Technology group Wärtsilä has been selected as the electrical integrator for a battery extension project on the Wasaline ROPAX ferry Aurora Botnia, which the company claims will create the world's largest marine battery hybrid system in operation.

The project will increase the ship's battery capacity by 10.4 MWh, from 2.2 MWh to 12.6 MWh. The order with Wärtsilä was booked in Q3 2025, with the system scheduled to be commissioned in early 2026.

Wärtsilä will lead the integration project and deliver the Energy Management System, as well as upgrade the power drives and control system integration. The Aurora Botnia ferry, operated by Wasaline, is equipped with dual-fuel engines and batteries and uses biogas and batteries for propulsion.

"Wasaline's commitment to decarbonised shipping operations is central to everything we do," said Peter Ståhlberg, Managing Director at Wasaline. "In this, our close cooperation with Wärtsilä is an essential element that benefits not only both our companies, and we can see that our cooperation sets standards for the whole marine sector."

The project will strengthen the existing collaboration agreement between Wärtsilä and Wasaline, with the Aurora Botnia acting as a floating test lab linked to Wärtsilä's Sustainable Technology Hub. According to the companies, this allows further development of hybrid technologies to optimise fuel efficiency and minimise exhaust emissions.

"Wasaline once again demonstrates its strong commitment to decarbonisation by extending the electrification capacity of this ferry," commented Roger Holm, President of Wärtsilä Marine & Executive Vice President at Wärtsilä Corporation. "Our latest contribution will optimise the ship's operations even further, creating fuel savings and a reduction in emissions."

The Aurora Botnia entered service in 2021 and operates with a range of integrated Wärtsilä solutions, including four Wärtsilä 31DF engines. The ferry operates between Vaasa in Finland and Umeå, Sweden.

Hybrid propulsion systems combine energy storage capabilities with conventional engines and can reduce fuel consumption and emissions. The systems have emerged as one solution for ferry operators seeking to reduce greenhouse gas emissions in their transition to more sustainable transportation.

According to Wasaline, the vessel operates carbon neutrally and is described by the company as one of the most environmentally sustainable ferries in the world.