Finnish technology group Wärtsilä will deliver and integrate the world’s largest marine battery hybrid system on Wasaline’s ferry Aurora Botnia, expanding the ship’s storage capacity nearly sixfold in an effort to cut fuel consumption and greenhouse gas emissions.
Battery Expansion to 12.6 MWh
The order, booked in the third quarter of 2025, will increase the ferry’s current 2.2 megawatt-hour battery capacity by an additional 10.4 MWh, bringing the total to 12.6 MWh. Wärtsilä said the new system will be commissioned in early 2026.
The Aurora Botnia already operates with dual-fuel engines and a smaller battery setup, using biogas and stored power to reduce reliance on conventional fuels.
The battery expansion marks a significant step in advancing the ship’s sustainability profile, making it the largest operating marine battery hybrid of its kind.
Push for Lower Emissions
Hybrid propulsion systems that pair energy storage with conventional engines are increasingly viewed as a route toward cleaner shipping. By enabling vessels to operate more efficiently, they can significantly reduce fuel consumption and greenhouse gas emissions.
“Wasaline’s commitment to decarbonised shipping operations is central to everything we do,” said Peter Ståhlberg, managing director of Wasaline, in the press statement. “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.”
Roger Holm, president of Wärtsilä Marine and executive vice president of Wärtsilä Corp., said the extended electrification would boost efficiency. “Our latest contribution will optimize the ship’s operations even further, creating fuel savings and a significant reduction in emissions,” he said.
Integration and Upgrades
Wärtsilä will serve as the electrical integrator for the project, delivering a new energy management system along with upgraded power drives and control system integration.
The upgrades are aimed at ensuring the ferry can manage its expanded battery storage effectively and maximize efficiency gains.
Floating Testbed for Hybrid Shipping
The initiative also deepens an existing collaboration agreement between Wärtsilä and Wasaline. The Aurora Botnia will serve as a floating test platform connected to Wärtsilä’s Sustainable Technology Hub, allowing the companies to further develop and refine hybrid technologies.
Commissioned in 2021, the ferry already features four Wärtsilä 31DF dual-fuel engines, which the company said have significantly reduced methane emissions.
The vessel operates daily between Vaasa in Finland and Umeå in Sweden, and is described by its owners as one of the most environmentally sustainable ferries in operation.
