Solar PV Glossary


Alternating Current (AC) -
A type of electrical current, 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 easily controlled.

BIPV (Building Integrated Photovoltaic's) - Photovoltaic systems integrated into a building, usually as a replacement for traditional building materials such as rooftiles.

BRE - Building Research Establishment

BREEAM - Building Research Establishment Environmental Assessment Method

Carbon Footprint - Normally measured in KG of CO2, a carbon footprint is the impact a person, building or organisation etc has on the world through their carbon emissions.

CCL - Climate Change Levy. This Levy is charged on industrial and commercial use of energy and is one of the Government's tools for reducing emissions of greenhouse gases.

CO2 - Carbon Dioxide

CREA - Confederation of Renewable Energy Associations

Crystalline Silicon - A type of photovoltaic cell made from a slice of single-crystal silicon or polycrystalline silicon.

DECC - Department of Energy and Climate Change

DEFRA - Department of Environment, Food & Rural Affairs

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. To be used for typical 120 volt or 220 volt household appliances, DC must be converted to alternating current, its opposite.

DTI - Department of Trade & Industry

Economic Payback - Economic payback is the length of time it takes for a renewable energy system to recoup the money that you have spent on it through cost savings.

Electrical grid - An integrated system of electricity distribution, usually covering a large area.

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.

Energy Audit - A survey that shows how much energy used in a home, which helps find ways to use less energy.

EST - Energy Saving Trust

FiT - Feed in Tariffs

Gigawatt (GW) - A unit of power equal to 1 billion Watts; 1 million kilowatts, or 1,000 megawatts.

Grid-Connected System - A solar electric or photovoltaic (PV) system in which the PV array acts like a central generating plant, supplying power to the grid.

H&S - Health & Safety

HSE - Health and Safety Executive

Inverter - A device that converts direct current electricity to alternating current either for stand-alone systems or to supply power to an electricity grid.

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) - In terms of PV systems, a kilowatt hour (kWh) is the output of a system depending on the orientation and system losses and is measured over a unit of time, typically a year.

Kilowatt Peak (kWp) - Kilowatt peak (kWp) is a measure of power output which stands for peak power. This value specifies the output power achieved by a solar panel under full solar radiation (1,000 watts per square metre), and allows a comparison to be made between different systems.

Life-Cycle Cost - The estimated cost of owning and operating a photovoltaic system for the period of its useful life.

LCBP - Low Carbon Building Programme

MCS - Microgeneration Certification Scheme

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.

Multicrystalline - A semiconductor (photovoltaic) material composed of variously oriented, small, individual crystals. Sometimes referred to as polycrystalline or semicrystalline.

Orientation - Placement of the solar cells with respect to the cardinal directions, N, S, E, W. In the UK the ideal orientation is South facing with no obstructions.

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.

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.

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(s) - The direct conversion of light into electricity.

PV Photovoltaics - Technology that produces electric power directly from the sunlight. "Photo" refers to light and "voltaic" to voltage.

REA - The Renewable Energy Association

RIBA - Royal Institute of British Architects

ROCs - Renewable Obligation Certificates - the digital certificates that hold details of exactly how a unit of electricity was made, by whom and finally who bought and used it. These ROCs are traded separately to the actual electricity itself and work as a bonus premium on top of the price paid for the unit.

SAP - Standard Assessment Procedure - the Government's standard for assessing the energy efficiency performance of dwellings.

Semiconductor - Any material that has a limited capacity for conducting an electric current. Certain semiconductors, including silicon, are uniquely suited to the photovoltaic conversion process.

STA - Solar Trade Association

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.

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).