Annual and seasonal energy rating of mono-Si, a-Si and GaAs test cells for the USA by the RRC method

The realistic reporting conditions (RRC) efficiency gives a site-dependent characterisation for solar cells, accounting for differences due to the variability of specific meteorological conditions /1,2/. A strong site and cell material dependence resulted for the the deviation of the RRC efficiency from the SRC efficiency. The calculation was performed for three test cells (mono-Si, GaAs and a- Si) and ten sites in the USA. Neither SRC nor NOCT conditions allow a realistic energy rating of solar cells: deviations of the RRC efficiency from the SRC efficiency of up to 18% were obtained on a yearly basis and up to 34% on a monthly basis. Deviations of more than 10% from the efficiency for NOCT conditions still resulted on a yearly basis for a- Si. The influence of the variable spectral distribution of the irradiance on the efficiency was not considered. For the global irradiance and the temperature, equivalent RRC values, i.e. constant values at which the cell has its RRC efficiency for the considered time basis, have been determined. They deviate strongly from the corresponding SRC and NOCT values.