During the 2025 GREEN4SEA Singapore Forum, Gavin Allwright, Secretary General of the International Windship Association (IWSA), discussed the potential of wind propulsion as a solution for reducing greenhouse gas and climate-impacting emissions in the maritime industry.
Understanding wind propulsion: A genuinely zero-emissions energy source
Wind propulsion is rapidly gaining traction as a key contributor to the maritime industry’s transition toward zero emissions. As a truly zero-emissions energy source, wind offers significant environmental benefits by producing no greenhouse gases, no underwater radiated noise, and no other climate-impacting emissions. While some may view this claim as controversial, it shouldn’t be: the evidence clearly supports wind propulsion as a clean and sustainable solution for the future of shipping.
Wind is entirely natural, it doesn’t need to be mined, refined, transported, bunkered, or stored on board. It arrives directly at the point of use, with no emissions and no cost, ever. That’s a major difference compared to other energy sources.
Importantly, wind systems require zero development time. They already exist, and most are automated. No new crew are needed, though some training is necessary. While these systems clearly have a significant upfront cost, they use free energy, so they pay themselves off over time.
We’re even seeing pilot projects where the capital cost is treated as operational expenditure through leasing or other models, allowing operators to pay monthly. Depending on the fuel type being replaced, these systems can pay themselves off within years.
Wind propulsion in members
When looking at ships over 400 gross tonnage, last year ended with 56 wind propulsion installations, along with 8 wind-ready vessels.
This year, this number is expected to double. In the first three months of 2025, there were already 62 installations, plus 7 more wind-ready ships. Furthermore, there are 100 vessels on order, some of which will be delivered into 2026. Among these, five vessels will rely primarily on wind for more than 50% of their propulsion.
The growth rate is doubling each year, and the manufacturing side is keeping pace. Production capacity in China is already at around 200 units per year, with Europe producing a similar amount, so supplying these systems isn’t a major barrier.
Beyond single-ship installations, fleet orders are starting to appear. For example, Union Maritime has ordered 34 ships, the first of which has already been delivered, using a mix of wing sails and rotor sails. In another example, MOL (Mitsui O.S.K. Lines) has set a target to have 80 ships equipped with wind propulsion by 2035.
How the industry sees wind propulsion
In a recent survey, IWSA polled 159 maritime stakeholders, including 39 shipowners. The responses were globally spread, though Europe had a strong showing. IWSA asked participants to choose five energy sources they see as viable for 2030 and for 2050.
Results from nuclear upward mirrored the findings of other think tanks, but most of those studies overlook wind propulsion, likely because wind provides energy, rather than just saving fuel.
When IWSA included both wind assist and primary wind in the options, the combined results indicated wind would form a major part of the future energy mix.
As mentioned, this was an IWSA survey, so we had plenty of wind advocates involved. However, IWSA also had critics participate, and the results still showed a meaningful role for wind. It’s not definitive, but it’s clearly indicative of a broader shift that wind is now seen as a serious contributor.
IWSA also surveyed 44 policymakers. Out of these, 29% were IMO flag states, another 20% were from industry bodies within the IMO, and the rest were from the EU or national governments. IWSA asked if wind propulsion would be necessary to meet decarbonization goals. Around 84% said it would be very or extremely important. That’s a strong endorsement. For the 16% who disagreed, those are conversations we’re continuing.
Barriers to adoption
As for barriers, the key issue is fuel price. When prices are low, there’s little motivation to reduce consumption. However, current fuel prices are artificially low. If we included external costs such as climate impacts, pollution, and health costs, the real price would be three to four times higher. We’re not naïve enough to expect fuel prices to increase by that much, but it’s important to acknowledge the hidden costs. In contrast, wind propulsion has a true cost of zero, and that won’t change.
Other barriers include capital intensity, route-specific performance, compliance, and some safety and maneuverability challenges. But each of these has known mitigation pathways.
Evaluating existing policy
The IMO’s 2030 GHG strategy mentions achieving 5–10% of “zero-emissions fuel, energy, or technology.” This is often misunderstood as referring only to fuels.
Wind propulsion qualifies under all three terms: it’s a non-commoditized fuel, an energy source, and a technology. Notably, wind energy is now included in the IMO’s lifecycle analysis for fuels and is rated at zero emissions. That’s a meaningful policy recognition.
Also at the IMO level, IWSA has proposed integrating wind propulsion directly into the greenhouse gas fuel intensity (GFI) formula, so that wind replaces part of the vessel’s required brake horsepower. This shifts the model from being purely fuel-based to more vessel-based, reflecting how wind contributes energy.
Interestingly, FuelEU Maritime has a wind reward factor. Ships that have wind propulsion installed receive a 1–5% emissions bonus, even if they don’t use the system. Stakeholders still benefit simply from having it installed.
Looking toward the future
The future needs to be shaped with an important thought in mind: transparency and honesty are the foundation of trust. We need to look beyond the market price of fuel and consider its true cost.
We also need to expand our emissions lenses. Greenhouse gases are only part of the picture: there are broader climate-impacting emissions, including substances like hydrogen, which may not emit greenhouse gases but still affect the climate.
The risk we face is pursuing a path that leads to stranded assets or creates bigger problems than it solves. We must proceed carefully. Once we’re confident we’ve got it right, we should accelerate quickly.
Finally, one last point on investment: we often focus on short-term return on investment (ROI), but policy should be based on the total cost of ownership. A vessel operates for over 25 to 30 years. Shipowners understandably think about surviving the next week or year, but regulators and policymakers need to consider the long-term future of the industry.
We shouldn’t base policy decisions on ROI alone; we need to prioritize what’s best for the sector in the medium to long term.
Above article has been edited from Gavin Allwright’s presentation during the 2025 GREEN4SEA Singapore Forum.
Explore more by watching his video presentation here below
The views presented are only those of the authors and do not necessarily reflect those of SAFETY4SEA and are for information sharing and discussion purposes only.
