Test Header

Glossary

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Dear visitor,

welcome to the ENTSO-E business glossary.

In this page you will find all the definitions which have been reviewed and analysed by our ENTSO-E experts.

To ENTSO-E members only: To follow the work currently done in new definitions, please follow the link here.​

Search Glossary

Term
OR
Definition
OR
Source
OR
Acronym
  
Definition
  
  
(N-1)-Criterion

The rule according to which the elements remaining in operation within a TSOs control area after occurrence of a contingency are capable of accommodating the new operational situation without violating operational security limits.

Select from existing list
(N-1)-Situation

​The situation in the transmission system in which one contingency from the contingency list occurred.

ENTSO-E
Accounting Point
An entity under balance responsibility where balance supplier change can take place and for which commercial business processes are defined.
Harmonized Role Model
Act
Eirgrid grid code
Activation Optimisation Function
The role to operate the algorithm applied for the optimisation of the activation of Balancing Energy bids within a Coordinated Balancing Area.
NC EB
Active Power
The real component of the apparent power at fundamental frequency, expressed in watts or multiples thereof such as kilowatts ('kW') or megawatts ('MW').
NC RfG
Active Power Reserve

​The balancing reserves available for maintaining the frequency.

System Operation Guideline
Actual Value
The greenhouse gas emission saving for some or all of the steps of a specific biofuel production process calculated in accordance with the methodology laid down in part C of Annex V.
Directive 2009/28/EC
Adequacy
The ability of in-feeds into an area to meet the load in that area.
ENTSO-E
Aerothermal Energy
Energy stored in the form of heat in the ambient air.
Directive 2009/28/EC
Aggregated Netted External Schedule
A Schedule representing the netted aggregation of all External TSO Schedules and External Commercial Trade Schedules between two Scheduling Areas or between a Scheduling Area and a group of other Scheduling Areas.
NC OPS
Alert State
The system state in which the system is within operational security limits, but a contingency from the contingency list has been detected and in case of its occurrence the available remedial actions are not sufficient to keep the normal state.
ENTSO-E
Alert State Trigger Time

​The time before alert state becomes active.

ENTSO-E
Allocated Capacity Area
A market area where the transmission capacity between the Balance Areas is given to the Balance Responsible Parties according to rules carried out by a Transmission Capacity Allocator. Trade between balance areas is carried out on a bilateral or unilateral basis.
Harmonized Role Model
Allocated Volume
An energy volume physically injected or withdrawn from the system and attributed to a Balance Responsible Party, for the calculation of the Imbalance of that Balance Responsible Party.
NC EB
Allocation Constraints
The constraints to be respected during capacity allocation to maintain the transmission system within operational security limits and have not been translated into cross-zonal capacity or that are needed to increase the efficiency of capacity allocation.
NC CACM
Allocation Platform
Single Allocation Platform or Regional Platform(s) for the attribution of Long Term Cross Zonal Capacity.
Allocation Rules
The rules for forward capacity allocation applied by the single allocation platform.
NC FCA
Alternator
A device that converts mechanical energy into electrical energy by means of a rotating magnetic field.
NC RfG
Ancillary Service
A service necessary for the operation of a transmission or distribution system.
Directive 2009/72/EC
Apparent Power
The product of voltage and current at fundamental frequency, and the square root of three in the case of three-phase systems, usually expressed in kilovolt-amperes ('kVA') or megavolt-amperes ('MVA').
NC RfG
Area Control Error

​The sum of the power control error ('∆P'), that is the real-time difference between the measured actual real time power interchange value ('P') and the control program ('P0') of a specific LFC area or LFC block and the frequency control error ('K*∆f'), that is the product of the K-factor and the frequency deviation of that specific LFC area or LFC block, where the area control error equals ∆P+K*∆f.

Select from existing listACE
Attempt to Manipulate the Market
(a) entering into any transaction, issuing any order to trade or taking any other action relating to a wholesale energy product with the intention of:(i) giving false or misleading signals as to the supply of, demand for, or price of wholesale energy products.(ii) securing the price of one or several wholesale energy products at an artificial level, unless the person who entered into the transaction or issued the order to trade establishes that his reasons for doing so are legitimate and that that transaction or order to trade conforms to accepted market practices on the wholesale energy market concerned. or(iii) employing a fictitious device or any other form of deception or contrivance which gives, or is likely to give, false or misleading signals regarding the supply of, demand for, or price of wholesale energy products.or(b) disseminating information through the media, including the internet, or by any other means with the intention of giving false or misleading signals as to the supply of, demand for, or price of wholesale energy products.
Regulation 1227/2011
Auction
The process by which long-term cross-zonal capacity is offered and allocated to market participants who submit bids.
NC FCA
Authorised Certifier
An entity that issues equipment certificates and power generating module documents and whose accreditation is given by the national affiliate of the European cooperation for Accreditation ('EA'), established in accordance with Regulation (EC) No 765/2008.
NC RfG
Automatic FRR
FRR that can be activated by an automatic control device.
Select from existing list
Automatic FRR Full Activation Time
The time period between the setting of a new setpoint value by the frequency restoration controller and the corresponding activation or deactivation of automatic FRR.
ENTSO-E
Automatic Voltage Regulator
The continuously acting automatic equipment controlling the terminal voltage of a synchronous power generating module by comparing the actual terminal voltage with a reference value and controlling the output of an excitation control system.
NC RfGAVR
Availability Plan
The combination of all planned availability statuses of a relevant asset for a given time period.
ENTSO-E
Availability Status

​The capability of a power generating module, grid element or demand facility to provide a service for a given time period, regardless of whether or not it is in operation.

ENTSO-E
Balance Group
An energy account under responsibility of a Balance Responsible Party used to determine balance considering predefined inputs and outputs within a specific Market Balance Area.
ENTSO-E
Balance Supplier
A party that markets the difference between actual metered energy consumption and the energy bought with firm energy contracts by the Party Connected to the Grid. In addition the Balance Supplier markets any difference with the firm energy contract (of the Party Connected to the Grid) and the metered production.
Harmonized Role Model
Balancing
All actions and processes, on all timelines, through which TSOs ensure, in a continuous way, to maintain the system frequency within a predefined stability range as set forth in [Article 19 Frequency Quality Target Parameters] of the Network Code on Load-Frequency Control and Reserves, and to comply with the amount of reserves needed per Frequency Containment Process, Frequency Restoration Process and Reserve Replacement Process with respect to the required quality, as set forth in [Chapter 6 Frequency Containment Reserves, Chapter 7 Frequency Restorations Reserves and Chapter 8 Replacement Reserves] of the Network Code on Load-Frequency Control and Reserves.
NC EB
Balancing Capacity
The contracted Reserve Capacity.
NC EB
Balancing Energy
Energy used by TSOs to perform Balancing.
NC EB
Balancing Energy Gate Closure Time
The point in time when submission or update of a Balancing Energy bid for a Standard Product on a Common Merit Order List in a Coordinated Balancing Area is no longer permitted.
NC EB
Balancing Reserves
All resources, if procured ex ante or in real time, or according to legal obligations, which are available to the TSO for balancing purposes.
Regulation 543/2013
Balancing Service Provider
A Market Participant providing Balancing Services to its Connecting TSO, or in case of the TSO-BSP model, to its Contracting TSO.
NC EB
Balancing Services
Either or both Balancing Capacity and Balancing Energy.
NC EB
Balancing Time Unit
The time period for which the price for balancing reserves is established.
Regulation 543/2013
Billing Agent
The party responsible for invoicing a concerned party.
Harmonized Role Model
Biofuels
Liquid or gaseous fuel for transport produced from biomass.
Directive 2009/28/EC
Bioliquids
Liquid fuel for energy purposes other than for transport, including electricity and heating and cooling, produced from biomass.
Directive 2009/28/EC
Biomass
The biodegradable fraction of products, waste and residues from biological origin from agriculture (including vegetal and animal substances), forestry and related industries including fisheries and aquaculture, as well as the biodegradable fraction of industrial and municipal waste.
Directive 2009/28/EC
Black Start Capability
The capability of recovery of a power generating module from a total shutdown through a dedicated auxiliary power source without any electrical energy supply external to the power generating facility.
NC RfG
Blackout State

​The system state in which the operation of part or all of the transmission system is terminated.

ENTSO-E
Block Energy Trader
A party that is selling or buying energy on a firm basis (a fixed volume per market time period).
Harmonized Role Model
Bottom-up Re-energisation Strategy
A strategy that does not require the assistance from other TSOs to re-energise part of the system of a TSO.
NC ER
Capacity Allocation
The attribution of cross zonal capacity.
Regulation 543/2013
Capacity Calculation Region
The geographic area in which coordinated capacity calculation is applied.
NC CACM
Capacity Coordinator
A party, acting on behalf of the System Operators involved, responsible for establishing a coordinated Offered Capacity and/or NTC and/or ATC between several Market Balance Areas.
Harmonized Role Model
Capacity Management Module
A system containing up-to-date information on available cross-zonal capacity for the purpose of allocating intra-day cross-zonal capacity.
NC CACM
Capacity Market Area
A market area where the transmission capacity between the Market Balance Areas is given to the Balance Responsible Parties in a price based process separated from trading carried out by a Transmission Capacity Allocator. Trade between Market Balance Areas is carried out on a bilateral or unilateral basis. For example The auctioning system between TenneT and RWE Net.
Harmonized Role Model
Capacity Procurement Optimisation Function
The role to operate the algorithm applied for the optimisation of the procurement of Balancing Capacity within a Coordinated Balancing Area in which Balancing Capacity is exchanged.
NC EB
Capacity Trader
A party that has a contract to participate in the Capacity Market to acquire capacity through a Transmission Capacity Allocator.
Harmonized Role Model
Central Counter Party
The entity or entities with the task of entering into contracts with market participants, by novation of the contracts resulting from the matching process, and of organising the transfer of net positions resulting from capacity allocation with other central counter parties or shipping agents.
NC CACM
Central Dispatch
A scheduling and dispatch arrangement in a Responsibility Area where the TSO performs the Integrated Scheduling Process, and where the TSO issues dispatch instructions directly to the dispatchable Power Generating Facilities and Demand Facilities.
NC EB
Certificate Area
A Certificate Market Area where a common set of rules relative to taxes and pricing for defined types of energy production are applied.
Harmonized Role Model
CIM Profile
It refers to the uniquely named subset of classes, associations and attributes needed to accomplish a specific type of interface and based upon a canonical model.ÿ The term profile may be used to define either the semantic model for an instance data payload or the syntactic schema for an instance data payload. A profile may be expressed in XSD, RDF, and/or OWL files. An instance data conforming to a profile can be tested in exchanges between applications. A profile is necessary in order to 'use' the canonical model.
ENTSO-E
Circuit Length
The circuit length of an electrical line or cable is the actual length of each of its conductors or the mean of the lengths of the conductors, if there is any appreciable difference in their lengths.
ENTSO-E Data Handbook
Classification of Power Units
According to the category of Primary Energy and fuel used for electricity generation, the UCTE statistics considers the following classification in its publications: Hydro, Nuclear, Thermal Conventional, Other Renewable (of which wind) not clearly identifiable in some publications, thermal conventional is also split into lignite, hard coal, gas, oil and mixed fuels and non attributable fuels.
ENTSO-E Data Handbook
Clearing Price
The price determined by matching the highest accepted selling order and the lowest accepted buying order in the electricity market.
NC CACM
Close To Real-Time

​The time lapse of not more than 15 minutes between the last intraday gate closure and real-time.

