In order to calculate the approximate efficiency of a solar panel as a percentage, there is a simple equation that can be used: panel power (measured in kW) divided by the length and width of the panel (measured in metres), and then multiplied by 100%.
From the get-go, it is important to understand that the efficiency of a solar panel is a matter of surface area, not power. A 10 percent efficient 100W panel and a 20 percent efficient 100W
