Can you put a battery in a rented business building?

Yes, a tenant can put a business battery in a rented building, but only with the landlord's written consent. Put three things in the lease or a side letter: who owns the battery, who insures it, and what happens when you leave. Do that before you order. It is cheaper than a heavier connection on a building that is not yours.

You rent a workshop, a shop or a warehouse, and the business is growing. The capacity tariff keeps rising, the vans need charging, and the installer says a battery would fix both. Then the doubts come. Is it worth paying for something in a building you do not own? What if you move in six years? And will the landlord even agree?

Here is what most tenants do not see. Without a written agreement, the battery can end up belonging to the landlord for free. A commercial lease also lets you leave every three years, so your payback must fit your exit dates. And the obvious alternative, a heavier connection, means works on the landlord's building. In Flanders, above 250 kVA, it means a customer cabin on his land.

That is where a battery helps. A plant nursery in Jabbeke needed more power for a new watering pump. The alternative on the table was medium voltage, at a high price. A semi-off-grid system with a battery of 92.4 kWh kept the existing 3x400 V 32 A connection as a charger. It now delivers the 63 A the pumps need.

Can a tenant install a battery in a rented business building?

Yes, but not on your own. A battery is wired into the switchboard, needs a spot that meets the fire rules and often a cable route through walls. That changes the building, so the landlord must agree.

For shops and craft businesses, the Belgian commercial lease law gives the tenant a real right. You may make any change that is useful for your business, if it costs no more than three years of rent. It must not harm the safety, health or look of the building, and you must inform the landlord first.

Is your battery bigger than three years of rent? Then that legal right does not cover it, and you need an explicit agreement in the contract (Advo-Recht). For most SME batteries this limit is not the problem. The hard part is the end of the lease.

Does the commercial lease law apply to your business building?

Only if you sell or serve directly to the public there. The law covers premises used mainly for retail, services or a craft business with direct contact with the public (UNIZO).

Parties can also choose the commercial lease law for a warehouse or office in their contract. Read your lease before you write to the landlord. It may already contain a clause on alterations, technical installations or solar panels.

How do you ask the landlord for permission to install a battery?

By registered letter or bailiff's notice, with the plans and the quotes attached. That is the route the commercial lease law sets. The landlord then has 30 days to object for good reasons. If he does not react, he is deemed to agree.

The law asks for plans and quotes. A good battery offer contains exactly that: the location, the cable route, the inverter power and the fire measures. Send the landlord the technical design, not a brochure. A clear file makes a refusal on "good reasons" much harder.

The works run at your risk. The landlord can ask you to insure the liability for your works, before or during them. That covers you, him and the owner, towards third parties and between you (commercial lease law, article 8). Without proof of that insurance, he can have the works stopped.

For a warehouse or office outside the commercial lease law, there is no fixed procedure. Ask anyway in writing, with the same file, and get a signed answer.

Who pays for a battery in a rented building, and who gets the savings?

The savings go to whoever pays the electricity bill, and that is usually the tenant. The capacity tariff, the peaks and the energy all sit on the connection in your name. The landlord gains when the battery stays and the building has more usable power.

So there is no single right answer to "who pays". There are three models that work, as long as they are in writing. For the financing itself (buy, lease or pay per use), see how a company can finance a battery.

The fixed part is what stays in the building anyway: a fire-safe room, a concrete base for a container, heavier cables to the switchboard. The battery modules are the movable part. Splitting along that line keeps the end of the lease simple.

Does the tenant pay? Then the battery must earn its money in the years you are sure to stay. Under a commercial lease you can leave at the end of every three-year period, with six months' notice. Size the battery on your peaks and your exit dates, not only on your bill. Our article on what peak shaving is and when a battery pays off explains the sizing. For the Flemish tariff, see how to calculate the capacity tariff for your business.

On tax: an investment deduction may apply to a business battery. Our article on subsidies and tax deductions for a business battery lists them. Ask your accountant how to write off equipment in a building you do not own.

What should the lease say about a battery?

Seven points, in the lease or in a signed side letter. Most disputes about installations in rented buildings start with one of them left open.

Who is liable if a battery catches fire in a rented building?

In principle the tenant, unless the tenant proves the fire was not his fault. Article 1733 of the Belgian Civil Code puts that burden of proof on the tenant (Civil Code, article 1733). A battery you installed yourself makes that proof harder, not easier.

That is why the inspection and the paperwork matter so much in a rented building. An installation that an approved body has inspected, placed where the fire rules allow it, is your best defence. Keep the inspection report, the design and the maintenance log together.

Tell your own insurer and ask the landlord to tell his. Some leases contain a waiver of recourse between the insurers of the tenant and the landlord. Check whether it still covers a building with a battery. Our article on whether a business battery is safe covers the fire service, the permits above 10 and 20 kWh, and the insurer.

Who registers the battery with the grid operator, the tenant or the landlord?

The grid user, and in a rented building that is usually the tenant. Fluvius says it plainly: as a grid user, you must report a storage system to your grid operator. That duty has applied since 1 January 2017 (Fluvius).

Before the report, an approved inspection body checks the installation against the AREI (the Belgian electrical safety code). Up to 25 kVA of inverter power you report it online. Above that, Fluvius handles it through a grid study. In Wallonia, ORES also asks for a declaration of the battery (ORES).

Check also whether your unit has its own connection. In a business park or a split building, several companies sometimes share one connection or one cabin. Fluvius only allows that exceptionally, with a contract between the users (Fluvius annex "cabin with several grid users"). A battery behind a shared connection then affects your neighbours too. Our article on energy sharing between businesses explains what is possible.

What happens to the battery when you leave the building?

It depends on whether the landlord agreed, and on what you wrote down. Without a clause, the commercial lease law sets the default.

That default comes from article 9 of the commercial lease law (text of the law). The legal default rarely matches what you want, so replace it with your own clause. Outside the commercial lease law, only your contract protects you.

Do you take the battery along? Then plan the move like a small project.

Loose lithium-ion batteries are dangerous goods in transport, under UN number 3480 in class 9 of the ADR (Faes). That is a job for the installer, not for your own van. Fluvius also notes that when a storage system is removed, it checks whether the grid needs changes.

A modular system makes the move easier. Our business battery systems are built in modules up to 1 MW and integrate with the existing electrical installation. At the new site, the battery can grow or shrink with your needs.

When is a battery in a rented building not a good idea?

When the lease ends before the battery pays for itself, and nothing says what happens then.

Some buildings simply have no good spot for it. Without a room or outdoor space that meets the fire rules, a battery is not an option there. Did the grid operator already refuse a heavier connection at your address? Then first read our article on what to do when a heavier connection is refused.

What happens when you ask us about a battery in a rented building?

We start with your peaks and your lease dates, and we give you a file you can send to the landlord.

1. Step 1: Analysis and sizing. We look at your peaks, your loads and how many years you plan to stay. If data is missing, we can monitor your consumption for a short period first.
2. Step 2: Technical design. Location, cable route, inverter power and fire measures: the plans and the quote you attach to your letter to the landlord.
3. Step 3: Installation and commissioning, after the landlord's consent.
4. Step 4: Monitoring and support. You follow the system in the app and the VRM portal. Our monitoring software also shows consumption per phase. Our article on service, warranty and maintenance of a business battery explains what to expect after installation.