ENTSO-E
Closed Distribution Network
A Network classified as Closed Distribution Network pursuant to Article 28(1) of Directive 2009/72/EC at national level. Article 28 of Directive 2009/72/EC defines such a Network as a system which distributes electricity within a geographically confined, industrial, commercial or shared services site and does not (without prejudice to a small number of households located within the area served by the system and with employment or similar associations with the owner of the system) supply households customers. This Closed Distribution Network will either have its operations or the production process of the users of the system integrated for specific or technical reasons or distribute electricity primarily to the owner or operator of the Closed Distribution Network or their related undertakings.
NC DCCCDN
Common Capacity Area
A Market Area where the available transmission capacity between the Market Balance Areas is given to the Balance Responsible Parties based on their bidding to the Market Operator. Trade between Market Balance Areas is carried out through the Market Operator.
Harmonized Role Model
Common Grid Model
A Union-wide data set agreed between various TSOs describing the main characteristic of the power system (generation, loads and grid topology) and rules for changing these characteristics during the capacity calculation process.
NC CACM
Common Grid Model Exchange Standard
An ENTSO-E standard used for the exchange of power system models between TSOs for the purpose of performing bilateral, regional or pan-European studies in the frame of TYNDP or TSOs' projects. It is based on IEC CIM Standards and further extended to meet Network Codesƒ?? and projectsƒ?? requirements. The standard defines a set of data model exchange profiles.
ENTSO-ECGMES
Common Merit Order List
A list of Balancing Energy bids sorted in order of their bid prices, used for the activation of Balancing Energy bids within a Coordinated Balancing Area.
NC EB
Compensation Rules
The rules according to which each TSO responsible for the bidding zone border, where long-term transmission rights have been allocated, compensates transmission right holders for curtailing the long-term transmission rights.
NC FCA
Congestion
A situation in which an interconnection linking national transmission networks cannot accommodate all physical flows resulting from international trade requested by market participants, because of a lack of capacity of the interconnectors and / or the national transmission systems concerned.
Regulation EC 1228/2003
Congestion Income
The revenues received as a result of Capacity Allocation.
NC CACM
Connecting TSO
The TSO which operates the Responsibility Area in which Balancing Service Providers and Balance Responsible Parties shall be compliant with the terms and conditions related to Balancing.
NC EB
Connection Agreement
A contract between the relevant system operator and either the power generating facility owner, demand facility owner, distribution system operator or HVDC system owner, which includes the relevant site and specific technical requirements for the power generating facility, demand facility, distribution system, distribution system connection or HVDC system.
NC RfG
Connection Point
The interface at which the power generating module, demand facility, distribution system or HVDC system is connected to a transmission system, offshore network, distribution system, including closed distribution systems, or HVDC system, as identified in the connection agreement.
NC RfG
Constraint
A situation in which there is a need to prepare and activate a remedial action in order to respect operational security limits.
ENTSO-E
Consumer
A party that consumes electricity.
Harmonized Role Model
Consumption Capacity
The consumption of a final customer of either electricity or natural gas at full use of that customer's production capacity. It comprises all consumption by that customer as a single economic entity, in so far as consumption takes place on markets with interrelated wholesale prices.For the purposes of this definition, consumption at individual plants under the control of a single economic entity that have a consumption capacity of less than 600 GWh per year shall not be taken into account in so far as those plants do not exert a joint influence on wholesale energy market prices due to their being located in different relevant geographical markets.
Regulation 1227/2011
Consumption of Pumps
The electrical energy absorbed by the motor pumps in raising the water into the upper reservoir for the generation of electrical energy, It should include the electrical energy consumed by the auxiliary equipment and transformer losses during pumping. See also Pumped Storage.
ENTSO-E Data Handbook
Consumption Responsible Party
A party who can be brought to rights, legally and financially, for any imbalance between energy nominated and consumed for all associated Accounting Points.
Harmonized Role Model
Consumption Schedule

​A schedule representing the consumption of a demand facility or of a group of demand facilities.

ENTSO-E
Consumption Unit
A resource which receives electrical energy for its own use, excluding TSOs and Distribution Systems Operators ('DSOs').
Regulation 543/2013
Contingency Influence Threshold

​A numerical limit value against which the influence factors are checked and the occurrence of a contingency located outside of the TSO's control area with an influence factor higher than the contingency influence threshold is considered to have a significant impact on the TSOs control area including interconnectors.

ENTSO-E
Contingency List

​The list of contingencies to be simulated in order to test the compliance with the operational security limits.

ENTSO-E
Continuous Trading Matching Algorithm
The algorithm used in single intraday coupling for matching orders and allocating cross-zonal capacities continuously.
NC CACM
Contracting TSO
In case of the TSO-BSP Model the TSO which has contractual arrangements with a Balancing Service Provider in another Responsibility Area or Scheduling Area when appropriate.
NC EB
Control
Rights, contracts or any other means which, either separately or in combination and having regard to the considerations of fact or law involved, confer the possibility of exercising decisive influence on an undertaking, in particular by:(a) ownership or the right to use all or part of the assets of an undertaking.(b) rights or contracts which confer decisive influence on the composition, voting or decisions of the organs of an undertaking.
Directive 2009/72/EC
Control Area
A coherent part of the interconnected system, operated by a single system operator and shall include connected physical loads and/or generation units if any.
Harmonized Role Model
Control Area Operator
Responsible for : 1. The coordination of exchange programs between its related Market Balance Areas and for the exchanges between its associated Control Areas. 2. The load frequency control for its own area. 3. The coordination of the correction of time deviations.
Harmonized Role Model
Control Block
The composition of one or more Control Areas, working together to ensure the load frequency control on behalf of RGCE.
Harmonized Role Model
Control Block Operator
Responsible for : 1. The coordination of exchanges between its associated Control Blocks and the organisation of the coordination of exchange programs between its related Control Areas. 2. The load frequency control within its own block and ensuring that its Control Areas respect their obligations in respect to load frequency control and time deviation. 3. The organisation of the settlement and/or compensation between its Control Areas.
Harmonized Role Model
Control Capability Providing TSO

​The TSO that shall trigger the activation of its reserve capacity for a control capability receiving TSO under the conditions of an agreement for sharing reserves.

ENTSO-E
Control Capability Receiving TSO

​The TSO calculating reserve capacity by taking into account reserve capacity which is accessible through a control capability providing TSO under the conditions of an agreement for sharing reserves.

ENTSO-E
Control Entity
A geographic area consisting of one or more Metering Grid Areas with an energy delivery responsibility. Each area is synchronously connected to another area. In most cases such areas have a load frequency responsibility and therefore may have to report to a higher level control entity.
Harmonized Role Model
Control Program
A sequence of set-point values for the netted power interchange of a LFC area or LFC block over alternating current ('AC') interconnectors.
NC OS
Conventional Transmission Capacity
A theoretical value based on parameters standardised within ENTSO-E (continental Europe) for calculation of the thermal load capacity of each Tie Line. These are: ambient temperature of +35§C, wind velocity of 0.56 m/s at a right angle to the line, as well as the voltage of the line.
ENTSO-E Statistical Glossary
Coordinated Balancing Area
A cooperation with respect to the Exchange of Balancing Services, Sharing of Reserves or operating the Imbalance Netting Process between two or more TSOs.
NC EB
Coordinated Capacity Calculator
The entity or entities with the task of calculating transmission capacity, at regional level or above.
NC CACM
Coordinated Net Transmission Capacity
A capacity calculation method based on the principle of assessing and defining ex-ante a maximum energy exchange between adjacent bidding zones.
Regulation 543/2013
Coordinated Net Transmission Capacity Approach
The capacity calculation method based on the principle of assessing and defining ex ante a maximum energy exchange between adjacent bidding zones.
NC CACM
Coordination Center Operator
Responsible for : 1. The coordination of exchange programs between its related Control Blocks and for the exchanges between its associated Coordination Center Zones. 2. Ensuring that its Control Blocks respect their obligations in respect to load frequency control. 3. Calculating the time deviation in cooperation with the associated coordination centers. 4. Carrying out the settlement and/or compensation between its Control Blocks and against the other Coordination Center Zones.
Harmonized Role Model
Coordination Center Zone
The composition of a number of Control Blocks under the responsibility of the same Coordination Center Operator.
Harmonized Role Model
Countertrading
A cross zonal exchange initiated by system operators between two bidding zones to relieve physical congestion.
Regulation 543/2013
Criteria Application Process

​The process of calculating the target parameters for the synchronous area, the LFC block and the LFC area based on the data obtained in the data collection and delivery process.

ENTSO-E
Critical Fault Clearing Time

​The maximum fault duration for which the transmission system retains stability of operation.

ENTSO-E
Critical Network Element
A network element either within a bidding zone or between bidding zones taken into account in the capacity calculation process, limiting the amount of power that can be exchanged.
Regulation 543/2013
Cross Zonal Capacity
The capability of the interconnected system to accommodate energy transfer between bidding zones.
Regulation 543/2013
Cross-border Flow
A physical flow of electricity on a transmission network of a Member State that results from the impact of the activity of producers and/or consumers outside that Member State on its transmission network.
Regulation 714/2009
Cross-Control Area Balancing
A balancing scheme where a TSO can receive bids for activation coming from other TSOs' areas. It does not include re-dispatching or the delivery of emergency energy.
Regulation 543/2013
Currency
Currency is euro if at least one part of the bidding zone(s) concerned is part of a country in which euro is a legal tender. In any other case it is the local currency.
Regulation 543/2013
Current
The rate at which electric charge flows which is measured by the root-mean-square value of the positive sequence of the phase current at fundamental frequency.
NC RfG
Cut-Off Time
The point in time where TSOs have to confirm all matched nominations to the market. The cut-off time refers not only to daily or intra daily markets but also to the different markets that cover imbalance adjustments and reserve allocation.
Regulation 543/2013
Data Provider
The entity that is sending the data to the central information transparency platform.
Regulation 543/2013
Day Ahead Firmness Deadline
The point in time after which cross-zonal capacity becomes firm.
NC CACM
Day-Ahead Market Gate Closure Time
The point in time until which orders are accepted in the day-ahead market.
NC CACM
Day-Ahead Market Timeframe
The timeframe of the electricity market until the day-ahead market gate closure time, where, for each market time unit, products are traded the day prior to delivery.
NC CACM
DC-connected Power Park Module
A power park module that is connected via one or more HVDC interface points to one or more HVDC systems.
NC HVDC
DC-connected Power Park Module Owner
A natural or legal entity owning a DC-connected Power Park Module.
NC HVDC
Deactivation Period
The time period for ramping, from full delivery or withdrawal back to a set point.
NC EB
Declared Export
The dispatch of electricity in one Member State on the basis of an underlying contractual arrangement to the effect that the simultaneous corresponding take-up (declared import) of electricity will take place in another Member State or a third country.
Regulation 714/2009
Declared Import
The take-up of electricity in a Member State or a third country simultaneously with the dispatch of electricity (declared export) in another Member State.
Regulation 714/2009
Declared Transit
A circumstance where a declared export of electricity occurs and where the nominated path for the transaction involves a country in which neither the dispatch nor the simultaneous corresponding take-up of the electricity will take place.
Regulation 714/2009
Default Value
A value derived from a typical value by the application of pre-determined factors and that may, in circumstances specified in this Directive, be used in place of an actual value.
Directive 2009/28/EC
Defence Service Provider
A legal entity with a legal or contractual obligation to provide a service contributing to one or several measures of the System Defence Plan.
NC ER
Delivery Period
A time period of delivery during which the Balancing Service Provider delivers the full requested change of power in-feed or withdrawals to the system.
NC EB
Demand
The netted value of Active Power seen from a given point of the system, computed as (load - generation), generally expressed in kilowatts (kW) or megawatts (MW), at a given instant or averaged over any designated interval of time.
NC ER
Demand Facility
A facility which consumes electrical energy and is connected at one or more Connection Points to the Network. For the avoidance of doubt a Distribution Network and/or auxiliary supplies of a Power Generating Module are not to be considered a Demand Facility.
NC DCC
Demand Facility Operator
The natural or legal person who is the operator of a Demand Facility.
NC OPS
Demand Facility Owner
The owner of the Demand Facility.
NC DCC
Demand Side Management
All the activities addressed to encourage customers to modify patterns of electricity usage, including the timing and level of electricity demand. DSM covers the complete range of load shape objectives, including strategic conservation and load management (see also Methodology section in Chapter III), as well as strategic load growth. It does not include (different from Directive 2003 / 54 / EC) energy and load-shaped changes arising from the normal operation of the marketplace or from government-mandated energy-efficiency standards. In system studies, the distinction is made between controllable DSM and uncontrollable DSM. Controllable DSM includes curtailment of interruptible loads and / or for emergency procedures such as voltage reductions and the anticipated effects of public appeals.
Energy Information AdministrationDSM
Demand Side Response
Demand offered for the purposes of, but not restricted to, providing Active or Reactive Power management, Voltage and Frequency regulation and System Reserve.
NC DCCDSR
Demand Side Response Unit Document
A document issued either by the Demand Facility Owner or Distribution Network Operator to the Relevant Network Operator or Relevant TSO pursuant to Article 9(3) for demand connections with DSR above 1000V. The DSRUD is intended to contain information confirming that the Demand Unit with DSR has demonstrated compliance with the relevant requirements of the Commission Regulations establishing Network Codes that have been adopted according to Article 6(11) of Regulation (EC) No 714/2009ÿ and provided the necessary data and statements including a Statement of Compliance.
NC DCCDSRUD
Demand Unit
An indivisible set of installations which can be actively controlled by a Demand Facility Owner or Distribution Network Operator to moderate its electrical energy demand. A storage device within a Demand Facility or Closed Distribution Network operating in electricity consumption mode is considered to be a Demand Unit. A hydro pump-storage unit with both generating and pumping operation mode is excluded. If there is more than one unit consuming power within a Demand Facility, that cannot be operated independently from each other or can reasonably be considered in a combined way, then each of the combinations of these units shall be considered as one Demand Unit.
NC DCC
Direct Current Line
A generation or transmission link using direct current technology. It can be withinÿa Bidding Zone or between two Bidding Zones.
Direct Line
Either an electricity line linking an isolated generation site with an isolated customer or an electricity line linking an electricity producer and an electricity supply undertaking to supply directly their own premises, subsidiaries and eligible customers.
Directive 2009/72/EC
Distributed Generation
Generation plants connected to the distribution system.
Directive 2009/72/EC
Distribution
The transport of electricity on high-voltage, medium-voltage and low-voltage distribution systems with a view to its delivery to customers, but does not include supply.
Directive 2009/72/EC
Distribution Network
An electrical Network, including Closed Distribution Networks, for the distribution of electrical power from and to third party[s] connected to it, a Transmission or another Distribution Network.
NC DCC
Distribution Network Connection
The electrical plant and equipment present at the Connection point, typically a substation, of either a new or existing Distribution Network to the Transmission Network.
NC DCC
Distribution Network Operator
Either a Distribution System Operator or a Closed Distribution System Operator.
NC DCCDNO
Distribution of Electricity
Distribution of electricity has the meaning set out in point (5) of Article 2 of Directive 2009/72/EC.
Regulation 1227/2011
Distribution of Natural Gas
Distribution of natural gas has the meaning set out in point (5) of Article 2 of Directive 2009/73/EC.
Regulation 1227/2011
District Cooling
The distribution of thermal energy in the form of steam, hot water or chilled liquids, from a central source of production through a network to multiple buildings or sites, for the use of space or process heating or cooling.
Directive 2009/28/EC
District Heating
The distribution of thermal energy in the form of steam, hot water or chilled liquids, from a central source of production through a network to multiple buildings or sites, for the use of space or process heating or cooling.
Directive 2009/28/EC
Disturbance

​An unplanned event that may cause the transmission system to divert from the normal state.

