We examine various types of charging strategies and infrastructure available today and report on the experience gained from rate structures for electric vehicle charging now being offered at four...
Top 10 EV Challenges
Utilities prepare for a bumpy road.
Electric cars are expected to account for 64 percent of U.S. light vehicle sales by 2030, according to a study commissioned by the University of California-Berkeley. It’s safe to say that in the next 20 years the odds are high that a typical electric customer will maneuver an electric car into the garage and plug it into the nearest outlet. As a result, customers’ reliance on the electric grid will double.
Along with this promise of electric transportation widely disbursed across the electric distribution system comes a significant new load that our grid wasn’t designed to accommodate. The act of simply plugging-in might seem to be a benign routine, but beneath the surface is a complex problem that hasn’t yet been solved.
The electric vehicle (EV) is far from a simple plug-in electrical appliance. But to promote adoption and drive our society to transform long-lived addictions to fossil-fueled transportation, the act of charging will have to appear as simple as plugging in a toaster. With new market forces at work, the EV paradigm will demand that significant change occurs within the utility, automotive supplier, car manufacturer and investor communities, requiring a clear vision, unprecedented collaboration—and a sense of reality.
As the utility industry contemplates the onset of the EVs plugging into their respective electricity distribution system, 10 challenges stand out as being most critical. They can be divided into factors involving grid operations, policy choices and customer service ( see Figure 1 ).
EVs and the Grid
#1—The Cul-de-Sac Factor: Central correlation, also referred to as the “cul-de-sac factor” or “clustering,” reflects the fact that the EV consumer purchase distribution won’t be the same as internal combustion engine (ICE) vehicles. EVs will gravitate to the wealthy neighborhoods and environmentally conscience communities. This variety of mass-market demographics might not be completely understood, but has been preliminarily correlated with the purchase history of the Toyota Prius.
Many can relate to the natural instinct of trying to keep up with the Joneses. A neighbor buys the latest and greatest plug-in hybrid. Someone sees this, and wanting to demonstrate their green conscience for the environment and the green in their bank account, they decide to follow suit. Then another neighbor joins the action and so forth. The block or cul-de-sac quickly becomes a social network of influence.
If all these trophy-cars in a condensed area are plugged-in overnight—or worse, if a few are fast-charged during the day at periods of peak electricity demand—a new challenge of optimized energy delivery could arise for the utility. For most utilities, the delivery system can accommodate this new load if it’s evenly distributed, but they might face a rude awakening if a more closely coordinated collaboration with this concentrated segment of consumer isn’t established.
Why is this projection an issue? The answer is: electricity distribution transformer loading.
#2—Transformer Overload: Clustering of EV ownership could quickly over-extend electricity distribution assets. To put this into perspective, consider that the Nissan Leaf charging on a 240 v, 15-amp circuit generates a