How Wind Affects Solar Trackers on PV Panels
In July 2022, the Electric Power Research Institute (EPRI) held a conference in Houston, Texas to help owner/operators of renewable energy systems overcome key challenges from performance monitoring and issue detection, to ensuring the successful life of a project.
Through discussions on the effects of weather and wind on solar panels, to leveraging data and AI to make informed decisions, the event included speakers and presentations from industry leaders, including RWDI’s own Zachary Taylor, Technical Director. As a specialist on wind effects on flexible structures, Zachary’s presentation at EPRI focused on the aeroelastic effects of wind on single axis trackers.
We spoke to Zachary to get the most important takeaways from his portion of the workshop.
Q: What are single axis trackers and aeroelasticity?
Zachary: Solar PV panels sit on top of single axis trackers. These trackers, and therefore the panels, rotate throughout the day to track the sun, facing from the east to the west. Tracking the sun in this way is what helps boost the efficiency of large-scale solar PV plants in their generation of renewable power.
Aeroelasticity refers to the interaction between the wind and a flexible structure. The motion this interaction causes can lead to larger wind loads. Some flexible structures are prone to experiencing divergent motion, which is also called aerodynamic instability.
Q: What is a key challenge for single axis trackers?
Z: As the structural efficiency of single axis trackers continues to evolve, several design challenges have appeared. Regardless of the exact design of these trackers, all of them must deal with the wind, and can face increased loading due to wind buffeting and wake effects. In addition, because the trackers are quite flexible, they are also vulnerable to aeroelastic effects and aerodynamic instabilities, including phenomena referred to as torsional divergence (or galloping) and torsional flutter.
In other words, high wind events can often cause the solar PV panels, which are mounted on these trackers, to vibrate with significant rotations increasing with wind speed. Enough of this movement can lead to significant structural damage and not only cause the panels to fail, but ruin them as well.
Q: What are the design implications for the wind-induced vibrations?
Z: The potential for wind-induced vibrations of the single axis trackers and the subsequent effects can have a significant impact on the design of these trackers and the racking the solar PV panels are mounted on. However, the exact design impacts can vary based on several factors.
When it comes to the site condition, it is important to consider the characteristics of wind turbulence and if there are topographical impacts, which can change the turbulence and therefore the response of the structure. The local wind climate surrounding the solar power plant is also a vital factor. Specifically, the wind speed and predominant wind directions can influence how the power plants’ panels and their structures respond.
The dynamic properties of the trackers have a massive influence on the design as well. This is because the specific details of the design matter. These details include the modes of vibration, the natural frequency, the effect of actuators, dampers, and array layout. The details are important to validate through field measurements and simulate accurately in wind tunnel testing.
Q: What is the number one takeaway from your workshop?
Z: I think it is vital for the wind effects on flexible solar PV installations to be addressed – thankfully, there are solutions available to mitigate these wind effects and preserve the life of the solar panels.
Ten years ago, no one was talking about this issue. Here at RWDI, we want to make considering the potential wind effects on flexible solar PV installations prevalent – this is why we attend workshops like this one and share our knowledge on how to solve this issue and maintain the power of solar panels.
By empowering solar farm owners and operators with this knowledge, they are less likely to encounter damages to their solar panels from wind, reducing costly damages or loss of power generation due to failure.