Cargo ships turn to ancient tech to curb modern pollution: wind
As shipping companies face mounting pressure to curb CO2 emissions, old-fashioned sails and new designs are helping to reduce the need for fossil fuels.
Grain de Sail II at sea (Pierrick Contin/Grain de Sail)
Billions of dollars worth of goods will flow into the United States this holiday season, carried on the decks and in the bellies of oil-burning freighters. But last week in Port Elizabeth, New Jersey, one particular shipment arrived from France using a far cleaner fuel to cross the Atlantic Ocean: wind power.
Grain de Sail II, a 170-foot-long sailing ship, brought 120 pallets full of natural wine, roasted coffee, chocolate bars, and luxury clothing from the French port city of Saint-Malo to the bustling East Coast cargo terminal. The eight-member crew sailed for 20 days over choppy waters and around blustery winter storms, propelled by the vessel’s 16,100 square feet of canvas sails.
“We were founded on the principle of trying to reduce the carbon footprint of maritime shipping,” said Stefan Gallard, chief marketing officer for the company Grain de Sail, which owns and operates the sleek white vessel and a smaller companion ship.
“And realistically, wind is the only means of propulsion today that grants very, very high decarbonization rates, if done properly,” Gallard said by phone from France.
Cargo handlers lower pallets full of tasty products into the vessel's hold before an August 2024 departure from Saint-Malo, France. (Grain de Sail)
International shipping contributes roughly 3 percent of the world’s greenhouse gas emissions every year, making it more polluting than all of Germany. But companies are facing rising pressure to curb their use of fossil fuels — both from regulatory agencies and the businesses that own the cargo on board.
Wind propulsion is making inroads amidst this decarbonization push, marking something of a comeback for an ancient technology that, since the turn of the 20th century, has largely lived in the smog-choked shadows of coal and diesel ships.
Easing off the diesel engines
For much of the last decade, the industry has chipped away at its emissions by tweaking vessel design and operations. Now such efforts appear to have hit their limits. Shipping emissions rose between 2018 and 2022, driven by the global surge in online shopping and the slowdown in efficiency improvements on oceangoing cruise and cargo ships, according to a new report by University College London (UCL) and the consultancy University Maritime Advisory Services.
Alternative fuels — such as green methanol and ammonia, potentially — could eventually replace the sludgy oil that powers most of the world’s 108,000-odd merchant ships. But the industry has barely begun to build up supply chains and design new systems for producing, distributing, and using lower-carbon fuels.
Wind, on the other hand, is abundant. With the U.N.’s International Maritime Organization poised to negotiate stricter climate policies next year, including a new carbon pricing mechanism and global fuel standard, more shipping companies are seriously considering the renewable resource as an immediate answer. While sails aren’t likely to outright replace the enormous engines that drive huge cargo ships, wind power could still make a meaningful dent in the industry’s overall emissions, experts say.
“As people are looking at their options and what’s available, and what’s going to truly deliver on reducing emissions and increasing efficiency, wind is going to be the obvious [solution],” said Natacha Stamatiou, a senior analyst on global shipping for the Environmental Defense Fund. Having enforceable policies in place that penalize pollution “is really going to kick things off” for wind and other energy-saving solutions, she added.
The owner of the Berge Olympus bulk carrier installed four Wind Wings, each measuring 123 feet tall, in September 2024. (BAR Technologies)
At least 48 large diesel ships to date have installed high-tech versions of traditional sails, including spinning rotor sails, giant towing kites, and steel-and-glass “wings” that mechanically rotate. That’s more than double the number of wind-blown devices in place two years ago, and dozens more projects are getting underway, according to the International Windship Association.
Unlike Grain de Sail II, which uses only wind power while at sea, these bigger ships harness the wind to lessen the workload of their diesel engines.
This hybrid arrangement has been shown to curb the fuel consumption of individual ships by around 20 to 30 percent. But results can vary widely depending on the type of ship and the routes and conditions of a particular voyage. That’s why, when spread across an entire fleet, the energy savings can be closer to 5 to 10 percent, said Tristan Smith, a professor of energy and transport at the UCL Energy Institute, who co-authored the recent emissions report.
Still, even those smaller figures represent “a massive potential and contribution to overall targets and objectives” for slashing shipping emissions, Smith said by email.
Sailing ships are scaling up
Meanwhile, more than 20 smaller, more traditional sailing ships are busy hauling batches of cargo by river and sea, including the two owned by Grain de Sail.
The company launched its flagship vessel in 2021, a newly built schooner with an aluminum hull and seven sails. The ship brought strapped-down pallets of organic wine in its foam-insulated hold to a private marina in Brooklyn, New York. From there, the crew carried donated medical supplies down to the Dominican Republic, then loaded up with coffee beans and cacao before sailing home to Saint-Malo.
Grain de Sail II, pictured right, is docked next to its smaller predecessor at the historic port city of Saint-Malo, France. (Easyride/Grain de Sail)
Today that ship sails on shorter routes within Europe, having been replaced by the larger Grain de Sail II, which has embarked on four trans-Atlantic journeys since its maiden voyage in March. Now the company is developing its third and largest vessel yet — one that will stretch twice as long and hold two times the cargo as the one that just docked in New Jersey. In another change, the 40-million-euro ship will use three Solid Sails, which can automatically hoist, lower, and rotate to more effectively harness the wind and speed up voyages.
Gallard, the chief marketing officer, said the company aims to generate no more than 2 grams of CO2 per metric ton per kilometer of transportation. (The vessels use small diesel engines when navigating in harbors and ports.) By contrast, conventional diesel ships can emit between 10 to 20 grams of CO2, he said.
Those carbon savings come at a significant financial price. Shipping boxes of, say, French cosmetics or leather wares with Grain de Sail can be anywhere from two to five times more expensive than hauling goods on a conventional cargo ship, mainly due to unfavorable economies of scale. The largest ships can hold over 24,000 containers of cargo; Grain de Sail III will hold close to 200 containers if completed as planned in 2027.
While Grain de Sail II uses cargo pallets, the company's third and largest vessel will be able to store standard shipping containers. (Grain de Sail)
For now, the company’s high-end clients are willing to foot the higher bill in the hopes of jumpstarting a wider shift toward cleaner shipping, Gallard said. And the per-ton price of shipping goods with wind power is expected to decline over time as high-tech sail technologies become more mainstream and mass produced, and as firms like Grain de Sail expand their fleets to operate more frequently.
“We hope that makes it more accessible … and allows us to get some more diversity in our client base,” he added.
In the meantime, Grain de Sail II is already making its way back to France. After unloading the cargo in New Jersey on December 1, the crew spent much of the last week bobbing off the waters of New York City, after a paperwork snafu kept them from docking at a private pier in lower Manhattan. The vessel, which is sailing home empty this time, expects to return to New York and New Jersey in early February with a cargo hold full of more coffee, wine, and chocolate.
Maria Gallucci
is a senior reporter at Canary Media. She covers emerging clean energy technologies and efforts to electrify transportation and decarbonize heavy industry.
