Solar radiation is the result of fusion of atoms inside the sun. Part of the energy from the fusion
process heats the chromosphere, the outer layer of the sun that is much cooler than the interior of the sun,
and the radiation from the chromosphere becomes the solar radiation incident on the earth [4]. Wind
energy is produced by continuously blowing wind and can be captured using wind turbines that convert
kinetic energy from wind into mechanical energy and then into electrical energy [5].
When the solar radiation enters the earth’s atmosphere (Fig. 1), a part of the incident energy is removed
by scattering or absorption by air molecules, clouds and particulate matter usually referred to as aerosols.
The radiation that is not reflected or scattered and reaches the surface directly in line from the PV module
s called beam radiation. The scattered radiation which reaches the ground is called diffuse radiation.
Some of the radiation may reach a receiver after reflection from the ground, and is called the albedo. The
otal solar radiation on a horizontal surface of PV module consisting three components is called global
rradiance. When the skies are clear and the sun is directly in line from the PV module, the global
rradiance is about 1000 W/m2 [6]. Although the global irradiance on the surface of the earth can be as
high as 1000 W/m2, the available radiation is usually considerably lower than this maximum value due
o the rotation on the earth and climate condition (cloud cover), as well as by the general composition of
he atmosphere. For this reason, the solar radiation data is the most important component to estimate
output of photovoltaic systems [4] [7] [8]. Solar radiation is greater than 3 kWh/m2 indicates that the sky
s clear, its intensity very high and very good for PV application [9].