ENTSO-E
Divisibility
The possibility for the TSO to use only part of the Balancing Energy bids or Balancing Capacity bids offered by the Balancing Service Provider, either in terms of power activation or time duration.
NC EB
Droop
The ratio of a steady-state change of frequency to the resulting steady-state change in active power output, expressed in percentage terms. The change in frequency is expressed as a ratio to nominal frequency and the change in active power expressed as a ratio to maximum capacity or actual active power at the moment the relevant threshold is reached.
NC RfG
Economic Precedence
The ranking of sources of electricity supply in accordance with economic criteria.
Directive 2009/72/EC
Economic Surplus For The Single Day-Ahead Or Intraday Coupling
The sum of (i)ÿÿ the supplier surplus for the single day-ahead or intraday coupling for the relevant time period, (ii) the consumer surplus for the single day-ahead or intraday coupling, (iii) the congestion income and (iv) other related costs and benefits where these increase economic efficiency for the relevant time period, supplier and consumer surplus being the difference between the accepted orders and the clearing price per energy unit multiplied by the volume of energy of the orders.
NC CACM
Electrical Time Deviation

​The time discrepancy between synchronous time and coordinated universal time ('UTC').

ENTSO-E
Electricity Balance
Computes the consumption (see also Methodology section in Chapter II) of electricity from the supply side (not metered in final consumer). In the UCTE, it is presented as the sum of Net Production (split by Classification of Power Units) minus the Consumption of Pumps plus Exchange Balance. Due to fact that consumption is computed from the supply side, the electricity balance includes the distribution and Transmission Losses.
Eurelectric
Electricity Derivative
A financial instrument specifiedin points 5, 6 or 7 of Section C of Annex I to Directive2004/39/EC of the European Parliament and of the Councilof 21 April 2004 on markets in financial instruments(1)OJ L 145, 30.4.2004, p. 1. (where that instrument relates to electricity.
Directive 2009/72/EC
Electricity Supply Contract
A contract for the supply of electricity, but does not include an electricity derivative.
Directive 2009/72/EC
Electricity Undertaking
Any natural or legal person carrying out at least one of the following functions: generation, transmission, distribution, supply, or purchase of electricity, which is responsible for the commercial, technical or maintenance tasks related to those functions, but does not include final customers.
Directive 2009/72/EC
Eligible Customer
A customer who is free to purchaseelectricity from the supplier of his choice within the meaning of Article 33.
Directive 2009/72/EC
Embedded HVDC System
An HVDC system connected within a control area that is not installed for the purpose of connecting a DC-connected power park module at the time of installation, nor installed for the purpose of connecting a demand facility.
NC HVDC
Emergency State

​The system state in which one or more operational security limits are violated.

ENTSO-E
Energisation Operational Notification
A notification issued by the relevant system operator to a power generating facility owner, demand facility owner, distribution system operator or HVDC system owner prior to energisation of its internal network.
NC RfGEON
Energy
All forms of commercially available energy, including electricity, natural gas (including liquefied natural gas), liquefied petroleum gas, any fuel for heating and cooling (including district heating and cooling), coal and lignite, peat, transport fuels (excluding aviation and maritime bunker fuels) and biomass as defined in Directive 2001/77/EC of the European Parliament and of the Council of 27 September 2001 on the promotion of electricity produced from renewable energy sources in the internal electricity market (4 - OJ L 283, 27.10.2001, p. 33. Directive as amended by the 2003 Act of Accession.).
Directive 2006/32/EC
Energy Audit
A systematic procedure to obtain adequate knowledge of the existing energy consumption profile of a building or group of buildings, of an industrial operation and/or installation or of a private or public service, identify and quantify cost-effective energy savings opportunities, and report the findings.
Directive 2006/32/EC
Energy Distributor
A natural or legal person responsible for transporting energy with a view to its delivery to final customers and to distribution stations that sell energy to final customers. This definition excludes electricity and natural gas distribution system operators, covered in point (p).
Directive 2006/32/EC
Energy Efficiency
A ratio between an output of performance, service, goods or energy, and an input of energy.
Directive 2006/32/EC
Energy Efficiency Improvement
An increase in energy end-use efficiency as a result of technological, behavioural and/or economic changes.
Directive 2006/32/EC
Energy Efficiency Improvement Measures
All actions that normally lead to verifiable and measurable or estimable energy efficiency improvement.
Directive 2006/32/EC
Energy Efficiency Improvement Programmes
Activities that focus on groups of final customers and that normally lead to verifiable and measurable or estimable energy efficiency improvement.
Directive 2006/32/EC
Energy Efficiency Mechanisms
General instruments used by governments or government bodies to create a supportive framework or incentives for market actors to provide and purchase energy services and other energy efficiency improvement measures.
Directive 2006/32/EC
Energy Efficiency, Demand-side Management
A global or integrated approach aimed at influencing the amount and timing of electricity consumption in order to reduce primary energy consumption and peak loads by giving precedence to investments in energy efficiency measures, or other measures, such as interruptible supply contracts, over investments to increase generation capacity, if the former are the most effective and economical option, taking into account the positive environmental impact of reduced energy consumption and the security of supply and distribution cost aspects related to it.
Directive 2009/72/EC
Energy from Renewable Sources
Energy from renewable non-fossil sources, namely wind, solar, aerothermal, geothermal, hydrothermal and ocean energy, hydropower, biomass, landfill gas, sewage treatment plant gas and biogases.
Directive 2009/28/EC
Energy Not Supplied
An estimation of the energy not supplied to final customers due to incidents in the transmission network.
ENTSO-E Data HandbookENS
Energy Performance Contracting
Energy performance contracting: a contractual arrangement between the beneficiary and the provider (normally an ESCO) of an energy efficiency improvement measure, where investments in that measure are paid for in relation to a contractually agreed level of energy efficiency improvement.
Directive 2006/32/EC
Energy Savings
An amount of saved energy determined by measuring and/or estimating consumption before and after implementation of one or more energy efficiency improvement measures, whilst ensuring normalisation for external conditions that affect energy consumption.
Directive 2006/32/EC
Energy Service
The physical benefit, utility or good derived from a combination of energy with energy efficient technology and/or with action, which may include the operations, maintenance and control necessary to deliver the service, which is delivered on the basis of a contract and in normal circumstances has proven to lead to verifiable and measurable or estimable energy efficiency improvement and/or primary energy savings.
Directive 2006/32/EC
Energy Service Company
A natural or legal person that delivers energy services and/or other energy efficiency improvement measures in a user's facility or premises, and accepts some degree of financial risk in so doing. The payment for the services delivered is based (either wholly or in part) on the achievement of energy efficiency improvements and on the meeting of the other agreed performance criteria.
Directive 2006/32/ECESCO
Energy Storage
A device being used for storage of electrical energy and that can be used to balance the system.
NC ER
Entity
A regulatory authority, other national authority, system operator or other public or private body appointed under national law.
NC RfG
ENTSO-E Operational Planning Data Environment
The set of application programs and equipment developed in order to allow the storage, the exchange and the management of the data used within operational planning processes between TSOs.
NC OPS
Equipment Certificate
A document issued by an authorised certifier for equipment used by a power generating module, demand unit, distribution system, demand facility or HVDC system. The equipment certificate defines the scope of its validity at a national or other level at which a specific value is selected from the range allowed at a European level. For the purpose of replacing specific parts of the compliance process, the equipment certificate may include models that have been verified against actual test results.
NC RfG
Equivalent Time of Interruption
The duration of an interruption in minutes multiplied by the energy not supplied divided by the consumption for the last 12 months. This value allows a direct comparison of interruptions that occurred during a year.
ENTSO-E Data Handbook
Exceptional Contingency

​The simultaneous occurrence of multiple contingencies with a common cause.

ENTSO-E
Exchange Balance
The difference between the import and export physical flows on each interconnection line of a country.
ENTSO-E Data Handbook
Exchange of Balancing Capacity
The process of procuring Balancing Capacity by a TSO in a different Responsibility Area or Scheduling Area when appropriate than the one in which the procured Balancing Service Provider is connected.
NC EB
Exchange of Balancing Energy
The process of instructing the activation of Balancing Energy bids for the delivery of Balancing Energy by a TSO in a different Responsibility Area or Scheduling Area when appropriate, than the one in which the activated Balancing Service Provider is connected.
NC EB
Exchange of Balancing Services
Either or both Exchange of Balancing Capacity and Exchange of Balancing Energy.
NC EB
Exchange Of Reserves

​The possibility of a TSO to access reserve capacity connected to another LFC area, LFC block, or synchronous area to fulfil  its reserve requirements  resulting from its own reserve dimensioning process of either FCR, FRR or RR and where that reserve capacity is exclusively for that TSO, and is not taken into account by any other TSO to fulfil its reserve requirements resulting from their respective reserve dimensioning processes.

ENTSO-E
Excitation Control System
A feedback control system that includes the synchronous machine and its excitation system.
NC RfG
Explicit Allocation
The allocation of cross zonal capacity only, without the energy transfer.
Regulation 543/2013
External TSO Schedule
A schedule representing the exchange of electricity between TSOs in different scheduling areas.
ENTSO-E
Fast Fault Current
A current injected by a power park module or HVDC system during and after a voltage deviation caused by an electrical fault with the aim of identifying a fault by network protection systems at the initial stage of the fault, supporting system voltage retention at a later stage of the fault and system voltage restoration after fault clearance.
NC RfG
Fault

​All types of short-circuits (single-, double- and triple-phase, with and without earth contact), a broken conductor, interrupted circuit, or an intermittent connection, resulting in the permanent non-availability of the affected transmission system element.

ENTSO-E
Fault-Ride-Through
The capability of electrical devices to be able to remain connected to the network and operate through periods of low voltage at the connection point caused by secured faults.
NC RfG
Final Customer
A natural or legal person that purchases energy for his own end use.
Directive 2006/32/EC
Final Operational Notification
A notification issued by the relevant system operator to a power generating facility owner, demand facility owner, distribution system operator or HVDC system owner who complies with the relevant specifications and requirements, allowing them to operate respectively a power generating module, demand facility, distribution system or HVDC system by using the grid connection.
NC RfGFON
Financial Instruments for Energy Savings
All financial instruments such as funds, subsidies, tax rebates, loans, third-party financing, energy performance contracting, guarantee of energy savings contracts, energy outsourcing and other related contracts that are made available to the market place by public or private bodies in order to cover partly or totally the initial project cost for implementing energy efficiency improvement measures.
Directive 2006/32/EC
Financial Transmission Right
A type of Long Term Transmission Right and is either a Financial Transmission Right Obligation or a Financial Transmission Right Option.
Financial Transmission Rights Obligation
A right entitling its holder to receive or obliging its holder to pay a financial remuneration based on the Day Ahead Market results between two Bidding Zones during a specified period of time in a specific direction.
Financial Transmission Rights Option
A right entitling its holder to receive a financial remuneration based on the Day Ahead Market results between two Bidding Zones during a specified period of time in a specific direction.
Firmness
A guarantee that cross-zonal capacity rights will remain unchanged and that a compensation is paid if they are nevertheless changed.
NC CACM
Flow Based Parameters
Flow Based Parameters mean the available margins on Critical Network Elements with associated Power Transfer Distribution Factors.
Regulation 543/2013
Flow-Based Approach
A capacity calculation method in which energy exchanges between bidding zones are limited with power transfer distribution factors and available margins on critical network elements.
NC CACM
Force Majeure
Any unforeseeable or unusual event or situation beyond the reasonable control of a TSO, and not due to a fault of the TSO, which cannot be avoided or overcome with reasonable foresight and diligence, which cannot be solved by measures which are from a technical, financial or economic point of view reasonably possible for the TSO, which has actually happened and is objectively verifiable, and which makes it impossible for the TSO to fulfil, temporarily or permanently, its obligations in accordance with this Regulation.
NC CACM
Forced Outage
The unplanned removal from service of a relevant asset for any urgent reason that is not under the operational control of the operator of the concerned relevant asset.
ENTSO-E
Forward
The timeframe in which transmission rights are allocated ahead of the Day Ahead timeframe.
Forward Capacity Allocation
The attribution of long-term cross-zonal capacity through an auction before the day-ahead timeframe.
NC FCA
Frequency
The electric frequency of the system expressed in hertz that can be measured in all parts of the synchronous area under the assumption of a consistent value for the system in the time frame of seconds, with only minor differences between different measurement locations. Its nominal value is 50Hz.
NC RfG
Frequency Containment Process

​A process that aims at stabilising the system frequency by compensating imbalances by means of appropriate reserves.

