Advanced conversion technology (ACT)

New and developing thermal processes, such as gasification and pyrolysis, which can be utilised to dispose of municipal solid waste.

APX

Amsterdam Power Exchange

Balancing and Settlement Code (BSC)

The principal agreement governing electricity trading and settlement in England and Wales, and Scotland following the introduction of BETTA.

Balancing market

The market run by NGC using the Bids and Offers received to determine the most economic way to balance the system.

Balancing market unit (BMU)

The smallest trading block in the electricity generation and supply system that can operate independently and for which only one party is responsible.

Balancing mechanism (BM)

The mechanism by which electricity demand is matched with electricity generation. It currently operates from one hour ahead of delivery of the power up to the actual time of delivery.

Balancing services use of system changes (BSUoS)

The means by which the transmission system operator recovers elements of the costs of running the transmission system.

Baseload

Continuous steady demand.

Bilateral embedded generation agreement (BEGA)

A form of bilateral contract between NGC and a distributed generator.

Bilateral embedded licence exempt large agreements (BELLA)

A form of bilateral contract between NGC and a licence-exempt distributed generator.

British electricity trading and transmission arrangements (BETTA)

The commercial and practical arrangements for trading and balancing which apply to the whole of Great Britain from April 2005.

BCA

Bilateral Connection Agreement

Bids and offers

An indication of a willingness to reduce (bid) or increase (offer) the level of generation or increase (bid) or reduce (offer) the level of demand submitted to the balancing mechanism.

Bilateral

Refers to two parties. Normally used in connection with trading whereby two parties (for example a generator and a supplier) enter into a contract to deliver electricity at an agreed time and price in the future.

BMRS

Balancing Mechanism Reporting System

BOA

Bid-Offer Acceptance

BPS

Balancing Principles Statement

BSAD

Balancing Services Adjustment Data

BSCC

Balancing Services Contracts Costs

BSCCo

Balancing and Settlement Code Company

The Department for Business, Innovation and Skills (BIS)

Offers information on a range of services provided by the Department of Business, Enterprise and Regulatory Reform specifically to help small businesses. BIS is tasked with building a dynamic and competitive UK economy by: creating the conditions for business success; promoting innovation, enterprise and science; and giving everyone the skills and opportunities to succeed.

Buy out payments

The payments made by suppliers who did not submit sufficient Rocs to meet their targets for Renewable Obligation.

CADL

Continuous Acceptance Duration Limit

Capacity

In reference to electricity, the maximum load that a generating unit or generating station can carry under specified conditions for a given period of time without exceeding approval limits of temperature and stress.

CC

Competition Commission

Combined Cycle Gas Turbine (CCGT)

A gas fired electricity generation plant.

CEGB

Central Electricity Generating Board

Central dispatch

NGC may constrain the operation of a generator requiring more or less output or requiring the plant not to export.

CfD

Contract for Differences

Combined heat and power (CHP)

A plant producing useful heat (for process or other use) and electricity at the same time.

CHP quality assurance (CHPQA)

The programme run by Defra to ensure that the environmental benefits of CHP are achieved (supported by LECs).

Climate Change Levy (CCL)

A tax on the supply of electricity and gas collected by Suppliers from business consumers.

CMRS

Central Meter Registration Service

Cogeneration

The simultaneous production of electricity and another form of useful energy (such as heat or steam) through the sequential use of energy, resulting in increased efficiency of fuel use.

Connection and use of system code

Governance arrangements for connections to and use of the transmission system.

Consolidator

A party that buys the output of a number of generators and trades it in the wholesale market.

Counterparty

Conventionally the parties to a trading agreement are called counterparties. This term is used rather than buyer/ seller as the buying/ selling roles sometimes reverse in trading.

CP

Compliance Period

CSOBM

System Operator BM Cashflow

CVA

Central Volume Allocation

Data aggregator (DA)

Party that aggregates meter readings supplied by data collectors for presentation to settlements.

Data collector (DC)

Party that reads HH and/ or NHH meters and submits the readings to the DA and supplier.

DCI

Demand Control Imminent

The Dpartment of Energy and Climate Change (DECC)

The UK government department created in October 2008 to bring together energy policy and climate change mitigation policy.

