Design, construction and operation of a special electric vessel for water-city utilities service

This article presents an electric vessel for technical service that has been designed, constructed and put into service in Venice, Italy. It is a prototype in a program for replacing an existing fleet of 63-kW diesel boats. It had to preserve the present 12-m boats size, maneuverability with a 360° steering azimuth propeller, and onboard power drives, namely a large waste caisson with a compacting drawer, a crane for moving bins, and a collapsible cockpit for passing low bridges. The design was developed on the power and work demand acquired in a preliminary measurement campaign. Onboard drives had to provide full service at zero emission in most routes inside the historical city. Two 50-kW permanent magnet electric motors were chosen to power the propeller and the compactor, and smaller motors for other drives. The series hybrid powertrain has an 80-kWh lithium-iron-phosphate battery, flanked by a small 15-kW biodiesel generator as a range extender. The boat demonstrated to ensure a fuel saving of 72%–100% and an operating energy cost saving of 20%–36%, depending on the route driven in hybrid or full electric mode. The prototype is expected to contribute to a wider transition to waterborne electric mobility in Venice.