Is there a way to calculate shading percentage on solar arrays?

Performing Site Surveys

To calculate shading percentage on a solar array, start by performing a site survey. This involves documenting the location of nearby obstructions, such as trees, buildings, and power lines, and measuring their height and distance from the array. For example, if a tree is 10 meters away and casts a 5-meter shadow, you can estimate its impact on the array using a shading analysis tool.

Using Shading Analysis Software

Software-based shading analysis tools, such as PVsyst or Solar Pathfinder, can help you calculate shading percentage on a solar array. These tools use 2D and 3D modeling to simulate the shading effects of nearby obstructions. For instance, Solar Pathfinder’s built-in shading calculator can estimate the percentage of the day that a solar array will be shaded based on site surveys and satellite imagery. By entering the array’s dimensions, obstruction data, and local solar irradiance data, you can get a precise estimate of shading percentage.

Accounting for Shading in Array Design

To mitigate shading effects, consider designing your solar array with shading in mind. One technique is to orient the array slightly off-north (e.g., 10-20° east or west) to minimize shading from nearby obstructions. Another approach is to use a “bifacial” array design, which allows for sunlight to be captured from both the front and back sides of the panels. By incorporating these design elements, you can reduce the impact of shading on your solar array’s energy production.