ICP Solar provides you with a guide to solar energy terminology

A

AC - Alternating current. Electricity in which the flow of electron particles (current) continuously reverses its direction at regular intervals, called cycles. The frequency at which AC reverses is measured in cycles-per-second, or Hertz (Hz). This is the type of current used to power most household appliances. In North America, the standard is 60 cycles per second or 60Hz.

Advanced Thin Film (ATF) - ICP Solar’s amorphous silicon (thin film) technology.    

Alternative Energy - Popular term used to describe renewable energy sources, such as solar, wind, geothermal, etc.

Alternator - A generator that produces alternating current by rotation of a rotor, such as the alternator in a car.

Amorphous Silicon Panel (also called Thin-Film) - A non-crystalline solar panel that is made by spreading a micro-thin layer of silicon on glass. The voltage and current circuits are then created using laser technology.

Ampere (or Amp) - Electric current flow is measured in amperes or amps (A). One amp represents the amount of current that flows in a circuit at a force of one volt and at a resistance of one ohm.

Amp-hour - An Amp-hour (Ah) is the unit of measure of current flow (in Amperes) over one hour. This term is mostly used to quantify the amount of power (energy) contained in a battery (capacity).

Angle of Inclination - The angle (in degrees) that a solar panel is positioned above the horizontal.

Anode - The positive pole or electrode of an electrolytic cell (or battery).

Appliance - A device that converts one form of energy or fuel into useful energy or work.

Array, Solar - Used to describe a number of solar photovoltaic modules connected together to provide electricity.

ATF - See Advanced Thin Film   

AWG - This is the abbreviation for American Wire Gauge. This is the standard for rating the size of wires (electrical conductors). Note: The smaller the AWG number, the bigger the conductor.

B

Ballast - A device that is used to control the operating voltage in a fluorescent lamp.

Battery - A device that is used to store energy, which is composed of one or more electrolyte cells.

Battery Bank - A group of batteries wired together to store the energy produced for the solar system.

Blocking Diode - In a solar panel, a blocking diode is used to prevent current from flowing from the battery to the solar panel (reverse current protection). It will only permit the current to flow from the solar system to the battery.

Boron - A chemical element commonly used as the dopant in a solar cell.

Bus, Electrical - An electrical conductor in the panel that serves as a common connection for the solar cells that compose the solar module.

C

Capacity, Battery - Battery capacity ratings express the number of amps that a battery can deliver over a period of time (in minutes or hours) before the energy stored is exhausted. Amp-hours and reserve minutes are commonly used ratings.

Carbon Dioxide (CO₂) - This is a colorless and odorless gas that is naturally present in the air. It is a natural byproduct of animal and plant respiration. It is also formed by the combustion of carbon-based compounds such as fossil fuels (oil, coal, natural gas, etc.). CO₂ is commonly referred to as a greenhouse gas for its heat trapping properties in the atmosphere.

Cathode - The negative pole or electrode of an electrolytic cell (or battery). See Anode.

Cell, Photovoltaic - The photovoltaic (PV) cell is the basic component of a solar module or panel. PV cells convert solar energy into DC electricity. Multiple cells are assembled together to form the solar module.

Charge Carrier - A free and mobile electron or hole in a semiconductor.

Circuit - A device, or system of devices, that allows electrical current to flow through it and allows voltage to occur across positive and negative terminals.

Climate - The dominant or average weather conditions in a geographic region.

Climate Change - A term that is used to describe the effects on the Earth's climate that result from human activities, such as fossil fuel combustion and deforestation (and forest burning).

Combustion - The process of burning a material or fuel by applying heat.

Combustion Gases - The gas byproducts resulting from the combustion of a fuel.

Compact Fluorescent Lights - These bulbs are a smaller version of the standard fluorescent lamps. They can directly replace standard incandescent lights and typically use up to 75% less energy.

Conductor - A material through which electricity is transmitted, such as an electrical wire.

Controller, Charge - A device that is connected between the battery bank and the solar system. Its primary function is to constantly monitor the battery voltage and prevent overcharging when the batteries become fully charged.

Conventional Fuel - A commonly used term to describe fossil fuels, such as coal, oil and natural gas.

