Glossary of Terms

Search: (clear)
a
- AMRAutomated Meter Reading - automatic collection of data from meters which is transferred to a central database for billing and/or analysis.
- Annual offtakeThe expected or nominated annual consumption of gas at a supply point. Also referred to as AQ.
- Annual QuantityAnnual quantity. The sum of the annual consumption of all meters on a site. Measured in kWh or Therms.
- AQAnnual quantity. The sum of the annual consumption of all meters on a site. Measured in kWh or Therms.
- Automated Meter ReaderAutomated Meter Reading - automatic collection of data from meters which is transferred to a central database for billing and/or analysis.
- Availability chargeElectricity availability charges are based on an agreed level of required capacity and should be set at just above the anticipated maximum demand.
b
- Balancing and settlement codeCode governing the operation of the balancing mechanism and the imbalance settlement process and the relationships and responsibilities of all electricity market participants.
- Balancing MechanismThe mechanism by which electricity demand is matched with electricity generation as near to real time as possible. It currently operates from three and a half hours ahead of delivery of the power up to the actual time of delivery.
- BaseloadThe load continuously supplied by generators into the electricity networks over a period of time that demand does not fall below.
- Baseload DemandMinimum demand experienced by a generating plant.
c
- Calorific ValueThis relates to the British Thermal Unit Correction Factor, which transfers the volume of gas to a measure of heat. This figure changes on a monthly basis, according to the ambient pressure and temperature of the gas within the system and is the multiplier by which cubic feet as a volume is(...)
- CapacitanceThe property of a capacitor that determines the quantity of electric energy that it can store.
- CapacitorA device consisting of two conducting surfaces separated by an insulator and having the ability of storing electric energy. Also called a condenser. Capacitors can be installed to control and improve the power factor.
- CapacitySupply Capacity (or Availability) is a limit on monthly maximum demand agreed between the user and the regional distributor (normally via the supplier). Measured in kVA.
- Carbon reduction CommitmentAn intensive energy users requirement to reduce carbon emissions measured in Tonnes.
- CCAClimate change Agreement - a Gov't scheme in giving discounts to large energy users against their carbon emmisssion costs - CCL
- CCLA customs and excise levy charged to most commercial users of electricity since 2001. The levy is applied at a fixed rate per kilowatt hour.
- CFUsed by suppliers to calculate gas bills. The correction factor and the calorific value are the two variables used in the process of converting gas volume (as measured by the meter in cubic feet or cubic metres) into a measure of energy in kilowatt hours (kWh). Charges are based on kilowatt hours.
- CHPA power generation plant which produces electricity and uses the waste heat generated to warm a building or buildings. This may be small scale inside a factory or large scale where heat from a power station is used to provide heating for a local district containing domestic, commercial and(...)
- Climate Change AgreementClimate change Agreement - a Gov't scheme in giving discounts to large energy users against their carbon emmisssion costs - CCL
- Climate Change LevyA customs and excise levy charged to most commercial users of electricity since 2001. The levy is applied at a fixed rate per kilowatt hour.
- Combined Heat and PowerA power generation plant which produces electricity and uses the waste heat generated to warm a building or buildings. This may be small scale inside a factory or large scale where heat from a power station is used to provide heating for a local district containing domestic, commercial and(...)
- Communication ChargesCommunication charges cover the cost of the telephone line or cellular link used for remote access to the electricity meter. This applies to half-hourly metered sites only. Communication charges can be billed to the customer by either the meter operator or the supplier.
- Correction FactorUsed by suppliers to calculate gas bills. The correction factor and the calorific value are the two variables used in the process of converting gas volume (as measured by the meter in cubic feet or cubic metres) into a measure of energy in kilowatt hours (kWh). Charges are based on kilowatt hours.
- CRCAn intensive energy users requirement to reduce carbon emissions measured in Tonnes.
- Cubic FeetUnit of measure for volume of gas recorded by imperial meters.
- Cubic MetresUnit of measure for volume of gas recorded by metric meters. One cubic metre = 35.31 cubic feet.
