Photovoltaics
Currently, the most popular form of renewable energy is solar energy, or energy that is captured from the sun. The cornerstone for this industry is photovoltaic modules, which are currently available from many various manufacturers. There are many advantages of using photovoltaics in today’s world such as: high reliability, requires little maintenance, environmental friendlyness, remote location and small scale application use and relatively low cost in comparison to other types of renewable energy.
The photoelectric effect is the basic physical process by which a PV cell converts sunlight into electricity. When light shines on a PV cell, it may be reflected, absorbed, or pass right through, with the absorbed light creating electricity. The energy of the absorbed light is transferred to electrons in the atoms of the PV cell. With their newfound energy, these electrons escape from their normal positions in the atoms of the semiconductor PV material and become part of the electrical flow, or current, in an electrical circuit.
In order to induce the electric field within a PV cell, two layers of somewhat differing semiconductor materials are placed in contact with one another. One layer is an "n-type" semiconductor with an abundance of electrons, which have a negative electrical charge. The other layer is a "p-type" semiconductor with an abundance of "holes," which have a positive electrical charge. Although both materials are electrically neutral, n-type silicon has excess electrons and p-type silicon has excess holes. Sandwiching these together creates a p/n junction at their interface, thereby creating an electric field. A diagram of this is shown below:
Diagram of a Photovoltaic Cell (above)
New Jersey offers rebates for the purchase of photovoltaic modules at this time. For more information about photovoltaic modules, visit the U.S. Department of Energy website.