Current, Electrical - The flow of electrons (electricity) in a conductor (measured in amperes).

Czochralski Process - Developed by a Polish scientist named Czochralski, this method permits the production of single-crystal silicon by slowly lifting a seed crystal from a molten bath of silicon.

D

DC - Direct current. A type of electricity where electrons flow in one direction through the conductor. Solar panels and batteries provide DC energy.

Deep Cycle Batteries - Batteries that are designed to provide a steady source of power and can withstand many cycles of deep discharging / charging.

Deep Discharge - Discharging a battery to 20% of its full charge capacity.

Diode - An electronic device that allows electrical current to flow in one direction only.

Dopant - A chemical element added in small amounts (impurity) to a pure semiconductor material like silicon to modify the electrical properties of the material. An n-dopant introduces more electrons. A p-dopant creates electron vacancies (holes). Without the use of dopants, a solar cell could not create electricity.

Doping - The addition of a dopant to a semiconductor.

E

Earthing (or Grounding) - A secure electrical connection to earth (ground) using a rod (bar) or wire.

Electric Circuit - The path followed by the electrons from the power source, through an electrical system (conductors) and back to the source.

Electric Vehicle - A battery-powered electrically driven vehicle.

Electricity - The movement of electrons though a conductor, such as a wire.

Electrode, Battery - Battery electrodes are the conducting poles of a battery. The anode is the positive pole or electrode of an electrolytic cell (or battery). The cathode is the negative pole or terminal of a battery.

Electrolysis - A breaking of chemical bounds (separation) resulting from the passage of an electric current through an electrolyte. A common example of this is the electrolysis of water (H₂O). The elements that compose water, hydrogen (H) and oxygen (O), are separated through the use of a charging current.

Electrolyte - In a battery, a liquid solution that contains dissolved ions. This allows the conduction of electricity. Sulfuric acid is the electrolyte used in lead-acid batteries.

Electron - An atomic particle with a negative electrical charge. Electrons surround the positively charged nucleus of an atom and determine the chemical properties of the atom. The movement of electrons through a conductor is called electricity.

Energy, Electrical - The capability of doing work through the harnessing of the movement of electrons through a conductor. The electrical energy used by an appliance is measured by multiplying the watts used by a device by the number of hours it is draining power. This is measured in watt hours (Wh). A kWh is equal to 1000 Wh.

F

Fluorescent Light - A type of light bulb that uses an electrical charge to excite the atoms of a gas contained inside. The excited atoms of gas emit ultraviolet light, which is then absorbed by the phosphor coating inside the glass tube. The phosphor coating then produces the visible light.

Fossil Fuels - Fuels formed in the earth from the sediment remains of dead plants and animals. The process of transformation takes millions of years to create fossil fuels. Oil, natural gas and coal are all examples of fossil fuels.

Frequency - The number of cycles at which an alternating current passes through a conductor every second. In North America, the standard for AC electricity is 60 cycles per second (or 60 Hertz). In other parts of the world, the standard is usually 50 Hertz.

Fuel - Any material that can be burned to make energy.

Fuel Cell - A device that is used to transform chemical energy into electrical energy. Its operation is similar to that of a battery. However, contrary to a battery, a fuel cell will continue to produce electrical power as long as fuel is supplied. Only heat and water vapor are released through a fuel cell.

Full Sun - The amount of power received on the earth’s surface at noon on a clear day (about 1,000 watts per square meter).

Fuse - A safety device that is used as part of an electrical circuit to prevent damage to the components that make up the circuit. It will break the circuit if the current exceeds a predetermined value.

G

Generator - Any device that can convert mechanical energy (movement) into electrical energy.

Global Warming - A popular term that is used to describe the increase in average global temperatures due to the greenhouse effect.

Greenhouse Effect - A popular term that is used to describe the heating effect by greenhouse gases produced from natural and human sources.

Greenhouse Gases - A popular term that is used to describe the gases that contribute to the greenhouse effect. These heat-trapping gases include carbon dioxide, methane and low-level ozone.

Green Energy - A popular term that is used to describe energy produced from renewable resources, such as solar, wind and geothermal.

Grid - A term that refers to an electricity transmission and distribution system.

