Solar PV

Solar PV - Glossary of Terms - Photovoltaics

Alternating Current (AC) – An electric current that reverses direction periodically

Amorphous Semiconductor – A non-crystalline semiconductor material that has no long range order

Amorphous Silicon – A thin film Solar PV silicon cell with no crystalline structure that is manufactured by depositing layers of doped silicon on a substrate

Angle of Incidence – The angle at which the light rays strike the earth’s surface

Anti-Reflection Coating – A thin coating of a material that is applied to a Solar PV surface to reduce the light reflection and increases light absorption

Array – A number of Solar PV modules connected together electrically, to provide a single electrical output. (Also Solar PV panels)

Azimuth – The horizontal angle measured from true north, in a clockwise direction

Blocking Diode – A diode used to prevent current from flowing towards a failed Solar PV module or from a battery to the Solar PV array during periods of darkness or low current production

Building Integrated Photovoltaics (BIPV) - A term for the design and integration of Solar PV devices into the envelope of a building, typically by replacing conventional building materials

Bypass Diode – A diode connected in parallel with a Solar PV module to provided an alternative current path (by-pass) in case of module shading or failure

Cadmium Telluride (CdTe) – A thin film Solar PV technology used in the production of Solar PV modules

Cell - A Solar PV cell (also called photovoltaic cell) is a solid state device that converts the energy of sunlight directly into electricity by the photovoltaic effect

Charge Controller – A device in a Solar PV system that controls the charging rate and/or state of charge for batteries

CIS (or CIGS) - Copper Indium Gallium Selenide – A thin film Solar PV technology used in the production of Solar PV modules

Crystalline Silicon - the most prevalent bulk material for Solar PV cells (monocrystalline and polycrystalline)

Clean Energy Cashback – The name of the UK Government Feed in Tariff’s scheme

Converter – A device used in Solar PV systems to convert electrical direct current (DC) voltage to another DC voltage

Diffuse Radiation – Radiation received from the sun after reflection and scattering by the atmosphere and ground

Diode – Electronic component that allows current flow in one direction only (Also Blocking Diode and By-Pass Diode)

Direct Beam Radiation – Radiation received by direct solar rays

Direct Current (DC) – Electric current flowing in only one direction

Efficiency – The ratio of output power (or energy) to input power (or energy) expressed as a percentage

Electricity Grid – An electricity distribution network (Also Grid)

Feed in Tariffs - Feed in tariffs is a government sponsored incentive scheme designed to encourage the introduction of renewable energy sources

Fixed Tilt Array – A Solar PV array set in a fixed angle with respect to the horizontal

Flat Plate Array – A PV array that consists of non-concentrating Solar PV modules

Flexible Thin Film Solar - Flexible thin film cells and modules are created by depositing the photoactive layer and other necessary layers on a flexible background material 

Gallium Arsenide (GaAs) – A compound of the elements gallium and arsenic. A highly efficient crystalline semiconductor used in Solar PV modules

Grid – A transmission line electricity distribution network (Also Electricity Grid)

Grid Connected System – A Solar PV system in which the array acts like a central generating plant, supplying power to the electricity grid. (Also Grid-Tie System and On-Grid)

Hybrid System – A Solar PV system that includes other sources of electricity generation, such as wind turbines, small hydro or diesel generators

Insolation – The solar radiation incident on an area over time. Equivalent to energy and usually expressed in kilowatt-hours per square metre

Inverter – In a Solar PV system an inverter converts Direct Current (DC) to alternating Current (AC)

Irradiance - The solar power incident on a surface. Irradiance is usually expressed in kilowatts per square metre. Irradiance multiplied by time equals insolation

I-V Curve – The plot of current versus voltage characteristics of a Solar PV cell, module or array. Three important  points on the I-V curve are the opening-circuit voltage, short-circuit current and peak power operating point

Kilowatt (kW) – A unit of power equal to one thousand Watts

Load – Is the amount of electric power used by an electrical appliance at any given time

Maximum Power Point or Peak Power Point – That point on an I-V curve that represents the largest area rectangle that can be drawn under the curve. Operating a Solar PV array at that voltage will produce maximum power

Module – The smallest replaceable unit in a Solar PV array. An integral, encapsulated unit containing a number of Solar PV cells. (Also Solar Modules and Solar PV modules)

Monocrystalline Silicon –Single crystal wafer cells cut from cylindrical ingots. Produced made using the Czochralski process

N-Type Silicon – A Solar PV silicon material that has been doped with a material that has more electrons in its atomic structure than does silicon.

Orientation – Placement with respect to the cardinal directions, North, South, East and West. Azimuth is the measure of orientation from the North

Panel – A number of Solar PV cells combined together in a single unit (Also Solar Panel and Solar PV Panel)

Peak Load – The maximum load demand on a Solar PV system

Photovoltaic Cell – The treated semiconductor material that converts solar irradiance to electricity

Photovoltaic System – An installation of Solar PV modules and other components designed to produce power from sunlight and meet the power demand for a designated load.

Polycrystalline Silicon – A material used to make Solar PV cells which are made from large blocks of molten silicon carefully cooled and solidified. (Also Multicrystalline silicon)

Pyranometer – An instrument used for measuring global solar irradiance

Pyrheliometer – An instrument used for measuring direct beam solar irradiance. It uses an  aperture of 5.7 degrees to transcribe the solar disc

Semiconductor – A material that has limited capacity for conducting electricity. The silicon used to make Solar PV cells is a semiconductor

Silicon (Si) – The most common semiconductor material used in Solar PV devices

Single Crystal Silicon – Solar PV material with a single crystalline formation

Solar Cell - A Solar PV cell (also called photovoltaic cell) is a solid state device that converts the energy of sunlight directly into electricity by the photovoltaic effect

Solar Module – The smallest non divisible unit in a Solar PV Array (Also Solar PV Panel, Photovoltaic Module)

Stand Alone System – A Solar PV system that operates independently of the utility grid

Standard Test Conditions – Conditions under which a Solar PV module is typically tested in a laboratory

String – A number of Solar PV modules or Solar PV panels interconnected electrically in series to produce the operating voltage required by the load. (Also Solar Array)

System Operating Voltage – The voltage output of a Solar PV array under load. The system operating voltage is dependent on the load of batteries connected to the output terminals

Tilt Angle – The angle of inclination of a Solar PV collector measured from the horizontal

Thin Film Solar PV – A Solar PV cell that is made by depositing one or more thin layers (thin film) of Solar PV material on a substrate. The thickness range of such a layer is wide and varies from a few nanometres to tens of micrometers

Tracking Array – A Solar PV array that is mounted on a moveable structure that follows the path of the sun in order to maximise the array output

Triple Junction – Three extremely thin single junction cells, with different bandgaps, stacked on top of one another

Utility Interactive Inverter – An inverter that can function only when tied to the utility grid, and uses the prevailing line-voltage frequency on the utility line as a control parameter to ensure that the PV systems output is fully synchronised with the utility power

Wafer – A thin sheet of semiconductor material produced by mechanically slicing it from a single crystal or multicrystal ingot or casting

Zenith Angle – The angle between directly overhead and the line intersecting the sun. (90 degrees – zenith) is the elevation angle of the sun above the horizon

About Solar PV - BIPV - Thin Film Solar PV - Feed in Tariffs

With Acknowledgements to Sandia National Laboratories, California, USA