How Australia built the world’s biggest battery-powered ferry

When the world’s largest battery-powered passenger ferry hit the River Derwent in Hobart, Australia, for testing, there was an unexpected hitch.

It wasn’t the actual transport. The 427-foot aluminum catamaran — designed to carry 2,100 passengers and about 225 vehicles — moved easily through the waves in the January trial and comfortably hit its intended speed of about 25 knots.

“It was an exciting moment for our first electric ship, it was quite remarkable that the ship was so responsive,” said veteran shipbuilder Robert Clifford, the 83-year-old founder and chairman of Incat Tasmania, which built the ferry and other vessels for customers in more than 20 countries.

Yet without the loud rumble of diesel engines, other noises became more conspicuous, Clifford said in an interview. “The customer complained, because actually you heard the air-conditioning fans,” he said. “The rest of the ship was so quiet.”

China Zorrilla made its first commercial journey for ferry operator Buquebus last week on the roughly 75-minute route between Buenos Aires in Argentina and Colonia del Sacramento in Uruguay. The vessel is regarded as a breakthrough for clean shipping. It carries more than 250 metric tons of batteries, a system that’s roughly four times larger than any previous maritime installation.

While the ferry sector is only a fraction of a shipping industry dominated by container ships and tankers, advocates insist China Zorrilla will prove larger vessels can move away from polluting fuels. Greenhouse gas emissions from global shipping accounted for roughly 754 million metric tons of carbon dioxide equivalent in 2025, more than international aviation and only a little less than Canada, according to European Commission data.

“It’s quite a pronounced shift,” said Mike Corrigan, chief executive officer of Interferry, an industry group that represents more than 280 companies across the ferry sector. “When I look at the new build orders and what’s coming down the pipeline for our operators, I’m not seeing very many vessels that are being built to operate on our traditional fuel sources.”

Going electric has become possible as battery capabilities rapidly improve and equipment costs decline. The energy density of typical electric-vehicle battery packs has jumped more than 60% since 2010, while prices have plummeted about 93%, according to BloombergNEF data.

“This kind of cost-performance ratio improvement has really made the battery technology accessible,” said Shirley Meng, a distinguished professor and vice president (industry) at Nanyang Technological University in Singapore, and who jokes that her nickname is the “doctor for batteries.”

Just as electric trucks are starting to expand battery deployments on the road beyond passenger cars or motorcycles, ferries are the next step for vehicles at sea after powerboats, tugs and other small-scale vessels. The category is an ideal use case, because ferries move along predictable routes and stop at terminals to load and unload passengers and vehicles, providing regular opportunities to recharge.

The technology is already well established for smaller city ferries and being put to work in some types of container ships. In China, a policy announced in September calls for the number of so-called new-energy vessels on inland waterways to roughly double by 2028 and to include more than 1,000 electric ships.

“The electric ferry is the very beginning,” said Meng, who is also a professor at the University of Chicago Pritzker School of Molecular Engineering. “We’re seeing the maritime industry start to seriously consider batteries.”

The global fleet of battery-powered vessels either delivered or under order is now at least 2,000 commercial ships, including hybrid models, according to a registry maintained by the Maritime Battery Forum, which acknowledged it was probably undercounting the number operating in China.

“We are passing a crucial tipping point,” Managing Director Syb ten Cate Hoedemaker said this month. “It now makes clear economic sense to build larger, fully electric ships.”

Specialist shipbuilders and battery suppliers are readying for rising demand. Swedish hydrofoil startup Candela Technology AB raised $34 million in March in a new funding round, while Norway’s Fjellstrand shipyard, which completed the world’s first electric ferry in 2014, is building a new vessel. Contemporary Amperex Technology Co., the world’s biggest battery producer, has a dedicated marine unit and competitor BYD Co. last year partnered with sector specialist Corvus Energy.

Onboard the China Zorrilla, four small, tightly packed rooms house a total of 5,016 Corvus lithium-ion batteries, with the gleaming, silver components stacked more than 30 units high. “Anywhere between 500 and 600 EVs could be powered by the capacity that we have on this vessel,” said David Riseley, the shipbuilder’s head of projects, inspecting the equipment in a narrow space between the stacks.

For the world’s ferry fleet, which transports about 4 billion passengers a year, battery-powered journeys of up to 25 nautical miles are already standard, with a range of 100 nautical miles likely to be achievable within about a year and 200 nautical miles in roughly five years, Clifford said, sitting on the ship’s plush main passenger deck.

About 95% of ships on shorter routes will probably eventually switch to battery power, he said. “Electrics are going to be the mainstay of the ferry industry.”

Initial upfront costs for electric vessels are likely to be higher than traditional models, Clifford acknowledged. “The electric ship might be more expensive, but almost certainly it will pay for itself in the first few years,” he said. “In 10 years’ time, I don’t think there’s the slightest doubt that it will be much more economical to be electric.”

The total investment of $184 million for the vessel China Zorrilla included financing from Banco Santander SA and the World Bank’s International Finance Corp. The amount covered not only the ship, but the infrastructure needed for recharging — a task expected to take about an hour per trip.

Battery power still has limitations for shipping. It isn’t seen as an option for the largest vessels or for ocean-spanning journeys that can take days or weeks. China’s recent policy on inland waterways prioritizes electric vessels for smaller cargo and shorter distances, encouraging the use of methanol fueled-ships on more demanding routes.

Container vessels, bulk carriers and tankers carrying fuels or chemicals account for much of the shipping industry’s climate impact, with ferry categories responsible only for roughly 3% of the sector’s emissions, Organization for Economic Cooperation and Development data show.

“Long-haul cargo needs to look for alternative solutions,” said Meng, pointing to the potential use of hydrogen or nuclear power.

The appetite to decarbonize has also waned in parts of the shipping industry. Following complaints by President Trump’s administration in the U.S. and interventions from other nations, the International Maritime Organization last year postponed a decision on adopting a landmark charge on vessel emissions.

Even so, improved economics and technology mean virtually all ferry operators with routes of less than two hours are actively studying fully electric options, while others are examining hybrid solutions that pair batteries with traditional fuels, according to Interferry’s Corrigan.

In a vast construction hall at Incat’s shipyard in May, the aluminum outline of a new hybrid-electric vessel took shape as giant pieces of jet rooms and vehicle decks were hoisted into place. Under showers of bright sparks in a prefabrication shed along the marina, welders shaped large metal sheets into the modules that will form one of three fully battery-powered ferries for Denmark-based operator Molslinjen A/S.

With five new orders underway and demand forecast to rise, Clifford isn’t planning to step back. “I retired 15 years ago,” he said. “That hasn’t worked out well.”

Instead, Incat is adding new facilities and aims to lift production from its current rate of about two ships a year.

“Four ships a year is the immediate target,” Clifford said. “Ten ships a year, 12 ships a year is probably a five-to-10 year plan. We must do that, because the market absolutely is demanding that these ships be built.”

Stringer writes for Bloomberg.