Quote:
Originally Posted by SeanPlunk
Forgive my ignorance, but what's the limiting factor? Is it cost, size, or both?
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For fuel cells or the turbine combo?
For fuel cells it's at least a few obstacles.
1 - Cost. They typically use platinum as part of the fuel cell construction (forget the exact combination of properties why). The upside is there is some nano-tech substitutes that have the potential for being dirt cheap but is still a ways off.
2 - Efficient production of hydrogen. It may be the most abundant element in the universe, but it doesn't grow on trees here on earth. Typically it's dissociated from water, but hey look, that requires an energy input.
3 - Infrastructure. Building a substantial hydrogen infrastructure would be a massive undertaking. Totally doable of course, but it wouldn't happen over night.
4 - If a few thousand psi tank of H were ruptured and ignited with the oxygen in the atmosphere, it'd be a hell of a boom.
As for turbine combos. I have a couple guesses.
1 - Heat. They are damn hot and that's got to go somewhere.
2- Emissions. The heat of combustion has to create some gnarly NOX I would imagine and you can't put highly restrictive cats on the output of a turbine. Or at least not easily as I understand it. They really have to breathe freely.
3 - They are damn loud and there's only so much you can do about that.
4 - Startup procedures for turbines are dirty and require a lot of fuel.
They have a lot going for them though. The turbine would probably only need to be about the size of a large coffee can or so in order to generate enough current to electrically power a mid size car. They're extremely well understood. They can burn a wide variety of fuels, and things like CNG (which we have a lot of in the US) would work fine.