How Does Solar PV Work?

Mon, 2011-05-30 16:41

Everblue Solar EducationA little about Solar PV
Certain materials are semi-conducting, meaning they are capable of releasing small amounts of electricity during physical or chemical interactions – in this case, interaction with the sun’s rays. This interaction between the sun’s rays and a semi-conducting material to produce electricity is known as the photoelectric effect. It is the basic physical process in which a photovoltaic (PV) cell converts sunlight to electricity.

Electricity is produced when energy from light hitting a silicon substrate (the semi-conducting material) displaces electrons in the silicon from their normal orbit. These free electrons are now available for use in any external circuit.

What’s With All The Different Types of Solar?
All solar systems use the abovementioned process to create electricity from the sun. However, they use different materials to create free electrons. The differences lie in the energy-collecting surface. The terms crystalline, thin film, and concentrator describe the nature of the collecting surface and the way in which the semi-conducting material is processed and optimized to turn the sun’s rays into electricity.

Solar Backpacks, Shingles and More: So-called thin film solar cells use an extremely thin semi-conducting material that is attached to a flexible (usually silicon) substrate. They have the advantage of being flexible and versatile. While thin film solar is not widely used yet, it is the future of solar.

The Solar Cells of the 70s: Solar technology for the residential home has been around since the 1970s. Crystalline solar cells are the solar panels that we are used to seeing on homes. They are made of a wafer-like material that is semi-conducting. As the names implies, these cells are “crystal-like” and are more fragile than thin film solar cells. Nonetheless, they are made to withstand extreme heat, rain, snow and wind.

Solar Power Plants: Geographic areas that receive a surplus of solar radiation have the ability to house utility-scale industrial power plants that create electricity for entire metropolitan areas. These concentrating solar cells use a plastic lens to focus large amounts of sunlight onto a much smaller semi-conducting material. These are the solar applications usually associated with large commercial operations in the deserts of the American Southwest.

Regardless of the semi-conducting material used, the amount of power produced by an individual solar cell is directly related to its surface area, its efficiency, and the intensity of solar radiation. Most solar cells have an efficiency rating between 10% and 15% and produce between 0.8 watts and 2 watts of power. To produce more power, individual solar cells work together in large arrays.