Home battery in Belgium in 2026: is it still worth it without the premium?

What happened to the premium

Flanders paid a premium for home batteries from 2021 onwards, at most 40 percent of the invoice and capped at 850 euro per battery in the first quarter of 2023. Batteries with an electrical inspection certificate dated after 31 March 2023 no longer qualified. The application counter closed on 1 December 2024 and the premium was wound up completely on 1 July 2026, so no new or pending files can be processed.

If you move into a home that already has a battery, nothing changes for you: the premium was paid to the original buyer and is not transferable. For anyone buying a battery today the starting point is simple: the full installed price is yours, and the return has to come from your energy bill.

Why batteries still sell without a subsidy

Two things changed in Flanders in the same period, and both favour storage. The first is the digital meter. With an old analogue meter the disc ran backwards when your panels produced more than you used, so the grid acted as a free battery. The digital meter measures offtake and injection separately. You pay roughly 0.28 to 0.35 euro per kWh for what you take from the grid, all in, and you receive only about 0.03 to 0.06 euro per kWh for what you inject. Every kilowatt hour you can shift from injection to self-consumption is worth the difference, roughly 0.25 to 0.30 euro.

The second is the capaciteitstarief, the capacity tariff that grid operator Fluvius has applied since 1 January 2023. Part of your grid costs are now based on your highest quarter-hour power draw each month, not only on the kilowatt hours you use. A battery that discharges while the oven, the heat pump or the car charger is running keeps that peak lower. The mechanics are explained in the article on the capacity tariff.

A worked example for a typical household

Take a family in the Kempen with 4,000 kWh of annual consumption and 4 kWp of solar panels producing about 3,800 kWh a year. Without a battery, a household that is out during the day typically uses about 30 percent of its own solar power directly and injects the rest. With a 10 kWh battery that share rises to about 60 to 70 percent in practice, because the evening and night load is served from storage.

That means roughly 1,200 to 1,400 kWh a year shifts from injection to self-consumption. At a difference of 0.27 euro per kWh, the battery saves about 320 to 380 euro a year on energy. Add the capacity tariff: if the battery trims your average monthly peak from 5 kW to 4 kW, that is one kilowatt less at roughly 45 euro per kW per year, so about 45 euro. The total is around 370 to 420 euro a year.

The installed price of a battery depends on its capacity, the brand and whether your inverter needs replacing, so the payback below is a worked example, not a quote. Assuming an installed price of 5,000 euro (an assumption for the calculation, not a Roakus-E price) the simple payback is 12 to 13 years; at an assumed 7,000 euro it is closer to 17. Manufacturers typically guarantee 10 years or around 6,000 cycles, so the economics are tight for a household that is already home during the day, and reasonable for one that is not.

When it does and does not add up

The numbers improve when one or more of these apply:

• You inject more than half of your solar production because nobody is home on weekdays
• You have a dynamic or two-rate contract, so the battery can also charge from the grid at night when prices are low and discharge during the expensive evening hours
• You have, or plan, an EV charger or heat pump that would otherwise push your monthly peak to 7 kW or more
• Your inverter is due for replacement anyway, so a hybrid inverter that handles both panels and battery removes a separate cost
• You want backup power during an outage, which a battery with a backup function can provide for a few essential circuits

Sizing, registration and inspection

A common rule of thumb is 1 kWh of storage per kWp of panels, or roughly 1 kWh per 400 kWh of annual consumption. Oversizing is the most frequent mistake: a 15 kWh battery on a 4 kWp roof will rarely be full in winter and the extra capacity never earns its price. A good installer sizes on your real quarter-hour data from Mijn Fluvius, not on the roof.

Every battery in Flanders has to be inspected by an accredited inspection body (the keuring) and registered with Fluvius, the distribution grid operator, before it goes into service. Registration is the owner's responsibility even when the installer handles it, so agree in writing who does what. The battery also needs its own circuit and protection in the fuse box, which is why the work is best done by an electrician rather than a battery reseller.

In practice home battery installation at Roakus-E starts with your consumption data, a calculation with a realistic payback time, and only then a quote with capacity, brand and a fixed price. Inspection and Fluvius registration are part of the job.