Bird droppings

Definition

Unlike general soiling, a bird dropping covers a small area completely. The part of the cell that is shaded cannot produce current and the cell can heat up. Because rain does not wash it off easily, it can stay in the same spot for a long time.

Signs in the imagery

In the RGB image it shows as white or light-coloured spots with sharp edges on the panel surface. Because the spots are small, detection requires RGB imagery at 1 cm per pixel or finer. If the spot covers enough of a cell, the thermal image also shows a hot spot at the same place.

Possible causes

• Perches such as panel top edges, poles and cables
• A water source, farmland or nesting area near the plant
• No measures in place to deter birds

Effect on production and safety

A single spot has a small effect on production, but the covered cell can heat up and develop into a hot spot. Spots left for a long time can mark the glass surface. Droppings concentrated on certain rows show that the same spots are being soiled again and again.

Recommended action

Spot-clean the affected panels. Washing the whole site is usually unnecessary. Identify the perches on the rows where spots concentrate and consider bird deterrents. If there is also a thermal hot spot at the same place, confirm at the flight after cleaning that it has gone.