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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?

#461

Post by zejn »

boozy12345 wrote: post #457
zejn wrote: post #402

Earlier quoted context omitted.

I disagree it's a chicken-egg problem, nor is it not worth buying an EV (aka "going green"). You can charge an EV with electricity made from several different energy sources. You could even charge it with gas or diesel generator, if such a need would arise. You can't really fill an ICE car with home-brewed gas. The real issue a) range and b) if your car use maps well to an EV's need to have it plugged in for several…

I mean, you can run an ICE on home-brewed ethanol. You can even use solar to distill it. You're probably going to want a small farm though...

... yep, you could, though I don't think a small farm would cover my yearly needs for gas.

A small roof can cover an EV.

Best thing here is electrons are very pure, no matter the source. Chemicals - not so much. Distilled alcohol still has a significant amount of water, and if you're trying to get biogas, that one needs to be desulfurized. It's just messy.

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

#462

Post by sholladay »

VBprogrammer wrote: post #276
sholladay wrote: post #214

They keep falling for it because fixed route busses are the one use case where hydrogen could theoretically make sense. The bus can fill up far faster than it could recharge an equivalent battery. The bus gets lighter and more efficient as it uses fuel. And crucially, it can always fill up at the same place, which really ought to be the central depot where all the buses in that network return to. But inevitably with…

> The bus gets lighter and more efficient as it uses fuel. This argument is weak. To get any kind of reasonable energy density you have to compress hydrogen to 10,000psi. The tanks to contain a gas at that pressure are heavy enough that the weight of gas inside is almost negligible. Especially in ground vehicles which aren't hugely sensitive to weight.

The tank weighs at least 10x what the hydrogen weighs, so yes it’s relatively little per trip, but it does add up over the lifetime of the vehicle and I thought it was worth mentioning. Same goes for very high voltage in BEVs. There’s weight savings to be had by maximizing voltage which allows you to reduce the thickness of the wiring. But the savings are small compared to the weight of the battery.

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

#463

Post by sholladay »

danmaz74 wrote: post #362
sholladay wrote: post #214

They keep falling for it because fixed route busses are the one use case where hydrogen could theoretically make sense. The bus can fill up far faster than it could recharge an equivalent battery. The bus gets lighter and more efficient as it uses fuel. And crucially, it can always fill up at the same place, which really ought to be the central depot where all the buses in that network return to. But inevitably with…

Aren't buses with a fixed route also a great candidate for battery swap solutions? As all the buses are managed by the same company, I would be curious to know if there are any hidden issues with this approach: while an bus is riding with a battery, the replacement battery gets charged, and when necessary you just swap the battery.

Maybe. There are certainly companies doing this, such as SUN Mobility and BYD. But I think battery swapping will remain fairly niche, unless and until a few standardized battery shapes, sizes, and connectors emerge. Fixed route buses might be able to rely on custom solutions but that will of course increase the price and make it less tenable for the long-term.

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

#464

Post by BigGreenJorts »

rsynnott wrote: post #241
KeplerBoy wrote: post #148

Earlier quoted context omitted.

Busses are not going to be quiet. Around here we have pretty cool "Van Hool ExquiCity" trolley busses and they can glide gracefully at slow speeds, but when they are hurtling down patched up streets they are not much quieter than the traditional busses.

Most city buses spend most of their time going fairly slowly. The electric buses are absolutely a lot quieter, at least around here. Crucially, also, they don’t vibrate; I’ve never been on a diesel bus where vibration from the engine wasn’t at least somewhat noticeable.

On the older busses in the city I live in, the level of vibrations actually make me sooo motion sick, I have gotten off the bus and immediately evacuated my insides.

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

#465

Post by BigGreenJorts »

AnthonyMouse wrote: post #116
01HNNWZ0MV43FF wrote: post #23

Because people are allergic to hybrids and I don't know why "Electric is short range, fuel is expensive, guess I have to pick one" The ideal drivetrain was invented over 20 years ago by Toyota and apparently nobody but me and Honda noticed it!

