A kWp is the kilowatt ‘peak’ of a system. This is a standardized test for panels across all manufacturers to ensure that the values listed are capable of comparison.
When the solar PV (Photo Voltaic Solar Panel) panels are working they will over an hour convert the suns irradiance into energy, which is measured in kilowatt hours (kWh). A PV system with a kWp of 3kW which is working at its maximum capacity (kWp) for one hour will produce 3kWh.
What does kWp and kWh mean?
Solar electricity systems are given a rating in kilowatts peak (kWp). This is essentially the rate at which it generates energy at peak performance for example at noon on a sunny day. The kWp of a domestic system will vary depending on how much a customer wants to spend and the roof area available to accommodate the panels.
The total amount of electricity the system actually generates in a year is measured in kilowatt hours (kWh). This will depend on the system’s orientation, shading and how sunny your site is, as well as the size of the system (in kWp) that you have installed.
A typical domestic Solar roof array system is between 1kWp would typically generate 1350 to 1400kWh per year depending on size, keeping tilt angle same as latitude angle.
By contrast an average home uses 2000kWh of electricity per year on lights and appliances. However, an energy efficient home using A rated appliances and lighting could conceivably use half this value.