We have put together an FAQs and Glossary section to help you understand everything a Solar installation involves so you can make an informed decision as to whether Solar PV is right for you.
We understand there is a lot of information to absorb so we have broken down the FAQs into sections to make it easier for you.
If there are any questions that are not answered in our FAQs please do us a favour and let us know here and we will add your question!
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We have put together a glossary of the most used terms in Solar Photovoltaic technology to help you understand the language of Solar PV.
If however it still feels like a minefield!… please pick up the phone for advice on 01825 880 600 or fill in our simple quote form here for more info!
Alternating Current (AC) – A type of electrical current, the other being DC (see DC) the direction of which is reversed at regular intervals or cycles. In the United Kingdom, the standard is 100 reversals or 50 cycles per second, Hertz (50). Electricity transmission networks use AC because voltage can be controlled with relative ease. Your solar system converts the current for use within the home.
Amorphous Silicon – A thin-film, silicon photovoltaic cell having no crystalline (regularly repeating) structure. Manufactured by deposition of layers of doped silicon on a substrate.
Ampere (amp) – A unit of electrical current or rate of flow of electrons. One volt across one ohm of resistance causes a current flow of one ampere.
Annual Solar Savings – The energy savings that your solar power system provides as you are not buying your electricity from the grid.
Antireflection Coating – A thin coating applied to a solar cell surface that reduces the light reflection and increases light transmission.
(Building-Integrated Photovoltaics) BIPV – A term for the design and integration of photovoltaic (PV) technology into the building shell, typically replacing conventional building materials. This can include the replacement of facades, glass, skylight systems or other increasingly innovative manners. This needs to be built in to the design of new buildings at the start.
Crystalline Silicon – A type of photovoltaic cell made from a slice of single-crystal silicon or polycrystalline silicon.
Current at Maximum Power (Imp) – The current at which maximum power is available from a module.
Direct Current (DC) – A type of electricity transmission and distribution by which electricity flows in one direction through the conductor, usually relatively low voltage and high current. This is also the type of electricity the photo voltaic panels produce. To be used for typical 120 volt or 220 volt household appliances, DC must be converted using an inverter to alternating current, its opposite. (see AC).
Electric Circuit – The path followed by electrons from a power source (generator or battery), through an electrical system, and returning to the source.
Electricity – Energy resulting from the flow of charge particles, such as electrons or ions.
Electron – An elementary particle of an atom with a negative electrical charge and a mass of 1/1837 of a proton; electrons surround the positively charged nucleus of an atom and determine the chemical properties of an atom. The movement of electrons in an electrical conductor constitutes an electric current.
Electric Current – The flow of electrical energy (electricity) in a conductor, measured in amperes.
Electrical grid – An integrated system of electricity distribution, usually covering a large area. Also referered to as the National Grid.
Energy – The capability of doing work; different forms of energy can be converted to other forms, but the total amount of energy remains the same. The sun being an infinate source of energy.
Energy Audit – A survey that shows how much energy used in a home, which helps find ways to use less energy. We can recommend companies that can do this for you.
Gigawatt (GW) – A unit of power equal to 1 billion Watts; 1 million kilowatts, or 1,000 megawatts. This would only be relevant for huge projects/farms.
Grid-Connected System – A solar electric or photovoltaic (PV) system in which the PV array supplys power to the grid.
Hybrid System – A solar electric or photovoltaic system that includes other sources of electricity generation, such as wind or diesel generators.
Incident Light – Light that shines onto the face of a solar cell or module.
Inverter – A box device that converts direct current electricity to alternating current.
Joule – A metric unit of energy or work; 1 joule per second equals 1 watt.
Kilowatt (kW) – A standard unit of electrical power equal to 1000 watts, or to the energy consumption at a rate of 1000 joules per second.
Kilowatt-Hour (kWh) – 1,000 thousand watts acting over a period of 1 hour. The kWh is a unit of energy. 1 kWh=3600 kJ.
Life-Cycle Cost – The estimated cost of owning and operating a photovoltaic system for the period of its useful life.
Load – The demand on an energy producing system; the energy consumption or requirement of a piece or group of equipment. Usually expressed in terms of amperes or watts in reference to electricity.
Load Circuit – The wire, switches, fuses, etc. that connect the load to the power source.
Load Current (A) – The current required by the electrical device.
Megawatt (MW) – 1,000 kilowatts, or 1 million watts; standard measure of electric power plant generating capacity.
Megawatt-Hour – 1,000 kilowatt-hours or 1 million watt-hours.
Modularity – The use of multiple inverters connected in parallel to service different loads.
Multicrystalline – A semiconductor (photovoltaic) material composed of variously oriented, small, individual crystals. Sometimes referred to as polycrystalline or semicrystalline.
N-Type – Negative semiconductor material in which there are more electrons than holes; current is carried through it by the flow of electrons. This is then combined with a P-Type system to create a diode.
Orientation – The direction solar panels are places in relation to North,South , East and West.
Peak Demand/Load – The maximum energy demand in a specified time period. e.g. The annual peak load might be winter, whilst the daily peak load might be 17.00 20.00hr.
Peak Power Point – Operating point of a solar cell or photovoltaic module where the product of the current value times the voltage value is a maximum.
