First, we must distinguish between energy and power. En […]
First, we must distinguish between energy and power. Energy is the amount that can be stored: for example, chemical energy in a battery; mechanical energy in a hydroelectric dam; thermal energy in a molten salt tank. In the International System of Units, energy is measured in joules (J); in actual systems, it is measured in kilowatt hours (kWh), that is, kilowatts x hours, where 1 kWh = 3.6 MJ, and "M" means "million". Power is the rate of energy production or use in watts (W).
Solar panels do not "generate" energy, but convert one form of energy (solar energy) into other forms (such as electricity and waste heat). In addition, solar panels cannot rely solely on stored energy. For this you need a battery. Therefore, solar panels are specified by their power generation capacity in watts (J / s)
Solar panels have different power capacities (sometimes called "peak power" or "rated power"). The amount of solar energy converted into electricity depends on the time it is exposed; how cloudy the sky is; the orientation of the panel and the angle of inclination relative to the horizontal line; the season of the year (affecting the angle of the sunlight collector); the efficiency of the solar module.