Grid-tie - A popular term that refers to the connection of a solar system to the electricity grid.

Ground (see Earthing) - A ground is a device (rod or wire) that is used to protect against electrical shock.

H

Hertz - A measure of the number of cycles at which an alternating current passes through a conductor every second. In North America, the standard is 60 Hertz. The standard in other countries is usually 50 Hertz. The abbreviation is Hz.

Hole - In a solar cell, a hole is a term used to describe the vacancy where an electron would normally exist. A hole behaves like a positively charged particle.

Hybrid System - An energy system that includes two different types of energy technologies (for example, a photovoltaic system combined with a wind turbine).

Hydroelectricity - Electricity created by harnessing waterpower through a turbine.

Hydrogen - A chemical element that is used as a fuel (notably in fuel cells).

Hydrometer - An instrument that is used to measure state-of-charge of a battery.

I

Incandescent - Bulbs that produce light through the use of an electrically heated Tungsten filament.

Insolation - The amount of solar energy hitting the surface of a defined area and orientation, usually expressed as watts per square meter.

Inverter - A device that is used to convert direct current (DC) electricity into alternating current (AC) to either operate appliances or to supply power to an electricity grid.

Ion - An electrically charged atom or molecule that has lost or gained electrons. A loss results in a positively charged particle. A gain makes the particle negatively charged.

J

K

Kilowatt (kW) - A kW is equal to one thousand watts (1000W). See Watts.

Kilowatt-hour - A Kilowatt-hour (kWh) is equal to 1000 watt-hours. See Watt-hour.

Kinetic Energy - Energy available as a result of motion.

L

Lead Acid Battery - A battery that uses lead and lead oxide for electrodes and sulfuric acid for the electrolyte.

LED - Light Emitting Diode. LEDs are being used more and more in lighting because of their very low power requirements.

Line Loss (or Drop) - Voltage drop due to inefficiencies in the transmission of electricity under specific conditions. Line loss results when the wire is too small for the amount of current being transmitted, or when the distance is too long.

Load - The energy consumption of an appliance or group of appliances in the electrical system.

Lumen - A measure of the quantity of light.

Lumens / Watt (lpw) - A measure of the efficiency of lamps. It indicates the amount of light (lumens) produced by the lamp for each unit of electrical power (watts) it uses.

M

Megawatt - One thousand kilowatts or 1 million watts. Usually used to describe the generating capacity of a power plant.

Megawatt-hour - One thousand kilowatt-hours or 1 million watt-hours.

Module - A solar module, also called a panel, is a device constructed of photovoltaic cells connected together and mounted onto a mounting structure to provide a DC power output.

Motor - A machine that converts external energy into motion.

N

Natural Gas - A hydrocarbon gas used as a heating fuel, which is obtained from underground sources. See Fossil Fuels.

Net Metering - The use of a single meter to measure how much power is consumed and produced by a house with a solar energy system (or other renewable power source). The energy consumed is purchased from the utility at a given price. Any electricity produced by the solar power system is then sold back to the utility at the same price. When more power is being produced than used, the meter spins backwards.

Nonrenewable Fuels - Fuels that cannot be easily renewed, such as oil, natural gas and coal.

N-Type Silicon - Silicon produced by doping the semiconductor with an electron-donor impurity (phosphorous is a commonnly used dopant).

Nuclear Energy - Energy released from splitting atoms of radioactive materials, such as uranium. The production of nuclear energy produces radioactive waste material.

O

Ohms - A measure of the electrical resistance of a material.

Ohm's Law - In an electrical circuit, the amount of current in amps (I) is equal to the pressure in volts (V) divided by the resistance in ohms (R). I = V / R.

Oil - A product of crude oil that is used for heating, engines and electrical generation.

Open-Circuit Voltage - The maximum possible voltage produced by a photovoltaic panel under full sunlight when no current is flowing (no load connected).

Orientation - The alignment of a solar panel in number of degrees, east or west, of true south.

P

Panel, Solar - An individual solar module constructed of photovoltaic cells connected together and mounted onto a structure to provide a DC power output.

Parallel Connection - Joining photovoltaic modules together by connecting positive leads together and negative leads together. This configuration increases the current but not the voltage.

