As more people plug in, is smart charging more important than fast charging?


Electric-car converts (or shoppers) tend to boast about how fast their EV might be able to charge—in miles (of range) per hour. And while that’s useful for road trips and the occasional unplanned errand, the more important question might be whether an electric car can charge smartly.

Reuters has reported on the results of a small study of electric-car owners conducted in a wealthy Stuttgart, Germany suburb. The study looks at how to be smart about getting cars charged for the time when that charge is needed—without overtaxing the local grid. 

Local grid operator Netze BW studied just 10 households in the same neighborhood and found that when everyone left their vehicles plugged in overnight and agreed to a smart-charging process, only half of the vehicles charged simultaneously—reducing their top load on the grid versus when they charged independently. 

Netze BW smart charging trial – screencap from Reuters

The participants were given 22-kwh EVSE wall boxes for their garages—potentially faster than most Level 2 U.S. charge points—plus two charge points in the street. 

Charging slowly, outside of peak hours, is the answer for utilities to provide the juice needed by electric vehicles without costly upgrades of substations and high-voltage transformers. 

Reuters mentions a study by the Norwegian energy regulator NVE showed that the country’s infrastructure investment cost for the next 20 years could fall to about $440 million with evening charging and drop to near zero in such a controlled overnight scenario. That’s before considering the potential of vehicle-to-grid (V2G) technology.

BMW Smart Charging App for i3 and i8

BMW Smart Charging App for i3 and i8

While these issues have been overshadowed by charging-speed bragging rights, they aren’t new concerns. Back in 2009, leading up to the launch of the Leaf, Nissan launched a smart-charging program with GridPoint that looked at the issue of many households plugging in and optimized grid loading. BMW, among other automakers, has for years provided a Smart Charging App that taps into off-peak rates. And in Colorado, the Platte RIver Power Authority has teamed up with eMotorWerks to track 250 study participants who use smart chargers to guide charge times toward off-peak and low-load charge times. 

Although it’s not as glamorous as the fast charging, the smart charging revolution is happening, too—just slowly.