As we know, wind energy is one of the most promising renewable sources for the global energy transition. However, its efficiency and optimization depend heavily on our understanding of the atmospheric phenomena that influence wind behaviour. One such phenomenon, particularly relevant in complex terrains, is wind shear and veer. These two concepts are key to understanding how wind interacts with the terrain and how it affects wake development (the trail of slower and more turbulent air left by turbines) and the overall efficiency of wind farms.
What are Wind Shear and Veer?
Wind shear refers to the change in wind speed with height. In complex terrains, this phenomenon is amplified by irregular topography, which can lead to significant variations in wind speed at different altitudes.
On the other hand, veer describes the change in wind direction with height. Wind veer has a smaller impact on shorter turbines with smaller rotor diameters because they are effectively sampling less of the atmosphere and therefore experience less variance. With larger rotor diameters and higher hub heights, the turbine rotor plane samples more of the atmosphere leading to greater variance in wind direction and speed across the entire rotor plane [1].
Both factors are critical for predicting wind behaviour and optimizing the design and operation of wind turbines. In complex terrains, such as hills, valleys or mountainous areas, shear and veer can be highly variable. This is because wind flow is altered by terrain roughness, the presence of obstacles and temperature differences. These variations can significantly impact the formation of wakes behind wind turbines, which in turn affects the overall efficiency of the wind farm.
The Challenge of Complex Terrains
Wind farms located in areas with challenging topographies, where wind flow can be highly turbulent and variable, may experience reduced energy production and increased turbine wear due to additional loads generated by turbulence.
To address these challenges, it is essential to improve the understanding of wind flow conditions and how they influence wake development. This is where high fidelity simulations using advanced tools like OpenFOAM come into play, allowing us to model wind behaviour in complex terrains with a high degree of accuracy.
AIRE: Understanding Flow and Optimizing Wind Farms
At AIRE, one of our primary goals is to understand wind flow conditions in complex terrains. This includes improving our understanding of wake development and optimizing OpenFOAM simulations to more accurately predict wind behaviour under these challenging conditions.
Our work is being carried out in several wind farms across Europe, such as Alaiz (CENER) and Buseco (CAPITAL) in Spain. In these projects, we are applying advanced modelling and analysis techniques to decipher the dynamics of wind shear and veer, aiming to enhance the efficiency and profitability of these wind farms. Importantly, the insights gained from these projects could be applied to many other wind farms in the future.
Wrapping up
Wind energy in complex terrains presents both a technical challenge and a significant opportunity. If we fully grasp the concepts of shear and veer, we can optimize the design and operation of wind farms, generating more energy while keeping maintenance costs down.
At AIRE, we are committed to innovation and excellence in the field of wind energy. Our work in wind farms like Alaiz or Buseco among others in the project is just the beginning. We will continue to study wind flow in complex terrains, improving performance and ensuring long-term reliability. If you are interested in learning more about our work or collaborating with us, please do not hesitate to get in touch!
Author: Oria Pardo
Editor: Lucia Salinas
March, 2025
