But from an engineering point of view, I just don't find ICEs elegant. Too many moving pieces, and all that for about 30% efficiency (the remaining 70% is lost as waste heat). Good thing gasoline is so energy-dense, because when you're wasting 70% of your energy, you need that.
I would argue that efficiency and low emissions do not preclude something from being elegant. Steam plants can also be elegant, and they can be extremely efficient and low-emissions, but a steam plant cannot be bolted onto a motor car or a small aeroplane for which a turbine would be inappropriate. All forms of heat engines have their upsides and downsides.
Anyway, at the end of the day, consumers don't care one iota about engineering elegance.
The real question is where that fuel will be sourced.
I address issues of alternate fuels in a prior post, and suspect we'll see liquid hydrocarbons, of some stripe, for quite some time.
http://news.ycombinator.com/item?id=5204104
Edit: speling
A fair number of people can't put it together. The fact that we've extracted and re-released to the atmosphere a significant fraction of the hydrocarbons which have been sequestered via biological activity over a ~260 million year period, within a century, seems to escape a lot of folks.
As does the distinction between energy sources and energy media. And while technically fossil fuels are themselves a medium for sunlight, humans don't have to drive that particular conversion.
Besides, pedantism is one of the rare pleasures of old age.
I'd like to see efforts at using energy sources to manufacture gasoline from environmental sources of carbon, making the fuel carbon-neutral. How does that compare to electric vehicles?
There have been efforts to do this; basically any form of biodiesel that is produced by bacteria can probably be considered carbon-neutral.
While I see us moving from fossil fuel, I still see liquid fuels playing an important role in mechanized transit (ground, water, air) for as long as we're technologically capable of doing so.