How do you read and lower your business peak demand?

Your peak demand is the quarter-hour in a month when your business draws the most power from the grid. In Flanders it sets part of your network costs through the capacity tariff. You read it on your digital meter or in Mijn Fluvius. You lower it in four steps. Find the quarter-hours that set it and separate the loads that run together. Let a controller cap the rest. Add a business battery only for the part you cannot move.

It is Monday, just after eight. The lights go on, the compressor starts, the ventilation and the heating kick in, and the first vans are plugged in. Nobody does anything unusual. Yet at the end of the month your network costs are higher than expected. Mijn Fluvius shows a peak you do not recognise.

What you do not see is that this quarter-hour is not an accident. It comes back every working day, so it sets your peak every month. A one-off peak weighs only a little in your yearly average; a peak that repeats weighs the full year. And the obvious fix, asking staff to be careful, rarely holds. The loads that start together usually run on timers, thermostats and shift times.

A farm in Tielt shows another way. Its connection was too small to grow, and the next step would have been medium voltage. A battery system now gives the site more power, so a heavier connection was not needed. A smart control also sends surplus solar power to the boilers.

What is peak demand on your electricity bill?

Peak demand is how much power you draw at the same time, in kilowatts (kW). It is not your consumption in kilowatt-hours (kWh), which is the energy you use over time. Ten machines of 5 kW that each run for one hour use 50 kWh, whether they run one after the other or together. Run them one by one and your peak is 5 kW. Start them together and it is 50 kW.

The meter does not look at a single instant. Your digital meter takes the average power of every quarter-hour. The highest quarter-hour of the month is your monthly peak. For the capacity tariff in Flanders, Fluvius averages your monthly peaks over the last 12 months. The minimum is 2.5 kW per month.

• Only offtake counts. Power you inject into the grid does not raise your peak.
• The time of day does not matter for the capacity tariff: a peak at three in the morning costs the same as one at eight.
• The tariff depends on your network area. In 2026 it is about 53.39 euro per kW per year on average (excl. VAT).

Our article on how to calculate the capacity tariff for your business has the full calculation, with examples for low and medium voltage.

How do you read your peak on the digital meter?

You can read your monthly peak on the meter itself. Press the button to the left of the display until you see code 1.6.0. The value next to it, in kW, is the highest quarter-hour peak of the current month.

In Mijn Fluvius you see the peaks your bill is based on, month by month. Large consumers with a peak meter can follow their peaks there too and simulate a different access power.

To act on your peak, one number per month is not enough. You want to know which quarter-hour it was and what ran at that moment. Download a year of quarter-hour data from Mijn Fluvius and look for the days and hours where the peaks cluster.

Want to see it live? An energy meter in your installation shows your power per phase. Before we size anything, we can measure your consumption for a short period. Our monitoring software shows consumption per phase, with reports per minute, hour or day.

What causes peaks in a business?

In many businesses the peak is not one big machine. It is several loads that run in the same quarter-hour. The usual suspects:

• The start of the working day. Machines, compressors, ventilation, heating or cooling all switch on around the same time.
• Electric vehicles arriving together. Two chargers of 22 kW can draw 44 kW at once when both cars start charging. Read how to install chargers without a heavier connection. Forklifts that all go on charge at the start of a shift do the same: see how to charge forklifts on solar power.
• Kitchens, ovens and dryers in hospitality, bakeries and care homes.
• Heating and cooling that restart together after a setpoint change or a pause.
• One heavy machine. Running a flax processing company in Wielsbeke on the street connection would have needed a large medium voltage cabin. A generator was used to start the processing machine instead.

Short spikes weigh less than you think. The meter averages each quarter-hour. A machine that draws 10 kW for five minutes adds only about 3.3 kW to that quarter-hour (10 kW x 5 of 15 minutes). A load of 10 kW that runs the full quarter-hour adds the full 10 kW. A motor start of a few seconds can trip a fuse, but it barely moves your quarter-hour peak. So look for loads that run together for longer, not for the loudest start.

How much does one peak cost your business?

A peak that returns every month costs about twelve times more than a one-off peak. That follows from the way the capacity tariff works in Flanders: it takes the average of the last 12 monthly peaks. Take 20 kW extra at the 2026 average tariff of about 53.39 euro per kW per year:

• Every month: the 20 kW is in all twelve monthly peaks. That costs about 20 x 53.39 = 1,068 euro a year (excl. VAT).
• Once a year: the 20 kW is in one monthly peak. Your 12-month average rises by about 1.7 kW, which costs about 89 euro (excl. VAT).

So the daily routine matters more than the exception. The Monday someone forgot to spread the machines costs you a little. The start-up that happens every morning costs you the full amount. On medium voltage the stakes are higher: one quarter-hour above your access power is charged for 12 months at 150%.

How do you avoid peak demand in your business?

Work from cheap to expensive: first move loads, then control them, and only then store energy.

How much battery power and energy you need is explained in what peak shaving is and when a battery pays off. With a dynamic energy contract, the same battery can also charge when power is cheap. Charging must not create a new peak, though.

When is a battery the right answer for your peaks?

A battery is worth it when your peak is structural and cannot be moved, or when the battery does more than one job.

The farm in Tielt is an example of that last case. The battery system gives the site more power, so it did not need a heavier connection. The farm expects to take only about 5% of its yearly use from the street.

Do the same rules apply in Wallonia and Brussels?

No. The capacity tariff described above is the Flemish system. Before you size anything, check which rules apply to your site:

• Wallonia, low voltage up to 56 kVA: the standard tariff has no capacity term. The optional IMPACT tariff has one, but ORES has set it at 0 euro per kW for 2026 to 2029. Here the time of use matters more: since 2026 there is an extra off-peak period between 11:00 and 17:00.
• Wallonia, professional sites with peak metering: ORES charges a capacity term in euro per kW. Two thirds are based on the monthly peak, which is the eleventh highest quarter-hour of the month. One third is based on the annual peak, the highest monthly peak of the last 12 months.
• Brussels: Sibelga applies its own tariff structure. Check your invoice or ask Sibelga before you plan a battery for peaks. The detail per grid operator is in what a peak costs a business in Wallonia and Brussels.

What happens when you ask us to lower your peak?

We start with your data, not with a battery.

1. Step 1: Send us a year of quarter-hour data from Mijn Fluvius, or your latest invoices. Add your connection size and the loads you plan to add.
2. Step 2: If data is missing, we can measure your consumption for a short period first.
3. Step 3: Analysis and sizing. We look at which quarter-hours set your peak and which loads you can move, before we size a battery.
4. Step 4: Technical design, installation and commissioning.
5. Step 5: Monitoring and support. You follow consumption and the battery in the app and the VRM portal, and get an alert when the battery runs low.

Our business battery systems range from small SME installations to modular systems up to 1 MW, with chargers up to 180 kVA.