VESSEL REVIEW | Ecocat Dos & Ecocat Tres – Electric commuter ferries to operate in Barcelona, Spain

UK-based transport company the Mobico Group, via its Spanish operating arm Alsa, has launched Bus Nàutic, a new zero-emission boat service connecting Drassanes and Llevant wharfs in the city of Barcelona.

This service is a key step by Port de Barcelona towards port-city integration and provides a viable alternative to land transport, thus helping relieve traffic congestion on the Colom and Joan de Borbó avenues. Alsa was selected to provide the service, which introduces a fleet of electric vessels in compliance with the city’s sustainability plans.

One design with two different passenger capacities

The new service operates at least 12 hours a day, with frequencies ranging from 15 and 30 minutes for the 10-minute service. It is being served by the 15-metre (49-foot) long aluminium catamaran ferries Ecocat Dos and Ecocat Tres, which provide capacities for 56 and 84 passengers, respectively. Ecocat Tres' increased passenger capacity is due to its having a roof deck fitted with additional seats.

The boats, which were built by local shipyard Metaltec Naval, are capable of generating zero emissions and will save 180 tonnes of CO2 a year. The zero emissions are made possible by electric propulsion systems augmented by PV panels.

Electric propulsion configured for continuous operations

The propulsion and power solution supplied by Azimut Marine delivers a top speed of 12 knots, though limiting sailing to a constant speed of five knots will allow each boat to operate continuously for up to 21 hours.

To enable the ferries to achieve the required performance, Azimut Marine integrated a suite of advanced solutions designed to function as a single, fully coordinated system. Each element not only operates independently, but integrates and communicates with the others, including the necessary accessories and add-ons to ensure efficient, safe operation and an intuitive user experience.

The selected propulsion system is based on two ARIES i50 Molabo electric motors installed in the twin catamaran hulls of each vessel. These motors, which operate at 48 V, minimise the risks associated with high-voltage systems and offer quiet propulsion with minimal vibrations, improving onboard comfort.

Its energy efficiency, rated at over 90 per cent, optimises consumption and allows the range of each boat to be significantly extended, thus achieving up to 20 per cent greater performance compared to other similar electric solutions. Azimut Marine said this level of efficiency has been key to guaranteeing and exceeding the six hours of continuous navigation initially required.

Backup and safety features

The power system was designed with Mastervolt MLI 24/6000 lithium-ion battery banks. A total of 36 batteries (18 per hull) are installed on each catamaran, generating a total capacity of 216 kWh per boat and guaranteeing a sustained rated current of approximately 4,000 Ah, with peaks of up to 16,000 Ah.

In addition, 12 fast chargers per boat (six per hull) of 48 V and 50 Ah were incorporated, significantly improving charging times and ensuring continuous and efficient operation. A solar power system with four MPPT regulators and a power system for services and emergencies was added, providing optimal performance even in critical situations.

Although not part of the project requirements, an advanced monitoring solution based on Czone technology, customised and integrated within a Raymarine navigation display, was incorporated on each boat to ensure efficient and simplified handling. This system allows operators to monitor and control all the systems of each boat in real time, optimising operability and facilitating energy management.