Fifteen years and counting: The reliable long-term performance of the first grid-connected, building-integrated, thin-film photovoltaic installation in Brazil

The first grid-connected, building-integrated, thin-film solar photovoltaic generator was installed in Brazil in 1997, and has been continuously operating ever since. The fully-monitored, 2kWp installation uses 40m² of glass-glass, double-junction, thin-film amorphous silicon (a-Si) PV laminates, which were installed as an overhang on the North-facing façade of the Solar Energy Laboratory at Universidade Federal de Santa Catarina (UFSC) in Florianopolis - South Brazil (Lat: 27°S). In this work we present some of the performance parameters over these 15 years of continuous operation, based on high-resolution operational data including AC and DC electrical parameters, temperature (ambient and back-of-module), and irradiance (horizontal and plane-of-array) measurements. Performance ratios (PR), annual energy yields, normalized power output, output degradation, seasonal annealing and other effects are also presented and discussed. The generator currently operates at a PR around 76%, and has an average annual energy yield of 1160 kWh/kWp for an average 1530 kWh/m²/year irradiation level at the site. After stabilization, PV modules annual degradation rates averaged at 0.55%/year over the 15 years period.