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Which part of the physics though? I am not entirely convinced that a standard hydrogen PEM fuel cell is the only way to generate energy for a car.
by syntaxing 7y ago
Which part of the physics though? I am not entirely convinced that a standard hydrogen PEM fuel cell is the only way to generate energy for a car.
- Reason077 7y agoCurrent fuel cells are said to be in the 40-60% efficiency range. That’s actually not bad, especially if you can do something with the waste heat. But when you look at the overall round-trip efficiency of the hydrogen lifecycle (production, compression/liquefaction, distribution, storage/leakage, compression again), it’s pretty woeful. Many estimates come in well below 20%. If we came up with a more efficient fuel cell, it wouldn’t improve the overall efficiency much.
- Rury 7y agoI don't see efficiency as nearly problematic as most seem to make it out to be (as far as the physics goes). Estimates online roughly estimate that the amount of power from the sun that strikes the Earth in an hour is more than the entire world consumes in an year. Capturing just 0.0001% of that power would cover our needs. And I don't the worse efficiency of hydrogen being problematic in that regards.. but I can understand arguments regarding the economics.
- syntaxing 7y agoHow does this compare to the efficiencies of batteries and gasoline engines? I know otto cycle engines are limited to low 10s% efficiency for just the car as a system as a whole. I haven't seen much about the efficiency in terms of "round-trip" which would be interesting to compare to fuel cells.