Optimizing wind propulsion for the new Age of Sail

Ships have been harnessing the power of the wind for generations. 

Today, with deadlines for global climate goals fast approaching, wind propulsion’s appeal as an inexhaustible and emission-free resource is once again on the rise. And this trend is predicted to continue, with 30% of the world’s fleet expected to embrace wind power by 2050. 

The challenge now lies in optimizing wind propulsion systems for maximum performance and scalability.

Why wind propulsion?

The key benefit of wind propulsion systems onboard ships is the energy savings they enable. Installing a wind propulsion system on a vessel reduces carbon dioxide (CO₂), nitrogen oxide (NOx) and sulfur oxide (SOx) emissions. Reliance on wind power also lessens the amount of engine vibrations that cause harmful underwater radiated noise. Wind therefore has an important role to play in the decarbonization of the marine sector.

Wind propulsion systems also offer potential long-term economic benefits for shipowners and operators. Although the initial costs of installing these systems can be high, once they’re up and running, they can reduce operating costs through decreased fuel consumption.

Wind is, of course, a freely and widely available resource. Better yet, while traditional fuel sources require transport, storage and bunkering infrastructure, wind does not. It can even produce energy that can be captured and used for other purposes onboard.

One other favorable factor is that the Earth’s major weather systems are generally well known, making wind patterns highly predictable. This means it is relatively easy to charter a course that takes advantage of this energy source.

Assessing suitability for merchant ships

Wind propulsion technology can be installed on many kinds of vessels. However, determining if it is a viable option on a given ship depends on a number of factors, including the ship’s size, type, operational profile and trading area. The cost and performance characteristics of the available wind propulsion systems also impact the assessment.

Generally, wind propulsion systems are better suited to ships that have a high sail area to displacement ratio. This means that wind propulsion may be particularly useful for smaller ships, as they have relatively lower propulsive power requirements that can be more efficiently met by wind propulsion systems. However, many smaller ships spend less time at sea and more time docked or maneuvering, periods where wind propulsion systems cannot be used.

Wind propulsion systems can also be used on large ships, especially considering their greater deck space. The size and power requirements of these ships mean that wind propulsion is likely to have more limited benefits, but such systems can work alongside other means of propulsion to increase energy efficiency.

How can wind propulsion systems be optimized?

The performance of wind propulsion depends on several factors. There are different ways that the lift and drag performance of a wind propulsion system can be assessed:

• Computational fluid dynamics simulations use mathematical models to simulate the flow of air around the system and identify areas of high drag and turbulence.
• Wind tunnel testing uses a physical scale test model of the system in a controlled wind tunnel environment to provide information on its aerodynamic performance.
• Onboard testing assesses the aerodynamic performance of wind propulsion systems on actual ships.

A Performance Prediction Program, which is a type of computer simulation, can be used to predict a ship’s performance under different wind and sea conditions. The shipping industry has also developed highly specialized weather routing systems that, when combined with a Performance Prediction Program, can determine the optimal route that a given ship should take. Optimal routes prioritize sailing with favorable winds, avoiding calms and storms, to allow ships to take full advantage of wind power.

The efficient operation of a wind-powered ship relies on effective energy management. On ships with fuel power and wind propulsion, the wind energy supplements engine power. This increases energy efficiency by reducing the engine load, fuel consumption and emissions.

Routing studies have demonstrated that, at certain times, it can be more efficient to convert wind energy into electricity rather than to use it to propel the ship directly. This is an alternative use of wind systems that can work in tandem with their principle use as a means of propulsion in the right weather conditions.

Bureau Veritas is supporting pioneering wind propulsion systems

As a member of the International Windship Association (IWSA) and an active participant in EU and IMO Working Groups, Bureau Veritas is highly engaged in the development of wind propulsion. We are by our clients’ side to support them in assessing the suitability of wind propulsion for their ships and selecting the right technology. 

We continue to develop our NR 206 Rules for wind propulsion systems and WIND PROPULSION class notation to help shipowners and operators navigate the latest developments in wind propulsion.

Our global Future Shipping Team is also there to guide maritime stakeholders, focusing on pragmatic, viable solutions for maritime decarbonization, including wind propulsion. The team unites more than 200 of our experts, tasked with assisting our clients along their chosen decarbonization pathway.

Interested in diving even deeper into the world of wind propulsion? Read our latest Technology Report here.