- Renewable & Alternative Energy
About Photovoltaics PV Solar Power
Photovoltaics (PV) is a solar, renewable energy source. Photovoltaics is a system that uses cells made of coated semiconductor material to directly convert sunlight into energy (electricity). PV is different from some solar systems that use sunlight to directly convert water to heated water. To best collect the needed sunlight, a PV system is designed to maximum the amount of sunlight exposure throughout the day. Some PV systems have panels that can be adjusted to collect more sunlight either manually or automatically.
PV systems have been around a while. For years PV technology has powered satellites in space, powered calculators, scales, and watches. With improvements in materials and technology, PV systems are becoming a better economic alternative to supplementing grid power consumption for home and business owners. This is particularly true in areas that have more direct sunlight such as the southern United States.
A photovoltaic system requires several parts including the PV array, wiring to handle the produced electricity, an overcurrent protection system, a controller, batteries (if power will be stored), and an inverter to transform the produced electricity from DC to AC current. Household appliances and electronics devices such as TV’s, computers, and toasters run on AC power.
Generally there are 3 types of PV panels that are used:
Amorphous silicon (thin film)This of solar cell is a made up of non-crystalline materials. Application of thin film can be made to flat, curved or even flexible surfaces allowing a wide array of uses such as roofing material, glass, or siding. The current efficiency is around 10%, but is improving.
Single crystal (monocrystalline)This type of solar cell is the most efficient at converting sunlight to electricity. Each cell typically produces 0.5V and cell panels generally are produced with 36 or 72 cells producing 12-24 volts. Larger panels, however, are produced with up to 720 cells producing 240 volts. These type of cells are somewhat fragile and must be mounted in a rigid frame.
Multicrystalline (polycrystalline)This type of panel is made up of cells cut from multiple crystals that are grown together. There type of panels cannot be damaged as easy as single crystal cells, but are less efficient.
Photovoltaic systems can be set up to completely power a house using either a battery system that stores energy for night use or by using net metering. Net metering is where the PV system is tied to the electrical grid. When excess power is produced by the PV installation, the power is allowed to be released into the grid. As the electricity is release the electric meter spins in the opposite direction, reversing any charges that occurred when the PV system did not produce enough electricity.