Lidar and Ultrasonic Anemometers Enhance Wind Measurement Accuracy and Propulsion Efficiency
Wind propels innovation not just in power generation but also in other sectors such as maritime transportation. While wind turbines capture the power of air currents to generate electricity, the maritime industry increasingly harnesses wind energy to move ships across the seven seas. With the maritime industry prioritising decarbonisation goals, wind-assisted ship propulsion (WASP) presents a promising approach for reducing vessel emissions. Much like the wind energy industry relies on precise meteorological data for optimal site assessment and turbine efficiency, WASP systems demand accurate and reliable wind measurement for maximum thrust. Recent research indicates a significant evolution in how the industry approaches wind measurement and optimisation, particularly emphasising advanced sensing technologies and data integration strategies. Lidar systems, widely used in wind energy generation to assess potential sites and monitor turbine performance, are now being adapted for use at sea.
By Floriane Grussenmeyer, Sales Manager for Maritime, Weather and Environment, Vaisala, France
A comprehensive industry survey conducted in 2024, building on baseline data from 2022, reveals substantial shifts in how wind-assisted ship propulsion (WASP) system suppliers and shipping companies view wind measurement technologies. The joint Vaisala–International Windship Association (IWSA) survey, which gathered insights from manufacturers of various WASP technologies – including wings, soft sails, rotors, rigid sails and suction sails – as well as shipping companies operating roll-on roll-off vessels, bulk carriers and tankers, highlights growing sophistication in wind monitoring technologies in the fight against climate change across industries.
Challenges in Traditional Wind Measurement
Efficient WASP system operations demand accurate wind measurement to dynamically adjust their mechanisms, maximising thrust while minimising drag. As is the case in wind power generation, traditional measurement methods such as meteorological masts and anemometers present significant limitations, especially in the marine environment.
Ship superstructures create turbulence and airflow distortion, often leading to ‘masking effects’ that compromise anemometer readings. In fact, with only incorrectly situated cup anemometers, wind speed measurements can experience over 50% variance. Sensors mounted on masts or other parts of a vessel may experience structural interference, resulting in inaccurate wind speed and direction measurements.
In addition, anemometers provide localised data that reflects local wind effects at their specific installation points rather than a broader, undisturbed representation of the entire wind environment. This limitation makes understanding the wind dynamics affecting the vessel as a whole perplexing, impeding WASP system optimisation.
Even worse, mechanical anemometers, particularly cup and vane models, are prone to wear and tear in the harsh maritime environment, where salt water, moisture and extreme weather wear moving parts on equipment.
Advanced Technologies Overcoming These Challenges
Ultrasonic anemometers measure wind speed and direction using sound waves, providing greater accuracy and reliability than mechanical anemometers. Because they have no moving parts, they are more durable in harsh marine environments. Installing multiple ultrasonic anemometers on different sides of a vessel helps deliver a better flow of high-quality wind data. Placing sensors in various locations - such as the bow, bridge and stern - helps ensure that accurate and representative wind data is always available.
Lidars emit laser beams into the atmosphere and analyse the backscatter from airborne particles. Unlike anemometers, they are not subject to structural disturbances because they operate beyond the immediate physical influence of the ship, delivering undisturbed and accurate wind data.
The remote sensing technology provides a detailed wind profile by capturing data simultaneously at multiple altitudes and distances, delivering a multidimensional view of the wind environment that enables real-time adjustments to optimise WASP systems. For example, lidar can measure wind conditions ahead of the vessel and at various heights, allowing WASP systems to trim sails or adjust rotor systems at precise powering intervals.
Wind lidar systems facilitate the integration of their high-quality, undisturbed wind data with on-board ultrasonic anemometers. During sea trials, lidar data can help validate and refine the algorithms used by WASP systems, aligning real-world performance with predicted outcomes to enhance the reliability of wind measurement and system optimisation.
