Glossary
Green Energy
carbon footprint
The total of all greenhouse gas emissions produced by an individual, company or organisation, event or product.
CO2 emissions
Carbon dioxide which is released when fossil fuels are burned: a major contributing factor to global warming.
Export Tariff
Through the Government Feed-In Tariff system, this is the per unit payment made for renewable energy which is exported back to the national grid for redistribution.
Feed-In Tariffs system
Government system to incentivize renewable electricity generation whereby payments are made for every unit of power generated through renewable energy systems.
Feed-In Tariff
The payment rates per unit of renewable electricity generated, set by the Government from a specific time and for a stipulated period.
fossil fuels
Natural gas, oil, and coal - fuels formed by natural resources.
Generation Tariff
Through the Government Feed-In Tariff system, this is the per unit payment made for all renewable energy which is generated.
government grant
A fixed sum of money awarded by the government for a particular purpose, which does not have to be paid back at any point.
micro-generation certificate
Certificate awarded to products and installers of micro-generation systems through an independent scheme - the Micro-generation Certification Scheme (MCS) - in accordance with consistent standards. The scheme evaluates against robust criteria providing greater protection for consumers and is the only certification scheme to cover all microgeneration products and services. It has support from the Department of Energy and Climate Change, industry and non-governmental groups.
renewable energy
Energy which is produced naturally, eg by wind, sun, and which is sustainable or is easily replenished .
Electricity/ Energy General
AC - alternating current
Alternating current occurs when electrons or charge carriers in a conductor or semiconductor periodically reverse their direction of movement. Domestic utility current is AC with a frequency of 60 complete cycles per second (recorded as 60 hertz). The radio-frequency current in antennas and transmission lines is another example of AC.
battery store
A storage system used to store energy to be used at a later date.
DC - direct current
Direct current is the uni-directional flow or movement of electrons /electric charge carriers. Although the intensity of the current may vary, the general direction of movement remains constant. DC, when used as an adjective refers to voltage whose polarity never reverses.
Direct current is produced by photovoltaic cells. In contrast, the electricity required by household systems and available from utility mains is AC.
When required, AC can be converted to DC by means of a power supply consisting of a transformer, a rectifier (which prevents the flow of current from reversing), and a filter (which eliminates current pulsations in the output of the rectifier). Almost all electronic and computer hardware needs DC to function.
electrical energy
Energy created through the flow of electric through a conductor.
energy provider
A large scale supplier of energy ie. one of the standard companies from whom electric power from the national grid may usually be purchased for domestic/commercial consumption.
energy yield
The amount of energy which is produced.
generator
A system which converts mechanical energy into electrical energy.
inverter
An electrical device which converts direct current to alternating current.
kinetic energy
The energy produced due to an object’s motion.
kWh – Kilowatt Hour
This is a unit of energy equal to 1000 watt hours or 3.6 mega joules. Energy in watt hours = power in watts x time in hours. The kilowatt hour is most commonly known as a billing unit for energy delivered to consumers by electric energy providers.
kWp – Kilowatt-peak
The unit used to describe the power output of photovoltaic systems for installation in buildings.
load
The amount of electric power being consumed at any given moment. In an electrical circuit,it refers to any device or appliance that is using power. The load for a utility company varies greatly with time of day and season.
mechanical energy
A term used in physics, referring to the total of probable energy and kinetic energy present in the components of a mechanical system.
national grid power
The general purpose electric power supply.
on-grid
A property linked to the national grid supply of electricity (also possibly water and gas).
off-grid
A property (often in a remote location) not linked to or using public utilities such as electricity (also possibly gas, water and mains sewerage). A totally off-grid home or building is completely autonomous and operates independently without any reliance on any central supply of power or water.
three phase electricity
Three-phase electric power is a common and economical method of alternating-current electric power transmission. It is used for overhead cables.
