The Swedish company serving ferry traffic in the Stockholm archipelago has put in operation Yxlan, a diesel-electric vessel built by the Estonian Baltic Workboats and equipped with a hybrid drive from Danfoss Editron.

The ferry operates with two diesel engines and a battery pack (in good weather conditions, Yxlan can operate with one diesel engine and the battery pack system). The Danfoss Editron marine system consists of two hybrid drivetrains with permanent magnet electrical motors and generators.

The hybrid propulsion system is integrated into a single common unit controlled by Baltic Workboats' monitoring and alarm system. The hybrid system is also controlled by software that optimises each individual component of the hybrid drivetrain, allowing for an intelligent management of power distribution.

In addition, Yxlan has also installed an exhaust cleaning elective catalyst reduction system to cut the emission of nitrogen oxides.

The 27.5 m-long ice class ferry is able to take up to 150 passengers on-board and sail through 0.25 m-thick ice.

The ferry will help the capital of Sweden with its goal of becoming a fossil fuel-free city by 2040. Additionally, back in 2015 the members of the Swedish Shipowners' Association committed to becoming zero-carbon by 2050.

"A hybrid vessel was the perfect choice for the city of Stockholm. The ferry will have to operate across all seasons, so we needed a system that would enable the crew to switch to diesel-electric or batteries in case of engine failure. We chose to work with Danfoss Editron because their marine system is robust yet lightweight, plus delivers high efficiencies. Their equipment is also really compact, which is a crucial factor to consider when building small hybrid vessels [According to the manufacturer, the system is half the size of a conventional, diesel-electric propulsion system]," Peeter Raamat, Head of Technical Department, Baltic Workboats, commented.

Kari Savolainen, Project Manager, Danfoss, added to this, "As countries adopt regulations to advance towards carbon neutrality, we can expect demand for such hybrid electric solutions to grow rapidly. Electrifying marine transport is set to become a key trend and Scandinavian countries are leading the way."

Photo: Robert Levin/Baltic Workboats