- CurtilageThe area of land within a boundary surrounding a property when not crossed by public highways, rail lines etc. Gas meter points sharing common ownership, purpose and curtilage may be aggregated to reduce transportation charges.
- CVThis relates to the British Thermal Unit Correction Factor, which transfers the volume of gas to a measure of heat. This figure changes on a monthly basis, according to the ambient pressure and temperature of the gas within the system and is the multiplier by which cubic feet as a volume is(...)
d
- DAThe organisation appointed to aggregate electricity meter reading data received from data collectors to forward to suppliers.
- Daily meteredA gas supply point whose consumption is measured each day by means of a data logger.
- Data aggregatorThe organisation appointed to aggregate electricity meter reading data received from data collectors to forward to suppliers.
- Data collectorThe organisation responsible for collecting, processing and validating the meter reading data which is then passed on to the data aggregator.
- DataloggerDevice fitted to a meter that can record, store and transmit readings and measurements.
- DCThe organisation responsible for collecting, processing and validating the meter reading data which is then passed on to the data aggregator.
- De MinimisIf the amount of electricity supplied to a commercial site is less than 33 kWh per day and gas supplied less than 145 kWh per day respectively over a billing period then de minimis applies and VAT is charged at the reduced rate (currently 5%).
- DemandThe rate at which electric energy is used in any instant or average over a period of time. Usually expressed in kilowatts (kW) or kilovolt-amperes (kVA). See also Maximum Demand.
- Demand levelThe consumption of electricity in half-hourly intervals actually used on a national basis.
- Demand-side ResponseWhen large gas users turn down their gas usage in response to prices. See also interruptible supply. Distribution Network Operators (DNOs) DNOs are ex-Public Electricity Suppliers that came into existence on 1 October 2001. There are currently 14 Distribution Network Operators (DNOs) in the UK.
- Distribution lossesCharges relating to electrical losses that occur as electricity is transmitted through the lines of the DNO (see below).
- Distribution network operatorManages the installation and upkeep of their cabling and the distribution of electricity from the point where it leaves the transmission system to the supply point. They are also often referred to as the host Regional Electricity Company (REC).
- Distribution use of systemCharge levied by the DNO for the transmission of electricity through its local network.
- DMA gas supply point whose consumption is measured each day by means of a data logger.
- DNOOne of 14 local distribution companies responsible for maintenance of the local distribution zone.
- Domestic SiteA site with an annual gas consumption of less than 73,200 kilowatt hours or 2,500 therms.
e
- EHVExtra High Voltage.
- ElexonThe balancing and settlement code company that procures and provides services to administer and implement the balancing and settlement rules. Signatories to the BSC contribute to the costs of Elexon. Charges are levied to recover the costs of running Elexon.
- Emission allowanceTypically, emissions reduction schemes set a cap for total emissions for each participant over a period and allocate each participant tradable units, called emissions allowances, up to the cap. Participants buy and sell emissions allowances and at the end of the period must hold allowances or(...)
- Emissions capThe limit on emissions applicable to a participant over a period of time used to allocate emissions allowances.
- Emissions creditCountries and companies can earn tradable emissions credits by undertaking projects that reduce emissions over and above what would occur in a business as usual scenario.
- Emissions tradingCountries and companies can trade emissions allowances and emissions credits. Emissions trading is one of the Kyoto mechanisms for reducing emissions of greenhouse gases contributing to climate change.
- Entry capacityThe quantity of gas that a shipper is entitled to put into the system at a particular input point on a day.
- EU-ETSCountries and companies can trade emissions allowances and emissions credits. Emissions trading is one of the Kyoto mechanisms for reducing emissions of greenhouse gases contributing to climate change.
- Exit capacityThe quantity of gas that a shipper is entitled to withdraw from the national transmission system in order to meet the requirement of its customers on a day.
- Exit zoneA geographical gas distribution area wholly contained within a local distribution zone which groups supply points together that, on a peak day, receive gas from the same national transmission system offtake point(s). Supply points in the same exit zone attract the same exit capacity charge rate.
