The widely-used passenger and car ferries, sailing regularly and carrying heavy loads, form a unique type of marine vessel, providing vital transportation links to the coastal regions. Modern ferry ships usually are equipped with multiple diesel engines as prime movers. These diesel engines consume a large amount of marine diesel fuel with high fuel costs, and high emissions of greenhouse gas (GHG) and other harmful air pollutants, including CO2, HC, NOx, SO2, CO, and PM. To reduce fuel costs and the harmful emissions, the marine industry and ferry service providers have been seeking clean ship propulsion solutions. In this work, the model-based design (MBD) and optimization methodology for developing advanced electrified vehicles (EV) are applied to the modelling, design and control optimizations of clean marine vessels with a hybrid electric propulsion system. The research focuses on the design and optimization of the hybrid electric ship propulsion system and uses an open deck passenger and car ferry, the MV Tachek, operated by the British Columbia Ferry Services Inc. Canada, as a test case. At present, the ferry runs on the Quadra Island – Cortes Island route in British Columbia, Canada, with dynamically changing ocean conditions in different seasons over a year. The research first introduces the ship operation profile, using statistical ferry operation data collected from the ferry’s voyage data recorder and a data acquisition system that is specially designed and installed in this research. The ship operation profile model with ship power demand, travelling velocity and sailing route then serves as the design and control requirements of the hybrid electric marine propulsion system. The development of optimal power control and energy management strategies and the optimization of the powertrain architecture and key powertrain component sizes of the ship propulsion system are then carried out. Both of the series and parallel hybrid electric propulsion architectures have been studied. The sizes of crucial powertrain components, including the diesel engine and battery energy storage system (ESS), are optimized to achieve the best system energy efficiency. The optimal power control and energy management strategies are optimized using dynamic programming (DP) over a complete ferry sailing trip. The predicted energy efficiency and emission reduction improvements of the proposed new ship with the optimized hybrid propulsion system are compared with those of two benchmark vessels to demonstrate the benefits of the new design methodology and the optimized hybrid electric ship propulsion system design. These two benchmarks include a conventional ferry with the old diesel-mechanical propulsion system, and the Power Take In (PTI) hybrid electric propulsion systems installed on the MV Tachek at present. The simulation results using the integrated ship propulsion system model showed that the newly proposed hybrid electric ship could have 17.41% fuel saving over the conventional diesel-mechanical ship, and 22.98% fuel saving over the present MV Tachek. The proposed optimized hybrid electric propulsion system, combining the advantages of diesel-electric, pure electric, and mechanical propulsions, presented considerably improved energy efficiency and emissions reduction. The research forms the foundation for future hybrid electric ferry design and development. / Graduate

The purpose of this study is to compare the life-cycle cost and environmental impact of the existing fuel-based propulsion system, on public commuter ferries in Stockholm, with a battery based propulsion system. The study is divided into multiple layers. First, the operating characteristics of the route Line 80 within Stockholm’s waterborne public transportation (WPT) are collected, such as fuel consumption, propulsion power output, speed, voyage time and propulsion system configuration. Second, based on the energy demand of the route, important parameters related to the existing fuel-based propulsion system and the battery-based propulsion system are accounted for and modeled. Third, Life Cycle Assessment (LCA) and the cost assessment methods are applied to examine the effectiveness of the electrification of commuter ferries on a financial and environmental scale. With the help of the software GaBi 2020, GREET 2020, and other literature studies, the environmental impacts at the construction, use and end-of-life (EOL) phase are evaluated. There are in total 8 scenarios considered, 4 for the fuel-based and 4 for the battery-based propulsion system. The environmental performance of these 8 scenarios are discussed in terms of Globalwarmingpotential(GWP), Acidificationpotential(AP), Eutrophicationpotential(EP) and Photo-chemical ozone