The Reaper:
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Straight electric motors from a battery would be more efficient?
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Just off the top of my head on that, sir. But generating hydrogen and oxygen from water wastes a lot of energy. With all this talk about moving toward a hydrogen economy, there are a lot of chemists trying to develop efficient electrocatalysts for water-splitting. It's so easy to split water with electrical current, but it's very hard to store as chemical energy even half of the electrical energy you spend in the process. Then once you have the hydrogen and oxygen you burn them. What's the efficiency of an internal combustion engine? Forty percent or so, from fuel to crankshaft?
I think you'd have to come out ahead just sending the current straight to an electric motor, instead of an electrolysis/combustion sequence. But I should have made clear that I'm guessing on that point for now. Actually, I should have figured it out for sure before posting; sorry for the speculation. Going now to try to see if I can disprove myself.
Edited to add: A statement above, that it is difficult to store half of the electrical energy used in water-splitting as chemical energy, is inaccurate. Overall energy-efficiency of hydrogen production by electrolysis is 20-25% efficient, but this takes into account the energy wasted in generating the electricity commercially in the first place. Once you have the electrical current, electrolysis can be 75-80% efficient:
Argonne
I regret the error, and will do my homework better in the future.