- Extra High VoltageExtra High Voltage.
f
- Firm gasA guaranteed supply of natural gas that will not be subject to interruption.
- Firm SupplyA firm supply of gas is one that is guaranteed for a fixed period and will not be subject to an interruption or closure.
- Forwards contractAn agreement to buy electricity from another party at a specified time in the future at a specified price with money changing hands at the delivery date.
- Fossil fuelCoal, natural gas and fuels derived from petroleum.
- FundamentalsFactors other than psychological or technical that influence the price development on the physical or futures market, e.g. physical supply and demand, stock levels, currency exchange rates, interest rates, weather forecasts etc.
- Futures contractSimilar to a forwards contract these are normally traded through an exchange on standard contract terms with profits or losses calculated and paid daily.
g
- Gas yearPeriod commencing 06:00 1 October through to 06:00 1 October the following year.
- Gate closureIn relation to a settlement period, the time 3.5 hours before the start of that settlement period. It defines the moment when bilateral contracting ends and the Balancing Mechanism for each associated trading period begins.
- GeneratorProducer of electricity.
- GigawatthourThe equivalent to one thousand megawatts or one million kilowatts (kW).
- Grid supply pointPoint between transmission and distribution systems where responsibility for electricity supply transfers from National Grid Transco to the local REC.
- GWHThe equivalent to one thousand megawatts or one million kilowatts (kW).
h
- Half hourly dataHalf-Hourly data. Electricity consumption data recorded every half hour and collected by the metering system.
- Half hourly meteredDescribes measurement of electricity consumption in half hourly intervals through a meter complying with the relevant Code of Practice (COP). COP3 for 1MW+ sites or COP5 for sites with demand over 100kW and up to 1MW.
- HHMDescribes measurement of electricity consumption in half hourly intervals through a meter complying with the relevant Code of Practice (COP). COP3 for 1MW+ sites or COP5 for sites with demand over 100kW and up to 1MW.
- High VoltageHigh Voltage. Supply voltage above 1000 volts (1kV).
- HMC&EHM Customs & Excise.
- HVHigh Voltage. Supply voltage above 1000 volts (1kV).
i
- I&CIndustrial and Commercial (non-domestic sector).
- ImbalanceSituation where there is a difference between the amount of power produced (supply) and the amount of power contracted or sold (demand).
- Imbalance costCost to supplier of being in an imbalance situation.
- Industrial & Commercial (I&C) siteA site with an annual gas consumption of more than 73,200 kilowatt hours or 2,500 therms.
- InterconnectorA cable connection allowing electricity to flow between two countries or markets. There are interconnectors between the north of England and Scotland and between the south of England and France.
- Interruptible gasGas supply that may be interrupted by Transco or supplier to maintain the transmission/distribution system to allow supplies to firm gas consumers when there is a constraint on the system. Customers with an interruptible gas supply must have an alternative power supply should an interruption(...)
- Interruptible SupplyAn interruptible supply is one whereby an agreement has been reached with the user that the service may be interrupted throughout the year, for a pre-determined nuAn interruptible supply is one whereby an agreement has been reached with the user that the service may be interrupted throughout(...)
k
- KilovoltampereKilovoltampere. Unit of measurement for electricity available capacity and in some cases maximum demand. Referred to as KVArh when used to measure reactive power.
- KilowattA unit of power, equal to 1,000 Watts. A watt is the standard power unit and a measurement of demand, including maximum demand.
- Kilowatt HourA measure of electrical energy. One kilowatt hour (kWh) of energy is the energy produced by one kilowatt acting for one hour. Electricity and gas meters record in kilowatt hours and electrical and now gas consumption is billed in kilowatt hours.(kWh) Gas used to be billed in therms but that(...)
- kVaKilovoltampere. Unit of measurement for electricity available capacity and in some cases maximum demand. Referred to as KVArh when used to measure reactive power.
- kWhA measure of electrical energy. One kilowatt hour (kWh) of energy is the energy produced by one kilowatt acting for one hour. Electricity and gas meters record in kilowatt hours and electrical and now gas consumption is billed in kilowatt hours.(kWh) Gas used to be billed in therms but that(...)
