"Ideally"

I've read several times that having renewable energy sources charge up automobile batteries is the ideal future for automobiles. But if we're talking about "ideal", how about using renewable energy to synthesize octane or nonane? These have a high energy density; we understand the safety issues very well; we have mature technologies for delivery and for engines.

The only thing we don't have is the synthesis technology. But the phrase was "ideal", not "feasible anytime soon."

Even if it was feasible, right now it is so cheap to distill octanes from oil that I can't see anybody trying to synthesize n-octane for anything other than curiosity's sake. And of course there's the "what's the raw material?" question--we'll run low on coal one of these days too. CO2 or plant waste would be "ideal" raw materials.

Different "ideals" send you in different research directions. Batteries or synthesis?