The object of the Storage Access Contract is to determine the conditions in which TIGF undertakes to take the quantities of gas delivered to it by the Customer to the Storage Transport Interface Point and subsequently return to the Customer, at this same point, quantities of gas equivalent to those previously delivered by the Customer.

The contract year runs from 1 April to 31 March (one summer, the injection period, followed by one winter, the decanting period).
The Storage Access Contract may be taken out at one month's notice for periods that must start on the first day of a month and must end on 31 March in a year. Multiannual subscriptions are possible. Subscription during the year leads to the application of Special provisions.

Access to TIGF natural gas storage infrastructure is possible from the South-West balancing zone.
TIGF offers two services for access to its storage infrastructure known as the Dynamic Service and the Balanced Service. Each of these services has Storage Units with specific characteristics (see Characteristics of Standard Services).

Under the Storage Access Contract a Customer subscribes to a whole number of Storage Units.

A Storage Unit is defined by:

- a Storage Unit Capacity (SUC) expressed in kWh
- a Unit Daily Nominal Decanting Capacity (UDNDC) expressed in kWh/d
- a Unit Daily Nominal Injection Capacity (UDNIC) expressed in kWh/d.

Thus, a Customer who has subscribed under a Storage Access Contract to a number n of Storage Units has:

-  a Storage Capacity equal to the product of the SUC and n
-  a Unit Daily Nominal Decanting Capacity equal to the product of the UDNDC and n
-  a Unit Daily Nominal Injection Capacity equal to the product of the UDNIC and n.

The rights related with these capacities are defined by the contractual rules  (see Contractual Rules).