How does increasing temperature affect a PV module's voltage, current, and overall power output at fixed irradiance?

How does increasing temperature affect a PV module's voltage, current, and overall power output at fixed irradiance?

• A. Increasing temperature increases Voc and decreases Isc, boosting overall power.
• B. Increasing temperature lowers Voc significantly, increases Isc slightly, and can slightly reduce fill factor; overall power output typically decreases.
• C. Temperature has no effect on Voc.
• D. Power output increases with temperature at fixed irradiance.

Answer: (B)

As temperature rises, the voltage of a PV module falls while the current increases only a little, and the overall power at a fixed irradiance tends to decrease. The reason is that the silicon bandgap narrows with temperature, so the open-circuit voltage (the voltage when no current flows) drops noticeably. The short-circuit current, which is driven by light-generated carriers, increases only modestly with temperature. The fill factor can also dip slightly because the diode and resistance characteristics shift with temperature, thinning the I–V curve’s knee a bit. Since power at the maximum point is roughly Pmax ≈ Voc × Isc × FF, the substantial drop in Voc dominates the small rise in Isc and the small FF change, leading to an overall reduction in maximum power output at higher temperature.

As temperature rises, the voltage of a PV module falls while the current increases only a little, and the overall power at a fixed irradiance tends to decrease. The reason is that the silicon bandgap narrows with temperature, so the open-circuit voltage (the voltage when no current flows) drops noticeably. The short-circuit current, which is driven by light-generated carriers, increases only modestly with temperature. The fill factor can also dip slightly because the diode and resistance characteristics shift with temperature, thinning the I–V curve’s knee a bit. Since power at the maximum point is roughly Pmax ≈ Voc × Isc × FF, the substantial drop in Voc dominates the small rise in Isc and the small FF change, leading to an overall reduction in maximum power output at higher temperature.