How do you calculate your business capacity tariff in 2026?

In Flanders you calculate the capacity tariff in three steps. Find your highest quarter-hour peak in kW for each month. Take the average over the last 12 months (minimum 2.5 kW) and multiply it by the rate of your network operator. In 2026 that is on average about 53.39 euro per kW per year, excluding VAT, according to the Flemish regulator (Vlaamse Nutsregulator, VNR, formerly VREG). Businesses on the low-voltage grid follow the same logic. Businesses on medium voltage pay a different formula: an access power chosen in advance plus the actual monthly peak, with a steep excess rate. To bring that peak down, a commercial battery can flatten your highest quarter-hours. Both calculations follow below, with worked examples.

What is the capacity tariff, and what is peak power?

The capacity tariff is the part of the Flemish distribution network tariffs that you pay for how heavily you load the grid, not for how much energy you use. The yardstick is your peak power: the highest average power you draw from the grid in one quarter-hour, expressed in kW.

A few terms you will find on your invoice and in Mijn Fluvius (the Fluvius customer portal):

• Quarter-hour peak: your average offtake over 15 minutes. Your digital meter records kWh per quarter-hour; Fluvius converts that to kW by multiplying by four. If you draw 11.5 kWh in one quarter-hour, your quarter-hour peak is 46 kW.
• Monthly peak: the highest quarter-hour peak of the month.
• Average monthly peak: the average of the monthly peaks of the previous 12 months.
• Billing peak: with an annual settlement, the average of the average monthly peaks over your billing period. Your supplier applies the rate in euro per kW per year to it (Fluvius).

Only offtake peaks count. Injection peaks from solar panels do not. And it does not matter when your peak falls: for the network tariffs there is no longer a day and night difference.

If you are thinking about a battery to flatten those peaks, the technical side is on our page about business batteries for peak shaving and lower network costs.

Does the capacity tariff apply in Wallonia and Brussels?

No, the capacity tariff described here is Flemish. Each region sets its own network tariffs: the CWaPE in Wallonia, Brugel in Brussels. In short:

• 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 (ORES tariffs 2026). Since 2026 there is an extra off-peak period between 11:00 and 17:00 (CWaPE).
• Wallonia, professional sites with peak metering: ORES charges a capacity term in euro per kW. Two thirds are based on the monthly peak (the eleventh highest quarter-hour of the month), one third on the annual peak (the highest monthly peak of the last 12 months) (ORES).
• Brussels: Sibelga applies its own tariff structure. Check your invoice or ask Sibelga before you plan a battery for peaks. For the full picture per grid operator, read what a business peak costs in Wallonia and Brussels with ORES, RESA and Sibelga.

How to read and lower your peak in each region is explained in our article on managing your business peak demand. The rest of this article covers Flanders.

How does Fluvius calculate the capacity tariff?

Fluvius calculates the capacity tariff from the readings of your digital meter, in four steps. Fluvius works with quarter-hour averages, not with the power of a single moment. Your energy supplier then puts the amount on your invoice (Fluvius).

On medium voltage and on a distribution cabin Fluvius calculates differently: with an access power plus the actual monthly peak. We work that out further down. The details are in the Fluvius FAQ on the capacity tariff.

Who pays which capacity tariff in Flanders?

The answer depends on your meter and on the voltage level of your connection.

A few nuances. Fluvius replaces a manually read meter above 56 kVA and above 80 A with an automatically read meter (AMR). Smaller ones become digital meters. Both meter types are settled the same way (Fluvius). The approved 2026 tariff list separates customers by the grid they are connected to: the low-voltage grid on one side, and 26 to 36 kV, 1 to 26 kV and distribution cabin on the other (VNR). Your invoice or your connection contract tells you which group you are in.

How much does 1 kW cost per network area in the 2026 capacity tariff table?

Flanders has eight distribution network areas, each with its own rate. The capacity tariff table below comes from the 2026 tariff list of the Vlaamse Nutsregulator. It applies from 1 January to 31 December 2026 to low voltage with a digital meter or peak metering. The regulator approves the rates every year; the 2027 tariff list had not been published at the time of writing (September 2026).

So the price per kW depends on your network area. Businesses usually calculate excluding VAT; the tariff list also shows the amounts including 6% VAT.

Two other elements in the same tariff list are worth knowing:

• There is a maximum rate per kWh (for low voltage with a digital meter about 0.33 euro per kWh excluding VAT in 2026). The minimum contribution of 2.5 kW still applies.
• The capacity tariff is only one part of the network tariffs. You also pay a kWh rate and a data management rate.

For households, the average monthly peak in Flanders is 4.24 kW according to the Vlaamse Nutsregulator. For an SME with compressors, cooling or charge points it is quickly many times higher, and that is where the capacity tariff starts to weigh.

How do you calculate the capacity tariff on low voltage?

