kWp - what does this acronym stand for?
kWp is the abbreviation for 'kilo Watt peak', which translated means 'kilo Watt maximum'. It is a unit of power that refers to the maximum production capacity of a photovoltaic (PV) module or the entire PV installation under certain conditions, known as Standard Test Conditions (STC).
The STC conditions under which kWp is measured are defined as:
- Insolation of 1000 W/m² (i.e. a very bright sunny day).
- Module temperature of 25°C.
- Sunlight spectrum at an incidence angle of 1.5 (AM1.5, corresponding to a typical midday sunlight spectrum in Central Europe).
For example, if a photovoltaic installation has a capacity of 5 kWp, this means that it is capable of producing up to 5 kilowatts of energy at any time under the above conditions.
However, it is worth noting that 'standard' conditions are rarely encountered in the real world, so the actual energy production of photovoltaic panels may be lower than their nominal kWp. In actual production conditions, factors such as cloud cover, angle and direction of light, and temperature can affect the performance of the panels.
Below are some examples of the daily performance of a photovoltaic installation on sunny days, depending on the time of year and the direction of the sun's rays (installation direction).
The unit kWp is commonly used in the photovoltaic industry as the standard measure for determining the output of PV panels and installations.
