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G-P of solar technology terms
10/8/2008
G
Global radiationTotal solar radiant energy impinging on a surface, equal to the sum of direct and diffuse radiation.
Grid-connected
A power system interconnected with the grid (or mains) of the local electric utility. Also referred to as utility-interactive.
Grid parity
The point at which the cost of renewable electricity is equal to the cost of conventionally generated power/ electricity.
H
HoleAn atom that has lost an electron.
Hybrid system
A power system consisting of two or more energy sources (e.g., a photovoltaic (PV) array and a wind generator).
I
I-V curveA current/voltage curve, which expresses the possible combinations of current and voltage output of a photovoltaic device.
Insolation
The solar energy received at a place over a given period. This may be expressed as peak sun-hours per day or kilowatt hours per square metre.
Inverter
A device which converts DC electricity to AC.
Isolation diode
A diode which prevents one segment of a photovoltaic (PV) array from interacting with another array segment. Usually used to prevent array energy from flowing backwards through a sub-voltage series string. May also serve the function of blocking diode.
M
Maximum powerAlso referred to as peak power. The point on a device's I-V curve where the product of I and V (Pmax, measured in Watts) is maximized. The points on the I and V scales which describe this curve point are named Imp (current @ max power) and Vmp (voltage @ max power.)
Module
A number of solar cells electrically connected, protected from environmental stresses, self-contained and not sub-dividable, providing a single electrical output.
Monocrystalline
A silicon wafer with single crystal grain structure (isotropic) made using a CZ or float zone method.
Multicrystalline
A silicon wafer which has multiple grain orientations. Often made using a modified directional solidification method.
N
n-type
Silicon which has been doped, often with phosphorus, to have electrons as the majority electrical carriers.
NOCT
Nominal Operating Cell Temperature; the temperature at which cells in a module operate under Standard Operating Conditions (SOC), which are: irradiance of 0.8 kW/m², 20ºC ambient temperature, and average windspeed of 1 m/s, with the wind oriented parallel to the plane of the array, and all sides of the array fully exposed to the wind.
Silicon which has been doped, often with phosphorus, to have electrons as the majority electrical carriers.
NOCT
Nominal Operating Cell Temperature; the temperature at which cells in a module operate under Standard Operating Conditions (SOC), which are: irradiance of 0.8 kW/m², 20ºC ambient temperature, and average windspeed of 1 m/s, with the wind oriented parallel to the plane of the array, and all sides of the array fully exposed to the wind.
O
Open-circuit voltageAbbreviated Voc, refers to a photovoltaic device's voltage potential when it is providing no current.
P
p-n junctionThe junction at the interface between two differently doped layers of semiconductor material, one layer doped with a positive-type dopant, the other layer with a negative-type dopant. An electrical field is established at the p-n junction which gives direction to the flow of light-stimulated electrons.
p-type
Silicon which has been doped, often with boron or aluminium, to have positive charges as the majority electrical carriers.
Parallel connection
Electrical connection where the positive terminals of a number of devices are connected together, as are their negative terminals. The output voltage of the paralleled devices is equal to the average of the devices, and the total current is the sum of the current of all the devices.
Peak power
Power generated by a utility unit that operates at a very low capacity factor; generally used to meet short-lived and variable high demand periods.
Photovoltaic
This is a term used to describe the solar electric effect.
Plasma enhanced chemical vapour deposition (PECVD)
Method used to apply anti-reflection coating which enhances the electronic properties of the wafer.
Polycrystalline
A silicon wafer which has multiple grain orientations. Often made using a modified directional solidification method.