Solar energy refers to sources of energy that can be directly
attributed to the light of the sun or the heat that sunlight gen-
erates [1]. Solar energy technologies can be classified along the
following continuum: (1) passive and active; (2) thermal and photo-
voltaic; and (3) concentrating and non-concentrating. Passive solar
energy technology merely collects the energy without converting
the heat or light into other forms. It includes, for example, maxi-
mizing the use of day light or heat through building design [3,12].
In contrast, active solar energy technology refers to the harness-
ing of solar energy to store it or convert it for other applications
and can be broadly classified into two groups: (i) photovoltaic (PV)
and (ii) solar thermal. The PV technology converts radiant energy
contained in light quanta into electrical energy when light falls
upon a semiconductor material, causing electron excitation and
strongly enhancing conductivity [13]. Two types of PV technology
are currently available in the market: (a) crystalline silicon-based
PV cells and (b) thin film technologies made out of a range of
different semi-conductor materials, including amorphous silicon,