Comment Comparing electric oranges and gasoline apples (Score 2) 172
Bear with me now. A gallon of gasoline, depending on blending and the amount of ethanol has a high heating value (HHV) of about 120,000 BTU per gallon. At 100 percent conversion efficiency, 3400 BTUs gives you 1 kWHr, so 100% conversion of a gallon of gas gives 35.3 kWHr. That is what the EPA means by "eMPG" -- the EPA is assuming 100% conversion efficiency, but that is counteracted by the eMPG rating being artificially high because of that assumption.
Apart from arguments on whether EPA mileage reflects actual mileage, and whether an electric vehicle (EV) takes a "bigger hit" in efficiency in cold weather than a gasoline car, the gasoline MPG combined with the MPG gives you the cents-per-mile; the same holds true for eMPG combined with the kWHr rate according to how eMPG translates into kWHr -- as supplied to the plug connection to the EV. Thus we have "real word" fuel consumption numbers on current-gen gas cars, "real world" kWHr consumption on current-gen EV's, and we don't have to get tied up in knots over figuring all the energy losses in gasoline cars and in EVs.
That Enerdel battery "costs" 18 cents/kWHr, and my Midwestern power company sells me electricity at 14 cents/kWHr. That is, the electric cost is 32 center/kWHr or $11.30 per "electric gallon", but for an EV getting 100 eMPG, that works out to 11 cents/mile.
For gasoline at 4 dollars/gallon (it is cheaper now but will probably climb in price next summer), that works out to 13 cents/mile.
OK, I am sold, that at least from a policy perspective, that if this price on batteries holds up or improves, and if gasoline keeps getting more expensive, a given but you never know for sure, and if electric rates don't increase, not really a given with current policies, or if through Smart Grid that EV owners are given a "deal" for charging at night or other off-peak times, this new battery tech is at least putting the EV "in play."
The other consideration is that $4/gallon is what I pay at the filling station and 14 cents/kWHr is what I pay at home as a retail electric customer. Is this $711 the retail price of that battery pack, or is it the wholesale price to an automobile manufacturer? If I want to replace a 30 kWHr battery pack in a LEAF, do I pay 21 grand or do I pay twice that amount at the Nissan parts counter?