What I do not understand is the efficiency of this system. Just with basic physics, we know that it will require enough energy from the gasoline engine to power the electric motor so that I can maintain a highway speed. This should be about the same amount of energy needed to propel a conventional gasoline car.
Is that right?
It's right, but you hit the nail on the head when you mention the efficiency of the system.
The conventional gasoline engine directly driving the car is slightly less efficient than a gasoline generator that drives an electric motor to propel the car (that's the traditional hybrid approach, which itself does get better gas mileage).
However, since the part actually driving the system is indeed an electric motor, naturally it can run off of any electricity it's provided - be that battery or from a generator.
The concept behind the Volt is pretty simple - give it enough battery to take it about 50 miles at a time. Most (not all, but most) people drive that or less in their daily business. So you can recharge it at night and stay on complete electricity. However, we all know that occasionally we'll want to take a longer trip, and batteries alone won't work for that. So, we fall back to a conventional fuel to take-up the slack. The gasoline generator kicks on and takes the car the rest of the way.
Also, as a benefit, since you can store excess energy via the battery, the engine needn't waste all that. For example when a conventional engine is running (even in a traditional hybrid) if there's no battery, then any excess energy generated simple gets bled off as heat. With a battery to store that however, the energy needn't be wasted. The engine might kick on for 45 minutes during which it drives your car and produces enough energe to recharge the battery too, so that after the 45 minutes it shuts back off for a while. You can also look at things like regenerative braking. Normally you tap the brakes and all your sped that you've built up gets bled off as heat from the pads touching the drum. If regenerative breaking is used though some of that excess energy can be bled off back into the battery so that you reclaim some portion of the energy again. It's not necessarily an efficient transfer, but it's better than nothing.
Again, at this point in time the Volt is still more expensive than it needs to be to make it worth it, but again, things get better in time. We've had 100 years to perfect the traditional gasoline car. Electric cars on a consumer scale are very, very new. This is just early generation. In time the price (of the cars and batteries) will come down, batteries will last longer, and ranges will improve, and overall the technology will improve. So will the used market when the good electric cars start showing up there in 15-20 years.
Again, it takes time, but I'd wager that when the batteries last on average 10 years, the replacement cost when they do fail is $1000, the charged range is up to 200 miles, and the initial cost of the car is $12,000 new with used ones on the market for half that, then a lot of us here will be looking at them pretty intently
. Particularly since by that time I wouldn't be surprised if gas was up to $6 or $7 per gallon.
Bottom line though is that the amount of crude oil available to refine is a fixed quantity - one that is always decreasing. Things like ethanol can be used as a renewable replacement (Brazil is largely running off ethanol but they make theirs from sugarcane, which yields better volumes than the corn we normally use), but it's not enough to act as the sole fuel. With the population steady growing we also are going to come to a point eventually when the farm land is simply more valuable producing food rather than fuel. The answer is to look for a way to relegate chemical fuels to a minimal role - using them as a stopgap only. That's the most sustainable solution long term. We just have to wade through the hiccups at the start of that trend to reap the benefits later
.