- Kyoto ProtocolAn international agreement signed in December 1997 that introduced emissions targets to be achieved by the period 2008 - 2012.
l
- LECExemption from the Climate Change Levy on the electricity to which the LEC relates. LECs are issued for electricity generated from renewable sources, good quality CHP and coalmine methane.
- Levy exemption certificateExemption from the Climate Change Levy on the electricity to which the LEC relates. LECs are issued for electricity generated from renewable sources, good quality CHP and coalmine methane.
- LFRatio of average energy demand (load) to maximum demand (peak load) during a specific period. Usually stated as a percentage, or number of hours used.
- Line loss factorIndicator within the electricity supply number of distribution line loss for a meter point.
- Line packMethod used for providing short-term gas storage in which natural gas is compressed in transmission pipelines, providing additional amounts of gas to meet limited peak demands.
- Liquified natural gasOilfield or naturally occurring gas, chiefly methane, liquefied for transport or storage.
- LLFIndicator within the electricity supply number of distribution line loss for a meter point.
- LNGOilfield or naturally occurring gas, chiefly methane, liquefied for transport or storage.
- Load FactorRatio of average energy demand (load) to maximum demand (peak load) during a specific period. Usually stated as a percentage, or number of hours used.
- Local distribution zone (gas)A geographic area for which the total input and output demand for gas can be measured each day. LDZs are supplied by groups of offtakes from the national transmission system.
- Local DistributorOne of 14 local distribution companies responsible for maintenance of the local distribution zone.
- Low VoltageLow Voltage. Electricity supply voltage below 1,000 volts.
- LVLow Voltage. Electricity supply voltage below 1,000 volts.
m
- Maximum annual quantityAnnual quantity of gas multiplied by the MAQ percentage.
- Maximum daily quantityMaximum aggregated daily quantity of gas to be delivered to a supply point.
- Maximum demandThe highest average electricity demand occurring in a half hour period. Maximum demand tariffs comprise of a) fixed monthly charge, b) an availability charge per kVA of the highest demand expected, c) a price per unit for day and night units, d) a maximum demand charge based on the measured(...)
- MDThe highest average electricity demand occurring in a half hour period. Maximum demand tariffs comprise of a) fixed monthly charge, b) an availability charge per kVA of the highest demand expected, c) a price per unit for day and night units, d) a maximum demand charge based on the measured(...)
- MegawattThe equivalent to one thousand kilowatts.
- Meter operatorThe organisation appointed to install and maintain metering equipment.
- Meter operator agreementAgreement between the customer and the nominated meter operator.
- Meter Point Administration NumberUnique 21 digit number assigned to electricity meter(s) by MPAS under PRS (two tier number printed on electricity invoices preceded by an S. Top line referred to as Supplementary, bottom line as Core). Also known as Supply Number.
- Meter Point Administration ServiceMeter Point Administration Service. Provides information regarding electricity supply to properties in their distribution network areas and regulates the registration process between electricity suppliers.
- Meter point reference numberGas meter reference number.
- MOPThe organisation appointed to install and maintain metering equipment.
- MPANUnique 21 digit number assigned to electricity meter(s) by MPAS under PRS (two tier number printed on electricity invoices preceded by an S. Top line referred to as Supplementary, bottom line as Core). Also known as Supply Number.
- MPASMeter Point Administration Service. Provides information regarding electricity supply to properties in their distribution network areas and regulates the registration process between electricity suppliers.
- MPRNGas meter reference number.
- MWThe equivalent to one thousand kilowatts.
n
- National Grid TranscoOperates the high voltage national electricity transmission network and the gas transportation networks in England and Wales.
- National offtakeA gas metering point defining the boundary between the national transmission system and the Local Distribution Zone.
- National transmission systemThe high-pressure network of pipes that transports gas between terminals, storage facilities and Local Distribution Zones for local distribution.
- NDMGas supply point whose meter is not fitted with a data logger and is read monthly, six monthly or at longer intervals.
