How Solar Panels Convert Sunlight Into Electricity

Solar panels can create energy by converting sunlight into electricity. The sun generates energy for us each day, and it isn't going to run out for 5 billion years.

There are a couple of types of solar panel widely used around the world today. One type is the solar thermal collector - used in many homes to heat water. Water heated by the sun can be used in the hot water taps, and in central heating systems. These types of panels do not create any electricity.

The other type is photovoltaic panels, these are the kind that convert sunlight to electricity. The photovoltaic panel is made up of many photovoltaic cells. If many panels are used together it is known as a photovoltaic array. Glass is used to cover solar panels, to enable sunlight to pass through, and protect them from the elements.

The source of energy from the sun is carried by protons. A proton is an elementary particle - it has no known substructure, and carries electromagnetic radiation. The protons hit the solar panel which is constructed with many p-n junctions. A p-n junction is made up of of Positively and Negatively charged regions. When electromagnetic radiation hits a p-n junction, electrons are emitted from the material, causing current to flow through it. In 1921 Einstein won the Nobel prize in physics for his work on this subject calling it the 'photoelectric effect'.

As the basic principle of converting sunlight into electricity has been known for many years, recent advancements have been about making panels more efficient. This has involved experimenting with new materials, making panels thiner, and cheaper to produce.

The output from the panel itself will be a direct current (current flowing in one direction). Most household appliance require alternating current, so an inverter is used to convert DC to AC. Synchronous solar panel inverters allow any extra energy produced by panels to be sold to the electrical grid. They will switch to using grid energy automatically when the panels are not producing power.

Published - Wed 4th Nov 2009 22:05:42