Install tip: Adjust module tilt to minimize inter-row shading losses

This installation tip was provided by Peter Abou Chacra, engineering consultant, SunModo

Tilted PV panels cast shadows on rows of modules behind them, necessitating a gap between rows to minimize the effects of production loss due to shadows. Here are a few ideas to mitigate the impacts of this phenomenon on your PV installation:

Reduce the tilt of your south-facing array. For peak energy production on a per-module basis, PV modules have an ideal incident angle with solar rays emanating from the sun. For some installations, however, it may make sense to reduce the tilt of the modules to a less optimal incident angle. Though this means less production on a per-module basis, it can mean a significant increase in the daily unshaded collection time for the array. This gain in effective collection time can offset the losses caused by a sub-optimal tilt for the module itself. Consider hiring a qualified PV design professional or using software dedicated to modeling and analyzing a system’s performance at a different tilt angle and inter-row spacing.

Locate your system on a south-facing slope. Even a 5° inclination can have a marked impact on the amount of inter-row spacing required. This can significantly increase the number of modules that can fit in a given area.

Consider three-in-landscape or four-in-landscape monoslope installations. Coupled with a low tilt, this strategy can reduce inter-row spacing significantly on a given installation since modules on the same structure and slope don’t require significant spacing between them. This can be particularly effective if you can gradually elevate the anterior monoslope PV structures as you work your way north through the site.
There are no one-size-fits-all PV module or racking solutions for optimizing a PV installation’s performance. Make sure to study the site, and select the products that best suit the geography, topography and engineering constraints of the installation site. If necessary, consider employing the help of a PV design professional to help you navigate the myriad options and select and design a system that will meet your objectives.