PV Module Technology Comparisons: Comprehensive Study Differentiating Soiling Spectral Effects, Operating Temperature, and Climate Conditions

Photovoltaic (PV) module performance depends upon a collection of inherent and related external parameters. The choice of a particular PV-technology for “best performance” at a location is sometimes based solely on the label specification or single operating condition—and may not consider multiple parameters that affect different technologies with distinctly different impacts. In this paper, the choice of appropriate PV technologies for moderate-to-harsh soiling/climate conditions is evaluated based upon frequently opposing parameters of spectral effects (relating to solar resource, module spectral response, and soiling layer properties) and module temperature (linked to module construction and absorber bandgap). This paper builds on a linear model based upon soiling rates and the temperature coefficients of the module technologies. The model is validated with extensive experimental soiling data for crystalline Si and thin-film CdTe, with model discussions for CIGS and a-Si:H—covering the range of bandgaps from 1.1 eV through 1.7 eV for valid intercomparisons. The paper provides analytical and correlated experimental information to predict, compare, and identify the “best-of-class” performances for these module types under tropical climate-zone conditions.