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Your grid operator calls to ask whether you can offer flexible capacity. Your consultant mentions it in every other sentence. And you think: probably, yes, but how much? In kilowatts, for how long, and without stopping production or leaving a truck stranded on the yard tomorrow morning.

That question can be answered. You don’t need a degree for it, you need your own quarter-hourly data and someone who knows how long each process can wait. Below are the definition, the formula and two worked examples.

TL;DR

Almost every business with a large grid connection has flexible capacity. It simply isn’t recorded anywhere.

  • Flexible capacity is power you can turn up or down temporarily to help prevent grid overload
  • You measure it in kW and in hours: 200 kW you can sustain for five minutes is not the same as 200 kW for four hours
  • In the worked example below, a distribution centre with twelve charging points, a battery and refrigeration holds 910 kW of flexible capacity
  • At Liander, a kilowatt of monthly peak in the medium-voltage bands costs € 3.57 per month in 2026, so shaving 480 kW is over € 20,000 a year
  • At Liander, you can offer flexible capacity from 100 kW on a large-business connection

Your flexibility already exists. The question is whether anything is steering it.

What is flexible capacity?

Liander puts it like this: you have flexible capacity if you can temporarily raise or lower your consumption or feed-in at times when the grid is busy. That helps prevent overload.

Three ways of doing it:

  • Je zonne- of windpark tijdelijk dimmen of juist activeren
  • Pieken in je verbruik naar een ander moment verplaatsen
  • Energieopslag inzetten om te verbruiken of terug te leveren

The word that matters in that definition is temporarily. Flexible capacity does not mean using less energy. It means using the same energy at a different moment. The trucks still get charged, the cold store stays at temperature, the batch still gets finished. Just not all at 08:15.

Which is exactly why most businesses have more of it than they think. Almost nobody draws their full connection capacity all day long. The peak sits in a handful of quarter-hours a month, and in those quarter-hours there is usually something that can wait.

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The formula: kW times hours

Flexible capacity is nearly always expressed in kW, and that is half the story. 250 kW of battery power that runs flat after twenty minutes will not solve a two-hour congestion problem.

So work out two things per asset:

  • 1
    How many kW you can turn up or down without affecting the process
  • 2

    How long you can sustain that

Then stack the assets and see what is left at one hour, two hours and four hours. Congestion events typically last a few hours, so those three blocks give you a usable picture.

The result is not a single number but a profile, and it shifts by time of day, season and occupancy. Your flexible capacity on a Friday afternoon in July is not the same as on a Monday morning in January.

Worked example 1: distribution centre

An example site, based on a profile we see often in logistics:

Worked example: distribution centre
Item
Value
Contracted transport capacity
1,250 kW
Base load outside peak hours
400 kWRefrigeration and lighting
Highest monthly peak last year
1,180 kW
Charging infrastructure
12 × 150 kWSimultaneously capped at 600 kW
Rooftop solar
600 kWp
Battery
500 kWh / 250 kW

The installed charging capacity of 1,800 kW exceeds what the connection can carry. That is common practice: a load balancing layer keeps the total within the limit, in this case 600 kW.

The 1,180 kW peak falls between 07:00 and 09:00: 400 kW base load, 600 kW charging and 180 kW for the sorting system starting up. Solar contributes nothing at that moment, because the annual peak lands on winter mornings. PV lowers your energy bill, but not your morning peak.

What can come out of that quarter-hour?

  • Deferring charging: 600 kW, four hours. The trucks sit on the yard for nine hours and need five hours of charging, which leaves four hours of slack. The system does need to know which truck leaves when.
  • Discharging the battery: 250 kW, two hours. 500 kWh divided by 250 kW, and that is the theoretical ceiling. In practice, allow a little less for round-trip losses and the reserve you hold back.
  • Pre-cooling: 60 kW, one hour. One extra degree of cooling ahead of the peak. Optional, and only where the responsible manager sets the acceptable band.

At one hour: 910 kW of flexible capacity. At two hours: 850 kW. At four hours: 600 kW.

You need 480 kW of that to bring the monthly peak down to 700 kW, and the charging sessions and battery cover it on their own. The rest is headroom for days that run differently than planned.

