How are PV cells affected by soiling?
The degree of soiling will depend on the location but usually dust accumulation and self-cleaning reach a steady state after a few weeks if the array tilt is at least 15 degrees. In extreme cases dust may cause a power reduction of about 10%. At low tilts horizontal glazing bars can trap debris which could lead to shading of part of the array. The design of the system should aim to minimise uneven soiling.
