In summer 2013, the world’s first two ferries with a hybrid propulsion system will be put into service. Owned by Caledonian Maritime Assets Ltd (CMAL), they are being built by Ferguson Shipbuilders in Glasgow. With its hybrid concept, the shipyard aims to reduce the ferry’s CO2 emissions by up to 20 percent.
The vessels will be the first of their kind to combine a diesel-electric propulsion system with lithium ion battery technology. The ferries will operate on various routes in the Scottish waters, which are characterized by strong currents and heavy winds. Both double-ended ferries will be equipped with two two type 16R5 EC/90-1 Voith Schneider Propellers with an input power of 375 kW per propeller.
Reducing Fuel Consumption and Noise
To take load off the diesel engine temporarily, the two lithium ion battery banks of each ferry are charged overnight from the grid. With the hybrid propulsion system the shipyard strives to reduce the ferry’s fuel consumption and thus its CO2 emissions with 20 percent. Apart from the economic benefits, the hybrid propulsion system leads to a significant reduction in mechanical stress and noise, in particular when entering and leaving ports.
Built to Port Infrastructure
Ferries are generally designed and built for the specific operating scenario in question, with the port infrastructure kept in mind. The new hybrid ferries are to be used on various routes in the Scottish waters to transport approximately 150 passengers and 23 cars per ferry with a service speed of approximately 9 knots. Many Scottish ferry landing areas consist of concrete ramps. The ferries dock without being moored tightly. Accurate control and positioning as well as the high maneuverability are essential for docking in rough seas. Therefore the propellers are arranged diagonally in recesses and not in central positions at the front and aft, as is otherwise the case, to protect them during docking manoeuvers.
Picture: the hybrid ferries are meant to save up to 20 per cent of fuel and emissions (source: https://www.cmassets.co.uk/en/our-work/projects/current-projects/hybrid-ferries-project.html[CMAL]).