Don wrote:...The only way to get a number than means ANYTHING is to get cost completely out of the equation...
Hi Don. Whereas we usually agree and complement (and compliment) each other, this topic is one we can roll up our sleeves on...
First off, let's agree that we are only talking about energy ('fuel') and fuel consumption of electric and gasoline vehicles. All other elements, although important when talking about total operating costs, are off the table. Similarly, we're not talking about reduced pollution, health benefits, etc., that may have been significant reasons why we bought our iMiEV in the first place.
Since we're in the US and discussing the Monroney sticker, we'll stick with gallons and mpg and not litres or litres/100km. Happily, kilowatts and kWh are universal.
Next, I am well aware that the EPA took the energy equivalency approach, using 33.7kWh/gallon of gasoline. Within the Monroney sticker is their assumed cost basis for electricity (12 cents/kWh), with gasoline assumed cost being well-hidden but if you work it backwards from 22mpg and 15K miles/year and $12,600 over 5 years that gives us $3.697/gallon.
Allright, with that out of the way, what's the beef?My contention is that COST is THE reason that "miles per gallon" is being discussed in the first place
. The consumer doesn't give a darn about relative efficiencies - the consumer simply wants to know how much it will cost to drive the vehicle
, with mpg and fuel cost in terms of cents/mile being reasonable and well-understood metrics.
The consumer looks at the iMiEV Monroney sticker 112mpge and thinks, wow, that's great! The examples alohart and you (Saudi Arabia) pointed out fully support my case. In terms of fuel cost per mile, in Hawaii alohart's efficient gasoline car costs less to drive (fuel cost) than our iMiEV
. Thus, I contend, the Monroney sticker utilizing energy equivalence is misleading the consumer - in that locale, the iMiEV fuel cost/mile will be greater than that of an efficient gasoline car.
On the other hand, my table clearly shows the mpg equivalence for a given price of electricity and gasoline which the consumer can directly compare to any gas-guzzling chariot's mpg in the area they live in.
Don't worry, I don't expect to see my chart showing up anywhere soon ... it's primarily of academic interest, anyway, and I suspect most consumers don't know their electricity costs in terms of cents/kWhr.
Thus, Don, we agree to disagree: I believe COST and not energy efficiency is the underlying common denominator in mpg discussions.
BTW, tonymil, my take is that the Monroney sticker is indeed EPA's attempt at an EnergyStar label.
PS Don - I used nine cents/kWh (not six cents/kWh) for my own case - if I paid for my electricity. With my solar panels amortized elsewhere I get infinite
mpg$ with my iMiEV.