Wind Load on Solar Structures: How to Calculate It According to Regulations and Ensure a Safe Design

13 Feb Wind Load on Solar Structures: How to Calculate It According to Regulations and Ensure a Safe Design

Wind load on solar structures is one of the most critical factors in the design of photovoltaic installations, both on rooftops and on the ground. An incorrect calculation can cause deformations, structural failures, production losses, and even system collapse.

In this article, we explain how to calculate wind load on solar structures according to current regulations in Spain and what aspects you should consider to ensure a safe, efficient, and durable design.

What is wind load on solar structures?

Wind load is the force exerted by the wind on a structure. In photovoltaic systems, this action generates:

• Pressure and suction on the modules
• Tensile and compressive stresses in the structure
• Bending moment in pillars and profiles
• Stresses in anchors and foundations

Because solar panels act as exposed surfaces, they can behave like “sails,” especially in inclined or elevated installations.

Applicable regulations for wind load calculation

In Spain and Europe, the calculation must be performed in accordance with:

• Technical Building Code (CTE)
• Eurocode 1 (EN 1991-1-4: Wind actions)

The CTE refers to Eurocode for detailed calculations, taking into account:

• Wind zone
• Height above ground level
• Terrain category (urban, rural, coastal, etc.)
• External and internal pressure coefficients
• Shape and inclination of the structure

Factors influencing wind load

• Geographic zone: Spain is divided into different wind zones. The basic wind speed depends on the location and directly affects the design pressure.
• Installation height: The greater the height, the greater the wind speed and, therefore, the greater the pressure.
• Terrain type: The surrounding environment modifies wind speed:
  • Open terrain → greater exposure
  • Urban environment → greater roughness, lower speed
• System inclination and geometry: Structures have different aerodynamic behaviors:
  • Coplanar
  • Inclined
  • With elevation above the roof
  • Solar tracking

Basic formula for calculating wind pressure

According to Eurocode 1, the basic dynamic pressure is calculated as:

Where:

• ρ = air density
• v = wind speed

Subsequently, exposure, pressure, and safety coefficients are applied.

In addition, the following must be considered in solar structures:

• Edge effect on roofs
• Corner areas with greater suction
• Channeling effect on flat roofs
• Potential turbulence

Differences between roof and ground

Solar structures on roofs

• • Greater risk of suction
  • Direct influence of building height
  • Need for specific calculations in perimeter areas
  • Special attention to ballasted systems

Solar structures on the ground

• • Greater influence of the terrain
  • Critical importance of the foundation
  • Overturning and sliding verification
  • Optimized structural design to minimize steel

Common errors in wind load calculations

• Failure to consider local edge coefficients
• Use of generic values ​​without specific analysis
• Failure to verify ultimate and serviceability limit states
• Failure to check the capacity of anchors or bolts
• Ignoring dynamic effects in solar trackers

These errors can compromise safety and generate subsequent cost overruns.

Wind Tunnel Model for Wind Load Calculation on Structures

How to Ensure a Safe and Optimized Design

To ensure a strong and cost-effective structure, it is essential to:

• Apply the Eurocode correctly
• Perform specific structural calculations for each project, such as wind tunnel testing.
• Optimize profiles without compromising safety
• Verify anchors and foundations
• Analyze combined loads (wind + snow)

In EPC projects and large-scale plants, an optimized design can lead to significant savings in steel and foundations, while maintaining full structural safety.