The number of large commercial cargo ships equipped with wind propulsion technology has passed 100 vessels, according to the International Windship Association (IWSA), marking what the organisation describes as a turning point in the uptake of wind energy in commercial shipping.

The IWSA, the industry body representing wind-assist and primary wind propulsion technology developers, says the fleet now comprises more than 100 vessels over 400 gross tonnes (GT), with a combined cargo-carrying capacity exceeding 5 million deadweight tonnes (DWT) and more than 230 individual wind propulsion systems installed. The association estimates these installations are delivering emissions reductions of more than 100,000 tonnes of CO2 equivalent per year, alongside reductions in other pollutants.

The figures do not include 12 wind-ready ships, more than 20 research ships, campaign vessels and small traditional rigged cruise vessels, nor dozens of smaller cargo ships under 400 GT that also use wind power.

The pace of adoption has accelerated sharply in recent years, with the number of equipped vessels roughly doubling year-on-year, according to the IWSA. In May 2022, 21 large commercial vessels were using wind propulsion technologies, representing approximately 1 million DWT of cargo-carrying capacity. Four years on, that figure has increased nearly fivefold.

Among the vessels counted are six primary wind ships — ranging from 80 metres to 220 metres in length — that operate predominantly on wind power.

By vessel type, tankers and bulk carriers lead adoption. At the time of the announcement, 37 tankers and 24 bulk carriers were equipped with wind propulsion systems, alongside 24 roll-on/roll-off and ro-pax vessels combined and 19 general cargo ships.

Wind propulsion solutions currently available to shipowners include suction sails, rigid and semi-rigid wing sails, rotor sails, traction kites and traditional soft sail systems, with technologies said to deliver between 5% and 20% of a ship's propulsive energy as a retrofitted wind-assist installation, or higher levels in purpose-built newbuild deployments.

Gavin Allwright, Secretary General of the IWSA, commented: "This surge of installations has been driven by a sustained rise in full-scale testing, independent verification and commercial validation of systems over the past five years, giving shipowners growing confidence in the operational and financial case for adoption. However, we can go further and faster on these installations, with everyone focused on scaling towards 1,000 ships and beyond."

Allwright added that despite uncertainty surrounding the International Maritime Organization's global decarbonisation framework and broader geopolitical pressures, the pipeline of retrofit and newbuild orders remains relatively healthy. He said: "We estimate that the number of wind propulsion installed ships will once again double in the next 12 months, amounting to around 200 large commercial vessels in total by this time next year."

Longer-term projections from EU-commissioned research and the UK Clean Maritime Plan have estimated a fleet penetration rate of up to 15% using wind propulsion by the early 2030s, rising to between 40% and 45% by the 2050s, though the IWSA suggests these figures could prove conservative if the industry and regulators pursue an ambitious zero-emissions course.

Allwright remarked: "Reaching the 100-ship, 200+ systems installed milestone represents an important market marker for wind propulsion technology. At this point, we can expect a sustained reduction in return-on-investment timeframes, particularly if fuel prices remain high, as manufacturing scales up and installation experience grows. It is increasingly clear why wind is such an attractive option for shipowners: it offers positive financial returns, increased energy security, measurable decarbonisation gains and technology pathways that can support compliance with tightening emissions regulation today."