Photovoltaic energy is produced when sunlight is converted into energy with the use of solar cells or semiconductors. These semiconducting cells are usually made of silicon and do not contain any corrosive materials or moving parts. As long as the solar cells are exposed to light, they will produce photovoltaic energy with a minimum of maintenance. This energy is also environmentally clean, quiet, and safe.
The term "photovoltaic" has two parts: photo, a Greek word meaning light, and voltaic, a reference to electrical energy innovator Alessandro Volta. In 1839, French physicist Edmond Becquerel discovered the photovoltaic effect, the production of a volt by use of a semiconductor. This discovery prompted further experimentation with light sources and semiconductors, which led to the invention of solar cells that produce photovoltaic energy.
Individual solar cells, also called photovoltaic cells, are manufactured in different shapes and sizes. Sometimes just one cell is needed to power a device, but most often many cells are connected to one another to form solar panels or modules. These modules can then be connected to create photovoltaic arrays that can be used to power small buildings or large complexes. The resulting output of photovoltaic energy is dependent upon the size of the array. The size may vary, depending on the amount of available sunlight and the amount of power needed.
Even though the power output of a photovoltaic energy system depends on the overall amount of light exposure, it will still generate energy on cloudy or overcast days. To store this energy for later transmission, a variety of storage systems are available to consumers. Most reliable storage systems use a combination of rechargeable batteries and energy-storing capacitors, some of which can be designed for AC or DC power.
The amount of power available on cloudy days and at night in a photovoltaic energy system depends on the energy output of the photovoltaic modules and the battery arrangement. Adding additional modules and batteries will increase the available power, but will also increase the cost of the system. For best results, a thorough analysis of needs vs. cost must be conducted in order to create a system design that will balance cost and need with convenience of use. Systems that are well-designed offer the opportunity for expansion or reduction as energy needs increase or decrease.
Photovoltaic energy is emerging as a viable solution to energy problems worldwide. Its current uses include power stations, transportation, rural electricity supplies, and solar roadways. While still a long way from becoming the world’s major energy source, ongoing research into photovoltaic energy may bring the promise of hope to the future.