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filmor 4 days ago

How is that efficiency calculated, respectively?

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philjohn 4 days ago | parent [-]

https://www.sciencedirect.com/topics/engineering/fuel-cell-e...

I believe all Hydrogen vehicles are using proton exchange membranes still, which have roughly 40-50% efficiency.

And that's before you take into account that even the most cutting edge hydrogen refining processes are around 70% efficient.

So 1kWh of energy input (electricity) will net you 3X the motive power when used directly in a BEV than first being coverted to hydrogen, and then converted back into electricity.[1]

[1] 0.5*0.7 = 0.35.

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marcosdumay 4 days ago | parent | next [-]

I don't think any hydrogen vehicle in actual use has a fuel cell (and if there's any, it's an incredibly rare exception). They are all internal combustion engines.

Proton exchange membranes are very unreliable and expensive. They are also not power-dense, one that powers a bus will be very large.

	▲	ch_sm 4 days ago \| parent \| next [-]
		It‘s actually the opposite: some hydrogen cars that use combustion exist, but they are really, really rare. Almost all hydrogen cars that are road legal use a fuel cell in combination with BEV parts to smooth out/extend power delivery.
	▲	pipodeclown 4 days ago \| parent \| prev [-]
		That is completely incorrect, it is the opposite.

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fluidcruft 4 days ago | parent | prev [-]

BEVs aren't 100% efficient though so it's closer to 2x rather than 3x.

	▲	philjohn 4 days ago \| parent [-]
		I’ve also gone for the max efficiency figures for the Hydrogen car. And that’s before we get to the fuel costs - £90 to go 400 miles in a Mirai, versus £5.50 to go 300 in an EV6.