Annual photovoltaic energy yield

African countries have an evident potential for solar energy. Knowing what amount of solar radiation reaches the earth's surface is of particular interest for solar photovoltaic (PV) installations. It can be represented by the average annual potential energy production (or yield): the total amount of electricity (kWh) produced in one year by a 1 kWp PV system at optimal angle, expressed in kWh/kWp.