available capacity — the part of the technical capacity that is not allocated and is still available to the system at that moment 20)

balancing period — the period within which the off-take of an amount of natural gas, expressed in units of energy, must be offset by every network user by means of the injection of the same amount of natural gas into the transmission network in accordance with the transport contract or the network code 10)

capacity — the maximum flow, expressed in normal cubic meters per time unit or in energy unit per time unit, to which the network user is entitled in accordance with the provisions of the transport contract 3)

congestion management — management of the capacity portfolio of the transmission system operator with a view to optimal and maximum use of the technical capacity and the timely detection of future congestion and saturation points 5)

contracted capacity — capacity that the transmission system operator has allocated to a network user by means of a transport contract 19)

contractual congestion — a situation where the level of firm capacity demand exceeds the technical capacity 21)

deliverability — the rate at which the storage facility user is entitled to withdraw gas from the storage facility 26)

firm capacity — gas transmission capacity contractually guaranteed as uninterruptible by the transmission system operator 16)

firm services — services offered by the transmission system operator in relation to firm capacity 1.

injectability — the rate at which the storage facility user is entitled to inject gas into the storage facility 27)

interruptible capacity — gas transmission capacity that may be interrupted by the transmission system operator in accordance with the conditions stipulated in the transport contract 13)

interruptible services — services offered by the transmission system operator in relation to interruptible capacity 12)

LNG facility capacity — capacity at an LNG terminal for the liquefaction of natural gas or the importation, offloading, ancillary services, temporary storage and re-gasification of LNG 24)

long-term services — services offered by the transmission system operator with a duration of one year or more 14)

network user — a customer or a potential customer of a transmission system operator, and transmission system operators themselves in so far as it is necessary for them to carry out their functions in relation to transmission 11)

nomination — the prior reporting by the network user to the transmission system operator of the actual flow that the network user wishes to inject into or withdraw from the system 7)

physical congestion — a situation where the level of demand for actual deliveries exceeds the technical capacity at some point in time 23)

primary market — the market of the capacity traded directly by the transmission system operator 22)

re-nomination — the subsequent reporting of a corrected nomination 8)

secondary market — the market of the capacity traded otherwise than on the primary market 6)

short-term services — services offered by the transmission system operator with a duration of less than one year 15)

space — the volume of gas which a user of a storage facility is entitled to use for the storage of gas 25)

storage capacity — any combination of space, injectability and deliverability 28)

system integrity — any situation in respect of a transmission network including necessary transmission facilities in which the pressure and the quality of the natural gas remain within the minimum and maximum limits laid down by the transmission system operator, so that the transmission of natural gas is guaranteed from a technical standpoint 9)

technical capacity — the maximum firm capacity that the transmission system operator can offer to the network users, taking account of system integrity and the operational requirements of the transmission network 18)

transmission — the transport of natural gas through a network, which mainly contains high-pressure pipelines, other than an upstream pipeline network and other than the part of high-pressure pipelines primarily used in the context of local distribution of natural gas, with a view to its delivery to customers, but not including supply 1)

transport contract — a contract which the transmission system operator has concluded with a network user with a view to carrying out transmission 2)

unused capacity — firm capacity which a network user has acquired under a transport contract but which that user has not nominated by the deadline specified in the contract 4)