ENTSO-EFCP
Frequency Containment Reserves

​The active power reserves available to contain system frequency after the occurrence of an imbalance.

ENTSO-EFCR
Frequency Control
The capability of a power generating module or HVDC system to adjust its active power output in response to a measured deviation of system frequency from a setpoint, in order to maintain stable system frequency.
NC RfG
Frequency Deviation

​The difference between the actual and the nominal frequency of the synchronous area which can be negative or positive.

ENTSO-E
Frequency Leader
The TSO managing Frequency within a Synchronised Region in order to restore System Frequency back to Nominal Frequency.
NC ER
Frequency Quality Evaluation Criteria

​A set of calculations using system frequency measurements that allows the evaluation of the quality of the system frequency against the frequency quality target parameters.

ENTSO-E
Frequency Quality Target Parameter

​The main system frequency target on which the behaviour of FCR, FRR and RR activation processes is evaluated in normal state.

ENTSO-E
Frequency Recovery Range

​The system frequency range to which the system frequency is expected to return in the GB and IE/NI synchronous areas, after the occurrence of an imbalance equal to or smaller than the reference incident, within the time to recover frequency.

ENTSO-E
Frequency Response Deadband
An interval used intentionally to make the frequency control unresponsive.
NC RfG
Frequency Response Insensitivity
The inherent feature of the control system specified as the minimum magnitude of change in the frequency or input signal that results in a change of output power or output signal.
NC RfG
Frequency Restoration Control Error

​The control error for the FRP which is equal to the ACE of a LFC area or equal to the frequency deviation where the LFC area geographically corresponds to the synchronous area.

ENTSO-EFRCE
Frequency Restoration Process

​A process that aims at restoring frequency to the nominal frequency and, for synchronous areas consisting of more than one LFC area, a process that aims at restoring the power balance to the scheduled value.

ENTSO-EFRP
Frequency Restoration Reserves

​The active power reserves available to restore system frequency to the nominal frequency and, for a synchronous area consisting of more than one LFC area, to restore power balance to the scheduled value.

ENTSO-EFRR
Frequency Sensitive Mode
The operating mode of a power generating module or HVDC system in which the active power output changes in response to a change in system frequency, in such a way that it assists with the recovery to target frequency.
NC RfGFSM
Frequency Setpoint

​The frequency target value used in the FRP, defined as the sum of the nominal system frequency and an offset value needed to reduce an electrical time deviation.

ENTSO-E
Frequency Stability

​The ability of the transmission system to maintain frequency stable in the N-situation and after being subjected to a disturbance.

ENTSO-E
Full Activation Time
The time period between the activation request by TSO and the corresponding full activation of the concerned product.
NC EB
Functional Group
A collection of Metering Points for consumption and generation within a Market Balance Area.
Harmonized Role Model
Generating Auxiliaries
The electrical energy absorbed by generating auxiliaries is the sum of the auxiliary power consumption for all generator sets under consideration during both the on-load and off-loads periods of the generator sets. Thus, it includes the consumption needed to support the operation of the power plant.
ENTSO-E Data Handbook
Generation
The production of electricity.
Directive 2009/72/EC
Generation Adequacy
An assessment of the ability of the generation on the power system to match the consumption on the same power system.
ENTSO-E Operational Handbook
Generation Schedule
A schedule representing the electricity generation of a power generating module or of a group of power generating modules.
System Operation Guideline
Generation Shift Key
A method of translating a net position change of a given bidding zone into estimated specific injection increases or decreases in the common grid model.
NC CACM
Generation Unit
A single electricity generator belonging to a production unit.
Regulation 543/2013
Geothermal Energy
Energy stored in the form of heat beneath the surface of solid earth.
Directive 2009/28/EC
Grid Access Provider
A party responsible for providing access to the grid through an Accounting Point and its use for energy consumption or production to the Party Connected to the Grid.
Harmonized Role Model
Grid Operator
A party that operates one or more grids.
Harmonized Role Model
Gross Final Consumption of Energy
The energy commodities delivered for energy purposes to industry, transport, households, services including public services, agriculture, forestry and fisheries, including the consumption of electricity and heat by the energy branch for electricity and heat production and including losses of electricity and heat in distribution and transmission.
Directive 2009/28/EC
Gross Generation
It is the sum of the electrical energy production by all the generating sets concerned, measured at the output terminals of the main generator.
ENTSO-E Data Handbook
Guarantee of Origin
An electronic document which has the sole function of providing proof to a final customer that a given share or quantity of energy was produced from renewable sources as required by Article 3(6) of Directive 2003/54/EC.
Directive 2009/28/EC
Head Installation
It defines the part of a power station, which forms an operating unit in which the generator sets can? either pass the intake flow through the turbines using the same characteristic head height (difference between water levels causing pressure),? or pump water from the lower reservoir to the upper reservoir.
Eurelectric
Horizontally Integrated Undertaking
An undertaking performing at least one of the functions of generation for sale, or transmission, or distribution, or supply of electricity, and another non-electricity activity.
Directive 2009/72/EC
Household Customer
A customer purchasing electricity for his own household consumption, excluding commercial or professional activities.
Directive 2009/72/EC
Houseload Operation
The operation which ensures that power generating facilities are able to continue to supply their in-house loads in the event of network failures resulting in power generating modules being disconnected from the network and tripped onto their auxiliary supplies.
NC RfG
HVDC Converter Station
Part of an HVDC System which consists of one or more HVDC Converter Units installed in a single location together with buildings, reactors, filters, reactive power devices, control, monitoring, protective, measuring and auxiliary equipment.
NC HVDC
HVDC Converter Unit
A unit comprising one or more converter bridges, together with one or more converter transformers, reactors, converter unit control equipment, essential protective and switching devices and auxiliaries, if any, used for the conversion.
NC HVDC
HVDC Interface Point
A point at which HVDC equipment is connected to an AC network, at which technical specifications affecting the performance of the equipment can be prescribed.
NC HVDC
HVDC System
An electrical power system which transfers energy in the form of high-voltage direct current between two or more AC buses. A HVDC System comprises at least two HVDC Converter Stations with DC transmission lines or cables between the HVDC Converter Stations. In case of a back-to-back system the HVDC System comprises only one HVDC Converter Station with direct DC circuit connection between the pair of HVDC Converter Units. A HVDC System has at least two Interface Points.
NC HVDC
HVDC System Maximum Current
An electrical power system which transfers energy in the form of high-voltage direct current between two or more alternating current (AC) buses and comprises at least two HVDC converter stations with DC transmission lines or cables between the HVDC converter stations.
NC HVDC
Hydro
Electricity derived from the potential and kinetic energy content of water. It can be classified as: Storage Hydro, Run of River, Pure Pumped Storage and Mixed Pumped Storage.
ENTSO-E Data Handbook
Hydrothermal Energy
Energy stored in the form of heat in surface water.
Directive 2009/28/EC
Imbalance
An energy volume calculated for a Balance Responsible Party and representing the difference between the Allocated Volume attributed to that Balance Responsible Party, and the final Position of that Balance Responsible Party and any Imbalance Adjustment applied to that Balance Responsible Party, within a given Imbalance Settlement Period.
NC EB
Imbalance Adjustment
An energy volume representing the Balancing Energy from a Balancing Service Provider and applied by the Connecting TSO for an Imbalance Settlement Period to the concerned Balance Responsible Parties, for the calculation of the Imbalance of these Balance Responsible Parties.
NC EB
Imbalance Area
The Imbalance Price Area or a part of an Imbalance Price Area, for the calculation of an Imbalance.
NC EB
Imbalance Netting Process
A process agreed between TSOs that allows avoiding the simultaneous activation of FRR in opposite directions, taking into account the respective FRCEs as well as the activated FRR and by correcting the input of the involved FRPs accordingly.
System Operation Guideline
Imbalance Netting Process Function
The role to operate the algorithm applied for operating the Imbalance Netting Process.
NC EB
Imbalance Price
The price, positive, 0 or negative, in each Imbalance Settlement Period for an Imbalance in each direction.
NC EB
Imbalance Price Area
ÿEither a Bidding Zone, part of a Bidding Zone or a combination of several Bidding Zones, to be defined by each TSO, for the purpose of calculation of Imbalance Prices.
NC EB
Imbalance Settlement Period
Time units for which Balance Responsible Parties` Imbalance is calculated.
NC EB
Imbalance Settlement Responsible
A party that is responsible for settlement of the difference between the contracted quantities and the realised quantities of energy products for the Balance Responsible Parties in a Market Balance Area.
Harmonized Role Model
Implicit Allocation
A congestion management method in which energy is obtained at the same time as cross zonal capacity.
Regulation 543/2013
Individual Grid Model
A data set describing power system characteristics (generation, load and grid topology) and related rules to change these characteristics during capacity calculation, prepared by the responsible TSOs, to be merged with other individual grid model components in order to create the common grid model.
NC CACM
Inertia
The property of a rotating rigid body, such as the rotor of an alternator, such that it maintains its state of uniform rotational motion and angular momentum unless an external torque is applied.
NC RfG
Influence Factor

​The numerical value used to quantify the greatest effect of the outage of a transmission system element located outside of the TSO's control area excluding interconnectors, in terms of a change in power flows or voltage caused by that outage, on any transmission system element. The higher is the value the greater the effect.

System Operation Guideline
Information
(a) information which is required to be made public in accordance with Regulations (EC) No 714/2009 and (EC) No 715/2009, including guidelines and network codes adopted pursuant to those Regulations.(b) information relating to the capacity and use of facilities for production, storage, consumption or transmission of electricity or natural gas or related to the capacity and use of LNG facilities, including planned or unplanned unavailability of these facilities.(c) information which is required to be disclosed in accordance with legal or regulatory provisions at Union or national level, market rules, and contracts or customs on the relevant wholesale energy market, in so far as this information is likely to have a significant effect on the prices of wholesale energy products. and(d) other information that a reasonable market participant would be likely to use as part of the basis of its decision to enter into a transaction relating to, or to issue an order to trade in, a wholesale energy product.Information shall be deemed to be of a precise nature if it indicates a set of circumstances which exists or may reasonably be expected to come into existence, or an event which has occurred or may reasonably be expected to do so, and if it is specific enough to enable a conclusion to be drawn as to the possible effect of that set of circumstances or event on the prices of wholesale energy products.
Regulation 1227/2011
Initial FCR Obligation

​The amount of FCR allocated to a TSO on the basis of a sharing key.

System Operation Guideline
Inside Information
Information of a precise nature which has not been made public, which relates, directly or indirectly, to one or more wholesale energy products and which, if it were made public, would be likely to significantly affect the prices of those wholesale energy products.
Regulation 1227/2011
Installation Document
A simple structured document containing information about a type A power generating module or a demand unit, with demand-side response connected below 1000V, and confirming its compliance with the relevant requirements.
NC RfG
Instantaneous Frequency Data

​A set of data measurements of the overall system frequency for the synchronous area with a measurement period equal to or shorter than one second used for system frequency quality evaluation purposes.

System Operation Guideline
Instantaneous Frequency Deviation

​A set of data measurements of the overall system frequency deviations for the synchronous area with a measurement period equal to or shorter than one second used for system frequency quality evaluation purposes.

System Operation Guideline
Instruction
Any command, within its authority, given by a system operator to a power generating facility owner, demand facility owner, distribution system operator or HVDC system owner in order to perform an action.
NC RfG
Integrated Electricity Undertaking
A vertically or horizontally integrated undertaking.
Directive 2009/72/EC
Integrated Scheduling Process
An iterative process that uses at least bids which contain commercial data and complex technical data for each Power Generating Facility or Demand Facility which explicitly includes the start-up characteristics, the latest Responsibility Area Adequacy analysis, and the Operational Security Limits, which then simultaneously optimises reserve procurement, congestion management and Balancing Energy procurement over a set time horizon in order to produce an indicative Active Power output schedule for the dispatchable resources in order to ensure Operational Security.
NC EB
Integrated Scheduling Process Gate Closure Time
The point in time when the submission or update of Integrated Scheduling Process bids is no longer permitted for the given iterations of the Integrated Scheduling Process.
NC EB
Inter TSO Compensation
The Inter TSO Compensation (ITC) market is composed of a group of System Operators that accept a common set of rules for the invoicing of energy flows over the border.
Harmonized Role ModelITC
Interconnected System
A number of transmission and distribution systems linked together by means of one or more interconnectors.
Directive 2009/72/EC
Interconnection Trade Responsible
Is a Balance Responsible Party or depends on one. He is recognised by the Nomination Validator for the nomination of already allocated capacity.
Harmonized Role Model
Interconnector
A transmission line which crosses or spans a border between Member States and which connects the national transmission systems of the Member States.
Regulation 714/2009
Interim Operational Notification
A notification issued by the relevant system operator to a power generating facility owner, demand facility owner, distribution system operator or HVDC system owner which allows them to operate respectively a power generating module, demand facility, distribution system or HVDC system by using the grid connection for a limited period of time and to initiate compliance tests to ensure compliance with the relevant specifications and requirements.
NC RfGION
Internal Commercial Trade Schedule
A schedule representing the commercial exchange of electricity within a scheduling area between different market participants
System Operation Guideline
Intraday Cross-Zonal Gate Closure Time
The point in time where cross-zonal capacity allocation is no longer permitted for a given market time unit.
NC CACM
Intraday Energy Gate Opening Time
The point in time when cross-zonal capacity between bidding zones is released for a given market time unit and a given bidding zone border.
NC CACM
Intraday Market Timeframe
The timeframe of the electricity market after intraday cross-zonal gate opening time and before intraday cross-zonal gate closure time, where for each market time unit, products are traded prior to the delivery of the traded products.
NC CACM
Island Operation
The independent operation of a whole network or part of a network that is isolated after being disconnected from the interconnected system, having at least one power generating module or HVDC system supplying power to this network and controlling the frequency and voltage.
NC RfG
Isolated System
A system which is designed to operate as a stand-alone system for a definite or indefinite time. It includes systems that bear DC or a single AC Interconnection to other synchronous areas.
ENTSO-E
LFC Block Operational Agreement

​A multi-party agreement between all TSOs of a LFC block if the LFC block is operated by more than one TSO and means a LFC block operational methodology to be adopted unilaterally by the relevant TSO if the LFC block is operated by only one TSO.

