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Energy glossary

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Energy glossary

Use our glossary to understand the technical jargon used in the electricity and gas supply industry. 

We've also tried to explain some of the common energy acronyms in 15 seconds! Watch the videos to see how we did.

In the context of renewable generation, additionality is about whether the customer’s action or decision has made a genuine reduction in emissions above and beyond what would have happened anyway.

Active Power
Also known as ‘Real Power’ or simply ‘Power’. Active power is the rate of producing, transfer or using electrical energy. Measured in watts and often expressed in kW or MW.

Advanced Conversion Technology
It is a new and developing thermal processes, such as gasification and pyrolysis, which can be utilised to dispose of Municipal Solid Waste (MSW).

Agreed Capacity
An agreed amount of electrical load for a property, as stated in the property’s Connection Agreement with the local Distribution Network Operator (DNO).

Air Handling Unit (AHU)
An equipment package that includes a fan or blower for providing heating, ventilation, and air conditioning (HVAC) to a building. Efficiency is improved through enabling control.

Air Source Heat Pump (ASHP)
The heat pump absorbs heat from the outside air and transfers the heat to the space to be heated in the heating mode. In the cooling mode the heat pump absorbs heat from the space to be cooled and rejects the heat to the outside air.

Alternating Current (AC)
Electricity that changes direction periodically. The period is measured in Cycles per Second (Hertz, Hz). 

The unit that measures the rate of flow of an electrical current.

Anaerobic Digestion
A biological process that produces a gas principally composed of methane (CH4) and carbon dioxide (CO2) otherwise known as biogas. These gases are produced from organic wastes such as livestock manure, food processing waste, etc.

Annual Quantity (AQ)
It is the sum of the annual consumption of all meters on a site. This comes from National Grid and is based on historical usage from previous years. Measured in kWh (electricity) or Therms (gas). Supply Point AQ is the total annual consumption of all meters on a site. Meter Point AQ is the AQ for a particular Meter Point.

Apparent Power
The product of the voltage (volts) and the current amps. Comprises both active and reactive power. Measured in kVa or MVa.

Automatic Meter Read (AMR)
AMR is the term given to a system that provides automatic meter readings remotely. It uses telephone technology and holds the ability to transfer data into a billing system.

Availability (KVA)
Availability (kVA) or Agreed Capacity refers to the limit of capacity for a site. E.g. if a site has an Availability of 150 kVA then maximum demand should not exceed that figure at any time. It is set and charged by the local Distribution Network Operator (DNO), according to the kVA of a premise. This fee covers investment and maintenance of the electricity network and can also be called the Capacity Charge. Customers pay a fee (per unit) according to the agreed capacity for that site. In theory, maximum demand should not exceed the agreed capacity at any time.

Available Supply Capacity (ASC)
Also known as the Agreed Capacity, this is an agreed amount of electrical load for a property, as stated in the property’s Connection Agreement with the local Distribution Network Operator (DNO).

Landfill Gas 
Municipal solid waste contains significant portions of organic materials that produce a variety of gaseous products when dumped, compacted, and covered in landfills. Anaerobic bacteria thrives in the oxygen-free environment, resulting in the decomposition of organic materials and the production of primarily carbon dioxide and methane.

Large Site Peak Day Demand 
Defined as the sum of Supply Offtake Quantity (SOQ) for all large sites.

Large Supply Point 
A supply point where the reference consumption actual quantity (AQ) is equal to or exceeds 732,000 kWh/25,000 therms per annum.

Levy Exemption Certificates (UK) 
Organisations that pay the CCL can enter into agreements with suppliers to purchase renewable electricity. The Levy Exemption Certificates (LECs) are evidence of CCL exempt electricity supply generated from qualifying renewable sources. LECs will be redeemed by suppliers to HM Customs and Excise to demonstrate the amount of non-climate change electricity able to be levied that had been supplied to non-domestic customers in the given period.

Line Loss Factor 
Line Loss Factor codes are used to calculate the related DUoS charges for an MPAN. The figure gives us the voltage scale of the Mpan and reflects both the amount of transmission infrastructure used to supply the point and the amount of energy lost through heat etc

Liquified Natural Gas (LNG) 
When natural gas is cooled to a temperature of approximately -160 degrees Celsius at atmospheric pressure, it condenses to a liquid called LNG.

The amount of electric power delivered or required at any specific point or points on an electrical system. The requirement originates at the energy-consuming equipment of the customer.

Load Factor 
Measures the relationship between unit consumption and maximum demand and is the percentage capacity utilisation figure of a site's power consumption. To calculate load factor take the total number of units of consumption, divide by the maximum demand, divide by the number of hours in the period, and multiply by 100.

Load Management 
Where sites are flexible as to when they use their electricity. This means that they can schedule their production and shift patterns according to the price of pool electricity. Consumers who can load manage are able to significantly reduce their consumption at the three times in the year when the National Grid takes the Triad maximum demand readings which are used to calculate the transmission charges.

Local Distribution Zone (LDZ
Local Distribution Zone is a Transco defined area for which the total input and output demand can be measured each day.

London Climate Change Agency (LCCA) 
A body set up to work closely with the private sector to tackle climate change. The LCCA has been formed as a Mayoral led agency by the London Development Agency to enable and deliver sustainable and renewable energy and energy efficiency projects that will lead to a reduction of carbon dioxide emissions in London.

Low Carbon Building Programme (LCBP)
Launched in 2006, the LCBP is a UK government porgramme that provides funding towards the cost of installing microgeneration and other low carbon technologies.

Low Voltage (LV) 
Low Voltage, normally at 240 or 415 Volts.

Low-enriched uranium 
Uranium enriched to less than 20% U-235. (That in power reactors is usually 3.5 - 5.0% U-235.).

CCS Framework membership benefits

Crown Commercial Service is delivering value for the nation through outstanding commercial capability and quality customer service. EDF Energy is one of the UK's largest energy companies and the largest producer of low-carbon electricity. Together, we're working to help public sector organisations simplify their energy purchasing, understand the market and save time and money. Find out more