creation potential (POCP). Themostpollutingphaseistheusephase for all scenarios. Propulsion system powered by diesel (scenario 1) is considered as a reference for comparative analysis of 7 other scenarios. The best performing system is the one powered by batteries with the assumption of an electricity mix based on hydro, wind and nuclear power, which is scenario 7 and 8 with a net reduction of GWP by more than 98%, AP by 90%, EP by 96%, and the POCP by 96%. If we consider the current Swedish electricity mix (scenario 5 and 6), the decrease in GWP, AP, EP and POCP are 90%, 80%, 82% and 91% respectively. Alternative fuels also present promising results for GWP in comparison to diesel (with the origin of the feed-stock creating mostly negative impacts) but the contribution to other impact categories is significantly higher. With inputs from the industry and the environmental evaluation, the cost assessment compares the costs related to fuel-based and battery-based propulsion systems with different energy sources. For the battery-based system, 3 scenarios are modeled for two different types of Li-ion batteries. The vessels in the developed scenarios are charged more frequently than the existing electric vessel and the number of charging stations is varied. The costs that are included in the assessment are the initial capital cost, the cost for fuel/electricity, maintenance cost, end-of-life cost and emissions cost. When concerning all the cost categories, the battery-based system is more cost-efficient than a fuel-based system, if run on the Swedish electricity mix, due to the lower cost for electricity and emissions. The reduction of cost is more than 68% when comparing traditional diesel with battery-based systems, but the source of the electricity is very important. / Syftet med denna studie är att jämföra livscykelkostnaden och miljöpåverkan av de befintliga framdrivningssystemen på pendelbåtarna inom Stockholms kollektivtrafik, med batteridrivna system på motsvarande båtar. De befintliga framdrivningssystemen drivs av olika typer av diesel. Studien är uppdelad i flera steg. Först samlas driftsegenskaperna in, såsom bränsleförbrukning, framdrivningseffekt, hastighet, färdtidochframdrivningssystemetsuppbyggnad, etc, på linje 80, som är en del av Stockholms vattenburna kollektivtrafik. För det andra undersöks det befintliga framdrivningssystemet som drivs av diesel eller alternativa bränslen som RME eller HVO och fullt batteridrivna system utifrån energibehovet. För det tredje tillämpas metoderna för kostnadsanalys och livscykelanalys (LCA) för att undersöka hur elektrifieringen av pendelbåtar påverkar ekonomin och miljön. Med hjälp av programmet GaBi 2020, GREET 2020 och andra litteraturstudier utvärderas miljöpåverkan av faserna tillverkning, användning och avfallshantering. Det är totalt 8 scenarier som övervägs, 4 för bränslebaserade och 4 för batteri baserade framdrivningssystem. Hur bra dessa 8 scenarier presterar miljömässigt diskuteras i termer av växthuseffekt (GWP), försurning (AP), övergödning (EP) och marknära ozon (POCP). Den fasen med mest utsläpp, för alla scenarier, är användningsfasen. Framdrivningssystemet som drivs av diesel (scenario 1) används som referens att jämföra de övriga 7 scenarierna mot. Det system som presterar bästa är det som drivs av batterier, med antagandet att elmixen är baserad på vatten-, vind-och kärnkraft, detta motsvarar scenario 7 och 8 med en reduktion av GWP på mer än 98%, AP med 90%, EP med 96% och POCP med 96%. Om vi tittar på den aktuella svenska elmixen (scenario 5 och 6) så är minskningen av GWP, AP, EP och POCP 90%, 80%, 82% respektive 91%. Alternativa bränslen ger också lovande resultat för GWP jämfört med diesel (där råvarans ursprung skapar mest negativa effekter) men bidraget till andra påverkanskategorier är betydligt högre. Med input från företag och miljöutvärderingen kan kostnadsanalysen jämföra kostnaderna för bränslebaserade och batteri baserade framdrivningssystem med olika energikällor. Det batteri baserade systemet modelleras även på 3 utvecklade scenarier för 2 olika typer av batterier. Fartygen i de utvecklade scenarierna laddas oftare än det befintliga batteridrivna fartyget och antalet laddstationer varierar mellan scenarierna. De kostnader som inkluderas i analysen är de initiala kapitalkostnaderna, kostnaden för bränsle/el, underhållskostnader, avfallshanteringskostnader ochutsläppskostnader. Medallakostnaderinkluderadeiberäkningarna är batteri baserade system mer kostnadseffektiva än bränslebaserade system om de körs på svensk elmix, tack vare de lägre kostnaderna för el och utsläpp. Minskningen av den totala kostnaden är mer än 68% när man jämför traditionell diesel med batterisystem, men elens ursprung är mycket viktig.