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How a "smart charger" could ease the transition to electric cars

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Imagine all the folks on the waiting list for the Chevy Volt or a plug-in Toyota Prius plugged in their cars at once. The result? Blackout, as the world's largest machine (otherwise known as the electric grid) is overloaded.

What's needed is a device that can sense when there's sufficient capacity to juice up an electric car and when there's not—a so-called "smart charger" (which would, of course, be a key component of a "smart" grid).

And that's exactly what engineers at the Pacific Northwest National Laboratory in Richland, Wash. have created. "If a million owners plug in their vehicles to recharge after work, it could cause a major strain on the grid," said PNNL engineer Michael Kintner-Meyer in a statement. "The Smart Charger Controller could prevent those peaks in demand from plug-in vehicles and enable our existing grid to be used more evenly."

The hand-size Smart Charger will do that for them, once programmed with a few key instructions (like how much you're willing to pay to juice up or times when it would be convenient). The charger would also connect to the overall grid wirelessly (like many "smart" meters today) to determine when it was a good time to charge.

A previous study out of PNNL had shown that there was more than enough spare electricity generated to handle a switch over of 70 percent of U.S. personal cars from internal combustion to electric engines. But most of that spare capacity is at night or other times when people are not up and about and plugging in their new electric vehicles. Enter the Smart Charger.

Ultimately, such smart chargers will need to be built into every electric vehicle, but that's still years off. So it's likely that the smart charger will hook into whatever cord links your home socket to your new vehicle. Charging your car this way (presuming variable pricing for electricity) could save consumers as much as $150 a year in costs. The charger itself will be "low cost" according to Kintner-Meyer, although an exact price has not been specified.

Image 1: Scientist Michael Kintner-Meyer (front) and his team at Pacific Northwest National Laboratory (from left: Nathan Tenney, scientist; Frank Tuffner, engineer; Vilayanur Viswanathan, engineer; Richard Pratt, engineer) developed the Smart Charger Controller to manage peak demands in the electric grid once a mass of electric vehicles hit the road. The Controller tells an electric vehicle's battery when to start and stop re-charging based upon existing stress in the grid. COURTESY OF PNNL


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Image 2: PNNL developed the Smart Charger Controller (pictured) to manage peak demands in the electric grid as more electric vehicles hit the road. The Controller tells the car's battery when to start and stop re-charging based upon existing stress in the grid. The Controller's interface screen allows users to understand what the Controller is doing at any particular time during the charging cycle. COURTESY OF PNNL

Image 3: PNNL Scientist Michael Kintner-Meyer assesses installation of a Smart Charger Controller device into a Toyota Prius plug-in hybrid electric vehicle (PHEV) provided by Energy Northwest. The Controller tells the car's battery when to start and stop re-charging based upon existing stress in the electric grid.COURTESY OF PNNL