Peak Watt - The maximum nominal output of a solar panel in watts (Wp) under standard test conditions.

Photon - A particle of light.

Photovoltaic - The generation of electrical energy though light. The commonly used abbreviation is PV.

Photovoltaic (Solar) System - A complete PV power system composed of the solar modules (array), electrical wiring, charge controllers, battery bank, etc.

Polycrystalline Silicon Cell - A silicon PV cell composed of multiple, small, individual crystals.

Power - Energy that is capable of accomplishing work. Usually measured in watts.

Propane - A hydrocarbon gas, C3H8, occurring in crude oil and natural gas. It is used as a fuel, a solvent and a refrigerant.

P-Type Semiconductor - A semiconductor in which "holes" carry the current. This is produced by doping a semiconductor with an impurity (dopant) that accepts an electron (boron is commonly used in silicon).

Q

R

Rated Power - The power output of a device under specific or nominal operating conditions.

Renewable Energy - Energy derived from resources that cannot be exhausted, such as hydro-electricity, solar, wind power, geothermal, etc.

Resistance - The characteristic of a material to inhibit the transfer of energy. Electrical resistance is measured in ohms.

Resistor - An electrical device that resists electric current flow.

S

Semiconductor - A material that has a limited capacity for conducting an electrical current. Silicon is the most commonly used semiconductor in the fabrication of solar cells.

Series Connection (of Solar Panels) - Joining photovoltaic panels together by connecting the positive leads to the negative leads. This configuration increases the voltage but not the current.

Short Circuit - A direct connection of the positive and negative terminals of a power source. This can be very dangerous in the case of a battery where nothing would restrict the flow of a high current.

Short Circuit Current - The rating of maximum current flowing through a circuit that has no load or resistance. When measuring the short circuit current of a solar panel directly on the two wires, the current is limited by the amount the panel can produce.

Silicon - One of the most abundant elements of the planet, silicon (periodic element Si) is an excellent semiconductor material. It is used to create solar photovoltaic cells. Silicon is the major component of sand.

Sine Wave - A type of alternative current generated by alternating current generators.

Single-Crystal Silicon Cell - Also called monocrystalline, this type of solar cell is created by using silicon grown into a crystalline ingot that is then cut into thin slices, called wafers. These wafers or cells are then used to build the solar panel.

Sizing - The process of properly designing a solar system to meet the energy demands of a building or home.

Solar Array - A group of solar panels or modules connected together.

Solar Cell - The solar or photovoltaic (PV) cell is the basic component of a solar panel. The PV cells convert solar energy into DC electricity. Multiple cells are assembled together to form the solar module.

Solar Energy - The energy transmitted from the sun (solar radiation).

Solar Irradiation - The amount of solar energy received at a given location.

Solar Module (Panel) - A photovoltaic (PV) device that is composed of multiple solar cells connected together (in series and/or parallel) to produce a specified amount of DC power at standard test conditions.

Square Wave Inverter - A type of inverter that produces a square wave output (as opposed to a true-sine wave inverter producing AC power equivalent to house current). This is the least expensive type of inverter on the market.

T

Thin Film Solar Panel (also called Amorphous Silicon) - A non-crystalline solar panel that is made by spreading a micro-thin layer of silicon onto glass. The voltage and current circuits are then created using laser technology.

Tilt Angle (of a Solar Panel) - The angle at which a solar panel is positioned to face the sun (in degrees relative to a horizontal position). The tilt angle is usually adjusted according to the season to maximize the energy production.

U

Ultraviolet - Electromagnetic radiation in the wavelength range of 4 to 400 nanometers.

V

Volt - A unit of measure of electrical force equal to the amount of force that will cause a steady current of one ampere to flow through a resistance of one ohm.

Voltage - The rating of the amount of electrical pressure or force, measured in volts, that causes electricity to flow between two points.

W

Wafer - A thin slice of a semiconductor (photovoltaic (PV) material) made by cutting it from a single crystal or ingot.

Watts - A watt is a measurement of total electrical power. Volts x Amps = Watts.

Watt-hour - One watt-hour is equivalent to the electricity consumption of one watt over a period of one hour. The abbreviation is Wh.

X

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