Capacity tariff costs can feel opaque until you see concrete examples. This article walks through typical SME scenarios: how a 10 kW peak increase affects your bill, why two sites with similar kWh can have very different capacity charges, what drives avoidable spikes, and key numbers to remember. Use our capacity tariff calculator to estimate your own costs and savings.
1. Example: The 10 kW peak jump
A small workshop runs at 75 kW peak for several months. One morning, HVAC, a compressor, and a process line all start within the same 15-minute window. The new peak: 92 kW. At a typical €4.50/kW/month capacity rate, that 17 kW jump adds roughly €918 per year. Same total kWh-just concentrated in time. Spreading the HVAC start to 07:20 and the line to 07:25 could drop the peak back toward 75 kW and avoid that extra cost.
2. Example: Same kWh, different capacity cost
Two SMEs each use 15,000 kWh per month. Site A draws steadily; its peak is 45 kW. Site B has a morning startup surge; its peak is 85 kW. Site B pays roughly twice the capacity charge of Site A, despite identical consumption. The lesson: peak concentration matters more than total volume for the capacity component. For Site B, staggering the morning load could cut the peak and bring capacity cost in line with Site A.
3. Example: Staggering pays off
A logistics centre reduces its peak from 120 kW to 95 kW by staggering EV charging and ventilation boost by 15 minutes. At €4.50/kW/month, that 25 kW reduction saves about €1,350 per year. No new equipment-just better sequencing. The EV chargers now start at 09:30 instead of 08:00, taking 22 kW out of the peak-forming interval.
4. Example: Office with EV charging
An office previously plugged in two company cars at 08:00 when staff arrived. The chargers and the building's morning load (lighting, HVAC, IT) sat in the same 15-minute block. The peak jumped by 22 kW. Moving the EV charge start to 09:30 (or a timer after 10:00) took those 22 kW out of the peak-forming interval. The next month's invoice showed a lower capacity line with no change in total kWh.
5. Key numbers to remember
Key numbers
Typical capacity rates for Belgian SMEs range from roughly €3 to €5 per kW per month depending on region (Fluvius, ORES, Sibelga, Resa) and connection class. At €4.50/kW/month, a 10 kW increase adds about €540 per year; at €5/kW/month, €600. The impact scales linearly: every kW you cut from your peak saves you the €/kW rate for the full year.
Use our capacity tariff calculator to estimate your costs by region, peak kW, and billing period. For a step-by-step playbook on reducing peaks, read our guide on how to reduce peak demand charges. capacity tariff calculator how to reduce peak demand charges.
6. What you can do
Map your main startup windows and identify overlap. Use our capacity tariff calculator to estimate your costs and savings. For a complete overview of how the capacity tariff works in Belgium, read our capacity tariff Belgium guide. capacity tariff Belgium guide.
Key takeaways
- 1. Peak (kW) drives capacity cost, not total kWh.
- 2. A 10 kW delta at €4.50/kW/month ≈ €540/year.
- 3. Stagger heavy loads by 10–20 minutes to reduce overlap.
- 4. Use the calculator and reduce-peak guide for next steps.