Photovoltaics
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A brief
introduction.
What is Photovoltaics?
Photovoltaics (PV) is a technology
that makes the conversion of solar radiation (sunlight) into electric current
possible.
How do Photovoltaics work?
Photovoltaics produce a flow of electrons. How? When light falls on the surface
of the panel, the photons in the solar cell become energised, in proportion to
the intensity and distribution of the light. When their energy level exceeds a
certain point an open circuit voltage is created across the cell. This is then
capable of driving a current through an external load.
For example: Envision a piece of metal such as the side panel of a car. As it
sits in the sun the metal warms. This warming is caused by electrons being
excited and bouncing back and forth creation friction therefore creating heat.
The solar cell simply takes a percentage of these electrons and directs them to
flow in a path. This flow of electrons is, by definition, electricity.
Why use PV systems as a source of electricity?
The majority of populations in need of electricity live in
dispersed communities and in remote areas. To provide these communities with
electricity from a large plant would be impractical and costly. Generator sets
are also impractical as there is no fuel source available.
Currently PV modules continue to provide an independent source of electricity: reliable and practical
for inaccessible remote areas. However moving from normal utility power in a
residential area to PV is not a cost effective move. Currently utility power is
more cost effective than PV systems, but the true cost of utility power will
only become evident in the years to come when we have exhausted all natural
resources and the emissions of Sulphur gas and nuclear waste disposals cause the
effects of global warming to become irreversible. When all these detrimental
effects are realised the cost of utility power will increase, making the use of
PV systems more substantial.
There are many advantages of
Photovoltaics:
 | PV systems have no fuel
requirements:
The cost of operating a PV system is marginal.
|
| PV systems are modular:
A system can be designed to meet the individual user's requirements,
minimising costs.
|
| PV systems improve the quality of
life:
It can provide a rural school or healthcare facility with electricity.
|
| PV systems are reliable:
They are significantly more reliable than generators and require less maintenance,
with routine maintenance being simple.
|
| PV modules have a long life:
Degradation in performance is less than 10% in 10 years and less than
20% in
25 years.
|
| PV systems are not environmentally
detrimental:
The use of fuels such as coal and oil is reduced.
No harmful pollution is released through the use of a PV system with no
contribution to the "greenhouse effect".
|
| PV systems are economically
feasible:
Considering the fact that PV systems have a small running cost compared
to the generator, more small applications can be run more efficiently using
a PV system. |