In a three-phase system, the currents in each conductor reach their peak values sequentially, not simultaneously; in each cycle of the power frequency, first one, then the second, then the third current reaches its maximum value: the waveforms of the three supply conductors are phased or offset from one another in time. This delay between phases has the effect of giving constant power transfer over each cycle of the current and also makes it possible to produce a rotating magnetic field in an electric motor.
Most domestic properties have a single phase electricity supply as standard.
Solar Photovoltaic
array / photovoltaic array
An assembly of modules and panels together with support structure to form a dc power generation unit.
cell / photovoltaic cell
A basic photovoltaic device which generates electricity when exposed to a light such as the solar radiation. All photovoltaic cells produce direct current.
hybrid photovoltaic cells
These are a mono-crystalline PV cell covered by an ultra-thin amorphous silicon PV layer. They are slightly more efficient than conventional silicon PV cells, but are therefore more expensive.
module / photovoltaic module
The smallest complete environmentally protected assembly of interconnected photovoltaic cells.
For crystalline silicon cells, the cells are interconnected and encapsulated between a transparent front (usually glass) and a backing material. This 'module' is then typically mounted in an aluminium frame.
Modules are normally rated between 50 and 200 W, although several manufacturers now offer modules above 200 W.
mono-crystalline photovoltaic cells
These cells are cut from a single crystal of silicon and have a smooth texture.They are slightly more efficient than the polycrystalline panels but are usually more expensive and are often the panel type used on schools and commercial buildings.
mounting structure
There are a wide range of ways of installing PV modules on buildings and also for mounting them on the ground. These include mounting structures for PV facades,roof profiles, flat roofs and even 'PV tiles' that can be used to replace conventional roof tiles.
panel / photovoltaic panel
A group of modules fastened together, pre-assembled and wired, designed to serve as an installable unit in a photovoltaic array.
photovoltaics
The process that produces electricity from sunlight. "Photo" = light and "voltaic" = voltage.
poly-crystalline photovoltaic cells
These cells are effectively a slice cut from a block of silicon, consisting of a large number of crystals and are an affordable option, ideal for domestic properties The panels have a speckled reflective appearance.
power system / photovoltaic power system
The set of interconnected elements eg. photovoltaic modules, inverters that convert DC current of the modules into AC. current, storage batteries and all installation and control components.
PV
Abbreviation for photovoltaic – either the adjective eg. photovoltaic panel or noun photovoltaics.
PVPS
Abbreviation of photovoltaic power system(s).
Wind Power
AMWS
Abbreviation for average mean wind speed.
blade
The rotor sail or fin of the wind turbine.
capacity factor
The ratio of actual output of power compared to the output which would have been produced at full capacity, taken over a certain period of time.
horizontal axis wind turbine
Horizontal-axis wind turbines (HAWT) are turbines which have the main rotor shaft and generator at the top of the tower, and must be pointed towards the source in wind in order to work.
micro-wind turbine
Generic term for small wind turbines suitable for domestic or small business use.
nacelle
The shell containing equipment on a wind turbine.
rotor
The rotating part of the turbine.
swept area
The area where the rotor blades of a turbine pass as they rotate in a circle.
synchronous generator
A wind turbine whose rate of rotation changes with respect to the wind speed; energy generated from these units must be passed through an inverter before feeding into an electricity grid.
tower-mounted
Also referred to as mast-mounted, the tower allows the wind turbine to be free-standing and make the most of an expose position.
triple safety system
The comprehensive safety system used by some wind turbine systems (notably Gaia-Wind ) which parks the rotor blades in high wind speeds.
turbine controller
This stops the turbine mechanism when wind speeds reach a certain level.
vertical axis wind turbine
Vertical-axis wind turbines (VAWT) are turbines whose main rotor shafts are arranged vertically, so they do not need to be pointed in the direction of the source of wind to work.
wind turbine
A machine which converts the kinetic energy from wind into mechanical energy.