How do you read the Fluvius grid congestion map in Belgium?

Look up your area on the monthly Fluvius map: orange means only flexible connections, yellow flexible from 1 MVA, green classic. In Belgium only Flanders publishes such a grid congestion map, for medium voltage from 100 kVA. On low voltage, a semi-off-grid system often keeps you on your street connection.

You are planning a new hall, a heat pump or a row of chargers. The bank, the architect or a supplier says: "Check the congestion map first." You open it and almost all of Flanders is orange. Is the grid full where you are?

Which grid congestion map applies to companies in Belgium?

In Flanders, the Fluvius congestion map is the public map for business connections. Wallonia and Brussels do not publish a comparable colour map. Other maps in search results answer other questions.

Belgian companies connected directly to the high-voltage grid deal with Elia, not with Fluvius.

What does the Fluvius congestion map show, and does it apply to you?

The map shows, per power supply area, which connections are still possible for high and very high power. A power supply area is the zone fed by one transformer station. The colour depends on the expected grid congestion in that area in 2035.

It is a forecast, not today. An orange area is not an area where the lights go out.

It is indicative and not binding. For a specific file, Fluvius can still find another solution, for example because of the Elia grid upstream or other factors.

Some companies panic and freeze a project the map does not even concern. Others see green, buy a building or order machines, and learn a year later that their address gets another answer.

It is about extra power on medium voltage. A high or very high power connection, which Fluvius calls a large-power connection, typically means medium voltage from 100 kVA. According to Fluvius, households are not affected, and the grid operator always keeps capacity for the low-voltage grid.

Small businesses are connected there too. On low voltage, demand grows through tens of thousands of small requests. On medium voltage, a single request for a very large power can change the free capacity of a whole area.

A workshop on 3 x 400 V that adds a machine may stay outside the map. The same workshop that has to move to medium voltage for that machine lands right in it. Our article on low voltage or medium voltage for a business explains where that line lies.

In June 2026, Voka reported that the Flemish majority parties had agreed to drop pure "first come, first served" in congestion areas. Low-voltage users and essential services would get the highest priority.

According to Voka, companies with a battery behind the meter could qualify too, as projects that reduce the load on the grid. Medium-voltage companies come in a second category. The regulator still has to turn this into rules.

What do orange, yellow and green mean for your expansion?

Orange means only flexible connections, yellow means flexible from 1 MVA of extra power, and green means classic connections are still possible. On the September 2026 map, most of Flanders is orange.

In Flanders, the flexible connection that Fluvius offers today is called Fall-Back Flex. You get the full power you asked for, but Fluvius may limit it temporarily at exceptional peaks. You can refuse it, but then your connection may wait until the grid is reinforced.

Our article on what to do when Fluvius refuses a heavier connection explains Fall-Back Flex in detail.

How do you find your site on the map, step by step?

Download the latest map, find the area around your site, and write down the colour and the date. Then check it against your own numbers.

1. Step 1: Open the Fluvius page with figures and maps and download the latest PDF. Check the date: an older copy may show another colour.
2. Step 2: Zoom in on your site. The areas follow the transformer stations, not the municipal borders.
3. Step 3: Note the colour and compare it with your request. How much extra power do you need, in kVA, and would it take you from low to medium voltage?
4. Step 4: Look at the table of open files on the same page. It shows how busy the queue is.
5. Step 5: Ask Fluvius for your own case. Only a request and an offer tell you what you get, when and on which terms.

What do the monthly Fluvius figures tell you about the queue?

They show how many large-power files are open, and at which stage.

Fluvius adds a warning: "Quote still to be made" is a normal internal step, not a queue for the connection itself. The table covers all open files for high and very high power and industrial batteries since autumn 2025.

About 1,800 projects were waiting for a new or heavier connection in Flanders in June 2026, according to Voka. In December 2025, 181 requests for a connection to the high-voltage grid were still being studied, VRT reported.

Elia and Fluvius said they aim to give those companies clarity within two years. They also said that speculative requests block the queue for real projects.

So ask early, and ask for what you really need. A realistic request with a clear load profile fits more easily into the capacity that is left.

Is there a congestion map for Wallonia or Brussels?

No public colour map of this kind exists in Wallonia or Brussels today. In Wallonia, ORES says the situation varies by region and several zones already have a high risk of congestion.

ORES distinguishes two kinds of congestion. Local congestion sits at the Elia transformer station that feeds the ORES grid. Upstream congestion sits on the Elia transmission lines and reduces what that station can deliver.

Both limit new connections and upgrades above 56 kVA for business customers. Without a map, the study is your map. An orientation study is paid and not binding, and only gives you information.

Only the detail study officially starts your request and reserves your place in the queue for that Elia station. In June 2026, 1,066 connection requests were waiting for an answer at ORES, 161 of them in the Mons-La Louvière area. Our article on a business connection with ORES or RESA explains the steps, costs and the flexible connection above 250 kVA.

In Brussels, we found no public congestion map from Sibelga. Ask Sibelga directly with your address and the power you need, before you plan the project.

Can a battery or a semi-off-grid system let you grow in an orange area?

Often yes, because the map is about extra power from the grid, not about the power a battery delivers on your own site. The battery charges when the site is quiet and adds its power when the machines run. Plan on the power you can be sure of, and cover the rest yourself.

For companies and farms on a standard 3 x 400 V connection, a semi-off-grid system goes furthest. Solar panels and a battery carry the site, and an automatic transfer switch changes over to the grid when needed. It works up to 75.6 kVA, which is 3 x 400 V with 63 A.

A plant nursery in Jabbeke needed a heavier connection for a new irrigation pump; the proposal was medium voltage, at a high price. The semi-off-grid system let it keep its 3 x 400 V, 32 A street connection. That connection now charges a system that delivers 63 A to the pumps; variable speed drives start the heaviest pumps smoothly.

In Tielt, a farm would otherwise have needed medium voltage to expand. The battery system gives the site more power instead. It is expected to take only about 5% of its yearly use from the grid.

Above 75.6 kVA, a business battery does the same behind a medium-voltage connection, keeping your draw under the power you have and covering the rest. More power without a grid upgrade shows the calculation for one machine; the peak demand of a business explains how to read your peaks first.