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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?

#111

Post by torginus »

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?

Most BYD PHEVs work like that - with the additional option of connecting the engine directly to the wheels via a clutch at highway speeds. I think Honda has a similar system.

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

#113

Post by Tijdreiziger »

PaulHoule wrote: post #75
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.

In Tompkins County we were early adopters of the electric bus, at least for the American market. We bought them from a startup which had trouble with the structural aspects and eventually they fell apart https://www.ithaca.com/news/ithaca/tcat-pulls-all-electric-b... Established bus manufacturers make good electric buses now but we don't have the money to buy replacements.

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

#114

Post by marcosdumay »

WalterBright wrote: post #42
myself248 wrote: post #11

Earlier quoted context omitted.

They're great for trainers. Short hops with immediate control, low maintenance and operating cost, and you can save the magneto/ignition/etc workload for a different lesson series.

I can see that. Although managing the engine is a major part of learning to fly.

So, make electric airplanes the initial license, reduce the amount of hours to get it, and have an entire course on monomotors before pilots can deal with combustion airplanes.

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

#115

Post by bluGill »

AnthonyMouse wrote: post #104
bluGill wrote: post #97

Earlier quoted context omitted.

Not that I know of - but there shouldn't be.

How do you get somewhere which is 20 minutes from the depot, or in general between any two points that are more than 15 minutes apart?

You put in a different depot for the 20 minute trip. With express buses the trip between the two depots may only be 5 minutes.

People through history have always considered about half an hour a reasonable daily commute. Doesn't matter if it is a hunter-gatherer going to their gathering grounds (if they follow herds they will move camp if the herd moves more than half an hour), or "modern man" going to the office, half an hour is what you get. Everything I said is based on making as many of those half hour trips possible as I can - but not all trips can be done that way and some locations will be left out.

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

#116

Post by AnthonyMouse »

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 model like the Prius is, so the only exterior difference is a hybrid badge on what is otherwise visually identical to the non-hybrid car/truck of the same model.

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

#117

Post by abdullahkhalids »

bluGill wrote: post #103
abdullahkhalids wrote: post #100

Earlier quoted context omitted.

There are two critical aspects to the bus routing problem. One is that no matter how well you design your system, there is always variance in the arrival times of a bus at any given stop. If you expect people to switch buses, then you need to account for this variance, and this means adding buffers. Nothing makes people stop using buses faster than missing your connection because your bus was late. The other aspect i…

I'm coming from a different perspective: regardless of all else (all those issues you raised are very real), people need to get where they are going in a reasonable amount of time. Most bus service fails to account for that, but if you can't get people there in a reasonable amount of time there is no point in trying.

I agree that a system that does not deliver is going to fail. Transit systems can have improved scheduling in two ways:

(1) Better scheduling system. My opinion is that most real world systems are not too far away from the optimal trade-off curves. There is always room for improvements, or choosing better trade-offs, but it will rarely drastically improve things.

(2) More ridership: Most problems with speed just disappear if more people ride. For example, you do need a solid buffer when buses come every 30 min or more. But buses that come every 10 min or less, you can get rid of all buffer. A lot of scheduling problems are just not-enough-users problem.

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

#119

Post by fraserharris »

AC Transit (eg: East San Francisco Bay) performed a detailed 2 year study (July 2020 - June 2022) comparing newer Hydrogen Fuel Cell & Battery -powered buses to existing Diesel, Fuel Cell, & Hybrid -powered buses, 5 of each type. The key results are the Hydrogen Fuel Cells have significantly more expensive infrastructure, fuel, and maintenance costs than Battery. However, both technologies are still less reliable than Diesel.

The results are broken down into 4 volumes, each covering 6 months. You can read them here: https://www.actransit.org/zebta

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

#120

Post by zizee »

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…

> That means the technology problem is now a money problem.

This is such an odd insight. Most problems in the world can be described as a "money problem", and it's usually the problem that problem solvers are pushing up against.

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