A common question we get asked is:
What happens to my solar power production when it’s cloudy?
Well, obviously light equals power, so the more direct light the panels receive, the more power will be produced. Which means less direct light will produce less amounts of power. Bright, sunny days will contribute to your system working at peak capacity. But on a day with thick cloud cover, power production will be much lower than average.
Besides direct light, solar panels will also absorb diffused light and albedo, or reflective, light. As an example of diffused light: a cloud may briefly cover the sun, but we still receive light from the whole sky. That light, though not directed in a beam towards the panels, will still be absorbed. Power production will be reduced by about half, but will not come to a complete standstill. Panels can also absorb reflective light from shiny or light-colored surfaces, such as we see with bodies of water or snow.
An unusual phenomenon also exists when there are patches of cumulus clouds drifting through the sun’s beams. Called the edge of cloud effect, as the sun peeks out of the spaces in between the clouds, the direct light combined with the reflective light will briefly boost your panels’ power production. The increase is relatively small and short-lived but interesting to note. Most inverters allow for this brief surge of power so there is little danger to your solar panel system.
As a case study, one of our customers discusses his experience with his solar power system production during cloudy/rainy conditions: