Rolls-Royce plc has signed a contract to deliver its Azipull propulsion and control system for the battery-powered “ferry of the future.” The new vessel is being built at the Fjellstrand yard in Norway, and will go into service in 2015 on the route between Lavik and Oppedal, across the Sognefjord, operated by Norwegian transport company Norled.

In 2010, the Norwegian Ministry of Transport announced a tender to develop a new ferry that was 15 to 20 per cent more energy efficient than existing vessels. The winner was the ZeroCat, an 80-meter aluminum catamaran that weighs half as much as a conventional ferry. Its two slim hulls offer minimal water resistance, and the Rolls-Royce Azipull propulsion system, which uses pulling propellers instead of conventional azimuth thrusters, further increases energy efficiency.

The ZeroCat can carry up to 120 cars and 360 passengers, and will operate at a speed of about 10 knots, taking 20 minutes for the crossing. Its electric motors are powered by a 1,000 kWh lithium-polymer battery pack that weighs 10 metric tons. The ferry will charge its batteries while loading or unloading cars, and overnight when moored. It only takes 10 minutes to recharge, using a 1,000 kW charger, but the local grids in the two small villages linked by the ferry aren’t equipped to deliver such a large amount of power. Therefore, batteries have been installed at each port, which will recharge the ferry’s battery during turnaround and then be slowly recharged themselves from the local grid.

The vessel currently serving this route uses some one million liters (264 thousand gallons) of diesel per year, and emits 570 metric tons of carbon dioxide and 15 metric tons of nitrogen oxides.

Neil Gilliver of Rolls-Royce said, “The combination of good maneuverability and reduced energy consumption provides a highly efficient ferry for Norled, with significantly reduced operating costs and improved environmental performance. This contract also marks the tenth anniversary of the delivery of our very first Azipull thrusters, which was also to Fjellstrand shipyard.”

Sources: Green Car Congress, Rolls-Royce