea rescue operations in Swedish waters.Sj¨or¨addningss¨allskapet would like to explore the possibility of making their rescue boat fleetentirely carbon-free, hence more sustainable.What may provide a suitable solution is an electric drive train with hybrid energy storage,composed by a battery pack and a fuel cell stack. The research question is whether it wouldbe feasible to combine fuel cell stacks and battery packs to provide power to a fast smallboat.From a sketch of a rescue boat, the drive train design for such boat is studied in itsintegrity, from the water jet pump to the battery and fuel cell systems.The required power has been calculated empirically, using data from online tests on waterjet boats. Di↵erent tests have been considered, resulting in a mean power curve and a meanconsumption curve and allowing comparison between the hybrid electric drive train withan internal combustion engine drive train.Three profiles of speed, power and consumption have been assumed for the calculation ofthe required energy and hence rate the energy storage system. A design has been proposedin terms of fuel cell capacity and battery capacity.The propulsion unit, composed by the electric machine and water jet, has been studied,focusing on di↵erent electric drive technologies. Few conclusions on both the weight andsustainability requirements are discussed.A sustainability analysis is carried out in terms of CO2 emissions, through a life cycleassessment accounting for the environmental impact of the system during the whole lifecycle, from cradle to grave.