Typical Volt owners are driving 1,000+ miles before they burn through a tank of gas. The tank is only 8.x gallons so this is pretty good. A plugin Prius would fit a slightly different drive profile: 12-14 miles in EV mode and the 50+MPG after that. I have only driven a Prius II for a few weeks, and I got well over 60MPG. If it was a plugin Prius III then it could be above 70MPG.
And since this is about efficiency, I want to say that I think that EV's with 300-400 mile range are quite possible with today's batteries. That is why I'm designing and building my open source 5 seat electric car, the
CarBEN EV5.
As we know, aerodynamics are huge part of the efficiency, and electric cars have some advantages over ICE powered cars; namely almost no cooling is required, and this would improve the Cd by about 10% right off the bat. Also, the lack of a hot exhaust system means the belly pan can be completely smooth (without also causing a heat problem) so that's probably another 10-15%.
Electric motors are 80-90%+ efficient. The force vectors within the motor are almost ideal, and there is no energy conversion from a storage medium to heat. ICE engines are limited by thermodynamics to roughly 54% efficiency, I think? And before you jump in and mention the generation and grid loses, please realize that gasoline doesn't appear out of thin air, either. The best estimates are that it takes more electricity to run a gasoline powered car than it takes to run an EV; because of all the necessary invested energy for everything from exploring for oil fields to drilling, extraction, transportation, refining, transporting, storage, etc. All the natural gas used to produce gasoline *also* has it's own overhead of invested energy, and that too accumulates into the actual energy consumed when you burn a gallon of gas in your car.
Each gallon of gasoline represents about 92 TONS of biological material, that has been "cooked" deep inside the earth for millions and millions of years. Gasoline packs an amazing amount of energy into a relatively small package, to be sure.
Then there's regenerative braking, which can regain some energy when you've overcooked your speed and cannot use the kinetic energy for coasting. This saves a lot of wear and tear on the mechanical brakes.
EV's have virtually no maintenance, and the motors will last a very long time -- I've heard numbers like 850,000 miles or even 1 million miles for an AC motor. Batteries should last 150-200K miles, or more. No oil changes, no coolant changes, either.
With an EV, there is no warm up time, and no idling. And most importantly, we can get electricity from several renewable sources. Renewable energy is all around us, and it will last until the sun explodes; in about 1 billion years.
Renewable energy has virtually no pollution, no spills, no explosions, no collapses, no radiation, no excess carbon dioxide, needs no military defense (the USA spends much more than ALL the other countries in the world COMBINED on our military!), and renewable energy is distributed almost everywhere on earth, so no one person, or one country can control it.