ChargeTO Report: How Utilities could reduce EV peak load by over 50%

July 4, 2017

A problem has surfaced with electric vehicles (EVs): The average electricity usage of a home in Ontario, Canada is 25 kilowatt hours (kWh) a day, but EVs, like the new Tesla Models S and X, have batteries that can store up to 100 kWh, or about four days’ worth of electricity.

How, then, would the electrical grid handle thousands of vehicles charging at once? A report just released by FleetCarma has a few answers.

Electric Vehicles on the Rise

Bloomberg New Energy Finance estimates that electric vehicles could account for 35 percent of new vehicle sales worldwide by 2040. That means 35 percent of homes will increase their electricity use by four times with the purchase of just one EV.

Moreover, the Rocky Mountain Institute recommends that utility companies prepare now for the rapid adoption of EVs so they can avoid the undue stress on the distribution network. By anticipating and planning for the growing load of charging EVs, the institute says utilities can both accommodate the increased load at a low cost and gain benefits for the entire system.

A Study to Find a Solution

To demonstrate one method of EV load management, the Ministry of Energy’s Smart Grid Fund, in partnership with Toronto Hydro, AddÉnergie Technologies, and FleetCarma, supported a pilot project named ChargeTO.

ChargeTO included 30 residential customers and EV owners in the Toronto region and was the world’s first known residential smart-charging demonstration to use data from the vehicle on a variety of plug-in electric vehicle (PEV) models.

By combining real-time vehicle and charging station data, this pilot tested and showed Toronto Hydro and its customers how to best balance the cost of charging a vehicle’s battery with the extra load the grid needed to manage. This is called “smart charging.”

Finding a Baseline and Getting Feedback From EV Owners

To start, though, the 30 participants charged their vehicles whenever and wherever they wanted to, i.e., without smart charging, from February to June 2015. The results of this period indicated when load on the grid could be shed in case of an emergency and when it could be moved to reduce peak loads on the local electrical infrastructure.

Here are a few more findings:

• There were three main peak periods during weekdays.
  Hybrid vehicles did not have a serious effect on the load.
  Long-range electric battery vehicles (e.g., those with 100 kWh batteries) posed a serious problem.

After the baseline was established, the participants were interviewed and shared some interesting insights:

• This first phase was relatively “invisible,” meaning it required little effort to participate.
• Of the participants, 72 percent wouldn’t have participated if vehicle-side data hadn’t been used.

Curtailing Load With FleetCarma’s Technology

Then came part two: curtailment, which means using several load management strategies to distribute the load on the grid.

To encourage participation in the project, participants received electric vehicle supply equipment (EVSE) and free use of a FleetCarma vehicle monitoring device and web portal. At the end of the project, participants retained full ownership of their new EVSE.

The project had several purposes:

• show the technical feasibility of the smart charging system,
• evaluate the system’s limitations,
• quantify the real-world curtailment availability of the PEVs,
• and capture each participant’s impressions of and responses to various incentive structures.

Participants had three options. First, to protect their transportation needs, they could set the car to send signals to their utility when they required charging. Second, they could program the vehicle to fully charge the battery before their next pre-set departure time. Third, they could opt-out of curtailment for 24 hours whenever they needed.

These three primary EV user settings gave participants the comfort they needed to participate in an active load management program on their vehicle’s charging without worrying about running out of electricity.

The Results?

The options proved successful: Over the 150 days curtailment was tested, participants could reduce peak load by over 50%.

In addition, the pilot project discovered that 70-80% of the charging load could be shed at peak load times in case of an emergency and still ensure that all vehicles were fully charged in time for a scheduled trip.

The report cautions that smart charging is only one possible solution. To know which solutions are appropriate for a utility’s EV load management strategies, the utility must gather data from its own customers.

A Framework for Further Research

FleetCarma says a similar approach to this study can be used: After establishing a baseline load profile for EV charging with local EV data, the utility company could then test supply-side and demand-side strategies to find the best approach to charging EVs on the network.

With the EV market growing globally, EV load on electricity systems is also on the rise. Utilities have many options at their fingertips to manage load growth. Infrastructure upgrades, price signals, and active load control devices have the potential to manage the EV load – but each utility network is unique, as are the customers it services. The report by FleetCarma outlines different approaches utility companies can use to find a solution customized to their needs.

For more information, download the entire report here.