Peak Sun Hours – The equivalent number of hours per day when solar irradiance averages 1,000 w/m2. For example, six peak sun hours means that the energy received during total daylight hours equals the energy that would have been received had the irradiance for six hours been 1,000 w/m2.
Photon – the photon is the elementary particle responsible for ‘light energy’ or electromagnetic phenomena. It is the carrier of electromagnetic radiation of all wavelengths, including in decreasing order of energy, gamma rays, X-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves.
Photovoltaic(s) (PV) – The direct conversion of light into electricity.
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. Not to be confused with a solar thermal cell.
Photovoltaic (PV) Conversion Efficiency – The ratio of the electric power produced by a photovoltaic device to the power of the sunlight incident on the device. Different cells have different efficiencies, but come at different costs.
Photovoltaic (PV) Device – A solid-state electrical device that converts light directly into direct current electricity. Solar photovoltaic devices are made of various semiconductor materials including silicon, cadmium sulfide, cadmium telluride, and gallium arsenide, and in single crystalline, multicrystalline, or amorphous forms.
Photovoltaic (PV) Effect – The phenomenon that occurs when photons, the ‘particles’ in a beam of light, knock electrons loose from the atoms they strike. When this property of light is combined with the properties of semiconductors, electrons flow in one direction across a junction, setting up a voltage. With the addition of circuitry, current will flow and electrical power will be available.
Photovoltaic (PV) Generator – The total of all PV strings of a PV power supply system, which are electrically interconnected.
Photovoltaic (PV) Module – The essentially planar assembly of solar cells and ancillary parts intended to generate direct current power under un-concentrated sunlight. The structural (load carrying) member of a module can either be the top layer (superstrate) or the back layer (substrate).
Photovoltaic (PV) Panel – Normally used interchangeably with PV module. 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 (PV) System – A complete set of components for converting sunlight into electricity by the photovoltaic process, including the array and balance of system components.
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.
P/N – A semiconductor photovoltaic device structure in which the junction is formed between a p-type layer and an n-type layer.
P-Type Semiconductor – A semiconductor in which holes carry the current; produced by doping an intrinsic semiconductor with an electron acceptor impurity (e.g., boron in silicon).
Qualification Test – A procedure applied to a selected set of photovoltaic modules involving the application of defined electrical, mechanical, or thermal stress in a prescribed manner and amount. Test results are subject to a list of defined requirements.
Rated Power – Rated power of the inverter. However, some units cannot produce rated power continuously. See duty rating.
Resistance (R) – The property of a conductor, which opposes the flow of an electric current resulting in the generation of heat in the conducting material. The measure of the resistance of a given conductor is the electromotive force needed for a unit current flow. The unit of resistance is ohms.
Semiconductor – Any material that has a limited capacity for conducting an electric current. Certain semiconductors, including silicon, gallium arsenide, copper indium diselenide, and cadmium telluride, are uniquely suited to the photovoltaic conversion process.
Solar Spectrum – The total distribution of electromagnetic radiation emanating from the sun. The different regions of the solar spectrum are described by their wavelength range. The visible region extends from about 390 to 780 nanometers (a nanometer is one billionth of one meter). About 99 percent of solar radiation is contained in a wavelength region from 300 nm (ultraviolet) to 3,000 nm (near-infrared). The combined radiation in the wavelength region from 280 nm to 4,000 nm is called the broadband, or total, solar radiation.
Solar Thermal Electric Systems – Solar energy conversion technologies that convert solar energy to electricity, by heating a working fluid to power a turbine that drives a generator. Examples of these systems include central receiver systems, parabolic dish, and solar trough. These are only used in large commercial systems.
Thin Film – A layer of semiconductor material, such as copper indium diselenide or gallium arsenide, a few microns or less in thickness, used to make photovoltaic cells.
Thin Film Photovoltaic Module – A photovoltaic module constructed with sequential layers of thin film semiconductor materials. See amorphous silicon.
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. Usually a domestic system will have an angle fixed.
Total Harmonic Distortion – The measure of closeness in shape between a waveform and its fundamental component. The level of closeness is handled automatically by the inverter and usually around 99% efficiency.
Two-Axis Tracking – A photovoltaic array tracking system capable of rotating independently about two axes (e.g., vertical and horizontal). These are primarily used by solar power stations.
Ultraviolet – Electromagnetic radiation in the wavelength range of 4 to 400 nanometers.
Volt (V) – A unit of electrical force equal to that amount of electromotive force that will cause a steady current of one ampere to flow through a resistance of one ohm.
Voltage – The amount of electromotive force, measured in volts, that exists between two points.
Voltage at Maximum Power (Vmp) – The voltage at which maximum power is available from a photovoltaic module.
Wafer – A thin sheet of semiconductor (photovoltaic material) made by cutting it from a single crystal or ingot.
Watt – The rate of energy transfer equivalent to one ampere under an electrical pressure of one volt. One watt equals one joule per second. It is the product of voltage and current (amperage).
Waveform – The shape of the phase power at a certain frequency and amplitude. This normally takes the shape of a sinewave.
Zenith Angle – the angle between the zenith (the outward normal of the earth; directly up) and the object being observed (in this case the Sun).