A photovoltaic array is an assembly of photovoltaic panels. Photovoltaic panels, or PV panels, are more commonly known as solar panels. They absorb light, particularly sunlight, and convert it into usable energy. The photovoltaic array is a key element in the production of solar energy. Concerns over the environmental effects of fossil fuels and new advances in PV technology have increased interest in solar energy in the 21st century.
Photovoltaic energy is produced through the photovoltaic effect, which was first discovered in the 19th century. Light particles called photons are directed to a PV cell or group of cells. The chemical properties of these cells cause the photons to agitate electrons, the subatomic particles responsible for electricity. The structure of the PV cell directs these electrons into an electronic circuit, converting them into usable electricity. The first photovoltaic array was built in the 1950s.
Initially, the photovoltaic array had limited uses, mainly scientific. PV arrays were first used to provide energy to orbiting satellites. They are still used for this purpose; the International Space Station and the Juno exploratory spacecraft are both powered by photovoltaic arrays. Earthbound uses include devices located in areas where connection to an electric power grid by power lines is impractical or impossible. Recreational vehicles and stand-alone highway signs are two common examples.
A photovoltaic array consists of a small or large group of connected PV panels, depending on the amount of power desired. The attached system often includes an inverter, to convert electricity into the alternating current (AC) form required by most household devices. Excess power is held in storage batteries, or, in some systems, can be directed into the local power grid, providing a credit toward future electricity bills. While PV cells can create power from any light, sunlight is by far the most common source. The photovoltaic array must be placed where it will receive maximum solar exposure during the day; even minor shade can greatly reduce its efficiency.
Early PV arrays were expensive and cumbersome, limiting their usage to those with deep pockets and serious commitments to alternative energy. In the 21st century, thin film cells were perfected, making the photovoltaic array more lightweight and economically feasible. At the same time, public concern was increasing about the cost and environmental effects of fossil fuels such as coal and gasoline. This led to government incentives and other initiatives toward alternative energy generation. As a result, solar technology has increased in popularity and usage around the world.