Frequently Asked Questions
How exactly does a shutdown work?
The transmission system operator Elia has divided our country into 8 shutdown tranches, numbered from 8 to 1, according to the distribution points. There is also a tranche 0: companies in this tranche are never shut down.
The 8 tranches do not correspond to geographical zones: a tranche contains municipalities from different parts of the country and a municipality - or even the same street - can be supplied by distribution points that are served by different power cabins. The situation can also change under the influence of, for example, work on the distribution network.
The Ministers of Energy and Economy decide on the eve of a possible deficit which tranche(s) to shut down, a priori during peak hours to avoid a general blackout.
In principle, only one tranche is shut down, but if the shortage becomes too large, multiple tranches can be shut down, in descending order, tranche 7, 6, 5 and so on.
A shutdown takes place in 4 steps:
Step 1: Elia interrupts specific connections between the transmission system and the distribution system (transformer stations) and informs the grid operators of the tranche or tranches they have to shut down.
Step 2: Distribution system operators shut down all customers in the affected tranches with the exception of priority customers. Priority customers are hospitals, emergency call centres and the network operators' own stations.
Step 3: Elia restores the connections. Electricity is now only supplied to priority customers.
Step 4: As soon as there is sufficient power again, the grid operators switch on the affected zones one by one.
Want to know more? Watch this short film of Synergrid, the Belgian Federation of Grid Operators.