|What is a solar Energy?|
|Solar energy is an alternative energy source that involves harnessing the radiant light energy emitted by the sun and converting it into electrical current.
Since the middle of the 20th century, the ability to harness and utilize solar energy has greatly increased, making it possible for homes and businesses to make use of the renewal energy source rather than rely on more conventional means of generating power.
Research into the applications of solar energy continue, along with the development of more cost-effective ways to capture and store the energy for future use.
|What is a solar module?|
|Solar modules, or panels, are series of solar cells wired together into strings and enclosed in self-contained glass units for harsh weather protection. Solar cells are mounted into groups called modules that produce about 0.5 Volts of current to power lights and appliances. On the sunward side, cells are protected by a highly transparent solar glass pane. The underside takes the form of an insulating film or a second pane of glass. A connection socket picks up the generated direct current. Modules are connected together via cables, which link them to the inverter.|
|When did solar cell technology developed?|
|Modern solar cells with practical efficiency were invented in the early 1950s, and have been used to power satellites since 1959. They became popular for terrestrial applications in the mid-1970s, mostly for remote telecommunications, navigational aids and other rugged, remote industrial uses including microwave, TV, radio and cellular repeater stations. They have been powering urban applications such as roadside emergency telephones and traffic signs since the mid-1980s. With prices dropping steadily, they are now becoming affordable for urban or remote homes and businesses.|
|What is a photovoltaic (PV) cell?|
|A photovoltaic cell, or "solar cell," is the smallest semiconductor element that converts sunlight into electricity. Each cell is made of silicon or another semi-conductor material, like a computer chip. The silicon is treated so that it generates a flow of electricity when light shines on it.
A stack of thin layers of semiconductor materials exhibit the photoelectric effect, such as silicon or cadmium telluride. The layers contain small amounts of doping agents (intentional impurities), such as the element germanium. The dopants give the semiconductor the ability to produce a current when exposed to light. Cells convert about five to fifteen percent of the solar energy they receive into electricity.
Solar cells are solid-state devices in which photons collide with atoms. This process transforms the resulting energy into electrons. These electrons flow into wires connected to the cell, thus providing electric current to appliances, lighting systems or other electrical loads. A typical PV cell is a thin 3"x3", producing only a small amount of electricity.
|How does photovoltaic (PV) technology work?|
|PV takes advantage of the characteristics of impure silicon crystals. Pure silicon is not electrically active, because its atoms are locked into a solid crystal structure. There are no spare electrons, and no open spots for electrons. Silicon impurities create crystal with either a slight tendency to lose electrons or a slight tendency to attract them. When the two kinds of silicon are placed close together and exposed to sunlight, photons (particles of light) knock electrons loose on the unattractive side. An electrical current is created as electrons travel across the junction to the attractive side.
Sunlight is composed of particles of energy called photons. When sunlight strikes a PV material, photons will either pass through, be reflected, or be absorbed. If the photon is absorbed, its energy will be transferred to an electron in an atom of the PV material. With new energy, the electron is able to escape from its normal position in orbit around that atom. In this way, the electron can become part of, and augment, the current in an electrical circuit. This photovoltaic effect is the basic physical process through which sunlight is converted into electricity.
Light-emitting diodes (LEDs) are made of similar materials and take advantage of the same physical principles, but in reverse. Powering LEDs with a PV panel works compatibly: photons in, electrons out; electrons in, photons out.
|What is a photovoltaic (PV) array?|
|A PV array is an interconnected system of PV modules that function as a single electricity-producing unit. The modules are assembled as a discrete structure, with common support or mounting. In smaller systems, an array can consist of a single module. A complete set of components for converting sunlight into electricity includes a module, a support structure, wiring, an inverter, a meter and other equipment.
|What is a Green Energy?|
|Green energy is renewable and sustainable. It is renewable because it is not depleted easily and is naturally replenished. Green Energy is sustainable because no matter how recklessly we use these resources the future generation is not likely to suffer because of that!
Solar power, hydro electric power, wind power, Geo Thermal power, bio fuels and wave power are some of the green energy sources that can be used to an alternative to our conventional sources of energy.
|Why is Green Energy important?|
Electricity generation is the leading cause of air pollution.
Most of our electricity comes from coal, nuclear, and other non-renewable power plants.
Producing energy from these resources takes a severe toll on our environment, polluting our air, land, and water.
Renewable energy is important because of the benefits it provides. The key benefits are:|
i. Environmental Benefits
Renewable energy technologies are clean sources of energy that have a much lower environmental
impact than conventional energy technologies.
ii. Jobs and the Economy
Most renewable energy investments are spent on materials and workmanship to build
and maintain the facilities, rather than on costly energy imports.