Every day, thousands of ships cross our ocean, carrying the goods that connect our world.
But moving global trade comes at a cost.
Shipping still depends heavily on fossil fuels. What if we could change that using a force that has powered ships for centuries?
We studied three routes to find out.
Three shipping routes. Three types of ships.
We tested what happens when ships harness the wind instead of relying entirely on their engines.
From Ghana to China:
What difference could wind propulsion make on a journey across the ocean?
We looked at a round trip between Accra and Shanghai, comparing three types of cargo ships equipped with two or four modern suction sails. The results show how harnessing the wind could reduce fuel consumption, cut costs and make shipping more energy-efficient.
For a bulk carrier fitted with four suction sails, the potential savings are particularly striking.
Save nearly $500,000 a year in fuel costs
By harnessing the wind, a bulk carrier fitted with four suction sails could save approximately $493,500 in fuel costs annually on this route, based on the study's modelled average conditions.
Instead of relying entirely on its engine, the ship uses the wind to help propel it forward, reducing the amount of fuel it needs to complete the journey.
That's almost half a million dollars saved by a single vessel, simply by making better use of a renewable energy source that's freely available.
Save up to $741,200 a year under optimal conditions
Wind conditions vary from one journey to another, which means the amount of fuel a ship can save also changes.
Under particularly favourable weather conditions, the same bulk carrier could achieve maximum annual fuel-cost savings of approximately $741,200.
This illustrates the potential of combining wind propulsion with intelligent weather routing, helping ships take greater advantage of the wind along their journeys.
Improve energy efficiency by up to 18%
Wind propulsion isn't just about saving money. It's also about reducing the energy needed to transport goods around the world.
Under optimal weather conditions, the study found that a bulk carrier equipped with four suction sails could achieve energy-efficiency savings of up to 18%.
That means less fuel burned to complete the journey, reducing both greenhouse gas emissions and dependence on fossil fuels.
And when scaled up across the global shipping fleet, those energy savings could make a significant contribution to shipping's transition away from fossil fuels.
From Brazil to the Netherlands:
What if crossing the Atlantic didn't have to come with such a high carbon footprint?
We examined a round trip between Rotterdam and Santos, exploring how modern wind propulsion could help three types of cargo ships reduce their greenhouse gas emissions.
The results show that equipping ships with suction sails could avoid thousands of tonnes of CO₂ emissions every year. And for ships operating on routes covered by the EU's Emissions Trading System (ETS), cutting emissions can also mean cutting costs.
Here's what the study found for a container ship equipped with four suction sails.
Avoid more than 3,250 tonnes of CO₂ emissions a year
By harnessing the wind to help propel the vessel, a container ship fitted with four suction sails could avoid approximately 3,254 tonnes of CO₂ emissions annually on this route, according to the study's modelled results.
That's thousands of tonnes of greenhouse gases that would otherwise be released into the atmosphere.
The principle is simple: the more work the wind does, the less fuel the ship needs to burn. And the less fuel it burns, the fewer emissions it produces.
More sails, greater emissions reductions
The number of sails installed can make a substantial difference.
For a container ship on the Rotterdam–Santos route, two suction sails could avoid around 1,550 tonnes of CO₂ annually. With four sails, that figure rises to 3,254 tonnes.
That's more than double the emissions savings, demonstrating how the design and configuration of wind propulsion systems can influence their environmental benefits.
Of course, the results also depend on the vessel, weather conditions and route. But the findings show the potential for wind propulsion to deliver meaningful emissions reductions on long-distance shipping journeys
Save up to $149,000 in EU carbon costs
Cutting emissions doesn't just benefit the climate. It can also make financial sense.
Under the EU Emissions Trading System, shipping companies must surrender emissions allowances for CO₂ released on covered voyages. By burning less fuel and producing fewer emissions, ships can reduce the number of allowances they need.
For a container ship equipped with four suction sails, the study estimates maximum annual ETS savings of approximately $148,995 under optimal weather conditions.
These savings come from avoiding carbon costs, rather than directly from buying less fuel. They demonstrate how climate policies can help reward shipping companies for investing in technologies that genuinely reduce emissions.
From Kenya to China:
Can investing in cleaner shipping technology actually pay for itself?
We examined a round trip between Mombasa and Shanghai to explore how modern suction sails could reduce fuel consumption on one of the trade routes connecting East Africa and Asia.
