Work out solar shading loss instantly with clear inputs, formula shown and shareable results.
A tilted row casts a shadow of length equal to its vertical rise divided by the tangent of the solar altitude. If that shadow plus the row's own horizontal footprint exceeds the pitch, the next row is shaded. Designers usually accept shading below a critical altitude of 15-25 degrees, since little energy is available then.
Shadow length
Shadow = collector height x sin(tilt) / tan(solar altitude)
No-shading pitch
Minimum pitch = shadow length + collector height x cos(tilt)
Series-connected cells are limited by the weakest cell, so shading one module row can suppress a whole string. Module-level bypass diodes and string layout parallel to row direction limit the damage.
Commonly the altitude at 9 am on the winter solstice, or a fixed 15-25 degrees. Requiring zero shading at all times leads to uneconomically wide spacing.