How Solar Energy is created from Solar Cells
Using the light of the sun to create electricity.
A solar cell consists of two layers of slighty different silicon-based semiconductor material. One p-type and the other n-type, sandwiched together to form a 'pn junction', This pn interface induces an electric field across the junction, When particles of sunlight ('photons') are absorbed by the semiconductor, they transfer their energy to some of the semiconductor's electrons, which are then able to move about through the material. For each negatively charged electron, a corresponding mobile positive charge, called a 'hole', is created. In an ordinary semiconductor, these electrons and holes recombine after a short time and their energy is wasted as heat.
In a solar cell, however, the electrons and holes near the pn junction are swept across in opposite directions by the action of the electric field whilst others charges diffuse toward the junction to replace them. This separation of charge induces a voltage across the device. By connecting to an external circuit, the electrons are able to flow - and this flow is what we call electricity.
Solar Energy Diagrams
Solar generated electricity is produced when sun light is absorbed onto the surface of a PV solar cell which is a semiconductor n-p junction device made from silicon as shown in the simplified diagram below.
Domestic PV solar panels harvest the sun’s energy. Solar panels mounted on the roof produce DC electricity. The DC current from the solar array is conducted to the inverter (yellow box), which converts the DC current into AC current. This power is then sent to the electricity switchboard and metering panel (white box) and thereafter distributed throughout the house to power domestic appliances e.g. lights, air conditioners TV’s etc. When there is surplus PV generated electricity, this power is fed back into the grid, earning the home owner valuable income in terms of Feed-In tariffs and even renewable energy credits.
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