Smart Charging can dramatically reduce the utility capacity and electricity costs of charging multiple electric vehicles. It is often seen as complicated and difficult, but it doesn’t have to be. We’ll explain how simple smart charging can earn most of the savings.

Most of the savings from smart charging are just due to limiting the peak demand charges (explanation), often accounting for 70% or more of the possible savings. (paper) Peak demand charges bill for the, typically 15min or 30min, interval with the highest average demand (kW) in the month, or year depending on the tariff.

The rare cases where many vehicles plug in about the same time causing a brief, high peak can add up and cause a substantial cost for just a few minutes of value per month. Simple grid limit (sometimes called dynamic load management) smart charging can avoid those peaks and substantially cut costs. In most cases the users won’t even notice if charging is slightly slower since they are parked for a longer period.
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‘Complete’ smart charging can mean a variety of things, depending who is selling to you. For some users it is deep integration with the power grid, where the smart charging system helps to support the grid by reducing load when the grid asks. Companies like Nuuve and Monta implement this. Deferring charging to use the cheapest energy is possible if you know when the vehicle needs to leave, Jedlix and others offer that. For fleets, planning charging so the vehicle has exactly the right amount of energy for its next assignment can minimize charging during expensive periods, but requires knowing when vehicles are leaving and predicting how much energy they will need. Knowing and planning that will often require broader changes than just the charge management system, such as vehicle telematics, driver and yard information terminals. These functionalities will likely be common in future, but are rare now. While these advanced techniques can help lower costs, even earn additional revenue from providing grid services, the bulk of the savings from smart charging can be achieved with a simple grid limit.

A good example of a simple smart charging application is an apartment parking lot, with many EV chargers, but not enough utility capacity to serve them all at the same time. For this case transparency and fairness are key requirements. If there isn’t enough power for all the vehicles, users likely expect it to be equitably distributed between the users, even if they don’t get the full power they want. Adding an app or user interface so people can specify departure times could help prioritize but adds complexities of user management. For this application a very simple average algorithm could be sufficient to allow the apartment to install chargers at every location, even with a limited grid capacity and no need for user apps or offsite interface. We’ll explain how to implement average charging in a coming edition.

Simple smart charging can deliver considerable savings, so don’t delay implementing it while waiting for the most comprehensive or advanced solution. The solution that works well starting today may well deliver more savings than the more elaborate solution deployed years later.

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