Impact of Soiling Deposition on CdTe and Si PV Modules in Different Climate Zones in Brazil

This preliminary case-study report summarizes 5-years of research on the contrasting soiling conditions in the tropical, subtropical, and semi-arid climates in Brazil. This paper presents a methodology to quantify the soiling ratio (SRatio) and soiling rate (SRate) in PV modules of thin-film cadmium telluride (CdTe) and polycrystalline silicon (p-Si) through measurements from monitoring soiling stations installed in different climatic zones in Brazil. In these studies, the meteorological data and the electrical and thermal parameters of the photovoltaic modules have been collected and analyzed, and a mathematical model was developed to determine the soiling ratio (SRatio) and soiling rate (SRate) for each site (in compliance with the IEC 61724-1 monitoring standard and IEC 62670-3). The SRatio for short-circuit current (SRatioI
_sc
) and maximum power (SRatio
_Pmax
) data from the PV modules were evaluated and compared with objective of characterizing the uniformity of the soiling deposition process and to monitor any associated issues with non-uniform thermal effects. Non-uniform soiling is dicussed associated with framed modules and with effects of precipitation. Finally, other parameters are discussed for these climate conditions.