We worked the 2026 capacity tariff through a real Flemish household’s bill. The finding is uncomfortable: the peak you can shave is worth more than the solar you can export — and most batteries are still being sold the wrong way.
Flanders now prices your electricity two ways at once. You pay for energy by the kilowatt-hour, and you pay for capacity by the peak you draw in any fifteen-minute window. The energy price gets the attention; the capacity price does the quiet, compounding work on your invoice.
This analysis puts real numbers through both. The source figures are the VREG 2026 capacity-tariff rate, the Eurostat household price for Belgium, and our own reader quote benchmark. Where a number could not be traced to one of these, it is not used.
Belgian households in the standard consumption band paid €0.3499 per kWh in the second half of 2025 — among the highest in the EU, behind only Ireland and Germany (Eurostat). On top of that, the Flemish capacity tariff charges an average of €53.39 per kW of monthly peak per year, before VAT (VREG).
That €53.39 is not a footnote. A household with a 4 kW average monthly peak pays about €214 a year in capacity charges alone — before a single kWh is priced. The minimum contribution already charges everyone for a 2.5 kW peak, even if your real peak is lower.
Take a semi-detached home in Leuven: 3,800 kWh of annual consumption, 4.6 kWp of solar on the roof, a digital meter, no battery. In 2025 its average monthly peak sat around 3.8 kW.
| Line | Before battery | After 10 kWh battery |
|---|---|---|
| Annual consumption (kWh) | 3,800 | 3,800 |
| Self-consumption share | ~32% | ~65% |
| Grid import (kWh) | ~2,580 | ~1,330 |
| Energy cost @ €0.35/kWh | ~€903 | ~€466 |
| Average monthly peak | 3.8 kW | 2.6 kW |
| Capacity charge @ €53.39/kW | ~€203 | ~€139 |
| Combined annual cost | ~€1,106 | ~€605 |
Illustrative model; self-consumption and peak values from our reader benchmark range, not a guarantee for any single home.
The combined saving is roughly €500 a year. Split it: about €437 comes from self-consumption (buying less from the grid), and about €64 from peak-shaving (the capacity tariff rewards flattening your evening peak). The battery pays back in six to eight years at installed prices of €470–€780 per kWh — faster if you add a dynamic contract that lets the battery time-shift cheap midday power.
The capacity tariff changes the sizing conversation. A battery sold to maximise self-consumption is sized to your evening load. A battery sold to store the summer surplus is sized to your roof — and that is the one that ends up oversized, because the extra kWh never get used before the next sunny day.
Our quote benchmark has flagged this for a year: roughly one in four batteries is quoted at least 30% larger than the household’s evening consumption needs. Under the 2026 tariff, oversizing is not neutral — you pay the hardware cost twice, once at purchase and once in capacity charges you could have shaved with a correctly sized unit and scheduled charging.
Method and sources as noted inline. No manufacturer or installer reviewed this before publication.
