Could Spain's blackout hit Belgium? What companies should do

A total blackout like Spain's is very unlikely in Belgium, but a planned or unplanned cut of a few hours is a real business risk. Find out which load-shedding slice your site is in and list what must keep running. Then choose backup power for your business to match those loads and that duration. Where a battery makes sense, our business battery systems can take over the critical loads by themselves.

The day after the lights went out in Spain and Portugal, many Belgian business owners asked the same thing. What if it happens here? What goes down first, and what keeps running? Some remember the winters when the load-shedding plan was front-page news, and the rule of thumb that a cut lasts about three hours.

What most companies do not see is where the risk really sits. It is rarely the dramatic blackout. It is the three-hour cut that you hear about the evening before, or not at all. The UPS that covers minutes, not hours. The generator nobody has started under load. The switchover that was never tested. Buying a big generator after the news does not fix any of that. And it needs permission from your grid operator before it can be connected.

Some sites are not exposed at all. Special Renting in Zele runs its warehouse, offices and electric lifting gear with no connection to the public grid: 30 kWp of solar panels, a battery system and an emergency generator. A load-shedding slice cannot switch off a site that is not on the grid.

What happened in Spain and Portugal on 28 April 2025?

On 28 April 2025 at 12:33, the power systems of continental Spain and Portugal went completely dark. A small area in southwest France was disrupted for a very short time. The expert panel of ENTSO-E, the association of European grid operators, published its final report on 20 March 2026.

The panel found no single cause. Voltage fluctuations and oscillations led to many generators disconnecting in Spain, especially plants connected through inverters. Voltage then rose fast, which tripped more generation on overvoltage protection. Within seconds, the Iberian grid lost its synchronism with the rest of the European grid.

The automatic defence plans were activated correctly, but they could not stop the collapse. Spain and Portugal then rebuilt their grids step by step. The transmission grid was restored in 12 hours in Portugal and 16 hours in Spain, according to the panel. Red Eléctrica, the Spanish grid operator, says 99.95% of demand was back by 7:00 the next morning.

The committee set up by the Spanish government came to the same picture: a problem of overvoltage with several causes, including too little voltage control. It also ruled out a cyberattack on the system operator, its control centres and the power plants it analysed.

Could a blackout like Spain's happen in Belgium?

No grid is immune, but a total blackout is very unlikely in Belgium. The National Crisis Centre rates the probability of an extreme disruption of electricity supply lasting at least a day as very low. The European experts call the Iberian event the most severe incident in the European power system in more than 20 years.

Belgium also has layers of protection. If the grid frequency drops to 49.0 Hz, relays automatically disconnect part of the demand to save the rest of the system. Elia, the Belgian high-voltage grid operator, calls such a drop very exceptional: the last time in Belgium was in 2006. After a blackout, Elia calls on contracted power plants to restart the grid.

The honest lesson from Spain is not that it will happen here. It is that even a well-protected grid can take hours to come back, and your company is on its own during those hours. That is true for a blackout, and it is just as true for a local fault or a load shedding.

What is the difference between a blackout, load shedding and a power cut?

A blackout is an unplanned collapse of the whole high-voltage grid. Load shedding is a controlled cut of part of the country to prevent that collapse. A power cut is the broad term for any interruption, often a local fault.

Sources for the table: FOD Economie (load-shedding plan and company FAQ), Elia (automatic load shedding) and the ENTSO-E final report (Iberian restoration times).

What is Belgium's load-shedding plan, and does it cover your business?

The load-shedding plan (afschakelplan in Dutch, plan de délestage in French) protects the Belgian grid against a complete blackout. It divides the country into 8 slices. Together they represent about a third of Belgium's gross electricity use, so not every site is in a slice. If yours is, it can be switched off.

The plan is only used in an extreme situation, when all other measures have failed. The federal ministers of Energy and Economy then decide which slice is switched off. If cuts are needed on several days, the slices take turns, so the same area is not hit every day.

Who is protected? After a cut, the grid operator can reconnect priority users first. According to FOD Economie these are mainly general and psychiatric hospitals, the emergency call centres (112, 100 and 101) and the grid operators' own stations. Care homes are not priority users. The plan also tries to spare city centres of municipalities with more than 50,000 inhabitants, provincial capitals, major ports and airports.

For most companies the answer is simple: if your site is in a slice, it can be switched off. A workshop, a farm, a shop or a warehouse is not on the priority list.

How do you find out which load-shedding slice your company is in?

Ask your distribution grid operator: Fluvius, ORES, RESA or Sibelga, for example. Their phone number is on your energy bill. FOD Economie shows per municipality which slices apply, but a municipality can be split over several slices. Street-level detail comes from your grid operator. In Flanders, Fluvius has an online lookup by street, or by EAN number for medium-voltage customers.

Companies connected directly to the Elia high-voltage grid contact their Key Account Manager at Elia instead.

What should a company do before a load shedding or a long power cut?

Start with a risk analysis, not with a purchase. FOD Economie asks companies to map what an interruption means for their machines, servers and processes, and to turn that into an action plan. These five questions structure it:

Does NIS2 require your company to plan for power cuts?

If your organisation falls under the Belgian NIS2 law, business continuity is a legal duty. The law has applied since 18 October 2024. It covers medium-sized and larger organisations in the sectors listed in its annexes, with energy at the top. Medium-sized generally means 50 employees or more, or an annual turnover and balance sheet above 10 million euro.

Among the security measures in article 30 of the law is business continuity, such as backup management, emergency plans and crisis management. The management body must approve those measures. NIS2 is a cybersecurity law, but a server room that stops in a power cut is a continuity problem all the same.

Not sure whether your company is covered? The Centre for Cybersecurity Belgium explains who falls under NIS2 and what is expected. Even if you are not covered, the same logic is a good template for any company.

When is emergency power worth it for a company?

Emergency power is worth it when an hour without power costs more than the backup over its life. It is also worth it when people, animals or data are at risk. For an office with laptops, a UPS for the server and a clear plan are often enough.

How the options compare in switchover time, autonomy and rules is explained in our guide to UPS, generator or battery backup for businesses. If your servers or machines cannot stand even a short interruption, read what a no-break set-up needs. Planning a generator next to a battery? Then see how a generator and a battery work together.

Critical infrastructure uses the same building blocks. Our media section shows a video of a Victron back-up system for an airport control tower.

What happens when you ask us to check your site?

We start with your critical loads, not with a product.

1. Step 1: You tell us what must keep running, and for how long. Add your connection size and your latest invoices.
2. Step 2: If data is missing, we measure your consumption for a short period first.
3. Step 3: Analysis and sizing: which loads are critical, how many kW and kWh they need, and whether a battery, a generator or both fit.
4. Step 4: Technical design, installation and commissioning, including the switchover and the protection.
5. Step 5: Monitoring and support. You follow the system in the app and the VRM portal, and get an alert when the battery runs low.

Our business batteries range from small SME installations to modular systems up to 1 MW. We are a Victron Energy Certified Partner, based in Zele.