System Operation Guideline
Limited Frequency Sensitive Mode - Overfrequency
A power generating module or HVDC system operating mode which will result in active power output reduction in response to a change in system frequency above a certain value.
NC RfGLFSM-O
Limited Frequency Sensitive Mode - Underfrequency
A power generating module or HVDC system operating mode which will result in active power output increase in response to a change in system frequency below a certain value.
NC RfGLFSM-U
Limited Operational Notification
A notification issued by the relevant system operator to a power generating facility owner, demand facility owner, distribution system operator or HVDC system owner who had previously attained FON status but is temporarily subject to either a significant modification or loss of capability resulting in non-compliance with the relevant specifications and requirements.
NC RfGLON
Load
The consumption corresponding to the short-term average active power absorbed by all installations connected to the transmission grid or to the distribution grid, excluding the consumption for pumping of the pumped-storage stations, excluding the consumption of power plants auxiliaries, including network losses.
ENTSO-E
Load-Frequency Control Area

​A part of a synchronous area or an entire synchronous area, physically demarcated by points of measurement at interconnectors to other LFC areas, operated by one or more TSOs fulfilling the obligations of load-frequency control.

System Operation GuidelineLFC Area
Load-Frequency Control Block

​A part of a synchronous area or an entire synchronous area, physically demarcated by points of measurement at interconnectors to other LFC blocks, consisting of one or more LFC areas, operated by one or more TSOs fulfilling the obligations of load-frequency control.

System Operation GuidelineLFC Block
Load-Frequency Control Structure

​The basic structure considering all relevant aspects of load-frequency control in particular concerning respective responsibilities and obligations as well as types and purposes of active power reserves.

System Operation Guideline
Local Market Area
A Market Area where there is no transmission capacity restrictions between the Market Balance Areas.
Harmonized Role Model
Long Term
A time period longer than 24 hours.
Long Term Firmness Deadline
A defined point in time before the Day Ahead Firmness Deadline.
Long-Term Planning
The planning of the need for investment in generation and transmission and distribution capacity on a long-term basis, with a view to meeting the demand of the system for electricity and securing supplies to customers.
Directive 2009/72/EC
Long-Term Transmission Right
A Physical Transmission Right or a Financial Transmission Right Option or a Financial Transmission Right Obligation acquired in the Forward Capacity Allocation.
NC FCA
Loop Flows
The part of the physical flow on a border between two control areas observed even without any transaction, i.e. flows over control areas caused by origin and destination within one control area.
Main Generating Plant
One or more of the principal items of equipment required to convert the primary source of energy into electricity.
NC RfG
Manual FRR Full Activation Time

​The time period between the setpoint change and the corresponding activation or deactivation of manual FRR.

System Operation Guideline
Margin Against Peak Load
The margin against peak load is the parameter defined as the difference between the load at the reference point and the Peak Load over the period the reference point is representative of. As reference points in the System Adequacy Retrospect are monthly, the related margin against peak load must also be monthly and is thus called the margin against monthly peak load (MaMPL). It is calculated as the difference between the actual monthly peak load metering and the load at the reference point.
Market Activities Restoration Triggers
The conditions that shall be met to start restoration of market activities.
NC ER
Market Activities Suspension Triggers
The conditions which when met, individually or cumulatively, could lead to a suspension of market activities.
NC ER
Market Area
An area made up of several Market Balance Areas interconnected through AC or DC links. Trade is allowed between different Market Balance Areas with common market rules for trading across the interconnection.
Harmonized Role Model
Market Balance Area
A geographic area consisting of one or more Metering Grid Areas with common market rules for which the settlement responsible party carries out a balance settlement and which has the same price for imbalance. A Market Balance Area may also be defined due to bottlenecks.
Harmonized Role Model
Market Congestion
A situation in which the economic surplus for single day-ahead or intraday coupling has been limited by cross-zonal capacity or allocation constraints.
NC CACM
Market Coupling Operator Function
The task of matching orders from the day-ahead and intraday markets for different bidding zones and simultaneously allocating cross-zonal capacities.
NC CACM
Market Information Aggregator
A party that provides market related information that has been compiled from the figures supplied by different actors in the market. This information may also be published or distributed for general use.
Harmonized Role Model
Market Manipulation
(a) entering into any transaction or issuing any order to trade in wholesale energy products which:(i) gives, or is likely to give, false or misleading signals as to the supply of, demand for, or price of wholesale energy products.(ii) secures or attempts to secure, by a person, or persons acting in collaboration, the price of one or several wholesale energy products at an artificial level, unless the person who entered into the transaction or issued the order to trade establishes that his reasons for doing so are legitimate and that that transaction or order to trade conforms to accepted market practices on the wholesale energy market concerned. or(iii) employs or attempts to employ a fictitious device or any other form of deception or contrivance which gives, or is likely to give, false or misleading signals regarding the supply of, demand for, or price of wholesale energy products.or(b) disseminating information through the media, including the internet, or by any other means, which gives, or is likely to give, false or misleading signals as to the supply of, demand for, or price of wholesale energy products, including the dissemination of rumours and false or misleading news, where the disseminating person knew, or ought to have known, that the information was false or misleading.When information is disseminated for the purposes of journalism or artistic expression, such dissemination of information shall be assessed taking into account the rules governing the freedom of the press and freedom of expression in other media, unless:(i) those persons derive, directly or indirectly, an advantage or profits from the dissemination of the information in question. or(ii) the disclosure or dissemination is made with the intention of misleading the market as to the supply of, demand for, or price of wholesale energy products.
Regulation 1227/2011
Market Operator
The unique power exchange of trades for the actual delivery of energy that receives the bids from the Balance Responsible Parties that have a contract to bid. The Market Operator determines the market energy price for the Market Balance Area after applying technical constraints from the System Operator. It may also establish the price for the reconciliation within a Metering Grid Area.
Harmonized Role Model
Market Participant
Any person, including transmission system operators, who enters into transactions, including the placing of orders to trade, in one or more wholesale energy markets
Regulation 1227/2011
Market Spread
The difference between the hourly day-ahead prices of the two concerned bidding zones for the respective market time unit in a specific direction.
NC FCA
Market Time
Central European summer time or central European time, whichever is in effect.
NC CACM
Market Time Unit
The period for which the market price is established or the shortest possible common time period for the two bidding zones, if their market time units are different.
Regulation 543/2013
Matched Orders
All matched, buy and sell, orders by the price coupling algorithm or the continuous trade matching algorithm.
NC CACM
Matching
The trading mode through which sell orders are assigned to appropriate buy orders to ensure the maximisation of economic surplus for single day-ahead or intraday coupling.
NC CACM
Maximum Capacity
The maximum continuous active power which a power generating module can produce, less any demand associated solely with facilitating the operation of that power generating module and not fed into the network as specified in the connection agreement or as agreed between the relevant system operator and the power generating facility owner.
NC RfG
Maximum HVDC Active Power Transmission Capacity
The maximum continuous active power which an HVDC system can exchange with the network at each connection point as specified in the connection agreement or as agreed between the relevant system operator and the HVDC system owner.
NC HVDCPmax
Maximum Instantaneous Frequency Deviation

​The maximum expected absolute value of an instantaneous frequency deviation after the occurrence of an imbalance equal to or smaller than the reference incident, beyond which emergency measures are activated.

System Operation Guideline
Maximum Steady-State Frequency Deviation

​The maximum expected frequency deviation after the occurrence of an imbalance equal to or less than the reference incident at which the system frequency is designed to be stabilised.

System Operation Guideline
Merit Order List Responsible
Responsible for the management of the available tenders for all Acquiring System Operators to establish the order of the reserve capacity that can be activated.
Harmonized Role ModelMOL Responsible
Meter
A physical device containing one or more registers.
Harmonized Role Model
Meter Administrator
A party responsible for keeping a database of meters.
Harmonized Role Model
Meter Operator
A party responsible for installing, maintaining, testing, certifying and decommissioning physical meters.
Harmonized Role Model
Metered Data Aggregator
A party responsible for the establishment and qualification of metered data from the Metered Data Responsible. This data is aggregated according to a defined set of market rules.
Harmonized Role Model
Metered Data Collector
A party responsible for meter reading and quality control of the reading.
Harmonized Role Model
Metered Data Responsible
A party responsible for the establishment and validation of metered data based on the collected data received from the Metered Data Collector. The party is responsible for the history of metered data for a Metering Point.
Harmonized Role Model
Metering Grid Area
A Metering Grid Area is a physical area where consumption, production and exchange can be metered. It is delimited by the placement of meters for period measurement for input to, and withdrawal from the area. It can be used to establish the sum of consumption and production with no period measurement and network losses.
Harmonized Role Model
Metering Point
An entity where energy products are measured or computed.
Harmonized Role Model
Metering Point Administrator
A party responsible for registering the parties linked to the metering points in a Metering Grid Area. He is also responsible for maintaining the Metering Point technical specifications. He is responsible for creating and terminating metering points.
Harmonized Role Model
Micro Isolated System
Any system with consumption less than 500 GWh in the year 1996, where there is no connection with other systems.
Directive 2009/72/EC
Minimum HVDC Active Power Transmission Capacity
The minimum continuous active power which an HVDC system can exchange with the network at each connection point as specified in the connection agreement or as agreed between the relevant system operator and the HVDC system owner.
NC HVDCPmin
Minimum Regulating Level
The minimum active power, as specified in the connection agreement or as agreed between the relevant system operator and the power generating facility owner, down to which the power generating module can control active power.
NC RfG
Minimum Stable Operating Level
The minimum active power, as specified in the connection agreement or as agreed between the relevant system operator and the power generating facility owner, at which the power generating module can be operated stably for an unlimited time.
NC RfG
Mixed Pumped Storage
Pumped Storage with a significant cumulative flow into the upper reservoir.
ENTSO-E Data Handbook
Mode of Activation
The implementation of activation of Balancing Energy bids, manual or automatic, depending on whether Balancing Energy is triggered manually by an operator or automatically by means of a closed-loop regulator.
NC EB
Monitoring Area

​A part of the synchronous area or the entire synchronous area, physically demarcated by points of measurement at interconnectors to other monitoring areas, operated by one or more TSOs fulfilling the obligations of a monitoring area.

System Operation Guideline
N-Situation

​The situation where no transmission system element is unavailable due to occurrence of a contingency.

System Operation Guideline
National Area
An area covered by a single set of national electricity arrangements established at government level. This is not necessarily the same as the geographical boundaries of a nation.
Harmonized Role Model
Net Generating Capacity
Net generating capacity is the maximum electrical net active power a power plant can feed-in continuously without exceeding the designed thermal limits.
ENTSO-E
Net Position
The netted sum of electricity exports and imports for each market time unit for a bidding zone.
NC CACM
Net Production
See Net Generation.
ENTSO-E Data Handbook
Netted Area AC-Position
System Operation Guideline
Network
A plant and apparatus connected together in order to transmit or distribute electricity.
NC RfG
Network Code
A set of rules drafted by ENTSO-E, with guidance from the Agency for the Cooperation of Energy Regulators (ACER), to facilitate the harmonisation, integration and efficiency of the European electricity market.
ENTSO-E
Network Reliability
Reliability is a general term encompassing all the measures of the ability of the system, generally given as numerical indices, to deliver electricity to all points of utilisation within acceptable standards and in the amounts desired. Network reliability (comprising generation and transmission facilities) can be described by two basic and functional attributes: Adequacy and Security.
ENTSO-E Data Handbook
New Interconnector
An interconnector not completed by 4 August 2003.
Regulation 714/2009
Nominated Electricity Market Operator
An entity designated by the competent authority to perform tasks related to single day-ahead or single intraday coupling.
NC CACMNEMO
Nomination
The notification of the use of long-term cross-zonal capacity by a physical transmission rights holder and its counterparty, or an authorised third party, to the respective TSOs.
NC FCA
Nomination Rules
The rules with regard to the notification of use of long-term cross-zonal capacity by a physical transmission rights holder and their counterparty,or an authorised third party, to the respective TSOs.
NC FCA
Nomination Validator
Has the responsibility of ensuring that all capacity nominated is within the allowed limits and confirming all valid nominations to all involved parties. He informs the Interconnection Trade Responsible of the maximum nominated capacity allowed. Depending on market rules for a given interconnection the corresponding System Operators may appoint one Nomination Validator.
Harmonized Role Model
Non-Household Customer
A natural or legal personspurchasing electricity which is not for their own householduse and includes producers and wholesale customers.
Directive 2009/72/EC
Non-Standard Intraday Product
A product for continuous intraday coupling not for constant energy delivery or for a period exceeding one market time unit with specific characteristics designed to reflect system operation practices or market needs, for example orders covering multiple market time units or products reflecting production unit startup costs.
NC CACM
Normal State
A situation in which the system is within operational security limits in the N-situation and after the occurrence of any contingency from the contingency list, taking into account the effect of the available remedial actions.
System Operation Guideline
Not Clearly Identifiable Sources
Not Clearly Identifiable Sources comprise Power Plants or Power Units, which, according to the primary energy used, cannot be categorised.
ENTSO-E Data Handbook
Nuclear
Electricity generated by the use of thermal energy released from the fission of nuclear fuel in a reactor.
Energy Information Administration
Observability Area

​A TSOs own transmission system and the relevant parts of distribution systems and neighbouring TSOs transmission systems, on which the TSO implements real-time monitoring and modelling to maintain operational security in its control area including interconnectors.

