What Is GTV?
GTV stands for Gecontracteerd Transportvermogen, which translates to contracted transport capacity. It is the maximum amount of electrical power your site is allowed to draw from the grid, as agreed with your network operator.
Think of it as the bandwidth of your electrical connection. Just like an internet plan has a speed limit, your grid connection has a power limit — measured in kilowatts (kW).
Why Your Grid Limit Matters
Exceeding your contracted capacity is not just a technical problem — it has real financial consequences:
- Penalty charges from your network operator for drawing more power than agreed.
- Forced upgrades to a higher capacity tier, which can be expensive and take months to arrange.
- Grid instability that can affect your own equipment and neighboring connections.
When you add EV chargers to a site that already has lighting, HVAC, machinery, or other loads, the total demand can easily push past your contracted limit — especially during peak hours.
How Stekker Monitors Your Connection
Stekker uses sensors installed at your grid connection point to measure real power consumption in real time. These sensors report the total load across your entire site, not just the chargers.
This gives the optimization engine a live picture of how much capacity is available for EV charging at any given moment. If your building’s HVAC system spikes, Stekker sees it and adjusts charging power accordingly.
How Power Gets Distributed
When multiple vehicles are charging simultaneously, Stekker’s EMS (Energy Management System) distributes the available power intelligently:
- It starts with your contracted limit.
- It subtracts the current non-EV load measured by the sensors.
- It subtracts a safety margin (more on that below).
- The remaining capacity is allocated across active charging sessions.
Sessions are prioritized based on departure times, battery state of charge, and other optimization goals like energy prices and solar availability. A vehicle that needs to leave soon gets priority over one parked overnight.
Why Stekker Leaves Headroom
Stekker never uses 100% of your contracted capacity for charging. A configurable safety margin is maintained to account for:
- Sudden load spikes from other equipment (elevators, compressors, heating systems).
- Measurement lag — the brief delay between a load change occurring and the sensors reporting it.
- Charger response time — chargers need a moment to adjust their output after receiving a new profile.
This margin ensures your site stays safely within its contracted limit, even during brief power fluctuations.
More Chargers Without a Grid Upgrade
This is where smart charging truly shines. Without Stekker, you would need your grid connection to support all chargers running at full power simultaneously. With Stekker, you only need enough capacity for the actual charging demand at any given moment.
The relationship is straightforward: the more flexibility you have (longer parking times, lower daily mileage), the more chargers you can support on the same connection.
Practical Example
Consider a site with a 50 kW grid connection and three 22 kW chargers. Without smart charging, running all three at full power would require 66 kW — well over the limit.
With Stekker managing the load:
- The building’s base load is 15 kW (lighting, HVAC, equipment).
- Stekker reserves a 5 kW safety margin.
- That leaves 30 kW available for EV charging.
- Stekker distributes those 30 kW across the three sessions — for example, 10 kW each, or 15 kW to the vehicle leaving first and 7.5 kW to each of the other two.
- As vehicles finish or the building load drops, the remaining sessions automatically receive more power.
The result: three chargers operating safely on a connection that would otherwise support only two — no grid upgrade needed.
Checking Your Setup
Your grid connection limit is configured in Stekker during onboarding. If your contracted capacity changes (for example, after a grid upgrade or a new contract), contact your Stekker administrator to update the setting. An incorrect limit could lead to either unnecessary restrictions or insufficient protection.
To understand how Stekker sends these power adjustments to your charger, see How Stekker Controls Your Charger.
