When I bought my BMW i3, it had a full gas tank, which contained around 2 gallons of gasoline.
When I bought my BMW i3, it was August 2014. When I took delivery of it, it was November 2014. I didn't use more than a tiny fraction of the gas in the tank between November 2014 and July 1015. So, the gas is now about 8 months old. It is okay to have gas that old around, altho at some point, it is wise to put some stabilizer in it, so it doesn't gum up your engine and cause all kinds of problems. But because the tank was full, it was summer (not winter any more) and so little had been used, it became a High Priority to run the charge down on the battery so that the engine would run and use up some gas.
On Monday, I went to Milford, NH to have dinner at the Red Arrow, and then to Mayberry to go to book group. My son and I gloried in the buzzing of the range extender engine almost the entire way home, consuming roughly a gallon of gas (that engine actually gets slightly worse miles per gallon than my Fits did).
So the _only_ gallon of gas I have driven my way through in 2015 was the gallon of gas my i3 consumed on Monday, purely so as to make space in the gas tank for stabilizer so the rest of the gas wouldn't cause the engine problems.
Related information: We used SolarCity to get solar panels on our roof. While presumably the i3 has increased our consumption of electricity, the solar panels have more than compensated for it. And the bottom line impact of the solar panels -- which have that weird financing structure that SolarCity uses -- is a very, very slight savings on our power bill.
Thus: putting panels on the roof and replacing a very high mpg car (Honda Fit 2011 Sport model, automatic transmission, so not the highest, but very respectable) with an electric vehicle has not meaningfully moved the needle on our electric power expenditure on a monthly basis, required no money outlay on the panels themselves, and has resulted in essentially the end of me spending money on gas. Of course, I _did_ have to buy the car. OTOH, you should be able to get pretty much the same effect, minus some of the entertaining conversations with random strangers about what kind of car that is, by buying a Leaf, which is hella cheaper.
When I bought my BMW i3, I don't think I really believed I wouldn't ever be buying gas again. I mean, I kind of hoped that would happen, but I didn't really believe it. I sure believe it now.
ETA: My husband is likely to point out that I have driven us home in his Honda Odyssey, after a trip to Northern NH to go to StoryLand and Santa's Village, thus consuming more than one gallon of gas during 2015. He will be correct, should he make this point. It is an instance of the basic observation that electric vehicles are best as the second car in the household, or when other transportation options abound. OTOH, it's not like we couldn't have rented a car in that situation.
ETAYA: Critical readers may want to make use of these numbers to point out that gasoline savings don't justify the high cost of my car purchase. And they would be correct, because I didn't buy it for this reason (if saving money had been the goal, a Leaf would have been a much better choice, and if I'd wanted to save money and not worry about range, maybe a Volt).
Per household gasoline expenditure expected to drop below $2000/household in the US in 2015, for the first time since 2009. So you _could_ argue that I picked exactly the wrong year to go electric. However, since this argument presumes a fair amount of economic sophistication, I would invite you to consider all the time I saved by not having to go get gas. I mean, my time is presumably worth _something_, amirite? Altho I'm not sure precisely how to go about calculating that, since I don't sell it for a wage, thus making the usual basis for calculation impossible.
ETA Still More: It might be worth pointing out that I spent a few thousand dollars having a fast charger installed in my garage, at the same time that I got the car.
Weird i3/Apple rumors published in a German magazine, described here:
"Zum Ende des Jahrzehnts sei ein Modell mit deutlich größerer Elektroreichweite geplant."
Good news! If that happens, around the time I'm thinking, wow, a charge just isn't lasting as long as it used it, I'll be able to buy a new model with significantly greater range! And judging by what I did with my last car, the resale value of my current i3 will not be a particularly pressing matter for me (viz. gave it to my mother-in-law).