Overnomination - Fluxys Belgium

Simply nominate and get your interruptible, Within-Day or Day-Ahead capacity at all Fluxys Belgium Interconnection points.


  • Fluxys Belgium: Yearly Auctions - Attention for Virtualys Exit offer

    Fluxys Belgium offers the market the possibility to give a strong signal that the amount of capacity from Belgium to France is still needed by subscribing these capacities during the yearly auctions of July 2024 in the long-term. Therefor, for the capacity subscriptions for period GY2027/2028 until GY2038/39, Fluxys Belgium will only accept and allocated long-term subscriptions, meaning subscriptions for a duration of at least 10 consecutive years.


What is Overnomination and when is it activated?

The Overnomination mechanism allows you to buy unbundled interruptible capacity in 2 cases:

CASE 1: When all capacity is sold out (on Interconnection points sold through auctions): 

  • After firm/backhaul day-ahead auction

CASE 2: In case of PRISMA’s unavailability, for within-day and day-ahead capacities

Overnomination is only applicable on entry-exit Interconnection Points (EE code) and cannot be activated for balanced routes (FL code).

How to use Overnomination?

You can nominate/renominate only after being notified via an Urgent Market Message (UMM) on the Electronic Data Platform that overnomination has been activated.

If your initial nomination (which was sent before the notification) exceeds the subscribed capacity, you will have to resend the nomination. 

How much interruptible capacity will be implicitly allocated?

Interruptible capacity at the IP is implicitly allocated until the end of gas day. 

For every hour, the quantity of implicitly allocated capacity is calculated as the maximum of: 

  • The difference between the last accepted nomination by the TSO (limited to the technical capacity of the IP) and the already subscribed capacity at the IP, and
  • Zero (0).

The effective implicit allocation of capacity through overnomination is done during the hour preceeding the hour for which the capacity is requested through the nomination.

When capacity has been allocated through overnomination, you will receive a service confirmation form with the confirmed quantity.


Overnomination capacities are charged for the period during which they are implicitly allocated and at interruptible tariff based on the nominated quantities. If the confirmed quantity is lower than the nominated quantity, you will pay the difference between the last accepted nomination and the already subscribed capacity.

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