The results show that wind propulsion can make a difference even on routes where conditions may be less favourable for harnessing wind. And while installing the technology requires an upfront investment, the fuel savings generated over time can help recover those costs.
Here's what the study found.
Save up to 490 tonnes of fuel a year
A bulk carrier equipped with four suction sails could save approximately 490 tonnes of fuel annually on the Mombasa–Shanghai route, according to the study's modelled results.
Instead of relying entirely on its engines, the vessel harnesses the wind to help propel it forward, reducing the amount of fuel needed to complete its journeys.
That's hundreds of tonnes of fossil fuel that no longer need to be burned, cutting both operating costs and greenhouse gas emissions.
Twice the sails, more than twice the savings
The number of suction sails installed can make a significant difference to a ship's fuel consumption.
For a bulk carrier travelling between Mombasa and anghai, two suction sails could save around 234 tonnes of fuel each year. With four sails, that figure increases to 490 tonnes.
These results show how the configuration of wind propulsion technology influences its performance. While savings vary according to the vessel, route and weather conditions, equipping ships to harness more wind can deliver greater reductions in fossil fuel consumption.
An investment that can pay for itself in 3–7 years?
Installing wind propulsion technology requires an initial investment, but the savings don't stop after the first voyage.
Every journey made using less fuel reduces operating costs, allowing shipping companies to gradually recover the money spent on the technology.
The study highlights a potential break-even period of approximately 3–7 years, after which accumulated savings can outweigh the initial investment.
For shipowners, this means wind propulsion isn't simply an environmental investment. It can also be a long-term financial opportunity, helping reduce exposure to fuel costs while cutting emissions.
Even on routes with more modest wind conditions, wind propulsion can reduce the fuel ships burn.
The report finds smaller savings here, demonstrating that geography, voyage duration and weather matter.
Old power. New technology.
For thousands of years, the wind carried ships across the world's oceans, connecting continents, transporting goods and opening up new trade routes. Then came the steam engine, followed by diesel-powered vessels, and shipping gradually turned its back on the very force that had powered it for centuries.
Now, as the industry faces the urgent challenge of moving away from fossil fuels, wind is making a comeback. But this time, with a technological upgrade.
Forget the traditional sails of the past. Today's wind propulsion systems use sophisticated engineering to harness the wind more efficiently. From towering rigid wings and rotating cylinders to automated sails, these technologies are designed to help propel some of the world's largest commercial vessels.
And the principle is surprisingly simple. By capturing energy from the wind, ships can reduce the power they need from their engines, burning less fuel and releasing fewer greenhouse gas emissions along the way. Modern weather-routing technology can also help ships make the most of favourable winds during their journeys.
Wind propulsion doesn't necessarily mean switching off the engine altogether. Instead, it means making the wind do more of the work, reducing the amount of fuel needed to move goods around the world.
It's an ancient source of power, reimagined for modern shipping. And unlike fossil fuels, the wind doesn't need to be extracted, manufactured or transported halfway around the world. It's already out there, waiting to be harnessed.
How does it work?
Wind propulsion systems generate aerodynamic force that helps move a vessel forward. Ships can still use their engines, but need less engine power when conditions are favourable.
Weather routing helps vessels take advantage of those conditions while respecting operational constraints.
An important detail to note is that the 2025 Seas At Risk study models suction wings specifically. Other wind technologies may provide slightly different outcomes.
Three routes showed us what wind can do.
But what if we looked at the entire shipping fleet?
We did.
DATA
1.74 billion
kilometres of real voyage data
EMISSIONS
6.3–9.4%
potential reduction in modelled wind-fleet fuel use
WIND
762 million
tonnes of cumulative CO₂ savings possible by 2050
Not every ship benefits equally.
But some ships — particularly bulk carriers and tankers — have enormous potential and because these ships consume large quantities of fuel, even relatively modest improvements in efficiency can translate into substantial reductions in emissions.
Now imagine what could happen if we scaled those savings across the global shipping fleet.
What if we scaled wind propulsion across the world's shipping fleet?
We've seen what wind propulsion can achieve on individual journeys. But what would happen if ships around the world started harnessing the wind?
To answer that question, Seas At Risk commissioned the first global study of its kind, analysing around 40,000 vessels, representing approximately 60% of global shipping emissions.
Using 1.74 billion kilometres of real voyage data — roughly the distance from Earth to Saturn — researchers modelled how wind propulsion could reduce fuel consumption and emissions across the shipping fleet.
And the findings reveal just how much potential is waiting to be unlocked.
