[hwillis]

More like 36 kWh. Average mpg of new cars is 25.5 mpg (.71 mi/kWh) while Teslas get 3.2-3.8 mi/kWh so the efficiency ratio is closer to 5x. With 4 gallons/minute, that's 7.2 kWh per gallon/1.73 MW. In the US pumps reach up to 10 gallons/minute so 4.3 MW and 17.3 MW for truck-filling pumps. Not all pumps hit 10 gallons/minute though.

2 or 3 MW would charging power would require a really specialized battery and will probably never be worth it. The real advantage of an electric car is letting it charge overnight and adding some extra time over long journeys isn't a big inconvenience- its less time than unexpected traffic would take up. Plus the time is overall made up for by never having to fill up if you come home to charge overnight once a week. Same thing applies to trucks. An hour-long fill up once a week gets replaced by nightly charging.

[saurik]

> Average mpg of new cars is 25.5 mpg (.71 mi/kWh)...

This is not a reasonable way of doing this math because it loads the numbers with "people who want a large and heavy car can't or wouldn't buy an electric, pulling down the average miles per gallon for gasoline powered vehicles"; to do this comparison fairly requires looking at the energy conversion efficiency of the engine, tank/battery, and transmission in isolation of the rest of the car body. Another way to put this: if you manage to buy an electric Hummer, you are going to be spending an insane amount of time charging it, because it would use as much more electricity as it uses more gas ;P. If you really need to estimate this using miles per gallon, you need to look at a gasoline-powered car which looks like a Tesla (being about the same size and contour), not the average new car purchased by a consumer. (FWIW, a quick eyeball of this is looking like 40 mpg.)

[hwillis]

The biggest factor towards overall mpg is actually engine size, not aerodynamics. Gasoline engines have to run at their ideal power to stay efficient, induction motors do not (for the most part). You're eyeballing the wrong places if you're getting 40 mpg. Compare a BMW 5, 6 or 7 series- 19/27, 21/30, and 21/29 mpg. 25 is, if anything, optimistic. The only cars that get 40 mpg are subcompacts and some compact cars. 25.5 is a good balance between all of the small cars and the SUVs/pickups, because the Model S is between them in size and weight. In fact it tends towards the upper end- although it is very aerodynamic, it is a quite large and quite heavy car.

When the model 3 comes out, we'll be able to make better comparisons to high mpg ICEs like the fit, fiesta and civic.