A Hybrid For Ice Work

Stockholm, Sweden-based Waxholmsbolaget has launched its first hybrid ice-going passenger ferry.

The 27.5 m vessel incorporates the Danfoss Editron hybrid electric propulsion system. The vessel, designed and built by Baltic Workboats, is serving the Stockholm archipelago and is built to transport up to 150 passengers at a time.

Since the ferry will be operated year-round, it has been specifically designed to be able to operate in ice up to 25 cm thick. The vessel operates with two Scania diesel engines and a battery pack, creating a hybrid power plant providing clean power to propulsion. With good weather conditions, the ferry can operate with one diesel engine and the battery pack system, further minimizing emissions, the company said The hybrid propulsion system is integrated into a single common unit controlled by Baltic Workboats’ monitoring and alarm system. The vessel is also equipped with an exhaust cleaning elective catalyst reduction system to further reduce emissions.

The Danfoss Editron marine system 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, making it the most compact and lightweight on the market, the company said. Editron’s permanent magnet machines cut fuel and running costs, resulting in significantly reduced CO₂ emissions and payback period, the company said. Editron powertrain systems are designed for hybrid and electric applications within the power range of 30 kW to 2000 kW.

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.

“A hybrid vessel was the perfect choice for the city of Stockholm,” said Peeter Raamat, head of Technical Department at Baltic Workboats. “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.”

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.