- NetworkA distribution system in which the secondaries of the distribution transformers are connected to common conductors for supplying power directly to a customer's service.
- Network CodeA document that lays out the rights and responsibilities of all those using a Public Gas Transporter (PGT) network. The Network Code is normally used to refer specifically to the PGT network.
- Nominated ConsumptionThe expected consumption of gas over a twelve month period used in a supply agreement.
- Nominated interruptionThe designation by National Grid Transco of a gas supply point as being interruptible, allowing Transco the right to interrupt the gas supply for operational reasons.
- Non-daily meteredGas supply point whose meter is not fitted with a data logger and is read monthly, six monthly or at longer intervals.
- NTS (National Transmission System)The pipeline network and supporting facilities that are used to transport gas around the UK.
o
- ObjectionA notice issued to a shipper who received an involuntary withdrawal indicating that they wish to retain responsibility for the supply point. Offtake Gas consumed by a site or customer.
- Offtake pointOutlet of any control valve at any gas supply meter point.
- OfgemThe Office of Gas and Electricity Markets. The industry regulator.
p
- Percentage DayThis refers to the percentage ratio of electricity used in the daytime against that used in the night. This information is used by suppliers to quickly identify the type of profile.
- PFThe ratio of active or real power in kilowatts (kW), to apparent power in kilovolt amperes or kVA. Power Factor is normally expressed as a figure between zero and one. Unity power factor is 100% (or 1.0) power factor which is the highest available. In practice 0.99 is the highest.
- PGTA pipeline network operator, the largest of which used to be Transco, but is now National Grid.
- Power FactorThe ratio of active or real power in kilowatts (kW), to apparent power in kilovolt amperes or kVA. Power Factor is normally expressed as a figure between zero and one. Unity power factor is 100% (or 1.0) power factor which is the highest available. In practice 0.99 is the highest.
- PROCTradable certificates issued by generators for each whole megawatt-hour of electricity generated from eligible renewable sources. ROCs can be converted into emissions allowances in the UK Greenhouse Gas Emissions Trading Scheme.
- ProducerA company that explores for gas, drills the wells and extracts gas from the seabed.
- Public Gas TransporterA pipeline network operator, the largest of which used to be Transco, but is now National Grid.
- Public gas transportersLicensed gas pipeline operators.
- Public registration systemSystem for registering electricity supplies using Supply Numbers and MPANs.
r
- Reactive power chargeCharge for reactive energy if the average power factor falls below a preset level, normally 0.9.
- Renewable energyGeneration of electricity from infinite resources, e.g. wind power or hydro-electricity.
- Renewable obligation certificatesTradable certificates issued by generators for each whole megawatt-hour of electricity generated from eligible renewable sources. ROCs can be converted into emissions allowances in the UK Greenhouse Gas Emissions Trading Scheme.
- Renewable sources of energyEnergy sources that occur naturally and repeatedly in the environment, eg from the sun, the wind and the oceans, and from plants and the fall of water. It also refers to the energy available from wastes and to the emerging clean technology of fuel cells.
- Renewables obligationAn obligation on electricity suppliers to source a specified percentage of the total electricity supplied to their customers in Great Britain is from eligible renewable sources. This must be evidenced by Renewable Obligation Certificates.
- ROAn obligation on electricity suppliers to source a specified percentage of the total electricity supplied to their customers in Great Britain is from eligible renewable sources. This must be evidenced by Renewable Obligation Certificates.
s
- SBPThe price paid in the Balancing Mechanism by a party that requires more energy to meet its contractual commitments. Prices are often volatile and very high.
- Settlement chargeA flat fee to cover the collection of electricity data by the data collector.
- Settlement periodA half-hour period ending on the hour or half-hour.
- Settlements AgencyThis is the body that "settles" the distribution of electricity to establish where and to whom the generated load has been distributed to.
- Settlements chargesA charge applicable to half-hourly metered supplies. Effectively a standing charge that covers balancing and settlement.
- ShipperAn organisation that contracts with National Grid Transco for the use of network code transportation and storage services.
- Shipper nominated interruptibleA gas supply that can be interrupted by its shipper to enable it to balance its supply and demand.