System Operation Guideline
Offered Capacity
The cross zonal capacity offered by the transmission capacity allocator to the market.
Regulation 543/2013
Offshore Grid Connection System
The complete interconnection between an offshore connection point and the onshore system at the onshore grid interconnection point.
NC RfG
Offshore Power Park Module
A Power Park Module located offshore with an Offshore Connection Point.
NC RfG
Onshore Grid Interconnection Point
The point at which the offshore grid connection system is connected to the onshore network of the relevant system operator.
NC RfG
Operational Security

​The transmission system's capability to retain a normal state or to return to a normal state as soon as possible, and which is characterised by operational security limits.

System Operation Guideline
Operational Security Analysis

​The entire scope of the computer based, manual and automatic activities performed in order to assess the operational security of the transmission system and to evaluate the remedial actions needed to maintain operational security.

System Operation Guideline
Operational Security Ranking

​The ranking used by TSOs to monitor the operational security on the basis of the operational security indicators.

System Operation Guideline
Order
An intention to purchase or sell energy or capacity expressed by a market participant subject to specified execution conditions.
NC CACM
Ordinary Contingency

​The occurrence of a contingency of a single branch or injection.

System Operation Guideline
Other Renewable Energy Sources
In the UCTE statistics, this category comprises all Renewable Energy Sources except total Hydro production.
ENTSO-E Data Handbook
Out-Of-Range Contingency

​The simultaneous occurrence of multiple contingencies without a common cause, or a loss of power generating modules with a total loss of generation capacity exceeding the reference incident.

System Operation Guideline
Outage Coordination Process
The process of coordinating the Availability Plans of all Relevant Assets.
NC OPS
Outage Coordination Region
A combination of control areas for which TSOs define procedures to monitor and where necessary coordinate the availability status of relevant assets in all timeframes.
System Operation Guideline
Outage Incompatibility
The state in which a combination of the Availability Status of one or more Relevant Grid Elements, Relevant Power Generating Modules and/or Relevant Demand Facilities and the best estimate of the forecasted electricity grid situation leads to violation of Operational Security Limits taking into account non costly Remedial Actions at the TSOs disposal.
NC OPS
Outage Planning Agent
An entity with the task of planning the availability status of a relevant power generating module, a relevant demand facility or a relevant grid element.
System Operation Guideline
Overexcitation Limiter
A control device within the AVR which prevents the rotor of an alternator from overloading by limiting the excitation current.
NC RfG
P-Q-Capability Diagram
A diagram describing the reactive power capability of a power generating module in the context of varying active power at the connection point.
NC RfG
Parent Undertaking
A parent undertaking within the meaning of Articles 1 and 2 of the Seventh Council Directive 83/349/EEC of 13 June 1983 based on Article 54(3)(g) of the Treaty on consolidated accounts ( 3 - OJ L 193, 18.7.1983, p. 1. ).
Regulation 1227/2011
Party Connected To Grid
A party that contracts for the right to consume or produce electricity at an Accounting Point.
Harmonized Role Model
Person
Any natural or legal person.
Regulation 1227/2011
Physical Congestion
Any network situation where forecasted or realised power flows violate the thermal limits of the elements of the grid and voltage stability or the angle stability limits of the power system.
NC CACM
Physical Energy Flow
It represents the real movements of energy between neighbouring countries metered in cross-border Tie Lines in both directions, in the system and out of the system.
ENTSO-E Data Handbook
Physical Transmission Right
A right entitling its holder to physically transfer a certain volume of electricity in a certain period of time between two Bidding Zones in a specific direction.
Planned
An event known ex-ante by the primary owner of the data.
Regulation 543/2013
Position
An energy volume representing scheduled injections, scheduled withdrawals or the sum of scheduled injections and withdrawals of a Balance Responsible Party, for the calculation of the Imbalance of that Balance Responsible Party.
NC EB
Power Factor
The ratio of the absolute value of active power to apparent power.
NC RfG
Power Generating Facility
A facility that converts primary energy into electrical energy and which consists of one or more power generating modules connected to a network at one or more connection points.
NC RfG
Power Generating Facility Operator
The natural or legal person who is the operator of a Power Generating Facility.
NC OPS
Power Generating Facility Owner
A natural or legal entity owning a Power Generating Facility.
NC RfG
Power Generating Module
Either a Synchronous Power Generating Module or a Power Park Module.
NC RfG
Power Generating Module Document
A document provided by the power generating facility owner to the relevant system operator for a type B or C power generating module which confirms that the power generating module s compliance with the technical criteria set out in this Regulation has been demonstrated and provides the necessary data and statements, including a statement of compliance.
NC RfGPGMD
Power Park Module
A unit or ensemble of units generating electricity, which is either non-synchronously connected to the network or connected through power electronics, and that also has a single connection point to a transmission system, distribution system including closed distribution system or HVDC system.
NC RfG
Power Plant
Power Plant consists of one or more Power Units, which usually have a common infrastructure and which are either able to operate independently or their operation is mutually influenced or limited by specific operating regimes and technology. Remark: Exact definition and delimitation of power units and power plants is up to each power producer, who provides data to a responsible TSO. For the UCTE, TSO is a source of such data.
ENTSO-E Data Handbook
Power Produced in Parallel Operation
It is the sum of the net electrical power produced in power stations participating in synchronous operation. It takes into account the spinning reserve, but excludes units injecting into systems, which are coupled to the interconnected network only by an AC / DC-link, and those, which cannot be operated with 50 Hz. Remark: Since January 2007, these data are no longer collected and published.
ENTSO-E Data Handbook
Power System Stabilizer
An additional functionality of the AVR of a synchronous power generating module whose purpose is to damp power oscillations.
NC RfGPSS
Power Transfer Distribution Factor
A representation of the physical flow on a critical network element induced by the variation of the net position of a bidding zone.
Regulation 543/2013
Power Unit
Equipment (a machine set) generating electricity, which generally consists of a few technological parts. For purposes of the UCTE, a power unit means: õÿ One AC generator in case of a thermal or a nuclear unit, õÿ One Head Installation in case of a hydro unit, õÿ One wind farm in case of a wind unit. See also: Power Plant.
ENTSO-E Data Handbook
Preparation Period
The time duration between the request by the TSO and start of the energy delivery.
NC EB
Prequalification
The process to verify the compliance of a reserve providing unit or a reserve providing group with the requirements set by the TSO.
System Operation Guideline
Price Coupling Algorithm
The algorithm used in single day-ahead coupling for simultaneously matching orders and allocating cross-zonal capacities.
NC CACM
Primary Energy
All energy consumed by end users, excluding electricity but including the energy consumed at electric utilities to generate electricity.
Energy Information Administration
Primary Owner of the Data
The entity which creates the data.
Regulation 543/2013
Probabilistic Approach
Calculated probabilities for the availability of Cross Zonal Capacities.
Process Activation Structure

​The structure to categorise the processes concerning the different types of active power reserves in terms of purpose and activation.

System Operation Guideline
Process Responsibility Structure

​The structure to determine responsibilities and obligations with respect to active power reserves based on the control structure of the synchronous area.

System Operation Guideline
Producer
A natural or legal person generating electricity.
Harmonized Role Model
Production Responsible Party
A party who can be brought to rights, legally and financially, for any imbalance between energy nominated and produced for all associated Accounting Points.
Harmonized Role Model
Production Unit
A facility for generation of electricity made up of a single generation unit or of an aggregation of generation units.
Regulation 543/2013
Profile
A geographical boundary between one bidding zone and several neighbouring bidding zones.
Regulation 543/2013
Protection Device
Equipment applied to electric power systems to detect abnormal and intolerable conditions and to initiate corrective actions to ensure continuity of electric service, to limit injury to people and to limit damage to equipment. These devices include lightning arresters, surge protectors, fuses and relays with associated circuit breakers, reclosers and so forth.
Sci-Tech Dictionary
Pump-Storage
A hydro unit in which water can be raised by means of pumps and stored to be used for the generation of electrical energy.
NC RfG
Pumped Storage
A hydro unit in which water can be raised by means of pumps and stored, to be used later for the generation of electrical energy. It can be classified as: Pure Pumped Storage and Mixed Pumped Storage.
ENTSO-E Data Handbook
Pure Pumped Storage
Pumped Storage without a significant natural cumulative flow into the upper reservoir.
ENTSO-E Data Handbook
Ramping Rate

​The rate of change of active power by a power generating module, demand facility or HVDC system.

System Operation Guideline
Re-energisation
The process of energising parts of the system that have been disconnected by reconnecting generation and Demand.
NC ER
Reactive Power
The imaginary component of the apparent power at fundamental frequency, usually expressed in kilovar ('kVAr') or megavar ('MVAr').
NC RfG
Reconciliation Accountable
A party that is financially accountable for the reconciled volume of energy products for a profiled Accounting Point.
Harmonized Role Model
Reconciliation Responsible
A party that is responsible for reconciling, within a Metering Grid Area, the volumes used in the imbalance settlement process for profiled Accounting Points and the actual metered quantities.
Harmonized Role Model
Redispatching
A measure activated by one or several system operators by altering the generation and/or load pattern in order to change physical flows in the transmission system and relieve a physical congestion.
Regulation 543/2013
Reference Incident

​The maximum positive or negative power deviation occurring instantaneously between generation and demand in a synchronous area, considered in the FCR dimensioning.

System Operation Guideline
Reference Load
The total load of a LFC Area including all consumption connected to both transmission and distribution systems and the losses on both transmission and distribution systems. It is usually calculated as the sum of all generation on the transmission and distribution systems (measured or estimated), excluding houseload of Power Generating Modules and importation balance of the LFC Area.
NC ER
Reference Points
The dates and times for which power data are collected. Reference points are characteristic enough of the entire period studied to limit the data to be collected to the data at the reference points.
ENTSO-E Data Handbook
Regional Allocation Rules
The rules for Forward Capacity Allocation applied by Regional Platform(s).
Regional Group Continental Europe Interconnected Group
The composition of a number of coordination center zones, operating under RGCE rules, where the exchange and compensation programmes within the zone must sum up to zero.
Harmonized Role Model
Regional Platform
A platform or regionally coordinated platforms for the attribution of Long Term Cross Zonal Capacity for a single border or set of borders.
Register
A physical or logical counter measuring energy products.
Harmonized Role Model
Regulatory Authorities
The regulatory authorities referred to in Article 35(1) of Directive 2009/72/EC.
Regulation 714/2009
Related Undertaking
Either a subsidiary or other undertaking in which a participation is held, or an undertaking linked with another undertaking by a relationship within the meaning of Article 12(1) of Directive 83/349/EEC.
Regulation 1227/2011
Relevant Asset
Any relevant demand facility, relevant power generating module, or relevant grid element partaking in the outage coordination.
System Operation Guideline
Relevant Demand Facility
A demand facility which participates in the outage coordination and the availability status of which influences cross-border operational security.
System Operation Guideline
Relevant Grid Element
Any component of a transmission system, including interconnectors, or of a distribution system, including a closed distribution system, such as a single line, a single circuit, a single transformer, a single phase-shifting transformer, or a voltage compensation installation, which participates in the outage coordination and the availability status of which influences cross-border operational security.
System Operation Guideline
Relevant Power Generating Module
A power generating module which participates in the outage coordination and the availability status of which influences cross-border operational security.
System Operation Guideline
Relevant System Operator
The transmission system operator or distribution system operator to whose system a power generating module, demand facility, distribution system or HVDC system is or will be connected.
NC RfG
Relevant TSO
The TSO in whose control area a power generating module, a demand facility, a distribution system or a HVDC system is or will be connected to the network at any voltage level.
NC RfG
Reliability Margin
The reduction of cross-zonal capacity to cover the uncertainties within capacity calculation.
NC CACM
Reliably Available Capacity
The RAC on a power system is the difference between the NGC and the Unavailable Capacity. The RAC is the part of the NGC that is actually available to cover the load at a reference point.
RAC
Remaining Capacity
The RC on a power system is the difference between the RAC and the Load. The RC is the part of the NGC left on the system to cover any unexpected load variation and unplanned outages at a reference point.
RC
Remaining Margin
The RM on a power system is the difference between the RC and the MaPL. In SAR reports, the RM is calculated with the MaMPL and with/without Exchanges.
RM
Remedial Action
Any measure applied by a TSO or several TSOs, manually or automatically, in order to maintain operational security.
NC CACM
Renewable Energy Obligation
A national support scheme requiring energy producers to include a given proportion of energy from renewable sources in their production, requiring energy suppliers to include a given proportion of energy from renewable sources in their supply, or requiring energy consumers to include a given proportion of energy from renewable sources in their consumption. This includes schemes under which such requirements may be fulfilled by using green certificates.
Directive 2009/28/EC
Renewable Energy Sources
Renewable non-fossil energy sources (wind, solar, geothermal, wave, tidal, hydropower, biomass, landfill gas, sewage treatment plant gas and biogases).
Directive 2009/72/EC
Replacement Reserves

​The active power reserves available to restore or support the required level of FRR to be prepared for additional system imbalances, including operating reserves.​

System Operation GuidelineRR
Representativity
That certain values might not cover the whole country. It is expressed as a percentage. There might be differences between the approaches of the UCTE statistics and System Adequacy reports (see methodologies of Chapter II and III).
ENTSO-E Data Handbook
Requesting TSO
The TSO that requests Balancing Energy.
NC EB
Reserve Allocator
Informs the market of reserve requirements, receives tenders against the requirements and in compliance with the prequalification criteria, determines what tenders meet requirements and assigns tenders.
Harmonized Role Model
Reserve Connecting TSO

​The TSO responsible for the monitoring area to which a reserve providing unit or reserve providing group is connected.

