Nick makes some excellent points in his analysis of hybrid and battery vehicles vs. gasoline engines. Obviously, some radical breakthrough in battery technology or something else could change the picture, but they've been working on batteries for years, and haven't really hit major paydirt. I can remember in college some cheery environmentalist handing me info on new batteries that had molten sulfur (!!) as a prime ingredient. This guy would have dropped a log if I had spilled a can of motor oil into Lake Superior, but apparently had no objection to cars barreling down the road filled with molten sulfur.

Some more thoughts:

There are many other factors that feed into the battery/hybrid/combustion tradeoff besides technical ones. The practicality of an electric or hybrid car increases in a situation with many starts and stops. Also, it is obvious that there is a size point where hybrid becomes practical. If hybrid technology is practical in huge locomotives (proven), but not in compact cars, where is the point where it trades off? Would hybrid semi-trucks be practical?

Higher oil prices or the availability of cheaper electricity (nuclear, space solar, fusion, etc.) would also change the picture. A glut of electrical power from non-petroleum sources would make both hydrogen fuel cells and pure electric cars look more attractive. The ideal would probably be hydrogen cracked from water and piped around to use in fuel cells. There are many interesting ways to store hydrogen other than compressed gas or extremely hard-to-handle liquid. Metal hydrides store more hydrogen per volume than either liquid or even solid hydrogen. And then there are things like this, which I ran across researching hydrides, and which kept my mouth hanging open for three minutes.

I have great confidence in human ingenuity, if it is left free to operate (which is becoming more difficult all the time). Two hundred years ago, a pessimistic futurist may have visualized running out of grass for horses, and being buried under seas of horse manure. Who knows what we will eventually come up with? But we'll think of something.