Solar Cells

How do solar cells work?

Solar cells collect light from the sun and turn it into electricity. They do this in the following way.

• Energy from the sun falls on a thin slice of silicon based material
• This causes the silicon material to have more energy
• The heat energy makes the electrons in the materialjump out of that slice into an adjacent piece of silicon material
• Moving electrons create electricity
• The second slice of material now has extra electrons, and they have to move on. Extra electrons, moving freely, become electric current when they move together
• The extra electrons flow out of the solar cells as electric current
• The greater the intensity of the sunlight the greater the current produced
• The output from a cell is at its maximum when perpendicular (at right angles) to the light beam.
• The amount of electrical power is affected by the temperature around the solar cell

Solar energy being used to generate electricity which is then stored.

Why are solar cells useful?

Solar cells are useful because they are a renewable source of energy. This means that however much we use there is always more. The advantages of solar cells over fossil fuels are:

• They do not cause a greenhouse effect, because they do not produce carbon dioxide.
• They can be used to produce electricity without any form of combustion.
• The excess power made can be stored in batteries or sold to the national grid.

Photovoltaic panels are used as external cladding on the south side of Bowater House. They provide enough solar energy for the lift, the lighting in the public areas and the automatic sensors for the ventilation system. Computers constantly monitor the power output from the photovoltaic cells and when there is insufficient solar energy, electricity from the National Grid is automatically connected.