At Liander, the kW max tariff in the band above 136 kW costs € 3.57 per kW per month in 2026 (2026 large-business tariff sheet). Achieve that 480 kW every month and you are looking at over €20,500 a year, on peak charges alone. In months where the peak is naturally lower, the saving is smaller.

If the lower peak holds for a full year, you can reduce your contracted transport capacity from 1,250 kW to 800 kW: 450 kW at € 2.29 per month, over € 12,300 a year. Exceed the new value once within twelve months of that reduction and the grid operator reverses it back to the date you applied. Reducing it only makes sense if your control layer genuinely enforces the limit. More on that in our article on whether to upgrade your connection or control it smartly.

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Worked example 2: manufacturing site

Smaller connection, different kind of flexibility. The site has a contracted transport capacity of 800 kW, a base load of 250 kW and a highest monthly peak of 780 kW. Assets: a 300 kWh / 150 kW battery, 400 kWp of rooftop solar and six 22 kW employee chargers.

Here the flexibility sits in the process itself:

  • Shifting a batch process: 180 kW, two hours. An oven or mixing line you start two hours later, provided the production schedule has room.
  • Battery: 150 kW, two hours.
  • Compressed air and cooling tower: 90 kW, thirty minutes. Bring the buffer vessel up to pressure beforehand, then hold off on topping it up.
  • Employee chargers: 90 kW, four hours. Six 22 kW points come to a maximum of 132 kW; 90 kW is a realistic simultaneous morning load. The cars are there all day, so this is the cheapest flexibility you have.

At one hour: 510 kW. At two hours: 420 kW.

The peak drops from 780 kW to roughly 400 kW, a reduction of 380 kW. That works out at over €16,000 a year on the same assumption as above: that you achieve the reduction every month. There is more on the approach per process step in our article on reducing peak demand in manufacturing.

Heating and cooling plant, heat pumps and climate control can join this list. We control them where that is wanted, always in consultation with the building manager and within the comfort limits they set. It is never the default.

What you need to know for certain

The worked examples above get you a long way, but three things determine whether the number holds up in practice.

  • A full year of quarter-hourly data. Your peak sits in a handful of quarter-hours. A monthly summary will not show them. Ask your metering company for the raw quarter-hourly values.
  • Process limits on paper. How far can a cold store drift? Which truck has to leave at 05:30? Without those limits any flexibility calculation is theory, and nobody on the operations side will let a system take control.
  • Control that actually executes. Flexible capacity on paper earns nothing. Something has to decide every five minutes which asset adjusts and when, based on price, weather, expected load and the charging needs of the next shift. Manually, that is not achievable, and fixed timers fall behind the moment anything changes. Tibo EMS recalculates the control schedule every five minutes across the next 48 hours, and she keeps total load within the limit you set.

At Enexis in Best, that approach delivered 45% lower energy costs and 50% lower emissions, without applying for extra grid capacity.

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What you can do with your flexible capacity

Briefly, because each of these routes deserves its own article:

From estimate to figure

Most businesses underestimate their flexible capacity, simply because nobody has ever worked it out. Using last year’s quarter-hourly data we build a digital copy of your site and run the control schedule on your actual consumption. You then see how many kW you can free up at which moment, what that saves on peak charges and how much room is left for expansion.

Want to know what sits inside your connection? Book a demo and we will walk through your profile together.

Frequently asked questions

Flexible capacity is power you can temporarily raise or lower at moments when the electricity grid is busy. You can do this by curtailing or activating generation, moving consumption peaks or deploying energy storage. You use the same energy, just at a different moment.

For each asset, establish how many kW you can turn up or down and how long you can sustain that without affecting the process. Add those figures up for durations of one, two and four hours. Use a full year of quarter-hourly data, because your peak sits in a small number of quarter-hours.

At Liander you can offer flexible capacity on a large-business connection above 3×80 amps, from 100 kW. For congestion management, customers with 500 kW or more inside a congestion area are approached directly.

Not if the limits are set in advance. You decide how far a cold store may drift, which truck has to be full and when, and which processes are off limits. The control system operates inside those limits.

No. Charging infrastructure, refrigeration, compressed air and shiftable batch processes are already on site and provide the bulk of the flexibility at many locations. A battery adds capacity you can deploy at any moment, including when there is nothing to shift, but it is not a prerequisite.

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