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

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

#481

Post by groone »

MayeulC wrote: post #312
jasonkester wrote: post #284

Earlier quoted context omitted.

Can you define your hydrogen colors for us? It sounds like you have something interesting to say, but I can’t parse what it is out of your company’s jargon.

These are common terms. A random link: https://www.weforum.org/stories/2021/07/clean-energy-green-h... * Green: produced from surplus renewable capacity (electrolysis) * Black, brown, grey: convert various fossil fuels to hydrogen via steam reforming. Basically strip carbon from hydrocarbons, emitting a lot of CO2. * Blue: same as black/brown/Greg but with carbon capture. There are other (less common) shades as well.

Red hydrogen: produce hydrogen from a thermochemical reaction between water, iodine, and sulfur at a high temperature, around 900°C, using the thermal energy from a nuclear reactor.

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

#482

Post by cbmuser »

tonyhart7 wrote: post #216
tonyhart7 wrote: post #215

Earlier quoted context omitted.

" Because Oil Companies are lobbying for inefficient hydrogen to delay a green revolution" well NO, contrary to popular belief. there is no such things because 1. Oil is scarce resource that not every country have 2. since not every country has, they must import it with expensive trade deficit meaning that Oil alternative or replacement is very much needed since country like china,south korea and japan that has massi…

that's why china is leading an EV revolution, government seeing that as very much important geopolitic and economic wise if hydrogen is feasible in mass scale, trust me someone in Asia would already make it

Most EVs sold in China are hybrids and not BEVs. Hence they call them NEV = New Energy Vehicle.

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

#483

Post by cbmuser »

psd1 wrote: post #325
rco8786 wrote: post #194

Earlier quoted context omitted.

It’s hard to imagine it not. And also kudos and crazy respect for all the thousands of engineers that poured their work into making combustion engines as efficient and reliable as they are. A true marvel of humanity, and something to be respected even as we leave it behind.

I see your point, but at best you're getting 40% thermal efficiency with IC. It's not great.

No one cares about thermal efficiency. What matters is the economic efficiency.

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

#484

Post by baq »

AlexandrB wrote: post #377
baq wrote: post #360

Earlier quoted context omitted.

I agree, that’s why I say tax the right things and subsidize the right things.

All well and good until you have producers burning (or otherwise using) the cheap, taxed fuel to produce the expensive, subsidized one while creating more net pollution in the process. It's hard to get this stuff right at the best of times.

Carbon credits should also fix that. The bigger problem is getting everyone to agree something needs to be done.

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

#485

Post by philipkglass »

thaumasiotes wrote: post #459
D_Alex wrote: post #289

Earlier quoted context omitted.

Natural gas is a mixture of methane and heavier hydrocarbons, the composition varies by region, depending largely on how the LPGs (propane and butane) are used. Ethane usually ends up in natural gas, unless there is a petrochemical complex nearby. So, 80% is a theoretical maximum, which is never achieved in practice. 75% hydrogen looks pretty right.

I'm still curious about the measurement "on a molar basis". If you have 20 moles of methane, and you process that to separate out the carbon, you'll end up with 20 moles of some form of carbon and 40 moles of hydrogen gas, right?

I think that "on a molar basis" is there to clarify that it's counting by number of atoms rather than grams. On a gram-for-gram basis, methane is ~75% carbon.

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

#486

Post by andix »

fuzzmz wrote: post #469
andix wrote: post #88

Earlier quoted context omitted.

Trolleybusses are surprisingly expensive to operate. Battery electric busses seem to be much cheaper to operate and often good enough.

There's also a sort-of-middle-ground here. There are trolleybusses which also have batteries, and can operate as regular busses where no overhead power is available. Basically you get continuous charge on parts of the route, while also being able to operate in other areas. Granted, this works for cities which already have trolleybus infrastructure in place.

With modern battery electric busses there is usually no need to charge while driving. Drivers need breaks, fast charging during the break time is enough. Fast charging infrastructure is much simpler to install and cheaper than overhead wires.

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

#487

Post by AnthonyMouse »

bluGill wrote: post #180
AnthonyMouse wrote: post #158

Earlier quoted context omitted.

You would then be subjecting people to indirect paths with multiple transfers. Instead of going from A to B you'd have to go from A to the first bus depot to the second bus depot to B, waiting for another bus at each transfer. If the trip was 30 minutes to begin with, now you've made it 45 (at best).

True for that trip. However in return I've made a large number of other trips possible that couldn't have been done.

Have you though? You're at A, near but not at the first bus depot. If there is a bus that originates at the depot, stops at A and then takes you all the way to B, you get there in 30 minutes. If it only takes you half way to B, you have to go half way, wait there for another bus from a different depot, take it back to that depot and wait for a third bus from the depot to B.

Not only is that slower, having the first bus stop there and turn around instead of going all the way to B hasn't benefited anyone else either. The route from the first depot to the halfway point is still being covered by the same bus route. The interval is determined by how many buses cover that route and not just by its total length, and another bus that covers that section of the route might even go somewhere other than B after reaching the point you'd have had it turn around to go back, also giving a faster option than multiple transfers for people who want to go from A to C. When A, B and C are all high density areas, creating direct routes between them makes sense even if they're each more than 15 minutes apart.

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

#488

Post by theshrike79 »

thfuran wrote: post #435
theshrike79 wrote: post #419

Earlier quoted context omitted.

But then you have even more losses when you convert the hydrogen back to energy. The formula is that 55kW of electricity used to generate hydrogen from water and then converted back to electricity in a gas turbine or fuel cell results in 15kW of energy. That's a lot more than 20%. Compare that to just storing the 55kW in batteries and using them to spin an electric engine. "Hydrogen economy" only makes sense if you h…

And don't you lose a significant amount compressing it for reasonable storage as well? Or is that considered part of the generation loss?

That's calculated in the total losses. You either need to compress it or freeze it. Usually for vehicles it's compressed, for long term storage or transfer it could be either.

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

#489

Post by D_Alex »

thaumasiotes wrote: post #459
D_Alex wrote: post #289

Earlier quoted context omitted.

Natural gas is a mixture of methane and heavier hydrocarbons, the composition varies by region, depending largely on how the LPGs (propane and butane) are used. Ethane usually ends up in natural gas, unless there is a petrochemical complex nearby. So, 80% is a theoretical maximum, which is never achieved in practice. 75% hydrogen looks pretty right.

I'm still curious about the measurement "on a molar basis". If you have 20 moles of methane, and you process that to separate out the carbon, you'll end up with 20 moles of some form of carbon and 40 moles of hydrogen gas, right?

"Molar" refers to a number of elementary entities, which could be atoms or molecules or w/e. So yes, if you are counting moles of H2 gas, but not if you are counting atoms...

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

#490

Post by thaumasiotes »

D_Alex wrote: post #489
thaumasiotes wrote: post #459

Earlier quoted context omitted.

I'm still curious about the measurement "on a molar basis". If you have 20 moles of methane, and you process that to separate out the carbon, you'll end up with 20 moles of some form of carbon and 40 moles of hydrogen gas, right?

"Molar" refers to a number of elementary entities, which could be atoms or molecules or w/e. So yes, if you are counting moles of H2 gas, but not if you are counting atoms...

But hydrogen gas is the only thing you can get from that reaction. There is a theoretical construct of monatomic hydrogen, also a gas, but you're guaranteed to get molecular hydrogen instead. And there will only be 40 moles of it. There isn't a way for you to end up with 80 moles of hydrogen product.
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