As the residential market in many parts of the world are moving towards densification to satisfy the growing population in urban centres, there is growing interest in providing EV chargers for high density residential facilities. High density residential developers and condo owners recognize the growing demand for EV chargers at their facilities – and that there is strong motivation to maintain the value of their properties by providing an EV charging capability.

 

One of the biggest challenges for EV charging in high density residential buildings is the peak power demand. In a residential complex, the cars tend to plug-in to chargers when the electricity demand is at its highest – around 5-8pm. Without intelligent power management, a large number of EV chargers will dramatically increase the peak demand for the grid.  This has a significant impact on the cost of electricity at the facility.

 

Intelligent / Building Integrated EV Charging

An intelligent power management for EV charging watches the peak demand of the building and does not allow EV chargers to exceed this limit.  The result is that the EV chargers have no impact on the peak demand for the grid. However, there is a limit to the number of EV’s that will be fully charged by the morning before the buildings peak demand will need to increase.

 

A study at a high density residential facility with 100 suites has shown that it could support up to 30 EV chargers and have them fully charged by 5am the next morning. However, to support 100 EV chargers for all the tenants, onsite electricity generation is required in order to maintain the same grid peak demand.

 

The next challenge is to determine how much additional power would be required in order to support 100 chargers. Even with intelligent power management, the building would need to increase its peak demand to 175kW, which would increase electricity costs by 53%.

 

Onsite Generation

With the introduction of a 50kW onsite generator, the facility is able to support 100 EV chargers and still maintain the original 125kW peak demand for the facility.  (See Case Study: EV Chargers)

 

When implementing an EV charging solution, there are a number of issues to consider

• How significant are the peak demand charges for the building

• How many EV chargers are required to support business demand

• Will additional onsite electricity generation be required to support the volume of EV chargers