Is this a picture of what the future of plug-in vehicle charging might look?
There are 54 million garages for the 247 million registered cars in the US, meaning that the majority of cars are parked overnight in parking structures, parking lots or curbside. As a result, most potential plug-in vehicle consumers do not have an adequate place to charge their vehicles. This problem is even more pronounced in urban areas like San Francisco, where only about 16% of cars are parked in garages overnight and the rest end up curbside or in parking lots.
Also, although the US power grid probably has enough overall capacity to supply energy to a nation of plug-in vehicles, it may not have the ability to charge them when they all plug-in and demand energy at the same time — say 6 pm every weekday.
Electric car charging station on a London street.
Imagine pulling into any old parking spot downtown, plugging your electric car into a box on the curb, running some errands, and coming back ten minutes later to find your car completely charged and your bank account automatically debited for the balance of your electricity use without you having to swipe any cards.
Now imagine you park your plug-in hybrid electric vehicle (PHEV) overnight on the curb outside your apartment after driving all day. You’ve driven enough that your batteries have stored excess energy from the combustion of a fuel (gas, ethanol, biodiesel, whatever).
As soon as you plug that PHEV in, it communicates to the power grid that it has excess energy. As it turns out, the power grid has a need for that extra energy at the moment you plug your car in. In response your car gives some of its stored energy back to the grid. Your account is then credited for the amount of energy you supplied back to the grid.
Later, in the wee hours of the morning when the energy demand is quite low, the grid tells your car (along with a smallish group of other plug-ins) that it can start charging. Ten minutes later, when your group of cars is done charging, another smallish group of plug-ins is told they can begin their charge cycle. And so on and so forth until all the cars that need to be charged are charged.