UNESCO resource kit - science and technology educa...

--------------------- UNESCO Nodule 21: Photovoltaic systems
Photovoltaic systems
Electricity from the SUD
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'Photovoltaic' (or PV for short) means turning light into electricity. Solar PV
systems provide electricity from sunlight. They can provide power for a wide
variety of uses. Calculators, lights,
fridges, homes and even whole
villages or towns can use solar
electricity as their energy source.
A solar panel is made up of lots of
small cells linked together. Each small
cell produces a tiny electric current
when the Sun shines on it. They can do
this because they are made of materials
called semi-conductors. Solar panels
can then be linked to form a large solar
PV array producing a lot of electricity.
Solar PV systems produce electricity
without noise, moving parts to wear out, or pollution. One of the advantages of
solar electricity is that you do not need to have a power station sending electricity
to you along wires. Even in the most remote parts of the world, PV systems
can supply solar electricity for all kind of uses.
Try to answer all of these questions. Be prepared to share your answers with a
partner, and with the rest of the class.
1 You may have seen a calculator-powered by solar cells. (You may even have
one.) Most pocket calculators are powered by batteries. What is the
advantage of using solar cells to power a calculator? Are there any
disadvantages?
2 Where else have you seen solar cells in use? What were they being used for?
Can you suggest why they were used for this purpose?
3 What is your main source of electricity? Is it produced from sunlight, or by
burning fuels, or by some other means?
4 Think about the word photovoltaic. It means 'turning light into electricity'.
Which part of the word means 'light'? Which part means' electricity'?
Suggest some other words which are related to each of these two parts.
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