Performance and reliability of a 15 kWp amorphous silicon photovoltaic system

Florida Power Corporation, in cooperation with the Florida Solar Energy Center, has installed a 15 kWp grid-connected photovoltaic system at one of its substations near Orlando, FL. The system utilizes thin-film amorphous silicon modules and was installed in August 1988. The system's performance has been monitored for 20 months of operation, and periodic diagnostic tests to evaluate subsystem reliability have been conducted. During the 20-month period, the power output of the photovoltaic array has degraded by about 25% of its original value and the array peak power efficiency was 4.0% in April 1990. Relatively high leakage currents of the photovoltaic array, particularly under wet conditions, have been detected. A significant corrosion build-up on 23 out of a total of 640 photovoltaic modules has also been observed in the 20-month period.<>