Clear answer, explained.
Ontario commercial electricity tariffs include demand charges based on the highest level of power drawn from the grid during a 15-minute billing interval in a month. Even a short-duration spike — from several EV chargers activating simultaneously at shift start — can set the demand charge at an elevated level for the entire month.
Smart charging systems address this by monitoring total building load in real time and queuing or reducing charger output when the facility approaches a predefined demand threshold. This allows facilities to operate more charger ports than the service capacity would support at full simultaneous draw, without increasing the recorded peak demand. The approach requires networked chargers with load management capability — non-networked chargers cannot coordinate loads.
Where battery storage is also installed, the battery provides a second layer of demand protection by discharging during peak EV charging events, preventing grid draw from being recorded at an elevated level. For facilities subject to Global Adjustment under the IESO ICI program, battery-assisted demand management during EV charging events can also reduce Global Adjustment exposure — a potentially larger saving than the demand charge reduction alone.
What this means in practice.
- Simultaneous charger activation spikes 15-min peak demand
- Ontario bills demand charges based on the highest recorded interval
- Smart charging queues sessions to stay under a demand ceiling
- Networked chargers required for load management
- Battery storage provides a second layer of demand protection
- Global Adjustment savings possible for Class A facilities
Best-fit environments.
- Commercial offices with large employee EV parking
- Fleet depots charging multiple vehicles simultaneously
- Facilities already near their demand charge threshold
- Industrial sites combining EV charging with production loads
