How Incat built a 2,100-Passenger ferry that runs only on batteries

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China Zorrilla, Incat’s Hull 096, has reached Uruguay on the back of a heavy-lift ship, because the world’s largest battery-electric ferry is built to run for only about 90 minutes on a charge.

This 130-metre aluminium catamaran just completed an epic journey halfway around the world as cargo. But getting it off the delivery ship required a spectacular engineering trick.

In mid-September, at a river port in Nueva Palmira, Uruguay, the massive transport ship flooded its own decks until it sat completely underwater, allowing this giant catamaran to safely float right off its back. Its name is China Zorrilla, after the Uruguayan actress loved on both sides of the Río de la Plata. At Australia’s Tasmanian shipyard that built it, it’s simply Hull 096.

It carries 2,100 passengers and 225 cars. It has no combustion engines and burns no fuel. It runs on more than 40 megawatt-hours of batteries, weighing over 250 tonnes.

So why did it need a lift? Because on a charge, it’s built to run for about 90 minutes. Enough to cross a river but nowhere near enough to cross an ocean.

So how do you make a ship this big run on batteries alone? What did the engineers have to give up? And will it actually work?

Hull 096 was ordered in 2019 by Buquebus, the company that runs fast ferries between Buenos Aires and Uruguay. It’s the ninth ship Incat has built for them. And it wasn’t meant to be electric.

Incat’s 2019 spec sheet shows four Wärtsilä dual-fuel engines burning liquefied natural gas, 8,800 kilowatts each, good for about 37 knots flat out. That made sense for Buquebus. It already runs Francisco, an Incat ferry with LNG-burning gas turbines that has hit 58 knots.

Then in January 2023, with the ship already being built, Buquebus and Incat went public with a plan to drop the gas and go fully battery-electric. Incat’s Craig Clifford called it ‘just swapping one method of propulsion for another’. On a fast ferry, though, nothing is ever just a swap. Because of weight.

A fast ferry lives and dies by weight. Every extra tonne means more drag, more power, and less speed. That’s why Incat builds in aluminium. Two long, slender hulls joined by a bridging deck. Built this way, the ship weighs about half what a steel version of the same design would.

Now add over 250 tonnes of batteries. And batteries make a poor fuel tank. Kilo for kilo, LNG or diesel holds dozens of times more energy than lithium-ion. And Buquebus didn’t shrink the job to make room. The ship still has to carry 2,100 people, 225 cars and a duty-free shop of about 2,300 square metres.

Run the numbers on this ship and the whole system stores roughly 160 watt-hours per kilo. That one figure decides everything else: how far it goes, how fast, and how often it has to plug in.

The batteries come from Corvus Energy in Norway, a system called Dolphin NextGen. There are 5,016 modules, arranged in 12 arrays of 418, spread across four dedicated battery rooms. For scale, that’s roughly the batteries of 500 long-range electric cars, inside one ship.

To save weight, the modules sit without conventional mounting racks. Each one is air-cooled by its own fan. The big fear with a battery this size is thermal runaway, where one overheating cell sets off the next. Corvus isolates every cell. As its CTO Lars Ole Valøen told IEEE Spectrum, if any cell goes into thermal runaway, it does not spread to neighbouring cells.

The first battery room was switched on in October 2025. In January 2026, the ship went out on Hobart’s River Derwent for harbour trials under its own battery power.

Everything between the batteries and the water comes from Wärtsilä. Energy management, power conversion, a DC hub, eight electric motors and eight Wärtsilä WXJ1100 waterjets.

Here’s how the power flows. The batteries store direct current. The DC hub pools it, converters turn it into the alternating current the motors want, and each motor spins a pump inside a waterjet. A waterjet pulls water in under the hull and fires it out the back.

No propellers hanging below the ship, which matters on the Río de la Plata, a huge and famously shallow estuary.

Each hull gets four jets. Two that steer, and two boosters that just push. The motors are reported at about 2.4 megawatts each, so roughly 19 megawatts in total. The gas version would have had about 35.

So the electric ship is slower. It’s expected to cruise at around 25 knots, and it reportedly touched 29 in trials with 600 tonnes on board.

Now the part that makes or breaks this ship. Buenos Aires to Colonia is about 30 nautical miles, roughly a 90-minute crossing. That’s about what one charge is built for, so it tops up at the dock on every crossing.

At Colonia, two high-power chargers have gone in, backed by around 20 million dollars of electrical works with Uruguay’s state utility UTE. In Buenos Aires, the terminal is fed by the grid company Edesur.

The plug connects itself. Norwegian firm Zinus is supplying an automated charging tower rated at 16,000 amps of direct current, and reports put a top-up at around 40 minutes.

Where that power comes from matters too. Uruguay makes nearly all its electricity from renewables, mostly wind and hydro. Argentina still relies on gas-fired plants for about half of its power.

a month ago

Transportation

How Incat built a 2,100-Passenger ferry that runs only on batteries

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