Why do transit agencies keep falling for the hydrogen bus myth?

Post by marshray » Sat, Mar 15, 2025, 8:53 AM UTC

somat wrote: post #254

marshray wrote: post #206

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The only sense in which "electricity" could be said to be fluid is in its definition. There's no such physical quantity, it's just a vague term for a variety of phenomena.

It flows, you use fluid equations to describe it's state. I will grant that it flows in a different medium than molecular fluids. but that does not prevent it from being a fluid. As for what is flowing, my understanding is that it is electrons in an em field. which if you think about it is almost the same thing that is flowing in a molecular fluid, only that has drag a bunch of protons around at the same time limitin…

Post by jimnotgym » Sat, Mar 15, 2025, 8:57 AM UTC

ZeroGravitas wrote: post #27

bombcar wrote: post #14

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Batteries have won this so hard (if you ignore CNG busses, which have existed forever and are "almost as good as hydrogen could be") - because even when they hadn't won it, you just needed more busses. Is it nice if the bus can do a driver's entire shift without a recharge? Sure! But if it can't, you just design the route so that the driver can switch busses and buy another bus. That means the technology problem is n…

The stop-start nature of city busses makes them a real low hanging fruit for battery electrification, benefiting from instant torque to start and regen to stop and, as you say, fixed known routes within larger fleets. The only nation that seems to have capitalised on this basic fact is China which bootstrapped its EV industry on busses, pulling ahead from 2010 and hitting 90% of global market share for EV busses in 2…

Post by Tade0 » Sat, Mar 15, 2025, 9:00 AM UTC

jimnotgym wrote: post #266

elric wrote: post #259

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> hydrogen buses must be more expensive than electric Fuel cells are presumably more expensive than battery packs. The former are barely produced, while the latter are made in gigafactories. You can't just fill up the gas tank with hydrogen, it will leak out and/or cause a violent reaction with oxygen. > somehow the hydrogen fuel must be a long way from the bus depot You can't just store hydrogen in a tank and call i…

> Fuel cells are presumably more expensive than battery packs. Maybe, but a tank of hydrogen burnt through an ICE is much cheaper than either For your storage and production concerns, here it is working in practice https://youtu.be/5rk1RsT64o4?si=LLmX51kT2_YeRp2g

Post by porridgeraisin » Sat, Mar 15, 2025, 9:02 AM UTC

jonp888 wrote: post #264

jimnotgym wrote: post #255

I can't agree with the underlying idea of this article at all. 1) hydrogen buses must be more expensive than electric. I don't see how that is true. Hydrogen uses an ICE that is much cheaper to purchase than batteries + motor. Of course early stage niche designs might be more expensive, but that doesn't mean that it will be more expensive at scale 2) somehow the hydrogen fuel must be a long way from the bus depot, be…

1) Hydrogen combustion engines exist, but are extremely inefficent. For this reason all Hydrogen buses currently in use use fuel cells, which are expensive and complicated. That you were unaware of this makes me doubt the rest of your commentary. 2) There is a huge existing logistics network which conveys diesel to all corners of the world. The same, in a sense for electricity. For Hydrogen this doesn't exist. 5) The…

Post by D_Alex » Sat, Mar 15, 2025, 9:05 AM UTC

thaumasiotes wrote: post #239

iamthemonster wrote: post #231

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I work for an oil and gas company. It has been specifically stated by my company that they are seeking support for hydrogen as a fuel because it adds value to their gas reserves - natural gas is roughly 75% hydrogen on a molar basis. The idea is to stimulate demand for "green-ish" hydrogen (that is by grid-connected electrolysis); once demand for the hydrogen is there, it can be supplied by blue hydrogen. The O&G com…

> natural gas is roughly 75% hydrogen on a molar basis I thought it was methane. Wouldn't that be 80% hydrogen on a molar basis? (Or... 67%, if we're counting moles of molecular hydrogen?) Is the discrepancy coming from impurities, or different types of fuel, or what?