What is a blackout? What is a selective power cut?

• A blackout is a total crash of the power grid due to an imbalance between power generation and power consumption.
• A selective power cut is a controlled shutdown of the power supply in a given area, so as to avoid a blackout.

Supply problem

As most of us are now aware: a significant portion of our power generation capacity is currently unavailable. If we need a lot of electricity in case of a cold spell, this capacity is not going to be enough to meet demand.

Blackout

In case of a power shortage, normally speaking we are able to rely on our neighbouring countries, who are able to send part of their surplus supply to our grid. If we are looking at a severe winter, however, our neighbours are going to need this electricity for themselves. Especially France, which has a longstanding tradition of using electric heating.

At such times, we could well see electricity demand exceed the supply. In that case, an imbalance is said to exist between generation and consumption.
This imbalance is also a dangerous thing as it could cause the Belgian - and even the European - electricity grid to crash. In that case, we would have a blackout on our hands, which is very much the worst-case scenario.

How long would a blackout last?

One of two situations may present themselves:

• either the grid can be restored with the help of the grids of our neighbouring countries: in this case, the first customers would have their electrical power supply restored after 4 hours, the last customers after 8 hours.
• or we need to start back from scratch: in this case, the first customers would have their electrical power supply restored after 10 hours, the last customers after 24 hours.

Selective power cut

To avoid the blackout, the Government has worked up a whole series of measures in joint consultation with the high-voltage grid operator (Elia), the operators of the distribution grids (such as Sibelga) and the crisis centre.
Among these measures is the selective power cut plan. As a last resort, this plan provides for the interruption of the electricity supply in certain areas.

In that case, this partial and deliberate reduction of the electrical power consumption is intended to enable the power plants to restore the balance.

How long would a selective power cut last?

These planned interruptions should last 3 to 4 hours in the areas in question.