SOLAR PV POWER
Solar photovoltaic cells produce electricity directly from light. These cells are usually made from forms of silicon and are protected by a sheet of glass, or sometimes plastic. Several such cells are connected together to form a solar panel.
Solar panels can be placed on the roof of a house or factory to produce some or all of their power needs. Or large numbers of panels can be used to generate power for the electricity grid.
How It Works
When certain materials are exposed to light they produce a small amount of electricity. Albert Einstein won his Noble prize for explaining why this happens - Photons of light can knock electrons in certain materials into a higher state of energy. These electrons can be made to flow to another material, creating an electric current. These materials are called “semiconductors” because only conduct electricity in certain circumstances.
Solar cells are made of two thin layers of this type of material (usually silicon) which is treated so that one layer will be positive and the other negative. When electrons are stuck by light they flow from the negative side to the positive side, forming a direct current.
Like solar thermal power plants, solar PV power plants are best located in areas where there is plenty of sunshine. However, solar pv uses sunlight rather than heat which means that it can be suitable for use in cooler climates and not just in hot desert areas..
If solar PV panels are located in deserts, on roofs, walls or any other place where plants would not normally grow, they have no adverse effect on the environment. while in operation.
However, the manufacture of solar PV panels does produce require a significant amount of electrical energy which, if not obtained from a green source, can create pollution. The amount of energy needed is far less than the energy produced when the PV cell is in operation - and this “payback period” is constantly being improved.
Solar photovoltaic array at Nellis US Air Force Base in Nevada