The drivetrain was actually invented several decades before that. It wasn't until around 20 years ago that the batteries got to the point to make it practical to use. They're also made by more than Toyota and Honda. The American automakers have been offering vehicles with a similar hybrid powertrain for around two decades and the German automakers for only a little less than that. But they're generally not a separate…

Not disagreeing with anything you're saying, just adding as a note, that as of a few years ago, Toyota's entire line-up of cars are hybrid vehicles.

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

#466

Post by Retric »

Heston wrote: post #431
Retric wrote: post #261

Earlier quoted context omitted.

Many batteries actually last significantly longer than common hydrogen storage tanks, hydrogen embrittlement is a major issue. Type III and IV tanks have a life cycle of 10 years. https://www.awoe.net/Hydrogen-Storage-LCA.html Hydrogen has also terrible volumetric energy density. It’s also really heavy until you scale to huge tanks.

Hydrogen's volumetric energy density is about as good as lithium-ion. The cost of replacing a hydrogen tank vs a lithium battery is absolutely massive. You also aren't considering the energy density lost in cold weather for batteries.

Almost the same in the short term requires you to liquify hydrogen and then use it immediately. Because the energy density rapidly goes to zero for any application with a moderately sized tank. On top of which you need a cryogenic tank, costing you even more volume.

Liquifying hydrogen also costs you another ~10-13 kWh /kg where Hydrogen only contains 33kWh if you want heat, but more like 10-15kWh/kg if you want to do useful work. So you’re roughly paying double the energy for the same amount of energy stored.

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

#467

Post by belorn »

mistrial9 wrote: post #400
belorn wrote: post #336

Earlier quoted context omitted.

Sweden was also on the same german track, shutdown some of the nuclear fleet, but is now going back and forth on the issue. They are also investing in new natural gas fueled thermal plants, with similar "future" plans of using green hydrogen. The national debate in Sweden is also similar. The right is arguing that the future is nuclear, and the left is arguing that green hydrogen is the future and natural gas is the…

except that there are more than two possibilities, but the debate is reduced to artificial Left and Right -- a miniature copy of the American political duopoly

That is correct, and I would add that the debate is also addressing the wrong questions. We should ask what role government should have in providing reliable and steady energy grid, what the values such grid provide to society, and how the costs should be distributed between market forces and taxes.

It is the failure to define what people actually want from the grid that results in people creating a religion behind power production, believing in a promise of a future that we have never seen.

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

#468

Post by sonthonax »

neves wrote: post #125

Why? Because Oil Companies are lobbying for inefficient hydrogen to delay a green revolution: https://adamtooze.substack.com/p/carbon-notes-5-green-hydrog... > The members of the hydrogen coalition are all obviously incumbent fossil fuel and petrochemical interests looking for a bridge to the new era. If realized, their ambitious hydrogen projects may overload the available supply of green power, for little real bene…

Just not true. Lots of oil companies have a vested interest in renewables now. A lot of the infrastructure for offshore oil is being redeployed for offshore wind.

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

#469

Post by fuzzmz »

andix wrote: post #88
aagd wrote: post #71

Also this: https://en.wikipedia.org/wiki/Trolleybus

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.

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

#470

Post by alvah »

ajb wrote: post #319
alvah wrote: post #252

Earlier quoted context omitted.

Hydrogen embrittlement is a massive issue, I’d be interested to hear how this can be engineered around. My understanding is it requires more exotic materials than those used in any existing NG or oil pipelines. Everything I’ve seen claiming it’s viable to use existing infrastructure seems reasonable at first glance, but invariably contains a massive hand-wave or 2.

The existing infrastructure was originally built for town gas which is ~50% hydrogen, and run successfully for many decades as such. So this is mainly about checking out the more recently designed parts. My understanding is embrittlement is mainly a problem for storage tanks, which need to use high strength materials due to the enormous pressure -and ironically those materials are more susceptable.

Existing infrastructure is designed for & can be used for hydrocarbons with varying levels of hydrogen in their molecular structure; I don't believe there's an issue there. Most of the H2 in town gas is in the form of hydrocarbons, which are less reactive than pure H2, even if there's a relatively high percentage of H2 in the mix (as the H2 is strongly bound to the carbon). Embrittlement is definitely an issue for more than just storage tanks.
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