Anemoi Marine Technologies has received independent verification from Lloyd’s Register Advisory on the performance of its Rotor Sail system following a year-long testing period aboard the TR Lady, a Kamsarmax bulk carrier.
Anemoi Marine Technologies, a wind-assisted propulsion technology company, has announced the results of a rigorous 12-month testing campaign that confirm the fuel and emissions savings of its Rotor Sail system. The assessment, conducted and independently verified by Lloyd’s Register Advisory, focused on three Rotor Sails installed on the TR Lady, a vessel owned in funds managed by Tufton Investment Management Ltd and chartered by Cargill.
The Rotor Sails—each 24 meters high and 5 meters in diameter—were fitted in June 2023. Over the year-long period, the TR Lady traversed diverse ocean routes, including the Indian Ocean, South Atlantic, Pacific regions, and critical chokepoints like the Strait of Malacca. The analysis spanned eight Laden and Ballast legs, collecting high-frequency operational data under real-world conditions.
The verified results showed average savings of 1.9 tonnes of fuel and 7.0 tonnes of CO₂ per day (well-to-wake), equating to a 9.1% net reduction in propulsion fuel and emissions. These figures are closely aligned with Anemoi’s predicted 10% savings. In some instances, such as a 22-day voyage across the North Pacific, savings reached as high as 21%.
Dr Dogan Uzun, Ship Performance Consultant at Lloyd’s Register Advisory, led the independent verification process. “We have independently verified Anemoi’s methodology to calculate thrust power and predict fuel consumption,” he said. “The findings show that wind-assisted propulsion, when supported by robust data and transparent methods, can significantly reduce uncertainty and contribute meaningfully to emissions reduction in commercial shipping.”
This verification was based on computational fluid dynamics (CFD) modeling and an analysis of over 167 rotor on/off tests. These tests demonstrated a clear correlation between Rotor Sail activation and both increased vessel speed over ground and reduced main engine power usage. Lloyd’s Register concluded that “there is close agreement between the predicted thrust coefficient trends and the measured values,” further validating Anemoi’s approach.
Clare Urmston, CEO of Anemoi Marine Technologies, emphasized the importance of transparency: “Lloyd’s Register Advisory’s rigorous and transparent approach gives shipowners and operators the confidence that our technology delivers measured fuel savings and emissions reductions in line with expectations.”
Nicolas Tirogalas, Chief Investment Officer and President of Tufton, called the verification “a key objective” and said the confirmed fuel savings matched Tufton’s original expectations. He highlighted both the operational and environmental benefits of wind-assisted propulsion demonstrated through this project.
Chris Hughes, Decarbonisation Specialist at Cargill, noted the significance of real-world testing: “By combining the data from more than 167 rotor on/off tests with the independent verification from LR, Anemoi installed confidence in the accuracy of their analysis. We’ve already used the results to fine-tune our weather routing digital twins for TR Lady.”
The TR Lady sails without a fixed route, providing a broad spectrum of wind conditions for testing. The Rotor Sails used were designed with a lower aspect ratio to meet air draft constraints, but Anemoi has confirmed that testing is currently underway on vessels with larger, 35-meter-high Rotor Sails expected to deliver even higher performance.
With operational data collected since 2013, Anemoi is among the few in the wind propulsion sector with a decade of empirical evidence backing its technology. The company continues to commit to sharing real-world performance data to support broader adoption of wind-assisted propulsion in commercial shipping.
Source: Anemoi
