NABCEP Solar Associate Practice Exam

As the average temperature of solar panels increases, the output voltage typically decreases. This phenomenon is due to the inherent characteristics of semiconductor materials used in solar cells.

In solar cells, as temperature rises, the increase in thermal energy causes more electron-hole pairs to be generated. While this might sound beneficial, the increase in temperature actually leads to a decrease in the bandgap energy of the semiconductor materials. The bandgap energy is the energy needed for electrons to move from the valence band to the conduction band, which is essential for generating electrical current.

As the bandgap narrows, the voltage produced by the solar cells diminishes. This effect becomes significant as the temperature rises above standard testing conditions, which are usually set at 25 degrees Celsius. Therefore, higher temperatures can lead to a reduced efficiency of the solar panels, resulting in a drop in output voltage.

Understanding this behavior is crucial for optimizing solar panel performance and system design, particularly in regions with high ambient temperatures.