Energy Glossary

Electricity Glossary

Active Power
The component of electric power that performs work, typically measured in kilowatts (kW) or megawatts (MW).

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

AMP
Unit which measures the rate of flow of electrical current.

Annualised Advance (AA)

The rate of electricity consumption for a Settlement Register over the period between two meter readings. The value is nominally expressed as kWh/Year, but this is only for ease of understanding and can not be relied upon as a true value.

Automatic Meter Read (AMR)
Using wireless radio transmitters; AMR remotely reads customer meters and then transfers the data into the billing system.

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

BSUoS - Balancing services Use of System

National Grid recovers the costs of balancing the System through BSUos charges.

Climate Change Levy (CCL)

This is a government levy on the business use of energy. The levy applies to electricity and gas (as well as coal and LPG). The levy is imposed to encourage businesses to use less energy to help reduce greenhouse gas emissions.

Combined Cycle Gas Turbine (CCGT)

A sophisticated and efficient means of generating electricity from Gas where two forms of generation are taking place. The first is driving a turbine through the initial combustion process the second is using the resultant hot gases to power a steam turbine.

Data Aggregator (DA)
Agent appointed to aggregate the meter reading data which is received from the Data Collectors (DC) and sent to the supplier.

Data Collector (DC)
Appointed by suppliers to retrieve and validate metering data and forward it to the Data Aggregator. The DC may be appointed by the customer however has to be accredited and used by the supplier

Data Logger
A device used to record various aspects of consumers use and demand.

Direct Current (DC)
Electrical current which flows in one direction in a circuit. Batteries and fuel cells are examples of this.

Distribution Losses (Dloss)
Losses for distributing electrical power through the distribution network to the end consumer.

Distribution Network Operators (DNO)
14 companies have responsibility for operating distribution networks connecting electricity consumers to the transmission system.

Distribution Use Of System Charges (DUOS)
These are published charges from each Distribution Network Operator for delivering electricity across their network to consumers.

Electric and Magnetic Fields (EMF)

Electric and Magnetic Fields are created around all electrical conductors due to the passage of electricity through them. EMF’s are produced by all electrical installations and equipment, including domestic appliances, over head lines and underground cables.

Estimated Annual Consumption (EAC)

An estimated rate of consumption, nominally expressed in kWh/Year, that is used in Settlement until an Annualise Advance (AA) is calculated.

Clock Time / Greenwich Mean Time

This refers to the operation of the electricity meter time switch. Time switches adjusted at the beginning and end of British Summer Time are described as Clock time, where there is no adjustment it is described as GMT.

Global warming
The gradual increase of the earths average surface and atmosphere temperature as a result of the green house effect.

Greenhouse Effect
Heat trapped in the earth’s atmosphere as a result of green house gas build up (commonly believed cause of global warming)

Greenhouse Gas (GHG)
A gas that absorbs infra-red radiation from the sun made up of:
• carbon dioxide (CO2),
• halogenated fluorocarbons (HCFCs),
• hydro fluorocarbons (HFCs).
• methane (CH4),
• nitrous oxide (N2O),
• perfluorinated carbons (PFCs),
• water vapour,
• zone (O3),
See greenhouse effect.

Grid Supply Point (GSP)
The point at which energy leaves the National Grid Transmission System into a local distribution system

Kilowatt Hour (kWh)
Is a measurement of how much electrical energy or power is in one hour

Load Factor

The ratio of average electric load to peak load, usually calculated over a 1-hour period. A high load factor means power usage is relatively constant. Low load factor shows that occasionally a high demand occurs.

Maximum Demand
Maximum Demand is the consumer’s highest peak of usage (kWh) in any Half Hour during a calendar month or between two meter readings measured in either kW or kVA. This value doubled to give an hourly MD.

Meter Asset Maintenance (MAM)
The meter operator will charge the supplier for managing each meter within a distribution area. Any work requested by the supplier carried out by the meter operator will be charged back to the supplier.

