Preserving Venice by boarding a hybrid vaporetto / with MG’s batteries

For more than a decade, Alilaguna has been active in the research and development of environmentally sustainable transport solutions to safeguard the lagoon environment and protect the delicate balance of the historic centre of Venice. Since the first prototype launched, the Liuto, a hybrid vaporetto with diesel-electric propulsion has been upgraded with the most current technologies.

Alilaguna

Project / story

Their challenge

When visiting the beautiful city of Venice there are to ways to get around: on foot or by water. In case the former is no option, a vaporetto is the way to go. It’s Italian for water bus and a large fleet makes up a public transport network for the city and province, transferring hundreds and thousands of passengers each day, from the mainland across the lagoon, through the canals and to the nearby islands.

The increase of tourists and therefor transportation has a dangerous impact on the delicate environment of the lagoon in general and the canals in particular, with many precious historic buildings on their banks. The constant navigation and frequent manoeuvring generates a lot of waves and washing water, which in turn leads to progressive erosion of their foundations, draining them of sand and clay.

Operating conditions of a vaporetto are very particular. Due to the many stops, congested traffic, varying speed limits and timetable optimisation their navigation pattern show high acceleration and deceleration performances. The heavy sequence of stop-an-go transitions requires a very irregular power supply. When supplied directly by a generator, this would lead to high diesel consumption and high exhaust emissions.

Enter Liuto: an acronym for Low Impact Urban Transport water Omnibus. It’s a vaporetto with a low resistance hull and a hybrid energy solution, designed around two decades ago. The 300kW Siemens propulsion system used to be powered by lead-acid battery pack, which in turn was charged by a diesel generator running at constant speed. This way the engine could operate at its optimum efficiency level, minimising fuel consumption, pollutant emissions, vibrations and noise.

At the time the hydrodynamic impact was reduced by the optimised hull and propeller, while the hybrid energy solution was a good compromise between technical, economic and environmental requirements. Recently its lead-acid battery bank has been upgraded to MG’s RS batteries, two strings of eight modules each, controlled by a HV Master. Together they operate as peak power supply and energy buffer, under very high but short charge/discharge power levels.

This is what our RS Series excel at. Compared to traditional lead-acid batteries these lithium-ion modules can take in and push out a large amount of power in a short time. Liquid thermal management keeps the battery cells on temperature, to improve performance and extend cycle life. A redundant BMS, a unique cell-to-cell propagation protection and a built-in fire suppression mechanism take safety to the next level. As an added advantage they’re compact and lightweight.

Compared to steel or aluminium vessels with traditional propulsion systems Liuto is a beautiful example of a more efficient, more economic and more ecological solution even in a challenging application such as urban water transport. It generates less wave motion pollution, less air pollution and increases comfort for all passengers. Now it’s ready to serve another decade while protecting the delicate and valuable context of Venice and its lagoon, for both tourist and inhabitants alike.

Our solution

Components used

Project / specs

System voltage

8 x 58 V

Total capacity

2 x 62 kWh

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