SUNLIGHT TO ELECTRICITY

HOW DO PHOTOVOLTAICS WORK?

Solar electricity is the direct conversion of sunlight into electricity. It is the cleanest energy option available today. Solar electricity is nearly inexhaustable and depends on two of the most plentiful natural resources on earth: sunshine and sand.

The technical term for "solar electricity" is "photovoltaics" a natural phenemenon first discovered in 1839 by French scientist Edmund Becquerel. Simply put: when sunlight strikes a solar electric cell, an electric current results - the basis for electricity. Photovoltaic (PV) cells consist of two very thin wafers made of silicon. One layer has a surplus of electrons (called the n-layer) and the other has a deficit of electrons (called the p-layer). When photons from sunlight hit the PV cell some electrons are liberated from the n-layer and start to flow to the to the metallic conductors on the PV cell. When these metallic conductors are conected to a load or battery you have an electric producing circuit as the electrons flow back to the p-layer.

A solar cell of four square inches will produce about 3.5 amps in full sunlight. Each solar cell generates about half a volt. Solar cells are connected in series to obtain higher voltages. A standard PV module contains 36 cells in series to provide enough voltage to charge a 12-volt battery. PV modules are laminated between glass and a plastic backing to protect the electrical circuits. Modules can then be connected in series for higher voltages or in parallel for more current.

THE BASIC IDEA IS SIMPLE

PV modules convert sunlight into electricity. Wire conducts the electricity to batteries where it is stored until needed. On the way to the batteries, the electrical current flows through a controller (regulator) which will shut off the flow when the batteries become full.

For some appliances, electricity can be used directly from the batteries. This is direct current (DC) and it powers such appliances as DC lighting, automotive audio equipment, portable radios and other DC loads. To run most appliances found in the home, however, we need to use alternating current (AC), the type which is found in most wall sockets. AC can be produce utilizing an inverter which transforms DC power from the batteries into AC. The inverter’s AC output powers the breaker box and the common outlets in your home.