  Hybrid-electric powertrains are among the most promising technologies for
abating emissions from marine vessels in sensitive areas. However, their
effectiveness strongly depends on the context they operate into. This paper
attempts to evaluate the potential impact on air quality of hybridizing the
diesel-powered waterbuses that currently operate in the city of Venice as part
of the local public transportation network. Simulation models for conventional,
series hybrid and parallel hybrid marine powertrains were developed and applied
to the typical operational mission of one of these waterbuses. For the hybrid
powertrains, an Energy Management Strategy is also obtained using a Dynamic
Programming - based optimization algorithm. The results show that both hybrid
architectures have high emission-reducing potential, with the series hybrid
offering the greatest benefits.
