VEZ, Vaporetto a Zero Emissioni (zero emission water-bus, grant agreement no. 650937) is a project funded under Horizon 2020, within the SME Instrument Phase 1 action, carried out by SATE on behalf of IMS – Industrie Meccaniche Scardellato S.p.a. (Casale sul Sile, TV, Italy). VEZ is a zero emission boat for public transports in water cities similar to the typical Venice “Vaporetto™”, which can be considered a worldwide reference for public water transports. VEZ was studied in two competing versions: one powered by a hybrid energy generation and management system based on hydrogen-air fuel cells, roof mounted PV cells and batteries, and the other based on purely electric energy storage by batteries suited for one day service endurance.
The study included a comprehensive technical activity aimed at identifying solutions to the inherent risks associated to hydrogen storage and handling, in compliance with the regulations applicable to water transports, taking into account also the ongoing applications to road vehicles. The fuel cell model, the power batteries and the storage bottle identified are all being produced and commercialized for land transports, particularly busses and trucks. Among the technical marine classification societies only DNV-GL has issued rules for classification specific for fuel cells and hydrogen storage and handling, in force since Jan. 2009. PEM fuel cells and Li-ion batteries were selected, the latter for both alternatives, yet with different requirements: sized as short term power buffer for H2/FC VEZ, sized for daily endurance for the Electric VEZ. Both solutions were analysed in detail based on validated propulsion power profile simulations that were compared in previous projects with real propeller shaft measurements on-board existing Venice water buses, producing detailed specifications, drawings and breakdown of costs for the competition comparison and business evaluation. The study assessed also the hydrogen availability perspective, concluding that the H2/FC VEZ would be economically and socially justified only if pure enough Hydrogen deriving as by-product from industrial processes or directly from renewable energy sources, but not from electrolysis, would be available in the area of utilization, i.e. close to inland or coastal waters interested to passengers transports, and upon the availability of a distribution infrastructure. This scenario is too far to justify a business development initiative based on the H2/FC VEZ concept. Instead an electric VEZ development could have a nearer term market interest, as long as the zero emission feature is credited value justifying the higher costs compared with conventional diesel powered motor boats.