Realistic reporting conditions -RRC- for site-dependent energy rating of PV devices

The RRC method /6,7/ provides a general, realistic, site-dependent approach for energy rating under realistic environmental conditions. New aspects of the dependence of the RRC efficiency deviation from the standard value on the cell material are presented. The influence of the spectral distribution of the irradiance on the deviation from the standard efficiency is calculated for an a-Si test cell, with the RRC algorithm. The RRC spectral and temperature- dependent deviation from the SRC efficiency is roughly determined by the material, the contribution of the global irradiance to the deviation depends on the specific test cell design. The site dependence of the efficiency deviation from the standard value is analysed for 14 sites in Europe. For the mono-Si test cell, the maximum deviation on a yearly basis is -10.3 %, it reaches -5.2 % for the GaAs cell and -24.7 % for the a-Si test cell. Besides extreme deviations, results are also presented for an "average" European site as compared to an "average" USA site /7/. Equivalent parameters were calculated for the test cells and European sites. For Geq a relatively narrow variation range resulted, far removed from the standard SRC and NOCT values. The paper clearly shows that neither SRC nor NOCT standard conditions are suitable for PV device assessment under natural environmental conditions and that the RRC method offers a realistic, solar cell and site-dependent energy rating means.