Silicon Wafer Manufacturing Solar Process
Photovoltaic
During the photovoltaic process, materials and devices are converted from light energy to electricity.
During the photoelectric effect, semiconductor materials are exposed to sunlight, and release small amounts of electricity. This effect refers to the emission, or ejection, of electrons from the surface of a metal in response to light. It is the basic physical process in which a solar electric or photovoltaic (PV) cell converts sunlight to electricity. The effect can occur in gasses, liquids and solids. The maximum solar radiation is between 0.35mm and 3mm wavelengths and solar cell material must be sensitive to that radiation.
Photovoltaic (PV) cells, also known as Solar Cells, are electricity-producing devices made of semiconductor materials. PV cells come in many sizes and shapes — from smaller than a postage stamp to several inches across. They are often strung together to form a PV module that may be up to several feet long and a few feet wide. Modules, in turn, can be combined and connected to form PV arrays of different sizes and power output capabilities. The size of an array depends on several factors, such as the amount of sunlight available in a particular location and the needs of the consumer.
Sunlight is made up particles of solar energy called photons, which contain various amounts of energy, corresponding to the different wavelengths of the solar spectrum. When photons strike a PV cell, they may be reflected or absorbed, or they may pass right through. Only the absorbed photons generate electricity. Then it transferred to an electron in an atom of the PV cell. (Semiconductor material)
The electron escapes from its normal position in an atom of the semiconductor material and becomes part of the current in an electrical circuit. By leaving its position, the electron causes a hole to form. Special electrical properties of the PV cell—a built-in electric field—provide the voltage needed to drive the current through an external load.
A PV system is made up of different components. These include PV modules (groups of PV cells), which are commonly called PV panels; one or more batteries; a charge regulator or controller for a stand-alone system; an inverter for a utility-grid-connected system and when alternating current (ac) rather than direct current (dc) is required; wiring; and mounting hardware or a framework.
The modules of the array make up the major part of a PV system, which can also include electrical connections, mounting hardware, power-conditioning equipment, and batteries that store solar energy for use when the sun isn't shining.
Photovoltaic (PV) system Efficiency
A 10% efficient PV system in most areas of the United States will generate about 180 kilowatt-hours per square meter. A PV system rated at 1 kilowatt will produce about 1800 kilowatt-hours a year. Most PV panels are warranted to last 20 years or more (perhaps as many as 30 years) and to degrade (lose efficiency) at a rate of less than 1% per year.