Solar Panels and Shading

Assess it across the year

The sun is much lower in winter, so a shadow that misses the roof in June may cover it in December. A proper shading assessment considers the whole year, not the day of the survey.

Near and far shading

Near shading — a chimney, a vent, a neighbouring dormer — is sharp and moves quickly. Far shading from a tree line, a hill or a tall building is softer and lasts longer. They are handled differently in design.

Mitigations, honestly stated

Move the array to a clearer part of the roof; re-string so shaded panels sit together; add optimisers or microinverters. All help. None makes shading free.