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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?

#221

Post by Retric »

Guthur wrote: post #218
dwaltrip wrote: post #198

Earlier quoted context omitted.

It'd be reasonable if hydrogen was competitive with electric, but it's not.

Electricity is a by product of some source of energy, it doesn't just materialise unless your taking about capturing lightening in a bottle.

Hydrogen is also a byproduct of some source of energy, it doesn’t just materialize.

The difference is batteries are vastly more efficient at storage and doing useful work with that stored energy. There’s use cases where that’s fine like rocketry, but efficiency or energy density is usually a dealbreaker.

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

#222

Post by alsodumb »

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…

I blame the transit agency for those missteps though - it doesn't have to be like that.

Take for example CUMTD (mtd.org), the transit agency serving Champaign-Urbana, a college town in Illinois with about 200k people. It's an excellent bus system, everyone in the city loves it, the people running the place always embrace new technology, and they actually have a hydrogen plant setup in their depot and the plant is powered 100% by solar energy: https://mtd.org/inside/projects/zero-emission-technology/

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

#223

Post by loeg »

mschuster91 wrote: post #25
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 ideal drivetrain was invented over 20 years ago by Toyota and apparently nobody but me and Honda noticed it! The problem is hybrid drivetrains are complex . You don't save anything on the complexity of a combustion engine and exhaust train (over 1000 individual parts that have to be machined at extremely low tolerances), but add a more complex transmission (it needs to be able to work with two distinct inputs)…

> virtually all modern cars have a turbocharger

This is not really true in the US, but maybe moreso in Europe, where engine displacement is penalized?

> that needs time to spin up

Porsche's latest 911 does something very cute here ("T-Hybrid"): they have a small electric motor in the turbo. They use the high-voltage hybrid battery to rapidly spin up the turbo on demand to significantly reduce turbo lag (one of the major drawbacks of a turbo engine). Then, at lower load, they can also regen the battery using the exhaust gases and that same motor.

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

#224

Post by csomar »

nyokodo wrote: post #201
xbmcuser wrote: post #186

Earlier quoted context omitted.

The current US administrations moves against renewables should make you realize how powerful the oil gas lobby is. They got some pushback from local politicians so were slowed down but the way they started they were looking to end all wind and solar for a false promise of nuclear tomorrow.

[flagged]

That could have been an argument for a suspicious individual but China has showed otherwise. China came late to the green transition and now they are ahead of anybody else. And they are big and not relatively rich.

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

#225

Post by loeg »

jshier wrote: post #32
mschuster91 wrote: post #25

Earlier quoted context omitted.

> The ideal drivetrain was invented over 20 years ago by Toyota and apparently nobody but me and Honda noticed it! The problem is hybrid drivetrains are complex . You don't save anything on the complexity of a combustion engine and exhaust train (over 1000 individual parts that have to be machined at extremely low tolerances), but add a more complex transmission (it needs to be able to work with two distinct inputs)…

As a simple driver of cars, I've never understood why no one has mass produced an EV with a built-in generator. That would avoid the complexity of the hybrid drive train, allow easy plugin and short range electric-only travel, and could even be offered as an optional attachment. So what am I missing? Is the efficiency gained by the generator offset by losses through the EV system?

You're talking about PHEVs, basically. Ramcharger is an example of one where the ICE engine only charges the battery; it's not connected to the drivetrain.

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

#226

Post by loeg »

AnthonyMouse wrote: post #96
jshier wrote: post #32

Earlier quoted context omitted.

As a simple driver of cars, I've never understood why no one has mass produced an EV with a built-in generator. That would avoid the complexity of the hybrid drive train, allow easy plugin and short range electric-only travel, and could even be offered as an optional attachment. So what am I missing? Is the efficiency gained by the generator offset by losses through the EV system?

That is called a series hybrid and the reason they're not popular is that the power split device in common hybrids is simply better. The power split device isn't an ordinary transmission, it's a set of planetary gears with a fixed gear ratio between three shafts. One goes to the wheels, the other two to the engine and the electric motor respectively. The ratio of the engine speed to the wheel speed is then set by the…

Ram is trying to commercialize this in the form of the Ramcharger. I don't know if it will succeed.

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

#227

Post by bawolff »

askvictor wrote: post #129
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…

Not just to delay, but they're hope is that they'll be able to control it when it happens. Oil companies move fluids, using pipes and tankers. Hydrogen is a fluid. They want to keep doing what they've been doing. Electricity doesn't fit into their M.O.

I don't think its really viable to transport hydrogen via existing (oil) pipelines.

Hydrogen leaks everywhere.

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

#229

Post by [deleted] »

bluGill wrote: post #178
busthrowaway23 wrote: post #142

Earlier quoted context omitted.

Am I misunderstanding you about the 15 minutes interval? Every workday I take a one-seat King County Metro bus ride that lasts about 1 hr. The bus starts at a layover facility and ends at a different layover facility. I don’t see how this 15 minute interval maps to my actual commute?

Very few people will accept commutes that long and so they are not something to optimize for.

[deleted]

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

#230

Post by jjani »

bombcar wrote: post #14
rsynnott wrote: post #6

Huh. I kind of thought that batteries had comprehensively won in this market, tbh. I still can't quite get used to the electric buses. A 20 tonne double-decker bus should sound like it might explode at any moment; it is unnatural for them to move around more or less silently.

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…

> (if you ignore CNG busses, which have existed forever and are "almost as good as hydrogen could be")

In most of the US yes, in dense big cities they're still quite a bit worse (especially if they run at night too) because they're very noisy compared to electric or hydrogen.

I live in such a place where the buses were all CNG and are now shifting to electric. Unfortunately the switch isn't going too quickly, but every time an electric bus goes by the peace and quiet is blissful. I think every new bus they buy is electric, but I get that they don't want to throw out all of the existing CNG stock.

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