Photovoltaic technology makes use of the abundant energy in the sun, and it has little impact on our environment. PV cells produce electricity from sunlight. Materials used in computer chips are similar to materials used in PV cells. These
materials absorb sunlight, which frees the electrons from their atoms and allows them to generate electricity.
The photovoltaic effect was observed as early as 1890 by Henri Becquerel, and was the subject of scientific inquiry through the early 20th century; Albert Einstein's only Nobel Prize, in fact, arose from solar power research.
In 1954, Bell Labs in the United States introduced the first solar photovoltaic device that produced a useful amount of electricity, and by 1958, solar cells were being used in small-scale scientific and commercial applications (especially for the space program.)
PV cells are great because they dont require high maintenance, are very reliable, and dont produce pollutants. The downside to this power resource is that it currently costs more than other energy sources and tends to work effectively only when the sun is shining. However, prices are falling making it more affordable each day.
When a home or business requires more electricity than the system is generating the need is automatically met by power from the utility grid. When less electricity is required than the system is generating, the excess is fed (or sold) back to the utility. At the end of the month, a credit for electricity sold is deducted from charges for electricity purchased.