- Site nominationProcess by which a shipper informs National Grid Transco it wishes to supply gas to a new customer supply point.
- Smart MeteringAutomated Meter Reading - automatic collection of data from meters which is transferred to a central database for billing and/or analysis.
- Smart metersAny meter which allows for the identification of consumption in more detail than a conventional meter. Smart meters will generally also include a means of communicating information to a central data collection site for energy management and/or billing purposes.
- Spill SurplusElectricity that a generator has produced but is not able to sell.
- SSPThe price paid in the Balancing Mechanism by a party that has produced more electricity than it had users to buy. Prices are very volatile and often negative, meaning that a payment would need to be made to dispose of the unwanted electricity produced.
- Standing chargeA charge designed to average over and recover from all customers on each tariff the elements of cost which are independent of consumption. Includes the costs associated with metering, billing and customer services.
- Supplementary numberMPAN top line. Indicates the profile class and meter and time switch details.
- Supply PointA group of one or more meters for which the PGT shall make natural gas available for offset by the Shipper.
- System Buy PriceThe price paid in the Balancing Mechanism by a party that requires more energy to meet its contractual commitments. Prices are often volatile and very high.
- System Sell PriceThe price paid in the Balancing Mechanism by a party that has produced more electricity than it had users to buy. Prices are very volatile and often negative, meaning that a payment would need to be made to dispose of the unwanted electricity produced.
t
- Take or payA contract whereby a customer must pay for a specific minimum quantity of gas irrespective of usage.
- TariffPublished standard charges applied to gas and electricity supplies that are not on a bespoke negotiated contract.
- TechnicalsFactors other than fundamental or psychological ones that influence future price developments e.g. trend indicators, moving averages, support and resistance levels etc.
- TerrawattTerawatt = 1,000GW.
- Terrawatt hourTerrawatthour = 1,000 GWH.
- ThermsA therm is an imperial measure of heat energy equivalent to 29.3071 kilowatt hours. Therms have been largely replaced by kilowatt hours as the standard unit of measure on gas bills and supply agreements.
- Third party accessRight of any gas or electricity supplier to have access to the national transmission system of that energy even though the system is operated and/or owned by another organisation.
- TNUoSCharges levied by the NGC for the transmission of electricity through the National Grid.
- TransformerAn electric device, without moving parts, for transferring electric energy from one or more circuits to one or more other circuits by electromagnetic induction.
- TransmissionThe transfer of electricity at high voltage from power stations across the UK through wires on pylons to points where it can be distributed to users.
- Transmission LossesIn transmitting electricity from generator to local REC area, some electricity is lost. Specific calculations have to be made by suppliers to determine the level of these losses.
- Transmission Use of SystemsCharges levied by the NGC for the transmission of electricity through the National Grid.
- TransportationMovement of gas from the beachhead terminal to Local Distribution Zones.
- Transportation AgreementThe agreement between an independent supplier of gas and the relevant PGT, for the movement of gas within the gas network.
- Transportation chargeThe charges associated with transporting gas from the beach to Local Distribution Zones. Prices are based on a distance related tariff system and vary depending on interruptible and firm supply.
- TriadThe National Grid takes readings of maximum demands three times a year. The average of the three readings is used by the National Grid to calculate the transmission charges.
- TWTerawatt = 1,000GW.
- TWhTerrawatthour = 1,000 GWH.
u
- UKDCSUK Data Collection Service. Former name of IM-Serv.
- UKPX (UK Power exchange)A trading arena in which electricity can be bought or sold normally up to two days ahead of real time, often via the internet.
v
- VoltageThe force that causes a current to move through some resistance, in this case, the National Grid. In industry terms, electricity moves round the main grid at a high voltage. When it is stepped down to the level of a smaller grid or an actual site it is regarded as low voltage. Low voltage(...)
w
- WholesalePrice paid on the open markets for energy only i.e. excluding transportation and distribution charges, supplier margins etc.
x
- XoserveThe company that maintains the gas sites and meters database and holds the key supply point data used throughout the industry.