Wind drives shipping forward

Maritime transport is a cornerstone of the infrastructure required for international trade. But there is no escaping the fact that the industry has a significant carbon footprint. Today, shipping accounts for about 3 percent of global CO2 emissions.

This figure is likely to rise to 10 percent without significant changes in the industry. The severity of the situation was highlighted when the International Maritime Organization (IMO) strengthened its climate strategy in July 2023, setting a new target for the industry to achieve net zero emissions by 2050.

To achieve this goal, researchers and industry stakeholders alike are working hard to find new solutions and refine existing methods. Electrification and alternative fuels are two major areas of activity, but there is another technology that is rapidly gaining ground: wind propulsion.

Wind has been used to power ships for thousands of years. Now may be the time to bring it back.

Up to 90 percent less fuel

Of course, it's not as simple as dusting off the blueprints of large sailing ships. But with the right planning and technical solutions, it is possible to significantly reduce the climate impact of maritime transport using wind propulsion.

"In principle, it's about giving ordinary modern ships a boost from the wind, a little extra forward speed that reduces fuel consumption," says Sofia Werner, lead researcher for wind powered ships at RISE.

"In theory, it would be possible to reduce fuel consumption by up to 90 percent," she notes, but quickly adds:

"In practice, it will be difficult to achieve these levels. Today's wind-powered ships reduce fuel consumption by up to about 10 percent. But more powerful turbines are being developed all the time, allowing wind to make an even greater contribution to operations."

Logistical requirements set the limits

There are various techniques for making wind propulsion work effectively in modern shipping (see box).

"At the moment, it's mostly a matter of modifying existing ships, but completely new designs adapted to wind are also under way," says Werner.

How far we can go with wind propulsion is ultimately not just a technical question, she says.

"It is also the logistics that will set the limits on how far wind can be utilized. It's about how fast ships can go and how punctual they are expected to be. Cargo owners have to accept more flexibility – and so do we consumers, because it is our goods they are carrying."

New regulations needed

Another challenge is safety when ships are equipped with wind assistance.

"Many people believe that ships will list more easily, but this is not a major risk. On the other hand, maneuverability can be affected and it becomes more difficult to give way. This can be avoided with an adapted design and good knowledge of how to handle the steering."

This also means that new regulations and standards need to be developed for wind-powered structures.

"Currently, there are various exemptions and discussions on a case-by-case basis, but work is underway, particularly within the IMO, to develop international rules. This is a pressing issue for them, as wind propulsion can be a key to climate-neutral shipping."

Suppliers have waiting lists

There are currently about 30 wind-powered cargo vessels in operation. Many more are expected in the coming years. According to EU forecasts, there could be up to 10,000 vessels in operation worldwide by 2030.

"At RISE, we are seeing a clear trend of increased interest in wind propulsion, in part because we are receiving more and more requests from the major shipyards for help in adapting the design of their vessels to accommodate it. We also know that many of the major suppliers of wind turbines have had to create waiting lists because demand has increased so much," says Sofia Werner.

RISE is also seeing a noticeable increase in interest in its other services in this area.

"Both shipowners and shipyards are contacting us because we can help with most aspects of adapting to climate-neutral shipping. This can range from preparing a feasibility study based on the route and ship, to test runs with real ships to verify that performance, maneuverability and safety are as planned."