The performance of a fully-monitored, double-junction a-Si grid-connected BIPV system after four years of continuous operation in Brazil

Thin-film amorphous silicon (a-Si) is a good choice of PV technology for operation in warm and sunny climates. A small temperature coefficient of power and a noticeable thermal annealing recovery effect of the light-induced degradation under high operating temperatures, render a-Si devices good performers in warm climate, low-latitude countries. Since 1997 LABSOLAR is continuously monitoring the performance of a thin-film, grid-connected, building-integrated photovoltaic (BIPV) system in Brazil. The performance ratio of this 2 kWp double-junction a-Si PV installation after more than four years of continuous operation averages over 83% AC and 91% DC. The degree of light-induced degradation is lower than usually reported in the literature for a-Si operating in more temperate climates. This is ascribed to higher operating temperatures over the year at the site, leading to a higher degree of thermal annealing of this BIPV system. Our results demonstrate that new generation multijunction a-Si performs well in BIPV systems in warm and sunny sites.