Wind propulsion could reduce fuel consumption across the modelled wind-assisted fleet by 6.3% to 9.4%. And that's before accounting for additional savings from measures such as weather routing, slower speeds and improved hull efficiency.
What starts as a reduction in fuel consumption on one ship could become a significant contribution to decarbonising global shipping.
40,000 vessels modelled
1.74bn km of voyage data
6.3-9.4% potential fuel reduction
A small share of ships could make a big difference
One of the study's most striking findings is that we don't need to start with every ship to make a significant impact.
In fact, just 16% of the vessels studied — predominantly bulk carriers and tankers — could deliver half of the total modelled emissions savings.
That means targeting the ships with the greatest potential could unlock substantial climate benefits, even before wind propulsion becomes widespread across the entire fleet.
And the opportunity is enormous. With ambitious deployment, wind propulsion could help avoid up to 762 million tonnes of CO₂ cumulatively by 2050.
That's not a distant technological dream. Wind propulsion systems are already available and can be installed on existing ships, delivering emissions reductions without waiting for the next generation of alternative fuels.
The question is no longer whether wind propulsion can make a difference.
It's how quickly we are prepared to scale it up.
The climate is nearing tipping points. Changes are beginning to appear and there is a potential for explosive changes, effects that would be irreversible, if we do not rapidly slow fossil-fuel emissions.
James Hansen , Director of the Climate Science, Awareness and Solutions, The Earth Institute.
Demand reduction
The shipping industry is facing an enormous challenge: how to move away from fossil fuels while continuing to connect people, countries and economies around the world.
Much of the conversation about shipping's future focuses on finding new fuels to replace the dirty ones used today. Green hydrogen, e-methanol and e-ammonia are among the alternatives being explored. But switching fuels alone won't solve the problem.
Producing these alternatives requires significant amounts of renewable electricity, new infrastructure and investment. As demand for energy continues to grow across the world, shipping will be competing for renewable resources that are also urgently needed to power homes, industries and communities.
So what if, instead of only asking how to replace the fuel ships burn, we started by asking how much fuel they really need?
This is where wind propulsion offers something different.
Unlike alternative fuels, wind doesn't need to be manufactured, transported or stored on board. It is an abundant, renewable source of energy that ships can harness directly. By using the wind to help propel vessels, shipping companies can reduce the amount of fuel their engines consume, cutting greenhouse gas emissions while reducing their dependence on future fuel supplies.
And the benefits go far beyond individual ships.
B4B-Na-Hiro-E-Pae-Credit-bound4blue
B4B-Na-Hiro-E-Pae-Credit-bound4blue
Every tonne of fuel saved means less demand for the energy, infrastructure and resources needed to produce its replacement. Scaling up wind propulsion across the global fleet could therefore make the transition to cleaner shipping not only faster, but more affordable and accessible.
This matters particularly for developing countries, which should not have to compete with wealthy shipping companies for access to limited renewable energy supplies. Reducing shipping's energy needs can help ease that pressure, leaving more renewable electricity available to support local development and essential services.
But using less energy is only part of the story.
For decades, the shipping industry has expanded alongside a global economy built around producing, consuming and transporting ever-increasing quantities of goods. Products routinely travel thousands of kilometres, sometimes crossing oceans several times before reaching their final destination.
This comes at a cost to the climate, the ocean and the communities affected by global supply chains.
Containers lost in the ocean
Containers lost in the ocean
A truly sustainable shipping industry must therefore rethink not only how ships are powered, but also how goods are produced, consumed and transported. That means making better use of resources, encouraging repair and reuse, shortening supply chains where possible, and ensuring that international trade meets people's needs without exceeding the planet's environmental limits.
Wind propulsion is an important part of this transformation. Combined with slower sailing speeds, smarter routing and more efficient ship operations, it can significantly reduce the energy required to transport goods.
But the ambition must go further than making an ever-growing shipping industry slightly more efficient.
The goal is a shipping system that uses less energy, moves goods more responsibly and operates within the limits of our planet.
Because the future of shipping shouldn't just be about finding new ways to power more ships.
It should be about building a better system that needs less in the first place.
The political choice
The wind is free. The technology exists. The evidence shows that wind propulsion can reduce shipping's fuel consumption, greenhouse gas emissions and operating costs.
So why aren't more ships using it?
Despite its potential, wind propulsion remains far from mainstream. While some shipping companies are beginning to invest in wind-assisted vessels, the industry's transition is moving far too slowly to meet the urgency of the climate crisis.
