How to keep electric cars from crashing the grid

Last year saw the U.S. surpass the milestone of 100,000 electric cars sold. E-car sales spiked up 84% in 2013 and, although this still represents a small share of the automotive market, such growth rates have causes people to ask if the grid can support a paradigm shift away from fossil fuels.

Many e-car fans answer that people will charge their electric vehicles overnight, during low power consumption periods, so there should be no problems. But it is not hard to imagine everyone coming home to dinner at 6:00 p.m., plugging in their car and powering up their kitchen, living room, and more all in an electricity demand "rush hour."

electric car parking spots for chargingGlen Wallace/CC BY-SA 2.0

Due to the "keeping up with the Joneses" phenomenon and the growth of localized charging spot density, it is likely that electric car clusters will form well ahead of the point in time when overall sales of electric cars passes a general tipping point for electric infrastructure -- so it is not too soon to start thinking about power supply security.

That is exactly what a team at the University of Vermont has been up to, resulting in a patent-pending power management plan described in an article entitled Packetized Plug-In Electric Vehicle Charge Management.

electric car charging polePer-Olof Forsberg/CC BY 2.0

"The key to our approach is to break up the request for power from each car into multiple small chunks — into packets,” says Jeff Frolik, a professor in the College of Engineering and Mathematical Sciences and co-author on the new study

An electric car would request a packet of charge. When that has been delivered, it would be back in line again, waiting for the next packet to be delivered based on the supply available.

A couple of mechanisms are key to the success of this vision. First, anyone who needed to recharge urgently would be able to opt for a high priority charge without the slow-down the packets cause. Ideally, opting to use packets would lower the electricity rates as an incentive not to go with the quick-charge.

Second, the requests for energy would be managed by a probability algorithm that would protect the identity of the homeowner requesting power, so it would not be possible for Big Brother or other malevolent forces to track an individual's driving habits.

Many options have been discussed to avoid grid problems, including peak rates to discourage charging in times of high demand and centralized optimization that uses demand predictions to supply power as needed -- but is less anonymous than the proposed method. With even those who say electric vehicles are not a problem admitting that localized crises could occur, it seems the time is ripe to start reviewing the options for smart power management as we shift further from fossil fuels.

Tags: Electric Cars | Electricity | Electric Vehicles


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