Wind-powered cargo ships hope for smooth sailing
Swedish firm bets on futuristic vessels to limit emissions
Two centuries after the first coal-powered steamships crossed the Atlantic Ocean, a Swedish company is designing a futuristic throwback: a huge, wind-driven cargo ship that could help end the fossil fuel era and tackle the climate crisis.
Shipping accounted for 2.9 per cent of man-made greenhouse gas in 2018, and the industry’s share of planet-heating emissions has been rising in recent years, according to the UN’s International Maritime Organisation.
One solution may be to turn the clock back to pre-industrial times and again hoist sails to carry cargo around the world.
Sweden’s Wallenius Marine AB, which designs and builds ships, is currently testing a sleek white model of an “Oceanbird” automobile carrier in a bay in the Baltic Sea.
Per Tunell, Wallenius’ chief operating officer, says results from the seven-metre model were encouraging
and that he was “very confident” the full-scale Oceanbird will be ready to order by the end of next year. The sail-driven ship could be in service in 2024 on Atlantic routes, he says.
The Oceanbird will be 200m-long with capacity to carry 7,000 cars. It may be the tallest sailing ship ever built, equipped with wing sails reaching 105m above the water.
The sails, however, look little like traditional billowing fabric sails, instead more closely resembling aircraft wings rising vertically from the deck.
The vessel will have engines as a backup, but aims to save 90 per cent of carbon emissions compared to a conventional ship run on polluting bunker fuel.
It will take Oceanbird about 12 days to cross the Atlantic, compared to eight for a fuel-powered ship.
“The design could also be applied as a cruise vessel, a bulk carrier, a tanker,” Tunell says. “One of the key conditions is that it shall be commercially feasible.”
Oceanbird would probably cost a bit more than a conventional car carrier, he says, declining to estimate the exact price. But operating costs would be lower, especially if governments trying to curb climate-changing emissions impose a price on carbon emissions from using fuel.
The Oceanbird is not the only emerging contender in the low-carbon shipping race.
Neoline in France is seeking orders for a smaller, 136m vessel, also suitable for transporting cars or farm machinery. Like Oceanbird, it reckons its carrier could cut emissions by 90 per cent.
Such cargo ships would mark a maritime revolution. Until now most companies trying to cut emissions have viewed sails as an add-on to curb fuel consumption, not as the main source of propulsion.
But new technologies, such as wing sails and tougher, lighter materials inspired by racing yachts in the America’s Cup, may enable a fuller shift to wind.
More reliable long-term weather forecasts also allow better route planning to avoid storms or doldrums.
“It makes sense to use this historic wind power, but also new technology,” says Jean Zanuttini, chief executive officer of Neoline.
He says negotiations were underway on possible contracts and shipyard deals, with the first “Neoliner” vessel likely to be in service by July 2023, at a cost of about €40-€50m (£35-45m).
Partners in designing and using the ship include carmaker Renault, he says.
Among early ocean-going steamships, the SS Savannah took 29 days to cross the Atlantic from the US state of Georgia to Liverpool in England in 1819. Paddle wheels on its sides to supplement sails were its main power source.
Later the SS Royal William crossed the Atlantic from Pictou in Canada to London in 1833, relying almost entirely on steam power from coal.
Many shipping companies trying to cut emissions are seeking a boost from sails, kites or Flettner rotors – tall spinning tubes that help push a ship forward in much the same way as wings on a plane provide lift.
Helsinki-based Norsepower, which has installed such rotors on cargo ships and cruise ships, says they can typically cut fuel use by 5 per cent to 20 per cent.
Diane Gilpin, head of the Smart Green Shipping Alliance in Britain, says wind-powered ships are alluring on the drawing board and sails are a “no brainer” for fighting climate change.
Nearly a decade ago, she led a company that designed a “100 per cent renewable-powered cargo ship” with
sails and an engine using biogas from municipal waste. Tests of a model were successful, but it has not been built.
“The biggest challenge is getting market uptake. Everybody loves the pictures, everybody loves the story. But nobody puts the money into it,” she says.
Still, the International Maritime Organisation has said it wants to cut climate-changing emissions from shipping by half by 2050, from 2008 levels, she says. That means that any ships ordered today, with an expected lifetime of 30 years, will have to be far less polluting.
With more than half of the journey costs for a ship coming from fuel, Gilpin says governments could spur a green shift by imposing a carbon emissions price of perhaps $50 a tonne on shipping.
Among the drawbacks for wind-powered vessels are that ports operate on strict deadlines, meaning an unexpected extra day at sea can mean missing a slot for unloading cargo in port and long, costly delays.
Both Oceanbird and Neoliner plan to use engines, powered by fossil fuels or biofuels, to stick to schedules if the winds they depend on calm en route. But Tunell says the engines and fuel tanks would be smaller than on a comparable vessel.
“Most of the other companies are focused on wind assistance. We are focusing on wind power. This is a sailing vessel,” Tunell says. Jakob Kuttenkeuler, a professor at the Swedish KTH Centre of Naval Architecture who is running tests for Oceanbird, says one research puzzle is what wind changes will be like as sails reach new highs above the sea surface.
Oceanbird’s wing sails, likely to be built from aluminium, steel and composite materials, will rise from a deck 35m above the water, reaching 105m (345ft) above sea level.
Most mariners have learned how to manage winds closer to the water line, where waves causes air turbulence.
“Not too many people have utilised this part of the atmosphere in the open ocean. Planes go higher and ships go lower,” he says.