generate elecricity from the sun's energy. PV systems are an organized array(s) of modules that contain certain materials that convert solar radiation into direct current electricity.

Compared to solar hot water, photovoltaic (pronounced: foh-toh-vol-tay-ik) is a relatively new technology. The first photoelectric effect was discovered by Edmund Becquerel, a 19-year old French experimental physicist in 1839. Albert Einstein who received a Nobel Prize in 1923 mathematically explained how the photoelectric effect is caused by absorbtion of light in a 1905 paper. But not until Bell Labs in 1954 did solar PV finally reach a level where its power began to be useful for commercial purposes, such as Western Electric’s dollar bill changer in 1955.

Unlike a solar hot water system, which is essentially a plumbing device, PV uses semi-conductors and sunlight to make electricity. The more solar modules a PV system or array has, the more electricity will be generated. DC electricity can be “inverted” into alternating current (AC), so it can be useable power for a home or business, which can off-set or even eliminate the electric bill.

As photovoltaic modules have proven
their reliability, warranty periods have
increased, with 25-year warranties
common since the late nineties.