Skip to main content

Research Repository

Advanced Search

Modelling photovoltaic soiling losses through optical characterization.

Smestad, Greg P.; Germer, Thomas A.; Alrashidi, Hameed; Fern�ndez, Eduardo F.; Dey, Sumon; Brahma, Honey; Sarmah, Nabin; Ghosh, Aritra; Sellami, Nazmi; Hassan, Ibrahim A.I.; Desouky, Mai; Kasry, Amal; Pesala, Bala; Sundaram, Senthilarasu; Almonacid, Florencia; Reddy, K.S.; Mallick, Tapas K.; Micheli, Leonardo


Greg P. Smestad

Thomas A. Germer

Hameed Alrashidi

Eduardo F. Fern�ndez

Sumon Dey

Honey Brahma

Nabin Sarmah

Aritra Ghosh

Nazmi Sellami

Ibrahim A.I. Hassan

Mai Desouky

Amal Kasry

Bala Pesala

Senthilarasu Sundaram

Florencia Almonacid

K.S. Reddy

Tapas K. Mallick

Leonardo Micheli


The accumulation of soiling on photovoltaic (PV) modules affects PV systems worldwide. Soiling consists of mineral dust, soot particles, aerosols, pollen, fungi and/or other contaminants that deposit on the surface of PV modules. Soiling absorbs, scatters, and reflects a fraction of the incoming sunlight, reducing the intensity that reaches the active part of the solar cell. Here, we report on the comparison of naturally accumulated soiling on coupons of PV glass soiled at seven locations worldwide. The spectral hemispherical transmittance was measured. It was found that natural soiling disproportionately impacts the blue and ultraviolet (UV) portions of the spectrum compared to the visible and infrared (IR). Also, the general shape of the transmittance spectra was similar at all the studied sites and could adequately be described by a modified form of the Ångström turbidity equation. In addition, the distribution of particles sizes was found to follow the IEST-STD-CC 1246E cleanliness standard. The fractional coverage of the glass surface by particles could be determined directly or indirectly and, as expected, has a linear correlation with the transmittance. It thus becomes feasible to estimate the optical consequences of the soiling of PV modules from the particle size distribution and the cleanliness value.


SMESTAD G.P., GERMER, T.A., ALRASHIDI, H. FERNÁNDEZ, E.F., DEY, S., BRAHMA, H., SARMAH, N., GHOSH, A., SELLAMI, N., HASSAN, I.A.I., DESOUKY, M. KASRY, A., PESALA, B., SUNDARAM, S., ALMONACID, F., REDDY, K.S., MALLICK, T.K. and MICHELI, L. 2020. Modelling photovoltaic soiling losses through optical characterization. Scientific reports [online], 10, article ID 58. Available from:

Journal Article Type Article
Acceptance Date Oct 30, 2019
Online Publication Date Jan 9, 2020
Publication Date Dec 31, 2020
Deposit Date Jan 23, 2020
Publicly Available Date Jan 23, 2020
Journal Scientific Reports
Electronic ISSN 2045-2322
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 10
Article Number 58
Keywords PV; Soiling; Ultraviolet; Infrared; Ångström turbidity equation; Particle; Size; Cleanliness
Public URL


You might also like

Downloadable Citations