The World’s Largest Marine Battery Retrofit Is Coming to a Ferry

In a bold move to slash emissions, the hybrid-electric ferry Aurora Botnia is getting a massive battery upgrade—one that will make it the largest marine battery retrofit in history. The 10.4MWh system, supplied by AYK Energy, will dwarf the ship’s current 2.2MWh capacity and edge out the previous record-holder, the Aida Prima cruise ship, by half a megawatt-hour.

A Greener Voyage

Built in 2021 and operated by Wasaline, the Aurora Botnia already runs on a mix of liquefied natural gas (LNG), biomass, and battery power. But the retrofit will push its fossil fuel dependence even lower, cutting annual energy use by roughly 10,000MWh and reducing emissions by nearly 25%. That’s a significant step for a vessel that shuttles passengers and cargo across the Baltic Sea.

“This isn’t just about breaking records—it’s about proving that large-scale marine electrification is viable now,” says an industry insider familiar with the project.

Battery Tech and Timeline

The new AYK Pisces+ battery system relies on Lithium Iron Phosphate (LFP) chemistry, a safer and more durable alternative to traditional lithium-ion. Installation will take place at Finland’s Turku Repair Yard, with work expected to wrap up by late 2025. If all goes to plan, the ferry will be back in service by January 2026.

AYK’s batteries are rolling out of a state-of-the-art 5,000-square-meter automated facility in Zhuhai, China, which opened last year. The plant currently produces 300MWh annually but can scale up to 1GWh as demand grows—and it’s clear that demand is surging.

The Rising Tide of Marine Electrification

AYK isn’t just supplying ferries. The company’s batteries are finding their way into tugboats, offshore support vessels, superyachts, and even container ships. As stricter emissions regulations loom, the maritime industry is scrambling for cleaner alternatives, and AYK is positioning itself as a key player in that transition.

For now, all eyes are on the Aurora Botnia. If this retrofit succeeds, it could set a new standard for how quickly the shipping world can decarbonize—one massive battery at a time.