Shading to sun rays from surrounding obstacles such as trees, building, structures, hills or mountains is often referred to as ‘far shading’.
The shaded area can be calculated from astronomical solar data. The diagram below shows for a sample the shading length from a tree line on a particular site.
Far shading may significantly reduces the PV system efficiency and must be avoided as much as possible.
The shading length is function of latitude, month, day, hour, and height of the obstacle and can be calculated with this tool created by EcoSmart.