Stockholm’s Hybrid Ice-Class Passenger Ferry

The Swedish shipping company Waxholmsbolaget in Stockholm has launched its first hybrid ice-going passenger ferry, Yxlan. The 90 ft. (27.5 m) vessel, designed and built by the Estonian shipyard Baltic Workboats, is serving the Stockholm archipelago (Sweden) and is built to transport up to 150 passengers at a time.

As the ferry will be running year-round, it has been specifically designed to operate in ice up to 10 in. (25 cm) thick with the vessel ice strengthened to ICE 1A and can go as fast as 4 knots in those conditions, according to Baltic Workboats website.

The vessel operates with two Scania diesel engines and a battery pack, creating a hybrid power plant. In good weather conditions, the ferry can operate with one diesel engine and the battery pack system. The hybrid propulsion system is integrated into a single common unit controlled by Baltic Workboats’ monitoring and alarm system.

As the vessel will also operate in winter, there are requirements of insulation, waste heat recovery, as well as heat recovery of the exhaust air. The vessel is also equipped with an exhaust cleaning SCR system to further lower the emissions.

The vessel is equipped with a Danfoss Editron marine system, which consists of two hybrid drivetrains with permanent magnet electrical motors and generators. The system is half the size of a conventional, diesel-electric propulsion system, Danfoss said. Editron’s permanent magnet machines cut fuel and running costs, resulting in reduced CO2 emissions and payback period.

Peeter Raamat, head of Technical Department at Baltic Workboats said, “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.”

This is the second partnership between Danfoss Editron and Baltic Workboats, following the delivery of a hybrid patrol ship to the Estonian border authorities earlier this year.

Kari Savolainen, project manager at Danfoss, said: “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.

Decarbonizing maritime transport has become both a major challenge and ambition for the industry, since the International Maritime Organization adopted a strategy to reduce at least 50% of greenhouse gas emissions from the global shipping sector by 2050. Sweden is at the forefront of decarbonizing marine transport. In 2015, the Swedish Shipowners’ Association became one of the first shipping associations worldwide to commit to zero-carbon shipping by 2050.

The electrified ice-class ferry will help the city of Stockholm achieve its target of becoming a fossil fuel-free city by 2040, while providing more comfortable transportation for passengers with lower noise and vibration levels. sdpriori