Declared net capacity (DNC)

The full definition is given in schedule 1 of The electricity class exemption order no.3270. The DNC is the maximum power avaliable from a generating station on a continuous capability basis less any power used to run the station. In the case of solar, wind, tidal or wave power the physical maximum continous power is multiplied by a factor reducing the effective DNC. The factors are: Tidal, wave 0.33; solar 0.17; and wind 0.43.

The Department for Environment, Food and Rural Affairs (Defra)

The UK government department responsible for policy and regulations on the environment, food and rural affairs.

Demand profile

The load shape, or pattern of energy usage over a given period of time, usually daily, seasonal or annual. Standard profiles take an assumed form of electricity usage in half hourly slots for every day of the year.

DGES

Director General Electricity Supply

DGFT

Director General of Fair Trading

DISG

Development and Implementation Steering Group

Distributed generation/ generators

Generation plant that is connected to a distribution network, i.e. not to the transmission network.

Distribution code

The code which covers all major technical aspects relating to connection to, and the operation and use of, licensed distribution networks.

Distribution losses

Electricity lost in the distribution system.

Distribution network operator (DNO)

The owner and operator of the local distribution networks. The DNO holds a distribution licence for the provision of network services in a defined area, including connection to the system, metering and data services. 

Distribution system

The regional electricity infrastructure used for delivering electricity from the transmission system exit point (GSP) to the consumer.

Distribution use of system charges (DSUoS)

Charging regimed used by DNOs to charge for use of their network.

DPCR

Distribution Price Control Review

DSO

Distribution System Operator

EC

European Commission

Energy contract volume aggregation agent (ECVAA)

Energy contract volume aggregation agent under BETTA.

ECVNA

Energy Contract Volume Notification Agent

EELPS

Embedded Exemptible Large Power Station

EEMPS

Embedded Exemptible Medium Power Station

EESPS

Embedded Exemptible Small Power Station

EFA

Electricity Forward Agreement

Elexon

Organisation responsible for ensuring the proper, effective and efficient implementation of the Balancing and Settlement Code (BSC).

Embedded benefits

The additional value of electricity generated by a distributed generator arising from its connection to the distribution system rather than the transmission system. E.g. due to the avoidance of transmission and distribution losses.

Embedded generation

Generation plant that is connected to a distribution network, an older term for distributed generation.

Emissions trading scheme (ETS)

The emissions trading scheme of the European Union, based on an allocated "cap" for each operatorwith the ability to trade for insufficient of excess allocations.

Energy from Waste (EfW)

Energy recovery of post recycling waste residue--an alternative to landfill.

ENTSO-E

European Network of Transmission System Operators for Electricity

EU

European Union

Exempt supplier services

A package of services provided by a licensed supplierto allow a licence exempt supplier to supply consumers connected to the local DNOs network.

Exit point

A point of connection at which a supply of electricity may flow between the Rec's system and the client's installation, suppliers installation or the distribution system of another person.

Extra high voltage (EHV)

22,000 volts or higher voltage

FGD

Flue Gas Desulphurisation

Financial services agency (FSA)

A UK regulatory body.

FPN 

Final Physical Notification

Gate closure

In relation to a settlement period, the time one hour 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. 

GBSO

Great Britain System Operator

GDUoS

Generator Distribution Use of System

GEMA

Gas and Electricity Markets Authority

Generation units

The smallest physical unit of generation.

Generator

A producer of electricity.

Grid

The transmission grid.

Grid code

The code that governs technical aspects of the operation of the transmission system.

Grid supply point (GSP)

The point on the transmission system at which distribution systems are connected.

Grid supply point group (GSP Group)

A collection of GSPs so that supply and demand data can be aggregated for settlements. Currently (May 2005) equivalent to all the GSPs in the relevant DNO area.

Grid trade master agreement (GTMA)

An industry standard trading agreement.

Half hourly (HH)

Refers to the measurement of electricity produced or consumed on a half hourly basis.

HMRC

Her Majesty's Revenue and Customs

HRDR

High Risk of Demand Reduction

HSE

Health and Safety Executive

HV

High Voltage

Hydro generating plant

A plant which uses natural water flows to turn turbines and generate electricity.

