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Friday, November 25, 2011

Car ChargingPower Points

With electric cars finally beginning to enter the domestic fleets of the world, we are going to need lots of charging points.  Everyone with an electric car will have a power point at home.  In fact you already do.  As long as you don't want fast charging, all you need is an extension cord from the nearest outlet.  This will give you somewhere between 10 and 25 amp charging, depending on your individual electrical set up.  However, here we are talking about charging away from home.

Commercial charging points will spring up in company parking lots, along streets instead of, or integrated into parking meters, at restaurants, in high rise commercial parking lots and so forth.  What characteristics should they have.

You should be able to swipe your card and then choose a number of options.

  With respect to the amount of power you want, you should be able to choose full charge or a given amount of money or a given number of kWh (kilowatt hours).  If, by chance, you chose more than your car can take at the time, you would only be debited for the amount you used; not the amount you asked for.

With respect to the supply options you should be able to choose Charge now (at the full day time cost per kWh) or option 1, 2 or 3.  Option 1 would cut in when the power company sends a signal down the line or over a dedicated phone chip that because of extra generating capacity, somewhat cheaper electricity is now available.  Option 2 cuts in when the uptake of electricity by offering Option 1 is not enough to balance the load with the supply and option 3 a further reduction in price to bring  even more load on line.  Each option gives the consumer less expensive electricity than the previous option and allows the power company to sell more electricity and not waste water.
This is supply balancing and has some definite advantages over the present supply balancing.  Every kWh you take when it is available is one less that you take when supplies are low.

At home, if you have a dedicated, smart-charging point you might even have option 4.  Option 4 is "Charge and Supply".  You would use this one when you are not going to be using your car for a while.  You might be on vacation overseas or you might only use your car on weekends so the car during your holiday or during the week  would be plugged into Option 4.  With this option, your car will receive charge when option 3 (the least expensive electricity) is available and will send power back to the grid when the power company signals that it needs some peak shaving (high load and hence a short term need for extra electricity).  In this mode, your electric vehicle will generate a small but very welcome revenue for you.

Hopefully, the power companies will be smart enough to realize that if they set up the system to allow the customer to save money and to have options, they gain as well.  They gain by being able to sell more of their power rather than letting water flow over the spillway or having to feather their wind turbines.  They gain by not having to build a dedicated, very economically wasteful  power station just for peak shaving and they gain by having the good will of their customers.  They also help their country and the world by putting less carbon into the environment.  Systems as described above are ideal for using intermittent renewable power sources such as wind, hydro and solar and if you have a charged battery in your car, charged when excess energy is available, you will  demand less  power when fossil fuel must be used to generate it.