The Charging Conundrum: How To Feed Electric Cars? Plug-in electric cars are in showrooms and on the highways, but there's currently no convenient way to recharge them. Electric grid engineers are now trying to build an infrastructure to handle the cars' erratic demand for electricity.

The Charging Conundrum: How To Feed Electric Cars?

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Those plug-in electric cars are now starting to show up in auto showrooms and on the highways, but there are a lot of obstacles, as we're going to hear this morning. NPR's Christopher Joyce reports on concerns facing would-be drivers and the utilities that would have to supply the electricity.

CHRISTOPHER JOYCE: Russell Rankin is an enthusiastic entrepreneur who's got 13 electric vehicles charging up at the back of the Loew's Hotel in Annapolis, Maryland. They're not quite cars, but they're more than golf carts.

RUSSELL RANKIN: So it has three rows of two seats, so everybody kind of calls it a golf cart on steroids or, you know, something maybe that you'd see at Disney or something like that. So it has a big bubbled roof on it, very futuristic looking.

JOYCE: They're made by Global Electric Motorcars, owned by Chrysler. Rankin's company, ECruisers, uses them to squire people around the city for free. Advertising on the cars pays the freight. After about 30 miles, the cars come back here to recharge.

RANKIN: Yeah, our vehicles just run off of just a regular household outlet. We have a regular, three-pronged plug that you'd have on any household appliance.

JOYCE: So that's easy. The hard part is keeping cars charged when they're needed.

RANKIN: But we still got to play a big cat-and-mouse game all day. How many vehicles do you have out? What is current charge? How many electrical outlets do we have that we can charge off of? Because if I've got 13 vehicles, but I only have 13 plugs, then I can't charge them all up as they come in and go out.

JOYCE: Have you ever been in a situation where you got a car that's out?

RANKIN: Oh, yes. Yeah. We know where every outlet is in three states and the District of Columbia.

JOYCE: Engineer Carl Imhoff at the Pacific Northwest National Laboratory looked into that.

CARL IMHOFF: We found that they could handle one to two to maybe three vehicles per home pretty easily if they are charged slowly, the same voltage that you have in your home for normal appliances, 120 volts.

JOYCE: Now, add millions of cars to the demand side. Imhoff says one way to keep the system balanced is to use smart chargers that tell grid operators how much juice these cars need.

IMHOFF: If you use smart charging, you can actually cycle the charge, turn the charge off, turn it on, turn it off, turn it on, to serve the local conditions of the power system.

JOYCE: Mark Lauby is with the North American Electric Reliability Corporation, the grid operators' organization.

MARK LAUBY: Presumably, automobiles are going to be smart enough to tell me that, hey, I'm here and I want to be charged - or hey, I'm here and I have energy available if you want it.

JOYCE: Christopher Joyce, NPR News.

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