In photovoltaics, the fundamental units of measurement include the watt-peak (Wp) and the kilowatt-hour (kWh).
Watt peak (Wp ): represents the maximum electrical power generated by a photovoltaic system under standard sunlight conditions. These conditions include :
- irradiance of 1,000 W/m², spectral distribution of radiation (AM 1.5) 2
- The spectral distribution of radiation, known as AM 1.5, represents the solar radiation reaching the Earth's surface after passing through an atmosphere with a mass of around 1 kg at an angle of 45 degrees.
- The panels are oriented to capture the maximum amount of direct solar radiation, with their surface perpendicular to the direction of the source of the direct radiation).
- Standard conditions also include a panel temperature maintained at 25°C.
Kilowatt-hour (kWh): In other words, one kilowatt-hour (kWh) is equivalent to the energy consumed by a device with a power of one kilowatt, operating for one hour (1 kilowatt × 1 hour).
