Smidge204 said:
On the other hand, the scenario I came up with is exactly in line with some Volt supporter's arguments in favor of it: "If my driving habits are such, I'll never even use any gas." Well if your driving habits are such, why are you even buying a car with a gas tank?
I think the argument is "I'll hardly ever use gas", not "I'll never use gas", and we are buying the car with the gas tank for our 10% non-EV miles, because 10% != 0%.
So to evaluate it properly we need case-by-case data. The "gap" into which you are burning more fuel with a Volt than with an BEV+Ice backup is actually quite large.
It depends how many trips you take in the ~40-80 mile range (or double this if you have workplace charging). For daily driving below 40 miles, which it seems most Leaf owners are doing according to Nissan statistics, there's basically no difference. In the "somewhat over Leaf range", the Volt has an advantage in less gas use even if your alternate car has better mileage than the Volt, since you get to cover some of the miles in EV mode rather than none of them. Say you had to go 90 miles (freeway, 65 mph, climate control, rather than trying to eke it out slower in a Leaf), you end up burning 1.8 gallons in a Prius, but only 1.25 in a Volt. And if the Volt's 40 mpg highway is > efficiency than your ICE backup you are saving gas on all the gas miles as well. Plus if you have destination charging available, you get to use EV around your destination, and EV for part of the way back.
For example, every time I go visit my mother, this involves an ~100 mile trip one-way. In the Volt, I end up doing 40 miles EV on the way there, 40 miles EV on the way back, and another maybe 30 miles EV driving around town for a few days while I am there. +120 gas miles, that's about 3 gallons. A Prius would have taken about 4.6. If I had kept my old Civic and bought a Leaf, that would have been 7 gallons. This extra 110 miles of EV driving obliterates the extra 2.5 miles of EV local driving a Leaf would have given me over the Volt so far in my 2.5 months of ownership (from maintenance mode kicking in, plus one time where I exceeded my Volt range by 2 miles).
Take a look at
this guy's driving habits. 56% all-electric driving, which means he should be doing ~65miles per day or so. But notice on his graph the sudden jumps?
Since these longer trips exceed a BEV's range he might have rented a car for those times and the gas he burned as a result would be more than offset by the gas he
didn't burn during his routine driving.
For this particular driver, I don't think you zoomed in close enough on his graph to get a clear picture of what is going on, since his mileage is so high 100 mile jumps aren't so visible. If you look at the entire range, there are sections that appear kind of flat, but aren't really. If you zoom in close enough to see daily range, you'll see there are days that he doesn't use any gas, and also days where he is doing 100+mile days, more than what would be possible in a Leaf (w/o midpoint charging, which it doesn't appear he routinely has). Not a lot of the 40-80 mile days where a Leaf would be able to "not burn gas during routine driving" while the Volt does. There may well be other drivers in the voltstats data set who are doing 60 miles daily and would be arguably better off in a Leaf, but not this particular driver, from what I see.
But for the most part - and some people don't have enough data yet - it seems a lot of these people could be driving BEVs instead.
If their daily driving is < 40 miles, what difference does it make, why do you care? It's only those with the daily driving in the > volt EV range, < Leaf EV range where the extra range of the pure BEV makes a significant difference in gas consumption.
And yes one could rent an ICE for longer trips. But it's inconvenient to have to deal with pickup & delivery. It's often difficult, more expensive to rent a car with better gas mileage than a Volt. And on a long trip, many would prefer the comfort & familiarity of one's own car, with all your favorite XM stations programmed in, familiar iPod interface, etc.