To wind or not to wind?

Wind-assisted propulsion systems (WAPS) are emerging as the poster child of zero-emission tech and have gained several supporters within the shipping industry.

Classification society DNV makes a strong case: “Wind propulsion is the only alternative system that harnesses a cheaper energy source than any current power or fuel option. This ensures a reliable return on investment and may become even more advantageous as carbon pricing takes effect and regulations mandate costlier low-GHG fuels,” it wrote in a recent whitepaper.

Interest in WAPS is rising rapidly. Dutch wind-power company Econowind recently sold its 100th WAPS unit. According to the company, 32 of these units are in operation, 33 are either in production or ready for installation and 37 are on order. DNV data shows that as of January, 52 sea-going vessels were equipped with WAPS, with another 97 newbuilds are on order.

This growing interest is partly driven by the “slower-than-needed” progress of alternative fuel projects, uncertainty around fuel availability and delays in delivering alt-fuel-capable ships, according to marine insurer Gard.

On paper, WAPS is a compelling alternative for improving vessel fuel efficiency. The technology is vessel-segment agnostic, can be installed or retrofitted on almost any ship and operates independently of fuel supply or bunkering, offering immediate cost savings. The International Windship Association (ISWA) even predicts that up to 10,700 WAPS installations could be in place by 2030, covering 50% of the existing bulk carrier fleet and up to 65% of tankers.

But several important issues must be addressed before WAPS can see widespread adoption.

For starters, installing WAPS can increase insurance premiums. “Additional insurance costs may include a slightly higher premium for Hull and Machinery due to increased value of vessel with system installed,” George Thompson, chief executive of GT Wings told marine insurer North Standard P&I.

Beyond insurance, high operational costs could also deter adoption. Operational expenses could include maintenance, spare parts, software upgrades and additional crew and training, noted Karmesh Tiwari, head of new technology at MC Shipping. One WAPS provider will charge a “subscription fee for weather routing & voyage optimization” while another will offer a “care package beyond the warranty period”. Such variables could also drive up post-installation costs.

Another challenge is the lack of specific regulatory guidelines or safety codes for the upcoming technologies in this segment. “These technologies impact multiple areas of safety, creating ambiguities and exposing gaps in existing regulations. These regulatory uncertainties may present challenges and potential risks for shipowners considering WAPS in vessel design and operations, as the industry needs to rely on interpretations or exemptions from current regulations,” the DNV report highlights.

Marine insurers also play a key role in WAPS adoption, and some remain cautious about its risks. Britannia P&I points to concerns such as “structural integrity, manoeuvrability, stability, heel, crew safety, and maintenance costs” as potential operational risks.

And finally, while this technology may reduce onboard fuel consumption, some installations will also require energy to operate. This could make its installation on ships counter-productive and undermine overall efficiency improvements.

“In the maritime industry’s green transition, the role of wind-assisted propulsion remains uncertain, potentially serving as a complement rather than a replacement for traditional fuels,” Britannia P&I noted. WAPS can improve fuel efficiency, but its long-term viability will depend on whether its associated costs align with future fuel savings and how urgently the industry addresses these key barriers.

In other news this week, Japanese classification society ClassNK has approved a concept of small-size low-pressure liquid carbon dioxide (LCO2) carrier designed by Mitsubishi Shipbuilding. The vessel is designed to transport CO2 from small-scale capture sites along the Seto Inland Sea to intermediate storage sites within Japan. From there, the captured carbon will be transferred to overseas storage locations.

South Korea’s Hanwha Ocean plans to debut an ammonia gas turbine-powered LNG carrier by 2028. The South Korean shipbuilder first introduced the concept in January last year, arguing that replacing dual-fuel internal combustion engines with a gas turbine on ships running on ammonia would eliminate reliance on pilot fuels such as diesel.

The alt-fuel vessel segment had a slow start to 2025, senior DNV consultant Kristian Hammer said. Only 12 alternative-fuel vessel orders were placed in January, all for LNG-capable ships. This brings the total LNG vessel orderbook to 628. There are also 338 methanol-capable vessels on order for delivery through 2030, and 31 ammonia-capable vessels for delivery towards 2028.

By Konica Bhatt

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