Meter Asset Provision (MAP)
The meter operator will charge the supplier a monthly standing charge for each meter it owns within its distribution area.

Meter Operator (MOP)
The organisation appointed to install and maintain metering equipment for the consumers.

Meter Point Administration Number

A unique 21 digit number allocated to an electricity supply. This is often printed on your invoice and provides details of your Distributor, Line Loss Factor and Meter timeswitch

Meter Point Administration Service (MPAS)

Organisation that holds MPAN information.

Meter Serial Number
Is a unique number which should be clearly visible on the front of the meter. This would change with the installation of a new meter.

Micro-Generation
Small-scale generation of energy used locally or feed back into network. Example would be domestic wind turbines and solar panels.

MOP Charge
The charge covers the cost of providing and maintaining metering equipment for the consumer.

National Grid Transmission System
Transfers electricity at high voltage from the point of generation to the local distribution network, owned and operated by the National Grid Company (NGC

OFGEM
OFGEM is the Office of Gas and Electricity Markets, regulating the gas and electricity industries in the UK.

Profile Class
Provides an indication to the pattern and use of electricity at the premises, see table below

Reactive Charge
The charge is applied to consumer’s invoices by certain Suppliers and Distribution Companies who enforce a penalty for Reactive Power use.
Reactive Power

(KVAR)
This is recorded on the Reactive register on the meter. Reactive Power is the difference between the electricity supplied and the electricity converted into useful power. If the difference is large, i.e. there is a large amount of power being wasted, its puts an additional strain on the distribution network.

Renewable Energy
Renewable energy is the term used to describe energy flows that occur naturally and continuously in the environment, such as energy from the wind, waves or tides. The origin of the majority of the sources can be traced back to the sun or the gravitational affects of the sun and the moon.

Renewable Obligation (RO)
Government mechanism to support renewable energy. An obligation on all electricity suppliers to supply a certain amount of their electricity sales from accredited renewable sources.

Service Industry Code (SIC)
Classification code which identifies the types of activity at the site.

Settlement Agency Fee
A fee based on using the settlements service

Settlements Agency
Organisation responsible for the financial settlement in the distribution (to who and where) of generated electricity.

Shipper
A shipper buys gas from producers/ importers, and transports it through the gas network and sells the gas to large consumers or to suppliers who then supply then end consumer.

Smart Metering
Smart Metering provides Non Half Hourly consumers far more detailed and accurate information relating to their electricity consumption real time.

Supply Number
S-Number (also known as MPAN - Meter Point Administration Number).

Supply point
A group of one or more meters at a site

Renewable Obligation (UK)
Renewable Obligation (RO) came into effect in April 2002 as part of the Utilities Act (2000). It requires suppliers to source a specified proportion of the electricity they supply to their customers from accredited renewable sources. This started at 3% in 2003, rising to 15.4% by 2015/16.

Renewable Obligation Certificate (ROC)
Eligible generators receive Renewable Obligation Certificates (Rocs) for each MWh of renewable electricity generated. Certificates can be sold to suppliers to help them fulfil their renewable obligation, or they can pay a ‘buyout’ price. All proceeds from buyout payments are recycled to suppliers in proportion to the number of ROCs they present.

Take Or Pay
Incorporated within many Suppliers Contracts, it details the minimum and maximum actual consumption a consumer can take without receiving any penalty charges. Generally seen as a % of the annual volume.

Tariff Structure
The structure by which a consumers are charged for their electricity consumption. The structure may reflect their pattern of usage by being a simple single rate, or a more complicated day night, evening weekend or Seasonal time of day structure.

Transformer
Equipment that is used to change the voltage of an electrical supply (increase or decrease)

Transmission Losses (Line Losses)
Losses associated in the transmission of Electricity across the National Grid Transmission network from generation to local distribution network.

Transmission Use of System (TUoS)
Charges incurred for transmitting electricity across the National Grid network from the source of generation to the distribution network of the local Distribution Company.

