When adopting electric vehicles (EV), consumers are now favoring long-range light-duty EVs^[1], with nearly all the growth coming from sales of long-range battery electric vehicles rather than short-range EVs or plug-in electric hybrids.^[2] Given this development, I focus here on the unique characteristics of long-range light-duty EVs charging. Long-range EVs have three characteristics that differentiate them from other residential electrical loads:

• EVs are large and mobile loads—they are not always connected to the grid, and not every day.
• EV charging is highly price elastic—drivers seek the cheapest electrons.
• Drivers easily control when to charge—charging is flexible with the large batteries and the telematics of modern long-range EVs. 

These characteristics—and especially customer behavior—mean that utilities can’t consider EVs like any other loads. Utilities need a new thinking to plan for EV charging and to assess how to best manage it to benefit ratepayers. These characteristics also have impact on public and workplace charging sites, their operators, and the businesses nearby.

Let’s see how different EV charging really is.

EVs Are Large and Mobile Loads 

Most electrical loads are fixed, like water heaters and clothes driers. Mobile loads, like cell phones, are small. But EVs are unique because they are mobile and large electrical loads. They are indeed large—typically, 4 to 8 kW for a level 2 charger, and often 100 kW or more with a public direct current fast charger (DCFC). And they are mobile: we drive our cars around (obviously) and do not always keep them plugged in when parked. In fact, parked long-range EVs are more often unplugged than plugged.

Compare this to traditional household electrical loads of a comparable magnitude, which are wired in, like water heaters, or permanently plugged, like clothes driers. Industrial loads in the 100-kW range are usually fixed and wired in.

So What?

This means that the EV charging load is less predictable than traditional electrical loads, both in space and time. An EV driver may charge at home with a level 2 charger, on the way to the cottage with a public DCFC, and on a 120-volt wall plug (level 1 charging) once they get there. Over time and with large numbers of EVs on the road, we may learn where and when EVs are being charged, on average, bringing greater predictability to this load. But, until then, we will have to go with some uncertainty. However, understanding what drive EV customer behavior and what drivers can control helps reduce uncertainty.

EV Charging Is Highly Price Elastic

EV charging is highly price elastic—an economic term meaning that consumers are sensitive to charging price and adjust accordingly. If charging prices at a given time or location rises, the demand for charging then and there should fall. Conversely, lower prices spur usage. 

Many studies confirm the high price elasticity of EV charging:

• Comparing the charging load profile in the Canadian provinces of Ontario (with time-of use electricity pricing) and Québec (without time-of-use) shows that time-of-use pricing is delaying peak charging by almost 2 hours, with a steep increase once off-peak pricing happens.^[3]