System Operation Guideline
Reserve Object
A resource technically pre-qualified using a uniform set of standards to supply reserve capabilities to a System Operator associated with one or more Metering Points and tele-measuring devices.
Harmonized Role Model
Reserve Providing Group

​An aggregation of power generating modules, demand units and/or reserve providing units connected to more than one connection point fulfilling the requirements to provide FCR, FRR or RR.

System Operation Guideline
Reserve Providing Unit

​A single or an aggregation of power generating modules and/or demand units connected to a common connection point fulfilling the requirements to provide FCR, FRR or RR.

System Operation Guideline
Reserve Replacement Process

​A process to restore the activated FRR and, additionally for GB and IE/NI, to restore the activated FCR.

System Operation GuidelineRRP
Resource Object
A resource that can either produce or consume energy and that is reported in a schedule.
Harmonized Role Model
Resource Provider
A role that manages a resource and provides the schedules for it, if required.
Harmonized Role Model
Restoration
The System State in which the objective of all activities in Transmission System is to re-establish the system operation and maintain Operational Security after a Blackout.
NC OS
Restoration Plan
The summary of all technical and organisational measures to be undertaken to restore the system back to Normal State.
NC ER
Restoration Service Provider
A legal entity with a legal or contractual obligation to provide a service contributing to one or several measures of the Restoration Plan.
NC ER
Resynchronisation
Synchronising two Synchronised Regions by connecting the two Synchronised Regions at the Resynchronisation Point.
NC ER
Resynchronisation Leader
The TSO in charge of Resynchronisation of two Synchronised Regions.
NC ER
Resynchronisation Point
The substation used to connect two Synchronised Regions by closing circuit breakers.
NC ER
Retail Energy Sales Company
A natural or legal person that sells energy to final customers.
Directive 2006/32/EC
Rotor Angle Stability

​The ability of synchronous machines to remain in synchronism under N-situation and after being subject to a disturbance.

Select from existing list
Run of River
A hydro unit at which the head installation uses the cumulative flow continuously and normally operates on base load.
ENTSO-E Data Handbook
Scenario
The forecasted status of the power system for a given timeframe.
NC CACM
Schedule
A reference set of values representing the generation, consumption or exchange of electricity for a given time period.
System Operation Guideline
Scheduled (Program, Declared) Energy Flow
The program export (respectively import) of electricity in one member state on the basis of an underlying contractual arrangement to the effect that the simultaneous corresponding take-up (program import (respectively export)) of electricity will take place in another Member State or a third country.
ENTSO-E Data Handbook
Scheduled Exchange
An electricity transfer scheduled between geographic areas, for each market time unit and for a given direction.
NC CACM
Scheduled Exchange Calculator
The entity or entities with the task of calculating scheduled exchanges.
NC CACM
Scheduling Agent
The entity or entities with the task of providing schedules from market participants to TSOs, or where applicable third parties.
System Operation Guideline
Scheduling Area
An area within which the TSOs' obligations regarding scheduling apply due to operational or organisational needs.
System Operation Guideline
Scheduling Coordinator
A party that is responsible for the schedule information and its exchange on behalf of a Balance Responsible Party. For example in the Polish market a Scheduling Coordinator is responsible for information interchange for scheduling and settlement.
Harmonized Role Model
Secondary Trading
The trading of Long Term Transmission Rights through which a Market Participant is able to buy or sell Long Term Transmission Rights which were initially allocated by the Allocation Platform(s) .
Secured Fault
A fault which is successfully cleared according to the system operator s planning criteria.
NC RfG
Security
Both security of supply and provision of electricity, and technical safety.
Directive 2009/72/EC
Security Plan

​The plan containing a risk assessment of critical TSOs assets to major physical- and cyber-threat scenarios with an assessment of the potential impacts.

System Operation Guideline
Self Dispatch
A scheduling and dispatch arrangement in a Responsibility Area where the schedule of all generation units and Demand Side Response is determined by the units owners.
NC EB
Setpoint
The target value for any parameter typically used in control schemes.
NC RfG
Shared Order Book
A module in the continuous intraday coupling system collecting all matchable orders from the NEMOs participating in single intraday coupling and performing continuous matching of those orders.
NC CACM
Sharing of Reserves

​A mechanism in which more than one TSO takes the same reserve capacity, being FCR, FRR or RR, into account to fulfil their respective reserve requirements resulting from their reserve dimensioning processes.

System Operation Guideline
Shipping Agent
The entity or entities with the task of transferring net positions between different central counter parties.
NC CACM
Single Allocation Platform
The European platform established by all TSOs for forward capacity allocation.
NC FCA
Single Day-Ahead Coupling
The auctioning process where collected orders are matched and cross-zonal capacity is allocated simultaneously for different bidding zones in the day-ahead market.
NC CACM
Slope
The ratio of the change in voltage, based on reference 1 pu voltage, to a change in reactive power in-feed from zero to maximum reactive power, based on maximum reactive power.
NC RfG
Small Distributor
Small distributor, small distribution system operator and small retail energy sales company: a natural or legal person that distributes or sells energy to final customers, and that distributes or sells less than the equivalent of 75 GWh energy per year or employs fewer than 10 persons or whose annual turnover and/or annual balance sheet total does not exceed EUR 2 000 000.
Directive 2006/32/EC
Small Isolated System
Any system with consumption of less than 3 000 GWh in the year 1996, where less than 5 % of annual consumption is obtained through interconnection with other systems.
Directive 2009/72/EC
Stability Limits

​The permitted boundaries for the operation of the transmission system in terms of respecting the limits of voltage stability, rotor angle stability and frequency stability.

System Operation Guideline
Stakeholder Committee for Forward Capacity Allocation
A group of appointed representatives comprising the European Commission, ACER, NRAs, Transmission System Operators and Market Participants (such as but not limited to traders, generation companies, industrial consumers, small supply companies involved in Forward Capacity Allocation) .
Standard Frequency Range

​A defined symmetrical interval around the nominal frequency within which the system frequency of a synchronous area is supposed to be operated.

System Operation Guideline
Standard Product
A harmonised Balancing product defined by all TSOs for the Exchange of Balancing Services.
NC EB
Statement Of Compliance
A document provided by the power generating facility owner, demand facility owner, distribution system operator or HVDC system owner to the system operator stating the current status of compliance with the relevant specifications and requirements.
NC RfG
Stator
The portion of a rotating machine which includes the stationary magnetic parts with their associated windings.
NC RfG
Steady State Frequency Deviation

​The absolute value of frequency deviation after occurrence of an imbalance, once the system frequency has been stabilised.

System Operation Guideline
Steady-State Stability
The ability of a network or a synchronous power generating module to revert and maintain stable operation following a minor disturbance.
NC RfG
Storage Hydro
A hydro unit, at which the head installations store their cumulative flows wholly or partially in their retaining works (dam) in order to generate electricity later. Depending on the period required to fill a reservoir, storage hydro can be defined as follows: pondage (between 2 and 400 hours) and reservoir (>400 hours). These head installations are normally operated in such a way as to allow load following. By extension, when the operation of a head installation is directly related to that of a reservoir upstream and the intermediate inflows are negligible, these head installations must be considered to belong to the same category as the one who governs them.
ENTSO-E Data Handbook
Structural Congestion
Congestion in the Transmission System that can be unambiguously defined, is predictable, is geographically stable over time and is frequently reoccurring under common circumstances.
NC CACM
Supply
The sale, including resale, of electricity to customers.
Directive 2009/72/EC
Support Scheme
Any instrument, scheme or mechanism applied by a Member State or a group of Member States, that promotes the use of energy from renewable sources by reducing the cost of that energy, increasing the price at which it can be sold, or increasing, by means of a renewable energy obligation or otherwise, the volume of such energy purchased. This includes, but is not restricted to, investment aid, tax exemptions or reductions, tax refunds, renewable energy obligation support schemes including those using green certificates, and direct price support schemes including feed-in tariffs and premium payments.
Directive 2009/28/EC
Synchronised Region
A subpart of a Synchronous Area covered by interconnected TSOs with a common System Frequency not synchronised with the rest of the Synchronous Area.
NC ER
Synchronous Area
An area covered by synchronously interconnected TSOs, such as the synchronous areas of Continental Europe, Great Britain, Ireland-Northern Ireland and Nordic and the power systems of Lithuania, Latvia and Estonia, together referred to asÿ Balticÿ which are part of a wider synchronous area
NC RfG
Synchronous Area Monitor

​A TSO responsible for collecting the frequency quality evaluation criteria data and applying the frequency quality evaluation criteria for the synchronous area.

System Operation Guideline
Synchronous Compensation Operation
The operation of an Alternator without prime mover to regulate Voltage dynamically by production or absorption of Reactive Power.
NC RfG
Synchronous Power Generating Module
An indivisible set of installations which can generate electrical energy such that the frequency of the generated voltage, the generator speed and the frequency of network voltage are in a constant ratio and thus in synchronism.
NC RfG
Synthetic Inertia
The facility provided by a power park module or HVDC system to replace the effect of inertia of a synchronous power generating module to a prescribed level of performance.
NC RfG
System Adequacy
System adequacy of a power system is a measure of the ability of a power system to supply the load in all the steady states in which the power system may exist considering standards conditions. System adequacy is analysed through Generation Adequacy and Transmission Adequacy (main focus on generation capacity and load and on simultaneous interconnection transmission capacity).
ENTSO-E Data HandbookSA
System Defence Plan

​The technical and organisational measures to be undertaken to prevent the propagation or deterioration of a disturbance in the transmission system, in order to avoid a wide area state disturbance and blackout state.

System Operation Guideline
System Operator
A party that is responsible for a stable power system operation (including the organisation of physical balance) through a transmission grid in a geographical area. The System Operator will also determine and be responsible for cross border capacity and exchanges. If necessary he may reduce allocated capacity to ensure operational stability. Transmission as mentioned above means ?the transport of electricity on the extra high or high voltage network with a view to its delivery to final customers or to distributors. Operation of transmission includes as well the tasks of system operation concerning its management of energy flows, reliability of the system and availability of all necessary system services?. (definition taken from the ENTSO-E RGCE Operation handbook Glossary).
Harmonized Role Model
System Security
The continuous process where collected orders are matched and cross-zonal capacity is allocated simultaneously for different bidding zones in the intraday market.
NC CACM
System State

​The operational state of the transmission system in relation to the operational security limits which can be normal state, alert state, emergency state, blackout state and restoration state.

System Operation Guideline
System User
A natural or legal person supplying to, or being supplied by, a transmission or distribution system.
Directive 2009/72/EC
Tendering Procedure
The procedure through which planned additional requirements and replacement capacity are covered by supplies from new or existing generating capacity.
Directive 2009/72/EC
Third-Party Financing
Third-party financing: a contractual arrangement involving a third party ? in addition to the energy supplier and the beneficiary of the energy efficiency improvement measure ? that provides the capital for that measure and charges the beneficiary a fee equivalent to a part of the energy savings achieved as a result of the energy efficiency improvement measure. That third party may or may not be an ESCO.
Directive 2006/32/EC
Time
The local time in Brussels.
Regulation 543/2013
Time To Recover Frequency

​For the synchronous areas GB and IE/NI, the maximum expected time after the occurrence of an imbalance smaller than or equal to the reference incident in which the system frequency returns to the maximum steady state frequency deviation.

