A business battery in Brussels: Sibelga, permit and space

A battery for a Brussels business needs three things in order. First a class 3 declaration at the commune, or a change to the environmental permit your site already has. Then an electrical inspection and a declaration to Sibelga within 30 days of commissioning. And a room that meets the Brussels battery conditions. A business battery system only pays off once all three are settled before the equipment arrives.

You run a print shop in Anderlecht or a bakery in Schaerbeek. Or you manage an office building in Etterbeek with a car park underneath. You want a battery for your solar panels, your peak or the chargers of your vans. Then the questions start. The installer from Flanders who would rather not work in Brussels. A 3 x 230 V grid, where the inverter datasheet asks for 400 V. A cellar where nobody knows what the fire rules allow.

What most managers find out too late is the order of the paperwork. A battery that is installed but not yet declared at the commune may not run. If your building already has an environmental permit for its car park, the battery changes that permit. You then wait for the official modification before you switch on. Every week it stands still is a week of savings lost.

Which Sibelga connection does your business have, and why does it matter for a battery?

Your connection decides how Sibelga bills your peak, which meter you have and which request you file. Sibelga draws the lines at 56 kVA and at 150 kVA, and above that sits the high-voltage connection with your own cabin.

An AMR meter sends quarter-hour power data to Sibelga once a day. Those are the data a battery needs to be sized on. How much a kW of peak costs in Brussels is explained in our article on grid tariffs for businesses in Wallonia and Brussels. Not sure whether you are on low or medium voltage? Our guide on low voltage or medium voltage for a business shows how to tell.

Is your Brussels building on 230 V or 400 V, and what does that change?

About 80% of the Brussels region is supplied at 230 V, according to Sibelga. The same breaker gives you less power on 230 V than on 400 V. And not every business inverter is made for a 3 x 230 V grid without neutral.

For a battery this has three consequences. The inverter must match the grid, or you need a transformer in between. You get fewer kVA from the same cable, so peaks hit the limit sooner. And 400 V is not available everywhere. Sibelga first runs a free study, and where 400 V is impossible, an autotransformer is the fallback.

A 230 V grid can also be weak at the end of the line. In Gedinne, a hunting lodge in the woods kept only 180 V on its 3 x 230 V connection. Our semi off-grid battery system there brings it to 3 x 400 V and uses the public grid only to charge the 46.2 kWh battery.

We have written a separate guide for sites where a 3 x 230 V connection is too weak. It covers the options in more depth.

Which environmental permit class does a business battery fall under in Brussels?

Stationary batteries and UPS units on the same circuit above 10,000 VAh are rubric 3 of the Brussels list of classified installations, class 3. Class 3 is the lightest class: a declaration at the environment department of your commune, not a full permit.

The threshold is low. Multiply the number of batteries by their capacity in Ah and their voltage in V. A 48 V battery of 210 Ah is already 10,080 VAh. Practically every business battery crosses the line.

Car batteries, forklift batteries and EV chargers are outside the battery conditions. A UPS with internal batteries is inside them, so a server room can already be a classified installation. Our article on many small UPS units or one central battery looks at that choice.

Bruxelles Environnement has a free online tool, MyPermit Environnement, to simulate your site. You select all your installations and it tells you the class and the authority.

What if your building already has an environmental permit?

In Brussels your site files one application for the highest class among all its installations. A battery on its own is class 3. The car park, transformer or generator next to it often sit in a higher class.

An office building with 60 parking spaces therefore already runs on a class 1B permit. Adding a battery is then a change to that permit. You tell the authority that issued the permit, and you wait for the official modification before you run the battery. The administration judges each change case by case. It can accept it, or ask for a new permit application.

That difference in time is large. A new class 2 permit has a 60-day decision period, a 15-day public inquiry and a 30-day period for the fire service (SIAMU) opinion. For class 1B the decision period is 160 days. Plan the permit before you order the battery.

How do you declare a business battery to Sibelga?

Sibelga treats a battery as a production unit under the Synergrid C10/11 technical rules, and declaring it is a legal duty. The declaration is due at the latest 30 days after commissioning, counted from the date on the inspection report.

For the Sibelga form you need the EAN code of the meter the battery is linked to and the total capacity in kWh. Add the conformity report and the single-line diagram. Two further rules can apply to a business site:

• Production above 30 kVA has a decoupling relay, which disconnects it from the grid when the grid fails. After Sibelga has adapted the relay in its lab, a Sibelga technician tests it on site.
• Production of 500 kVA or more must have a remote-control device. Sibelga can then limit your injection temporarily when the grid cannot absorb any more. Your supply from the grid stays guaranteed.

Adding more power at the same time? Above 150 kVA, a new connection or a power change is a separate Sibelga request with a price offer. File it early, with clear photos of the current situation.

What does the battery room need under the Brussels conditions?

The Brussels conditions for stationary batteries (arrêté of 17 December 2020) read like a room specification. Fire resistance, ventilation, access and the floor all have rules.

The fire rules behind these conditions, and what insurers ask, are in our article on business battery safety.

Where does a battery fit on a tight Brussels site?

On a Brussels site the question is rarely whether a battery is allowed, but where a compliant room fits. Each typical spot has its own catch.

Weight, cooling, noise and room size are the same in Brussels as elsewhere. Our guide on a battery container or a technical room goes through them. Renting your premises? Our article on a battery in a rented business building covers what the lease must say.

When is a business battery worth it in Brussels, and when not?

A battery earns most in Brussels on a connection above 56 kVA. There, Sibelga bills your highest peak-hour quarter-hour for a whole year. It also helps where the connection cannot grow and EV chargers or 3-phase machines keep being added.

• Good fit: an AMR connection with short, repeated peaks from ovens, lifts, compressors or chargers. The battery covers the peak and recharges at night or at the weekend. Our guide on peak shaving with a battery explains the sizing logic.
• Good fit: vans or cars to charge on a 230 V connection that cannot grow easily. See our article on charging points without a heavier connection.
• Good fit: a site that must keep running in a power cut. Our article on back-up power for businesses compares a battery with a generator.
• Weak fit: a small office up to 56 kVA without solar panels. There is no measured peak to cut, and the room and paperwork cost the same as for a larger system.

What happens when you ask us to look at your Brussels site?

We start with your connection, your permit and your space, not with a battery.

1. Step 1: Analysis and sizing. We read your Sibelga connection, 230 V or 400 V, your peaks and your current environmental permit.
2. Step 2: Technical design. We size the battery in kW and kWh, choose inverters that match the grid and check the room against the Brussels conditions.
3. Step 3: Installation and commissioning. Our business battery installations are modular up to 1 MW, with monitoring, control and optimisation included.
4. Step 4: Monitoring and support. You follow the system in our monitoring software, and we adjust the settings as your site changes.