The problem isn't simply technological. It's also political.
Photo by Stephen Crowley on Unsplash
Photo by Stephen Crowley on Unsplash
For decades, the shipping industry has relied on cheap fossil fuels, with the environmental costs of its operations largely borne by the planet and the people most vulnerable to climate change. Today, the rules governing international shipping still don't provide strong enough incentives to move away from that model.
Shipping companies making investments in cleaner technologies face significant upfront costs, while those continuing to burn fossil fuels are not consistently required to pay for the damage their emissions cause. Without ambitious regulations and financial incentives, technologies that could deliver emissions reductions today risk remaining the exception rather than the norm.
And the consequences of political inaction are significant.
Seas At Risk's global wind propulsion study shows that under a weak-policy scenario, wind propulsion could deliver emissions reductions of just 0.2% by 2050. Not because the technology lacks potential, but because deployment would remain far below what is possible.
The difference between wind propulsion remaining a niche solution and becoming a powerful tool for decarbonisation comes down to the choices governments make today.
At the International Maritime Organization (IMO), governments have an opportunity to create rules that reward ships for reducing their actual greenhouse gas emissions and energy consumption. Stronger energy-efficiency standards, ambitious emissions targets and effective economic measures can help make wind propulsion an attractive investment rather than an optional extra.
But regulations must do more than encourage a switch from one fuel to another. They must also recognise the value of avoiding fuel consumption altogether. A ship that harnesses the wind and burns less fuel should be rewarded for doing so, rather than disadvantaged by rules designed primarily around the carbon intensity of the fuels it uses.
Finance also has a crucial role to play. Revenue generated through international shipping climate measures could help accelerate the deployment of wind propulsion, particularly in developing countries that may otherwise struggle to access the technology and the investment needed to adopt it.
This is about more than cutting emissions. It's about ensuring that the transition to cleaner shipping is fair, that the benefits of innovation are shared, and that countries with fewer financial resources are not left behind.
And as Seas At Risk's One Planet Shipping vision makes clear, governments must look beyond technological fixes. A genuinely sustainable shipping system will require policies that reduce unnecessary transport, encourage more responsible production and consumption, and bring shipping's environmental footprint back within planetary boundaries.
We cannot rely on technology alone to solve a problem created by a system built on ever-growing fossil fuel consumption.
Wind propulsion offers a real opportunity to change course. But realising its potential will require governments to stop treating it as a promising technology for the distant future and start making it a central part of shipping's transition today.
The choice is clear: continue with policies that allow fossil fuel dependence to persist, or create the conditions for a shipping industry that uses less energy, produces fewer emissions and operates within the limits of our planet.
The wind is already moving. It's time for policy to catch up.
Stories from the waterfront: Wind First!
The drought in the Panama canal: The Panama canal connects the Atlantic and the Pacific ocean and has been a major thoroughfare for international trade for the past 100 years. Today, the canal allows up to 1000 vessels to cross every month, carrying over 40 million tonnes of goods.
April 2023 brought about severe droughts in the area, leading to low water levels. As a result, the canal authority imposed restrictions on ships and the amount of cargo they hold. The number of vessels passing through was cut down by more than a third, leading to long waiting times for merchant ships.
This drought caused major disruptions and delays in global trade, leading to an estimate of 1.1bilion USD of extra shipping costs and around 800 million USD loss in revenues.
To make up for the delays, shipping companies increased speed, burning more fuel per mile, and chose to reroute their voyages, following longer maritime routes.
It is hard to ignore that rising greenhouse gas emissions has a direct consequence on our planet and the climate crisis, making environmental disasters – like droughts – more frequent. And the shipping industry, so heavily impacted by drought, storms, and floods, is itself a major contributor to climate change.
The maritime industry needs to move away from fossil fuels and find greener and cleaner energy. Using high tech alternatives to reduce fuel burn is a viable alternative but availability and cost is an issue. Wind is all around us, and more so in the high seas. Tapping into this renewable energy is an immediate solution towards cleaning up shipping and the good news that it is already being deployed.
In Brittany, France, the wind propulsion industry has taken big steps to prove that it is a viable technology to reduce emissions. For around 10 years, companies have been developing systems for old and new vessels. And the regional government has adopted a roadmap for the wind propulsion sector to expand and develop the technology. With the right network, policies and incentive, Brittany shows that wind propulsion can be an immediate solution to reduce polluting emissions from vessels, helping the planet one step at a time.
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