IBC

Incentivised Balancing Cost

ICE

Intercontinental Exchange

IDNO

Independent Distribution Network Operator

IPE

International Petroleum Exchange

IPN

Indicative Physical Notification

IS

Imbalance Settlement

IWA

Initial Written Assessment

Kilovolts (kV)

Measurement of voltage (i.e. 1,000 volts)

Kilowatts (kW)

Meaurement of watts (i.e. 1,000 watts)

Landfill sites

Refers to electricity produced by burning the methane and other gases which are produced in landfill sites as refuse decays.

Levy exemption certificate (LEC)

Issued by Defra to "good quality" CHP to enable electricity to be supplied exempt from the Climate Change Levy.

LEG

Licence Exempt Generator

LEGA

Licence Exempt Generator Agreement

Licence exempt

Means that a licence is not required.

LLF

Line Loss Factor

LOLP

Loss of Load Probability

LV

Low Voltage

Market asset provider (MAP)

A party that provides the relevant meter asset.

Market cash out

The general term describing the system buy, system sell prices under BETTA and the buy buy price under the renewables obligation.

Master registration agreement (MRA)

The overall agreement which has to be signed by participants who wish to supply electricity to consumers.

Maximum Demand (MD)

Associated with electricity supplies, the MD is the highest value of energy used for a particular period of time. It is usually measured in kilowatts (kW)

MCUSA

Master Connection and Use of System Agreement

MDP

Maximum Delivery Period

MDV

Maximum Delivery Volume

MEL

Maximum Export Limit

Meter operations provider (MOP) or Meter operator (MO)

A company that contracts with either a consumer or a supplier to install and maintain electricity meters.

Meter point administration service (MPAS)

The meter point administration system, this tracks which suppliers are responsible for which meter points.

MID

Market Index Data

MIL

Maximum Import Limit

MNZT 

Minimum Non-zero Time

MPAN

Meter Point Administration Number

MtC

Million tonnes of Carbon

MVRNA

Meter Volume Reallocation Notification Agent

Megawatt (MW)

Measure of electrical power, i.e. Megs (million) Watts.

MZT

National balancing point (NBP)

A theoretical point within the National Transmission System (NTS) where gas is traded on the wholesale market.

NAO

National Audit Office

National grid

Another name for the transmission network.

National Grid Company (NGC)

The company that owns the transmission system in England and Wales and operates the balancing mechanism for the whole of Great Britain.

Netting off

The process by which the grossed up output of a distributed generator is deducted from a supplier's total take within a GSP group.

New electricity trading arrangements (NETA)

The arrangements for trading electricity and for balancing that applied in England and Wales prior to the introduction of BETTA in 2005.

NFPA

Non-Fossil Purchasing Agency

NIRO

Northern Ireland Renewables Obligation

NISM

Notification of Inadequate System Margin

NIV

Net Imbalance Volume

Non-fossil fuel obligation

The main instrumnet for encouraging the development of renewable generation prior to the introduction of the Renewables Obligation.

Non half hourly (NHH)

Refers to demand that is settled on a profiled basis, i.e. noy HH.

Notional balance point (NBP)

The (notional) point at which all electricity is traded in Great Britain.

Ofgem

Office of Gas and Electricity Markets

Ofreg

Office for Regulation of Electricity and Gas (Northern Ireland)

On-site

Refers to the consumption of electricity produced by a generator on, or immediately adjacent to the physical site occupied by the generator without use of either a private network or the DNOs network.

Over the counter trade

Refers to a common form of trade that is conducted in a similar way to buying and selling in a shop.

PAR

Price Average Reference

PES

Public Electricity Supplier

PGBT

Pre-Gate Closure Balancing Trade

Photovoltaic (PV)

Direct conversion of solar radiation into direct current electricity by the interaction of light with the electrons in a semiconductor device or cell.

PPP

Pool Purchase Price

Private networks

Electricity distribution arrangements that are not owned by a DNO and that are exempt from having to have a distribution licence.

PSP

Pool Selling Price

PTF

Power Trading Forum

PX 

Power Exchange

RCRC

Residual Cashflow Reallocation Charge

RDRE

Ramp Down Rate Export

RDRI

Ramp Down Rate Import

REC

Regional Electricity Company

Recycling (Renewables Obligation buyout)

The method for distributing the buy-out payments collected from suppliers who did not meet their Renewables Obligation targets and re-distributing it, in proportion to their share of all the Rocs redeemed that year.