The worked example below is illustrative. Take an SME on low voltage in the Fluvius Imewo network area (54.20 euro per kW per year, excluding VAT). From Mijn Fluvius the manager pulls the monthly peaks of the last 12 months:

1. Step 1: average monthly peak. The sum is 464 kW; divided by 12 that gives 38.67 kW. That is well above the 2.5 kW minimum.
2. Step 2: yearly cost. 38.67 kW x 54.20 euro = about 2,096 euro per year, excluding VAT, for the capacity tariff alone.
3. Step 3: check the pattern. With an annual settlement the billing peak is formally the average of twelve rolling averages, so the months before this period also count. If your peaks follow a similar pattern every year, the result is close to this simple calculation. With a monthly settlement you see your latest average monthly peak on every invoice, charged at the rate per kW per month.

Two lessons from this example:

• One bad quarter-hour counts for a whole year. The December peak of 46 kW stays in the average for 12 months.
• Flattening peaks saves a fixed amount per kW. Suppose you cap every monthly peak at 36 kW. The average drops to 34.92 kW and you save about 203 euro per year. That is real money, but on a small low-voltage connection it is rarely enough on its own to carry an investment. The picture changes once a battery also shifts solar power, provides backup power or makes a heavier connection unnecessary.

How does the capacity tariff work for businesses on medium voltage?

For customers outside the low-voltage group, Fluvius has used two components since 1 January 2023 (Fluvius):

• Access power: a power you estimate in advance and submit through Mijn Fluvius. The tariff list expresses it in kVA. It is the basis for about half of the network costs.
• Monthly peak: the actual peak power of the past month, in kW. That makes up the other half.

The rules are strict (Fluvius FAQ on peak metering):

• You can raise your access power every month.
• After the initial choice or after a raise, you cannot lower it for 12 months.
• If your monthly peak exceeds the access power, you pay an excess rate on the difference. That difference is charged for 12 months, at a rate 50% higher than the access-power rate.
• These customers always receive a monthly invoice.

The 2026 rates for Fluvius Imewo, excluding VAT, from the tariff list of the Vlaamse Nutsregulator:

How much does exceeding your access power cost?

Illustrative example: a manufacturer on the 1 to 26 kV grid of Fluvius Imewo chooses an access power of 400 kVA. In a normal month the monthly peak is 380 kW.

• Access power: 400 x 36.11 / 12 = about 1,204 euro
• Monthly peak: 380 x 54.23 / 12 = about 1,717 euro
• Total capacity component that month: about 2,921 euro, excluding VAT

Now in November a cooling installation coincides with a production line starting up, and the monthly peak reaches 430 kW:

• Monthly peak that month: 430 x 54.23 / 12 = about 1,943 euro
• Excess: 30 kW above the access power. It is charged for 12 months at 54.16 euro per kW per year = about 1,625 euro in total, spread over a year

So one badly timed quarter-hour costs more than 1,800 euro on top of a normal month here. If you grow to 430 kW for good, raising the access power makes more sense, but then you are tied to that higher value for 12 months. That is exactly where it pays to check first whether the peak can be avoided technically.

Where do you find your quarter-hour data and monthly peaks?

To calculate the capacity tariff, do not start from a rule of thumb or from the power in your connection contract. What counts is your measured profile.

• Mijn Fluvius: shows your monthly peaks and quarter-hour consumption. Customers with peak metering can also simulate and adjust their access power there.
• Display of the digital meter: press the left button until you see 1.6.0. The value in kW is your highest monthly peak so far (Fluvius).
• Your own measurement: an energy meter on your main distribution board shows not only the peak, but also which loads cause it. We start with an analysis and sizing on your profile. After installation you follow consumption per phase and the battery in the app and the VRM monitoring platform (monitoring).

When you analyse, look at three things. How high are the peaks, how long do they last (one quarter-hour or two hours) and how often do they return? Those three decide which solution works.

How do you lower your peak power?

From cheap to far-reaching:

Charge points deserve special attention. Fluvius advises avoiding large consumption peaks, for example by not using all appliances at the same time. As an illustration: an 11 kW charge point charging at full power during your heaviest quarter-hour pushes that monthly peak up by as much as 11 kW. If the same charge point charges under control outside that quarter-hour, the monthly peak stays the same. Planning several charge points on a connection that is already tight? Then read our article on charge points for a business without a heavier connection, which works out the numbers.

A battery is the tool for peaks you cannot shift: a production line that has to run, a cold room that has to cool. How to size such a battery, in kW and in kWh, is explained in our article on peak shaving with a battery.

When is a battery the better choice for other reasons too?

The capacity tariff is rarely the only argument. A business battery that flattens peaks can at the same time:

• shift solar power from midday to the late afternoon;
• take over the critical loads during a power cut, if the system is designed to run off-grid. That is the difference between a real energy system and a storage box;
• postpone or remove the need for a heavier grid connection or your own cabin, when the grid operator cannot supply extra power. A battery is then often the faster answer.

One example is our semi-off-grid installation at a flax processing company in Wielsbeke. Working on the grid there would require a large medium-voltage cabin. The company starts its heavy machine with a generator that keeps running during the work. Loading that generator a little more charges the battery, which supplies the electricity for the rest of the day. More on how such a system is set up is on our page about semi off-grid systems.

Security of supply is an engineering question, not a product purchase. That is why we always start from your measured quarter-hour profile, not from a standard package.