Energy Management Systems - What, Why, and How?

What are Energy Management Systems?

Energy Management Systems (EMS) are devices that manage the available power being distributed to a charger(s). They come in two types:

1. Hardware Solution – For preventing panel overloading

2. Software Solution – For implementing power sharing algorithms between multiple chargers

The Issue

Most residential homes come equipped with a 100A service. Once a customer adds a central air conditioner, hot tub, or other large electrical appliance to their panel, their peak load calculation will be above 65-70A. Adding a large charging unit would likely place their home too close to the allowable limit by Canadian Electric Code (CEC) standards, and as a result, would get denied by the City Permitting Office.

Without an EMS, your options for increasing your charger size would be:

• Increase home electrical service from utility provider ($10k – $60k)

• Install off-grid renewable energy solution ($10k - $20k)

How EMS Solves The Issue

Energy Management Systems allow Master Electricians to exclude the EV charging portion of the residential electrical load calculation as per CEC section 8-500 & 8-104. They work by monitoring the home electrical service in real time and calculate the total load being used by the house.

• If there is capacity available, it will close the EV charger circuit and allow it to operate.

• If there is a shortage of capacity, it will open the EV charger circuit to restrict its use. The goal is to eliminate the risk of panel overloading by installing an engineered control.

Often, the load being used is far less than the peak load used in CEC standards, therefore, EMS systems are popular options for customers looking to add more charging capacity to their home.

What You Need to Know

Energy Management Systems (EMS) are a cost-effective, add-on product that can help customers increase the size of the EV charger. They are appropriate for homes with numerous electrical loads and are recognized as technical solutions in the Canadian Electric Code.