These capabilities enable vessels equipped with WASP systems to:
- Optimise thrust generation: Real-time data allows ships to dynamically adjust their sails, wings, kites or rotor systems for maximum efficiency.
- Enhance safety: Precise wind profiling helps WASP systems anticipate extreme wind conditions, ensuring the safety of the crew and cargo during operations.
- Support route planning: Ships can chart more fuel-efficient courses by improving wind model forecasts with lidar data.
Given these technologies’ transformative potential in addressing wind measurement challenges, understanding how the industry perceives and adopts them helps drive widespread implementation. The follow-up survey conducted by Vaisala and IWSA delves deeper into the current state of wind measurement practices, highlighting trends, opportunities and barriers to integrating advanced tools such as lidar.
Understanding the Wind Propulsion Space
The survey reveals a marked increase in the importance placed on local wind measurements, with 75% of respondents now rating them as ‘very important’ compared with just 20% in 2022. This massive shift underscores the industry’s growing recognition of precise wind data as crucial to optimising WASP performance.
The technical landscape of wind measurement in WASP applications shows clear trends in sensor preferences and deployment strategies. Ultrasonic anemometers dominate current installations, with 68.8% of respondents utilising these devices. Their popularity stems from their precision, low maintenance requirements, and robust performance in marine environments. However, mechanical anemometers retain a significant presence, used by 43.8% of respondents.
A key technical challenge identified by respondents involves the complexity of wind-field interactions around vessels. The industry particularly emphasises the need to understand air mass instability and gusting patterns, which can significantly impact WASP system performance. However, sensor placement strategies reveal a sophisticated understanding of wind flow dynamics around vessels, with the most common sensor locations being mast installations (68.8% of respondents), bridge-top placements (56.3%), and bow-mounted sensors (50%). While previous data showed a preference for dual-sensor configurations, the 2024 survey indicates that 62.6% of respondents now prefer three-plus sensors per vessel, suggesting growing recognition of the value of comprehensive wind-field analysis and redundancy in measurement systems.
Perhaps the most significant technical development revealed by the survey is the dramatic increase in interest in remote sensing technologies, particularly wind lidar-based systems. While no respondents indicated interest in lidar in 2022, the 2024 data shows nearly 70% now view remote wind measurement as a desired data source for WASP vessels.
Why? The technical advantages of wind lidar systems are particularly relevant for WASP applications, providing upstream wind measurements that allow predictive adjustments to propulsion systems before wind conditions change at the vessel’s location. Survey respondents identified other consequential benefits of lidar technology, including system optimisation and adjustment (75%), enhanced safety capabilities (56.3%), and route optimisation potential (25%).
Advancing Wind Technology Across Maritime and Energy Sectors
The technical evolution of wind measurement in WASP applications offers valuable insights for the broader wind energy sector. The maritime industry’s growing sophistication in wind measurement and optimisation parallels the challenges wind farm operators face.
The sector’s shift towards remote sensing and multipoint measurement systems mirrors similar trends in wind farm optimisation. Both industries increasingly recognise the value of comprehensive wind-field analysis and upstream wind measurement for maximising energy capture and system efficiency. Technical challenges identified in WASP applications – such as measuring complex wind fields, managing turbulence effects, and integrating multiple data sources – closely align with ongoing difficulties in wind energy generation. Solutions developed for maritime applications may offer new approaches for wind farm operators.
As both sectors advance towards a decarbonised future, cross-pollination of technical innovations can further propel innovation. The maritime industry’s rapid adoption of sophisticated wind measurement technologies demonstrates the broader potential for wind energy applications across sectors, reducing emissions and fuel consumption to contribute to a greener global future.
Further Reading
International Windship Association (IWSA), https://www.wind-ship.org
Biography of the Author
Floriane Grussenmeyer is the Sales Manager in Vaisala’s Maritime and Offshore Operations team. She has extensive experience in global sales and business development of sensors and wind lidar-based solutions for various weather-related markets. Grussenmeyer contributes her expertise to developing new applications for Vaisala in the maritime sector.
