Photovoltaics are best known as a method for generating electric power by using solar cells to convert energy from the sun into electricity.
Solar cells produce direct current electricity from light, which can be used to power equipment or to recharge a battery. The first practical application of photovoltaics was to power orbiting satellites and other spacecraft, but today the majority of photovoltaic modules are used for grid connected power generation.
In this case an inverter is required to convert the DC to AC. There is a smaller market for off-grid power.
Building-integrated photovoltaics (BIPV) solar panels - are increasingly incorporated into new domestic and industrial buildings as a principal or ancillary source of electrical power, and are one of the fastest growing segments of the photovoltaic industry.
Typically, an array is incorporated into the roof or walls of a building. Even roof tiles with integrated solar cells can now be purchased.
Arrays can also be retrofitted into existing buildings; in this case they are usually fitted on top of the existing roof. Alternatively, an array can be located separately from the building but connected by cable to supply power for the building.
Where a building is at a considerable distance from the public electricity supply (or grid) - in remote or mountainous areas – solar power may be the preferred possibility for generating electricity, or solar power may be used together with wind, diesel generators and/or hydroelectric power. In such off-grid circumstances batteries are usually used to store the electric power.