Former industrial site in Wallonia: no usable connection?

On a former industrial site, do not assume the old connection still works or still belongs to you. Ask ORES or RESA in writing what the connection point still carries. Then size the new use, not the old factory. Does the site need up to 75.6 kVA? Then a semi-off-grid system with solar panels and a battery can carry it. It works on a small connection, or while you wait for one. Larger sites combine a business battery with a reused cabin or a new connection.

You have found the site: a hall with a solid roof, a yard, a price that looks right. Inside, the machines are gone. What is left is "a skeleton of wires", a padlocked cabin in the corner and a meter nobody has read for years. The seller says the site "was always on high voltage". The grid operator says it needs a new request.

That gap is where projects stall. The old power on paper is not the power you can use tomorrow. The cabin may fail its inspection. The transformer may contain PCB. And a new request above 56 kVA can join a long queue in a congested zone. Meanwhile you pay for an empty building, and your first tenant or your own machines wait.

A site without any usable connection can still run. On a farm in St-Georges-sur-Meuse, the street had no electricity connection, and the farm ran entirely on a generator. Solar panels and a 46.2 kWh battery now carry the farm, with 30 kVA of power. The generator only serves as back-up, and no street connection is ever needed.

How many former industrial sites does Wallonia have?

Wallonia counted 2,058 sites to be redeveloped in July 2023, covering 3,224 hectares, or 0.19% of its territory. These are the "sites à réaménager" (SAR) of the Walloon planning code. They include old factories, but also former schools, hospitals and public buildings.

The inventory was drawn up by the SPW, the Walloon public service, and published by IWEPS, the Walloon statistics institute. 245 of the 262 Walloon municipalities have at least one such site. Hainaut and the province of Liège hold most of them.

The code makes one distinction that matters for your budget. Any abandoned site that fits the definition is a SAR "in fact". A SAR "in law" has an official recognition order for its perimeter. According to IWEPS, that recognition can sometimes unlock regional funding for buying or redeveloping the site. Ask your municipality which status your site has before you plan the works.

What is left of the grid connection on an old industrial site?

Usually less than the seller thinks. A factory with heavy loads was usually connected to medium voltage, through a cabin the customer built and maintains. After years without use, each part of that chain can be missing or out of date.

Walk through the chain before you trust any number:

That installation file is not optional. The owner, manager or operator of a non-domestic installation keeps a file with the schemes and the inspection reports. Under federal rules, the file passes to every new owner, and on transfer the new owner becomes responsible. Ask for it before you sign.

Buying a building that is still in use? Our checklist on the grid connection of a business building covers the general questions. This article stays with sites that have stood empty.

Can you put an old medium voltage cabin back into service?

Sometimes, but only after an inspection, and often after replacing parts. Under the Belgian electrical safety code for high voltage (RGIE book 2), a new installation or a major modification needs a conformity check before use. After that, every high-voltage installation needs a yearly inspection.

A cabin that stood idle has usually missed years of those yearly visits. Worn switchgear, a missing earth measurement or a new transformer all mean work, and a major change means a new conformity check. For a new cabin, ORES also asks for an inspection by an approved body before it connects the site. The detail is in the ORES technical rules C2-112.

There is also a good reason to check before you strip the cabin. ORES states that when an upgrade takes a connection above 250 kVA, the power that already exists stays permanent. Only the extra power may become flexible. Whether a connection that has been dead for years still counts as existing is exactly what to ask ORES in writing.

Is the transformer in an existing cabin simply too small for the new use? Our article on a cabin transformer that is too small compares a new transformer with a battery behind it.

Does the new use still need medium voltage?

Often not. A factory that ran furnaces or presses needed hundreds of kVA. A hall split into workshops, a storage site or a farm building often needs a fraction of that. ORES handles requests in three bands: below 56 kVA, 56 to 250 kVA, and above 250 kVA.

The band decides the route. Below 56 kVA the route is simpler, and the access-to-power problem does not apply. Above 56 kVA, a paid detail study reserves your place in the queue. Above 250 kVA in a congested zone, you may be offered a flexible connection with only part of the power guaranteed.

Moving down from medium to low voltage is a new start, not a switch. ORES treats a site that moves from the high-voltage to the low-voltage grid as a new low-voltage customer. The full procedure applies, including a conformity certificate for the installation before it goes into service.

Not sure which grid your new activity belongs on? Our article on low or medium voltage for a business explains the difference. Our comparison of a medium voltage cabin or a battery shows when the cabin is still worth it.

What can you do when the connection is dead or the power is not available?

You have five realistic routes, and the right one depends on how much power the new use really draws. The ORES steps, study costs and waiting times are in our article on a business connection in Wallonia. Here is how they apply to an old site.

Is the new connection mainly expensive because the cable is long? Our comparison of grid extension cost and a battery shows when the battery costs less than the cable.

Can a battery and solar panels power a former industrial site?

Yes, for most SME and farm uses, either as a bridge to the final connection or for good. Old halls often have large roofs, and the battery turns that roof into power for the evening and for the peaks.

For sites on a standard 3 x 400 V connection, a semi-off-grid system lets solar panels and a battery carry the site. An automatic transfer switch changes over to the public grid when the battery runs low. It works up to 75.6 kVA, and the site can keep working during a grid outage. After a trial period, it can even go fully off-grid.

Two Walloon projects show the range. On the farm in St-Georges-sur-Meuse, the system replaced a generator that ran the whole site. In the woods of Gedinne, a weak line delivered only 180 V, and the system brings the site to 3 x 400 V. There, the weak grid is still used, but as a charger for the battery.

Larger sites use the same logic at a bigger scale. Our business battery systems are modular up to 1 MW, and they can sit behind a reused cabin or a flexible connection. In Wielsbeke, a flax processor avoided a large medium voltage cabin for one heavy machine. A generator starts it and charges the batteries at the same time.

Does the site need power during the works first? The temporary site connection has its own procedure: see our article on a construction site connection that comes too late.

Can one old cabin supply several new tenants?

Not freely. A site owner may pass electricity through their own installation to other customers on the site. The CWaPE, the Walloon energy regulator, calls that a private network. In Wallonia, private networks are banned in principle, with a short list of exceptions.

The exceptions include temporary use of up to twelve weeks a year, such as markets and events. Networks inside one office building are allowed, and so are private networks that only supply charging points. A redeveloped industrial site with several independent companies usually fits none of them. Without an exception, the rule is a direct connection to the public grid for each tenant.

A second category exists: the closed professional network. A new one needs prior authorisation from the CWaPE, and only in narrow cases. One case is integrated production processes. The other is energy used at least 75% by the owner or linked companies, where the tenants have no reasonable offer from the public grid.

Two connections on one site can still share a battery in some set-ups. Our article on two grid connections and one battery explains the rules. Our article on energy sharing between businesses covers the legal routes for neighbours.

What should you check before you buy or redevelop the site?

Six questions settle most of the risk. Ask them before the deed, not after the first tenant signs.

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

We start from the new use, not from the old factory.

1. Step 1: Analysis and sizing. We list the loads of the new activity, the peaks and the energy per day, and compare them with what is left of the connection.
2. Step 2: Technical design. We tell you whether a battery, a semi-off-grid system, an off-grid system or a cabin is the honest answer.
3. Step 3: Installation and commissioning.
4. Step 4: Monitoring and ongoing support. You follow consumption, yield and the battery level in real time.

When is it not for you? A site that will run heavy, continuous loads of several hundred kVA needs a cabin and a grid connection. A battery then helps with the peaks, not with the base load. Building from scratch with no connection at all? See our article on a new building without a grid connection, or our off-grid systems.