Technical evaluation of four amorphous silicon systems at NREL

The National Renewable Energy Laboratory (NREL) has been studying the performance of small grid-tied PV power systems since 1992. These 1 to 2 kW/sub AC/ systems are designed to conduct in-situ technical evaluations of the PV arrays in a high voltage configuration. This paper concentrates on the performance and reliability of four amorphous silicon systems currently being tested in Golden, Colorado, USA. The four systems include arrays from United Solar Systems Corp., Solarex and Advanced Photovoltaic Systems. Each of these systems is tied to the grid with an Omnion inverter. The data show that most systems employing amorphous silicon exhibit stable performance over time and are viable for commercial scale-up to larger systems.