Registered capacity

Full load capability of a generating unit as declared by the generator, less the energy consumed through the unit transformer.

Renewable

Energy from sources which occur naturally and repeatedly in the environment, e.g. from the sun, the wind and the oceans, and from plants and the fall of water. The energy available from waste is also included in some applications.

Renewable energy guarantee of origin (REGG)

A certificate that specifies the origin of renewable energy. Used to demonstrate the pedigree of renewable power. Separate to Rocs, which are redeemed by suppliers.

Renewables Obligation (RO)

The method used to encourage renewable energy generation in the UK. Suppliers are obliged to supply their consumers with an annually increasing percentage of electricity from renewable sources.

Renewables Oblogation Certificate (Roc)

The tradable certificates given to generators producing power from renewable energy sources. These certificates are used by suppliers to meet their Renewables Obligation committment.

RTFO

Renewables Transport Fuel Obligation

RURE

Ramp Up Rate Export

RURI

Ramp Up Rate Import

Seasonal time of day (STOD)

Season time of day tariff or pricing. The price varies according to the time of day and the season of the year.

SEL

Stable Export Limit

Settlement

The process by which suppliers and generators agree how much electricity was traded, the value of the trades and by whom.

Settlement agents

Parties approved to submit information required for settlement, e.g. metering parties.

SLC

Standard Licence Condition

SMP

System Marginal Price

SMRS

Supplier Meter Registration Service

SO

System Operator

SOIS

System Operator Incentive Scheme

SoLR

Supplier of Last Resort

SoS

Secretary of State

SRO

Scottish Renewables Obligation

Stand-by-supply

The amount of electricity required by a generator, e.g. for on site use, when they are unable to generate due to plant failure.

STC

System Operator Transmission Owner Code

STTEC

Short-term Transmission Entry Capacity

Supplier

A person or company, generator, broker, marketer, consolidator, or any other entity that sells electricity to consumers.

SVAA

Supplier Volume Allocation Agent

System buy price (SBP)

The price paid in the Balancing Market by a party that requires more energy to meet its contractual committments .

System sell price (SSP)

The price paid in the Balancing Market by a party that has delivered more electricity than its consumers wanted to buy. Prices are often negative, meaning that a payment would need to be made to dispose of the unwanted electricity produced.

TCMF

Transmission Charging Methodologies Forum

TEC

Transmission Entry Capacity

TISC

Trade and Industry Select Committee

TLM

Transmission Loss Multiplier

TO

Transmission Asset Owner

Top up and standby

Arrangements for supply from other sources when the output of a local generator is either insufficient or if the generator is shut down.

Top up supply

The amount of electricity required by a generator when they do not generate sufficient electricity to meet the demands of all the consumers they are contracted to supply.

Transmission

The transfer of electricity at high voltage from generating stations across the UK through overhead lines abd underground cables to points (GSP) from where it can distributed to users.

Transmission grid

The high voltage (HV) network that connects generating stations to the local distribution systems. In England and Wales this is owned by the National Grid Company, while in Scotland the transmission systems are owned by Scottish Power and Scottish and Southern Energy.

Transmission losses

Refers to the electricity that is lost in the transmission system.

Transmission Network Use of System Charges (TNUoS)

Charges levied by the TSOs for the use of their transmission systems.

Transmission system owner (TSO)

The owners of the three systems forming the transmission grid. In Scotland, these are Scottish Power and Scottish Electric and in England and Wales it is National Grid Company.

Triad

The three half hour periods of the highest demand on the transmission system, with at least 10 days between them, from the beginning of November in one year to the end of February in the following year.

TU

Trading Unit

TWh

 Terrawatt hours

UK emissions trading scheme

Based on the international Kyoto Summit on Climate Change agreement, this describes the UKs National Emissions Trading scheme designed to reduce a range of greenhouse gases, 80% of which is carbon dioxide.

UKPX

United Kingdom Power Exchange

Unbalance market

Difference between electricity production and demand.

VaR

Value at Risk

VOLL

Value of Lost Load