Bidding for volts

Recharging electric cars

Sep 6th 2011, 15:38 by The Economist online

ELECTRIC cars and hybrids could represent as much as 15% of the new car market by 2020, depending on the price of oil. This means that in some places a lot of vehicles will be plugged simultaneously into the mains after the evening commute home, in order to recharge their batteries for the following day. The sudden demand for power this will entail, on top of the existing evening peak, could put the small electrical transformers that serve local grids under considerable strain—possibly to the extent of causing brownouts.
To dissuade the owners of electric cars from recharging their vehicles at peak times, and encourage them to do so in the wee, small hours of the morning instead, some electricity companies are introducing off-peak pricing for electric cars. Off-peak pricing is a common way of persuading people to run appliances such as washing machines at times of low demand. It is, though, a rigid arrangement that cannot respond to fluctuations in the requirement for power. Far better, reckon Alex Rogers and his colleagues at Southampton University, in England, for car owners to be represented in their interactions with the local power supplier by agents that can negotiate a deal on their behalf. These agents would bargain with one another, and with the power company, to charge the cars in an area in the most efficient way. The twist is that the agents Dr Rogers proposes to recruit for the task are not people, but computer programs.
Electric cars are not like washing machines, which vary little from brand to brand in their electrical demands. Car batteries come in different capacities, have different recharging speeds and use different chemistries which have their own recharging criteria.

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