Triad – (Transmission Use of System Charges)
Is the mechanism used to calculate electricity transmission charges. These charges are based on the consumer’s average demand, at the three highest demands across the transmission network during the winter months (beginning November to end of February).

Voltage
The force pushing electrical current along wires and cables

Watt (W)

Electric measurement of power at one point in time, as capacity or demand. For example, light bulbs are classified by wattage (1000 watts = kW)

Gas Glossary

Annual Quantity (AQ)
Is the sum of the annual gas consumption of all meters on a site, based on historical usage from previous years.

Automatic Meter Read (AMR)
Using wireless radio transmitters; AMR remotely reads customer meters and then transfers the data into the billing system.

Calorific Value (CV)

The calorific value (CV) of gas is a measure of the heating power of gas. The CV refers to the amount of energy released when gas is combusted under specified conditions. The CV of gas is usually given in megajoules per cubic meter (MJ/m3).

Climate Change Levy (CCL)

This is a government levy on the business use of energy. The levy applies to electricity and gas (as well as coal and LPG). The levy is imposed to encourage businesses to use less energy to help reduce greenhouse gas emissions.

Daily Meter (DM)
A supply point whose annual quantity (consumption) of gas is in excess of 58,600,000kWh (2,000,000 therms per annum).

Data Logger
A device used to record various aspects of consumers use and demand.

Domestic / Non Domestic Supply
A gas Supply Point with an AQ of 73,200kWH (2500 therms) or less is deemed as a domestic site although they could be using it for business purpose. A supply point with an AQ of over 73,200kWh is deemed as non-domestic.

Gas Transporter (GT)
Organisations responsible for maintaining a gas supply network.

Global warming
The gradual increase of the earths average surface and atmosphere temperature as a result of the green house effect.

Greenhouse Effect
Heat trapped in the earth’s atmosphere as a result of green house gas build up (commonly believed cause of global warming)Greenhouse Gas (GHG)
A gas that absorbs infra-red radiation from the sun made up of:

carbon dioxide (CO2),

• halogenated fluorocarbons (HCFCs),

              hydro fluorocarbons (HFCs).

              methane (CH4),

            nitrous oxide (N2O),

            perfluorinated carbons (PFCs),

            water vapour,

            zone (O3),

See greenhouse effect.

Local Distribution Zone (LDZ)

There are 12 areas which determine gas transportation charges.

M Number Database
Provides basic site information for gas consumers, available on the web from National Grid

MPRN Gas (M Number)

Is a unique meter point reference number that identifies a specific gas meter.

Meter Serial Number
Is a unique number which should be clearly visible on the front of the meter. This would change with the installation of a new meter.

OFGEM

OFGEM is the Office of Gas and Electricity Markets, regulating the gas and electricity industries in the UK.

Pressure Tier

Shown below are the different types of pressure tiers that exist across gas transmission and distribution networks.

H.P High Pressure Up to 38bar

I.P Intermediate Pressure Between 2 and 7bar

M.P Medium Pressure 75bar and 2bar

L.P Low Pressure 19bar and 75bar

Service Industry Code (SIC)
Classification code which identifies the types of activity at the site.

Smart Metering
Smart Metering provides Non Half Hourly consumers far more detailed and accurate information relating to their electricity consumption real time.

Supply Hourly Quantity SHQ (Peak Demand)

This is the maximum hourly consumption at a given supply point.

Supply Offtake Quantity (SOQ)
Maximum daily consumption for a given supply point.

Supply point

A group of one or more meters at a site

Take Or Pay
Incorporated within many Suppliers Contracts, it details the minimum and maximum actual consumption a consumer can take without receiving any penalty charges. Generally seen as a % of the annual volume.

Therms
A unit measuring gas consumption, conversion of Therms to kWh times by 29.3

Transportation Charge
Charge for the transporting the shippers’ gas through the gas network (National, Regional Transmission system and low and medium pressure Distribution system) to the customer. Consisting of three elements which are dependent on the locations of the particular terminal and offtake site: capacity charge; commodity charge; and site charge.