FiddlerJohn, thanks for posting and I see there are some updates as well. What follows is a modification of a rant I published over a year ago...
The purpose of the EPA Monroney stickers is to give consumers some standardized idea of what it costs to drive a vehicle, considering only energy ("fuel"). To this end the EPA has spent a fortune designing models which attempt to simulate how a 'typical' consumer drives and how a vehicle behaves in those driving conditions.
The EPA, instead of recognizing that electric vehicles are a different animal whose metric is kWHr/100miles or miles/kWHr and simply using these units, decided to attempt 'equivalency' and get back to something everyone is used to: miles per gallon. They implemented this using the energy contained in a gallon of gasoline and converting it to kWHr, specifically, 33.7kWh/gallon. Sorry, but while technically correct, this metric shies away from the fundamental reason for using miles per gallon: COST.
Utilizing the same EPA standard drive cycle for both gasoline and electric vehicles and since cost is the motivation, I contend that there are only three variables which should be considered when comparing "fuel" consumption performance amongst vehicles using disparate energy sources: ENERGY QUANTITY, ENERGY COST, and DISTANCE, measured by gallons or litres from the pump and kilowatt-hours out of an EVSE, $/gallon or $/litre and $/KWHr for that "fuel", and miles or kilometers for distance driven. Although I recognize the various conversions amongst energy units, since the purpose of the EPA sticker is to compare "fuel" consumption COSTS, I contend that $$ paid by the consumer (and not energy content) is the most reasonable common denominator yielding an apples-to-apples comparison.
Upstream or downstream energy costs (be it electricity generation or liquid fuel production) and recovery benefits and all the associated social, political, production, transportation, tax-related, health-related, etc., costs and benefits, although important and worthy of separate discussion, I believe to be irrelevant when discussing out-of-pocket expenses for the "fuel" to drive a vehicle.
For standardization, I accept whatever drive cycle the EPA wants to put out there, recognizing that a hypermiler can very easily beat the current gasoline ratings and that judicious use of regen has a significant effect on extending an EVs range.
The iMiEV EPA sticker says 30KWHrs per hundred miles. I presume that is 30KWHr out of the EVSE (thus taking into account all the vehicle's subsystem's inefficiences), and that regeneration has been optimized. Although I personally think this number is high, for argument's sake, let's accept it.
I had written a bunch of examples to illustrate my point; however, it was easier to simply create a spreadsheet so you
can choose your electricity cost and current gas prices to yield the equivalent "miles per gallon".
Sorry, but whereas I understand how EPA used energy equivalency, I contend that $$
equivalency is the more valid metric as the whole idea is to compare COST
. I can understand why they didn't go this way - simply because of the ever-changing cost of both gasoline and electricity.