System Operation Guideline
Time To Restore Frequency

​The maximum expected time after the occurrence of an instantaneous power imbalance smaller than or equal to the reference incident in which the system frequency returns to the frequency restoration range for synchronous areas with only one LFC area and in the case of synchronous areas with more than one LFC area, the maximum expected time after the occurrence of an instantaneous power imbalance of an LFC area within which the imbalance is compensated.

System Operation Guideline
Top-down Re-energisation Strategy
A strategy that requires the assistance of other TSOs to re-energise part of the system of a TSO.
NC ER
Topology

​The data concerning the connectivity of the different transmission system or distribution system elements in a substation and includes the electrical configuration and the position of circuit breakers and isolators.

System Operation Guideline
Total Load
Total Load, including losses without power used for energy storage, means a load equal to generation and any imports deducting any exports and power used for energy storage.
Regulation 543/2013
Trade
One or more Matched Orders.
NC CACM
Trade Responsible Party
A party who can be brought to rights, legally and financially, for any imbalance between energy nominated and consumed for all associated Accounting Points.
Harmonized Role Model
Transfer of Balancing Capacity
A transfer of Balancing Capacity from the initially contracted Balancing Service Provider to another transfer receiving Balancing Service Provider.
NC EB
Transfer of Capacity Optimisation Function
The role to operate the algorithm applied for the optimisation of the Transfer of Balancing Capacity.
NC EB
Transit of Electricity
A transaction for the transport of electricity under the following conditions: (a) transmission is carried out by the entity or entities responsible in each Member State for a high-voltage electricity grid, with the exception of distribution grids, in a Member State's territory which contributes to the efficient operation of European high-voltage interconnections, (b) the grid of origin or final destination is situated in the Community, (c) the transport involves the crossing of one intra-Community frontier at least.
Directive 90/547/EEC
Transitory Admissible Overloads
The temporary overloads of transmission system elements which are allowed for a limited period and which do not cause physical damage to the transmission system elements as long as the defined duration and thresholds are respected.
System Operation Guideline
Transmission
The transport of electricity on the extra high-voltage and high-voltage interconnected system with a view to its delivery to final customers or to distributors, but does not include supply.
Directive 2009/72/EC
Transmission Adequacy
An assessment of the ability of a power system to manage the flow resulting from the location of Load and generation (see also Methodology section in Chapter 3).
ENTSO-E Data Handbook
Transmission Capacity Allocator
The entity empowered by TSOs to manage the allocation of cross zonal capacities.
Harmonized Role Model
Transmission Connected Demand Facility
A Demand Facility which has a Connection Point to a Transmission Network.
NC DCC
Transmission Connected Distribution Network
A Distribution Network which has a Connection Point to a Transmission Network.
NC DCC
Transmission Losses
The difference between the fed-in (generation) and the delivery energy to distributors. Own needs for the operation of the grid are included.
ENTSO-E Data Handbook
Transmission Network
An electrical Network for the transmission of electrical power from and to third party[s] connected to it, including Demand Facilities, Distribution Networks or other Transmission Networks. The extent of this Network is defined at the national level.
NC DCC
Transmission System Operator
A natural or legal person responsible for operating, ensuring the maintenance of and, if necessary, developing the transmission system in a given area and, where applicable, its interconnections with other systems, and for ensuring the long?term ability of the system to meet reasonable demands for the transmission of electricity.
Directive 2009/72/ECTSO
TSO Energy Bid Submission Gate Closure Time
The latest point in time when a Connecting TSO can forward the Balancing Energy bids received from a Balancing Service Provider to the Activation Optimisation Function. The TSO Energy Bid Submission Gate Closure Time is after Balancing Energy Gate Closure Time.
NC EB
TSO-BSP Model
A model for the Exchange of Balancing Capacity or the Exchange of Balancing Energy where the Contracting TSO has an agreement with a Balancing Service Provider in another Responsibility Area or Scheduling Area when appropriate.
NC EB
TSO-TSO Model
A model for the Exchange of Balancing Services exclusively by TSOs. The TSO-TSO Model is the standard model for the Exchange of Balancing Services.
NC EB
TSO-TSO Model for FRR and RR
A model for the Exchange of Balancing Capacity and the Exchange of Balancing Energy from Frequency Restoration Reserves and Replacement Reserves exclusively by TSOs.
NC EB
TSO-TSO Settlement Function
The role to perform the settlement of cooperation processes between the TSOs of a Coordinated Balancing Area.
NC EB
Typical Value
An estimate of the representative greenhouse gas emission saving for a particular biofuel production pathway.
Directive 2009/28/EC
U-Q/Pmax-Profile
A profile representing the reactive power capability of a power generating module or HVDC converter station in the context of varying voltage at the connection point.
NC RfG
Unavailable Capacity
This is the part of the NGC which is not reliably available to power plant operators due to limitations on the output power of power plants. It consists of the Non-Usable Capacity, Maintenance and Overhauls, Outages and System Services Reserve.
Underexcitation Limiter
A control device within the AVR, the purpose of which is to prevent the alternator from losing synchronism due to lack of excitation.
NC RfG
Use it or sell it (UIOSI)
The principle according to which the underlying cross-zonal capacity of physical transmission rights purchased and non-nominated is automatically made available for day-ahead capacity allocation and according to which the holder of these physical transmission rights receives remuneration from the TSOs.
NC FCAUIOSI
Validity Period
The time period when the Balancing Energy bid offered by the Balancing Service Provider can be activated, whereas all the characteristics of the product are respected. The Validity Period is defined by a beginning time and an ending time.
NC EB
Vertical Load
The total amount of power flowing out of the transmission network to the distribution networks, to directly connected final customers or to the consuming part of generation.
Regulation 543/2013
Vertically Integrated Undertaking
An electricity undertaking or a group of electricity undertakings where the same person or the same persons are entitled, directly or indirectly, to exercise control, and where the undertaking or group of undertakings perform at least one of the functions of transmission or distribution, and at least one of the functions of generation or supply of electricity.
Directive 2009/72/EC
Virtual Tie-Line

​An additional input of the controllers of the involved LFC areas that has the same effect as a measuring value of a physical interconnector and allows exchange of electric energy between the respective areas.

System Operation Guideline
Voltage
The difference in electrical potential between two points measured as the root-mean-square value of the positive sequence phase-to-phase voltages at fundamental frequency.
NC RfG
Voltage Control

​The manual or automatic control actions at the generation node, at the end nodes of the AC lines or HVDC systems, on transformers, or other means, designed to maintain the set voltage level or the set value of reactive power.

Select from existing list
Voltage Stability

​The ability of a transmission system to maintain acceptable voltages at all nodes in the transmission system in the N-situation and after being subjected to a disturbance.

Select from existing list
Week-Ahead
The week prior to the calendar week of operation.
System Operation Guideline
White Certificates
White certificates: certificates issued by independent certifying bodies confirming the energy savings claims of market actors as a consequence of energy efficiency improvement measures.
Directive 2006/32/EC
Wholesale Customer
A natural or legal person purchasing electricity for the purpose of resale inside or outside the system where he is established.
Directive 2009/72/EC
Wholesale Energy Market
Any market within the Union on which wholesale energy products are traded.
Regulation 1227/2011
Wholesale Energy Products
The following contracts and derivatives, irrespective of where and how they are traded:(a) contracts for the supply of electricity or natural gas where delivery is in the Union.(b) derivatives relating to electricity or natural gas produced, traded or delivered in the Union.(c) contracts relating to the transportation of electricity or natural gas in the Union.(d) derivatives relating to the transportation of electricity or natural gas in the Union.Contracts for the supply and distribution of electricity or natural gas for the use of final customers are not wholesale energy products. However, contracts for the supply and distribution of electricity or natural gas to final customers with a consumption capacity greater than the threshold set out in the second paragraph of point (5) shall be treated as wholesale energy products.
Regulation 1227/2011
Wind Energy
Kinetic energy in wind used to generate electricity in wind turbines.
International Energy Agency
Year-Ahead
The year prior to the calendar year of operation.
System Operation Guideline
Year-Ahead Forecast Margin
The difference between the yearly forecast of available generation capacity and the yearly forecast of maximum total load taking into account the forecast of total generation capacity, the forecast of availability of generation and the forecast of reserves contracted for system services.
Regulation 543/2013
Energy Identification Code
A 16 character code used in the European Energy Market to identify parties, areas and objects in all energy commodities. 
Circuit
An electrical circuit is a group of functional elements, in which electrical currents can flow. A circuit may consist of several circuit sections and have more than two endpoints and branch points.
System Operation Guideline
Information Provider
An entity providing information either of own origin or on behalf of one or more parties.
Harmonized Role Model
Average FRCE Data
The set of data consisting of the average value of the recorded instantaneous FRCE of a LFC area or a LFC block within a given measured period time.
System Operation Guideline
Entso For Electricity Operational Planning Data Environment
The set of application programs and equipment developed in order to allow the storage, exchange and management of the data used for operational planning processes between TSOs.
System Operation Guideline
External Contingency
A contingency outside the TSOs control area and excluding interconnectors, with an influence factor higher than the contingency influence threshold.
System Operation Guideline
FCR Full Activation Frequency Deviation
The rated value of frequency deviation at which the FCR in a synchronous area is fully activated.
System Operation Guideline
Flexible Alternating Current Transmission Systems
Equipment for the alternating current transmission of electric power, aiming at enhanced controllability and increased active power transfer capability.
System Operation Guideline
Frce Target Parameter
The main target LFC block variables on the basis of which the dimensioning criteria for FRR and RR of the LFC block are determined and evaluated and which are used to reflect the LFC block behaviour in normal operation.
System Operation Guideline
Frequency Coupling Process
A process agreed between all TSOs of two synchronous areas that allows linking the activation of FCR by an adaptation of HVDC flows between the synchronous areas.
System Operation Guideline
Frequency Quality Defining Parameter
The main system frequency variables that define the principles of frequency quality.

System Operation Guideline
Frequency Restoration Range
The system frequency range to which the system frequency is expected to return in the GB, IE/NI and Nordic synchronous areas, after the occurrence of an imbalance equal to or smaller than the reference incident within the time to restore frequency.
System Operation Guideline
Instantaneous Frce Data
A set of data of the FRCE of a LFC block with a measurement period equal to or shorter than 10 seconds used for system frequency quality evaluation purposes.
System Operation Guideline
Internal Contingency
A contingency within the TSOs control area, including interconnectors.
System Operation Guideline
Internal Relevant Asset
A relevant asset which is part of a TSOs control area or a relevant asset located in a distribution system, including a closed distribution system, which is connected directly or indirectly to that TSO‘s control area.
System Operation Guideline
K-Factor of an LFC Area
A value expressed in megawatts per hertz ('MW/Hz'), which is as close as practical to, or greater than the sum of the auto-control of generation, self-regulation of load and of the contribution of frequency containment reserve relative to the maximum steady-state frequency deviation.
System Operation Guideline
Level 1 FRCE Range
The first range used for system frequency quality evaluation purposes on LFC block level within which the FRCE should be kept for a specified percentage of the time.
System Operation Guideline
Level 2 FRCE Range
The second range used for system frequency quality evaluation purposes on LFC block level within which the FRCE should be kept for a specified percentage of the time.
System Operation Guideline
Local State
The qualification of an alert, emergency or blackout state when there is no risk of extension of the consequences outside of the control area  including interconnectors connected to this control area.
System Operation Guideline
Neighbouring Tsos
The TSOs directly connected via at least one AC or DC interconnector.
System Operation Guideline
Operational Security Indicators
Indicators used by TSOs to monitor the operational security in terms of system states as well as faults and disturbances influencing operational security.
System Operation Guideline
Operational Tests
The tests carried out by a TSO or DSO for maintenance, development of system operation practices and training and to acquire information on transmission system behaviour under abnormal system conditions and the tests carried out by significant grid users for similar purposes on their facilities.
System Operation Guideline
Outage Planning Incompatibility
The state in which a combination of the availability status of one or more relevant grid elements, relevant power generating modules, and/or relevant demand facilities and the best estimate of the forecasted electricity grid situation leads to violation of operational security limits taking into account remedial actions without costs which are at the TSO‘s disposal.
System Operation Guideline
Ramping Period
A period of time defined by a fixed starting point and a length of time during which the input and/or output of active power will be increased or decreased.
System Operation Guideline
Regional Security Coordinator
The entity or entities, owned or controlled by TSOs, in one or more capacity calculation regions performing tasks related to TSO regional coordination.
System Operation Guideline
Reserve Provider
A legal entity with a legal or contractual obligation to supply FCR, FRR or RR from at least one reserve providing unit or reserve providing group.
System Operation Guideline
Restoration State
The system state in which the objective of all activities in the transmission system is to re-establish the system operation and maintain operational security after the blackout state or the emergency state.
System Operation Guideline
Transmission System Element
Any component of the transmission system.
System Operation Guideline
Wide Area State
The qualification of an alert state, emergency state or blackout state when there is a risk of propagation to the interconnected transmission systems.
System Operation Guideline
Phase-Shifting Transfomer
A Phase-Shifting Transformer (PST) is a transformer for controlling the power flow through specific lines, without changing voltage level.
ENTSO-E