Photovoltaics (PV) is a way of creating electric power by changing radiant energy, usually sunlight, into direct current electricity using semiconductors that produce the photovoltaic effect.
Materials commonly used for PV are monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide/sulfide. The photovoltaic effect creates voltage or electric current in the materials when exposed to light. Photovoltaic materials, such as silicon, change light photons into electrons, creating direct current electricity. This electricity is used for recharging batteries, powering homes, streetlights, wristwatches, anything that uses electricity can be run on PV cells. This process is most commonly known to us as solar energy, or solar power.
PV cells, or solar cells, use substrate-based crystalline silicon cells or thin-film cells based on cadmium telluride or silicon. Some modules have concentrators which focus light on a smaller group of cells. The low voltage of a single PV cell requires that several cells be connected together in series called a laminate. PV cells require three things, the ability to absorb light, a separation of opposite charge types, and extraction of charge types. The laminate is then housed in a protective encasement, commonly known as a solar panel.
Each solar panel is created to protect all its modules from damage, such as, weather. Solar panels cannot collect all frequencies of light either. They cannot collect ultraviolet, infrared or diffuse lighting. An inverter is used for the conversion of DC power created by the modules into an alternating current. Solar panels are then combined to form PV arrays of different sizes and power outputs. A solar array can be as small as the one in a pocket calculator, or, as large as the 42 acre White Sands solar project initiated by the United States Army.
A PV array is used two ways, as a stand alone system or a grid-interfaced system. The stand alone system is designed to operate without a utility grid, and can be either direct coupling or with use of batteries. The direct coupling system may require a secondary energy source, such as, a generator to provide extra power when needed. Otherwise, a block of deep cycle batteries are used to store energy. The grid-interfaced system uses power from a utility company when needed, and may send surplus solar electricity back to the utility company. This system works with the electric utility grid to maintain constant power. An inverter, or power conditioning unit (PCU), is used to convert the DC power made by the array to AC power used by the utility grid.
In the end, there is clean, renewable electric energy. How much, or how little, is dependent on many factors, amount required, space available, and budget being the main factors. Photovoltaic energy is effective, cost efficient and is eco-friendly. Homes, businesses, and even the military, all over the world are looking for cheaper, cleaner, ways to power their lives. Solar power is quickly moving up the charts as the way to accomplish this. Eventually, fossil fuels will literally be a thing of the past.