distributed generation — DG refers to electricity that is produced at or near the point where it is used. A distributed solar energy generation system can be located on rooftops or can be ground mounted, and is typically connected to the local utility.
distributed power — Generic term for any power supply located near the point where the power is used. Opposite of central power.
distributed systems — Systems that are installed at or near the location where the electricity is used, as opposed to central systems that supply electricity to grids. A residential photovoltaic system is a distributed system.
energy audit — A survey that shows how much energy used in a home, which helps find ways to use less energy.
fixed tilt array — A photovoltaic array set in at a fixed angle with respect to horizontal.
flat-plate module — An arrangement of photovoltaic cells or material mounted on a rigid flat surface with the cells exposed freely to incoming sunlight.
grid-interactive system — Same as grid-connected system
kilowatt-hour (kWh) — 1,000 thousand watts acting over a period of one hour. The kWh is a unit of energy. 1 kWh=3600 kJ.
life — The period during which a system is capable of operating above a specified performance level.
life-cycle cost — The estimated cost of owning and operating a photovoltaic system for the period of its useful life.
module — See photovoltaic (PV) module
orientation — Placement with respect to the cardinal directions, N, S, E, W; azimuth is the measure of orientation from north.
panel — See photovoltaic (PV) panel
photovoltaic (PV) array — An interconnected system of PV modules that function as a single electricity-producing unit. The modules are assembled as a discrete structure, with common support or mounting. In smaller systems, an array can consist of a single module.
photovoltaic (PV) cell — The smallest semiconductor element within a PV module to perform the immediate conversion of light into electrical energy (direct current voltage and current). Also called a solar cell.
photovoltaic (PV) module — The smallest environmentally protected, essentially planar assembly of solar cells and ancillary parts, such as interconnections, terminals, (and protective devices such as diodes) intended to generate direct current power under unconcentrated sunlight. The structural (load carrying) member of a module can either be the top layer (superstrate) or the back layer (substrate).photovoltaic (PV) panel — often used interchangeably with PV module (especially in one-module systems), but more accurately used to refer to a physically connected collection of modules (i.e., a laminate string of modules used to achieve a required voltage and current).
photovoltaic-thermal (PV/T) system — A photovoltaic system that, in addition to converting sunlight into electricity, collects the residual heat energy and delivers both heat and electricity in usable form. Also called a total energy system or solar thermal system.
power — The amount of electrical energy available for doing work, measured in horsepower, Watts, or Btu per hour.
PV — See photovoltaic(s)
solar cell — See photovoltaic (PV) cell
solar energy — Electromagnetic energy transmitted from the sun (solar radiation). The amount that reaches the earth is equal to one billionth of total solar energy generated, or the equivalent of about 420 trillion kilowatt-hours.
solar panel — See photovoltaic (PV) panel
tilt angle — The angle at which a photovoltaic array is set to face the sun relative to a horizontal position. The tilt angle can be set or adjusted to maximize seasonal or annual energy collection.
tracking array — A photovoltaic (PV) array that follows the path of the sun to maximize the solar radiation incident on the PV surface. The two most common orientations are (1) one axis where the array tracks the sun east to west and (2) two-axis tracking where the array points directly at the sun at all times. Tracking arrays use both the direct and diffuse sunlight. Two-axis tracking arrays capture the maximum possible daily energy.
voltage — The amount of electromotive force, measured in volts, that exists between two points.
watt — The rate of energy transfer equivalent to one ampere under an electrical pressure of one volt. One watt equals 1/746 horsepower, or one joule per second. It is the product of voltage and current(amperage).