wind turbine, yaw impact, lidar, wind speed, wind turbulence

Impact of Yaw on Productivity and Wind Turbine life extension

  • By saralarde
  • août 25th, 2021
  • News

More than 60% of wind turbines show the presence of Static Yaw leading to performance loss and in half of these cases, the AEP loss is greater than 3%. Yet the importance of managing Static Yaw has not always been among the wind industry’s top priorities, especially with high subsidised wind energy prices.

But with the quest for affordable energy, a drive for productivity improvement is coming from all sides. Eliminating Static Yaw is one of the key sources of productivity improvement and hence a major priority today. 

The emergence and growth of a numerous actors providing improved measurement solutions is a testimony to this drive and the necessity of radically improve data precision to increase productivity and reduce maintenance costs. This growth is worldwide, with all countries vying for effective measurement solutions.



bannière epsiline


Advanced technology for high accuracy datas 

Anyone with experience sailing understands the interest of navigating closest to the wind : gain speed. And speed in the wind industry is everything. With productivity increasing with its cube, any improvement in this source of energy becomes a priority.

Furthermore, a good skipper knows that neither turbulence nor excessive direction variation is productive. This is why measuring accurately wind direction is important. It reduces turbulence and allows higher speeds. But since you don’t have a skipper, you need good measurement sensors.

New and affordable LiDAR based sensors such as the WindEagle provide this high accuracy. With advanced innovations such as those proposed by Epsiline, LiDAR are now cost efficient enough to be installed systematically on all wind turbines. Instead of six digit prices of the past generation of LiDAR, new devices measuring accurately Yaw reach 4 digit prices.

But it requires a mindset change to understand why Met masts and nacelle based anemometers are not adapted anymore, especially in the case of on-shore wind turbines, in particular when they are subject to turbulence from either terrain, obstacles or other wind turbines.


Why use the WindEagle Lidar rather than Scada 

Since the onset of the Wind Energy industry, Wind Turbine (WT) performance has been managed in contractual terms. Fixed and subsidised energy prices induced a contractual approach where measuring and controlling OEM commitments, not Yaw, remained at the heart of the productive activity. The backbone of this system was built on Supervisory Control And Data Acquisition (SCADA) and long distance wind measurement using expensive equipments such as met masts.

Nacelle based anemometers completed the information with limited efficiency. Their position behind the blades makes them susceptible to turbulence coming from the blades. With an accuracy limited at +/-3°, their contribution to improving productivity has always been very limited. They provide overall wind direction, but do not allow to steer up close to the wind, where the highest productivity is to be found.

To the point, anemometer based systems need to have findings validated by high accuracy Yaw sensors such as the WindEagle.


Wind turbulence 

Now, with energy prices falling, it is necessary to identify this potential margin of optimisation. The key to this undertaking is understanding the individual WT characteristics which drive the wind blades, in effect, the wind directly in front of the blades. Only with measurements directly in front can the fundamental characteristics driving performance be identified. Precise wind direction and its angle with the nacelle direction (YAW), Turbulence Intensity (TI), and Wind Speed are all necessary to understand how well an owner is doing with respect to absolute potential. 

This is where the most advanced and cost-effective technology comes into play, notably Epsiline’s WindEagle system. This combination of advanced sensors and algorithms provides accurate (precision > 0,5°) information for advanced monitoring, diagnostics and improvement.

At the core of the WindEagle lies our patented LiDAR technology which measures wind characteristics directly in front of the blades. Beyond its high wind measurement accuracy, Epsiline’s LiDAR brings this advanced technology to all by reducing cost by an order of magnitude. 


The WindEagle: the solution to monitor and improve performance 

Epsiline’s LiDAR technology forms the cornerstone of an advanced yet easily useable solution. Accurate measurements of wind caracteristics are completed by further sensors including Pressure, Temperature & Humidity (PTU), vibration and GPS. All these sensors are contained in the compact WindEagle which is installed in less than 2 hours on top of the nacelle. Data is transmitted via the cellular networks directly to Epsiline’s secure servers where the information can then be processed either through Epsiline’s advanced algorithms or through an API key for more customised analysis. Algorithm results and parameters are then accessed through Epsiline’s Webportal, giving full diagnostics to understand, monitor and improve performance.

In addition to Static Yaw, Epsiline’s WindEagle can contribute to reducing dynamic Yaw.

Beyond static Yaw analysis and productivity improvement, when the WindEagle is left permanently on the nacelle, automatic monitoring can be implemented to improve maintenance and ensure optimal productivity. Alerts are programmed to have email notifications sent whenever preset or customised thresholds have been crossed. Hence, if there is a derivation in Static Yaw, this can be automatically detected and the operator will be automatically informed thus saving time and money.

Epsiline’s WindEagle is positioned to support the Wind Industry in its transformation by focusing on optimal performance through state of the art sensors allowing for real-time and real-life data transmission, analysis and improvement.


More information on our brochure.

Contact:  / +33 5 32 10 83 50