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Hydrogen vs. Battery Buses: A European Transit Reality Check

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Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#111

Post by praseodym »

philjohn wrote: post #92
mmooss wrote: post #85

Earlier quoted context omitted.

If people followed that reasoning, there would be few EVs now because EVs had been tried for decades without success; so were airplanes and AI. If people quit as easily as you say hydrogen car manufacturers should, we wouldn't have much of anything.

Yes - but Hydrogen vehicles have not proven to match or even beat EV's in a lot of key metrics that matter. The biggest one is efficiency. 40% efficient is one figure I saw, versus 80% for EV's. Yes, you can refill quicker, but time to "refuel" EV's is dropping precipitously as well, and it's just all around safer than tanking around highly combustible liquid gas.

> Yes, you can refill quicker

Unless the hydrogen fueling nozzle freezes to the car, which is apparently quite common in high humidity weather and/or when multiple cars are fueled consecutively. See e.g. https://www.sciencedirect.com/science/article/pii/S036031992...

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#112

Post by CraigJPerry »

linedgolyi wrote: post #84
CraigJPerry wrote: post #81

Earlier quoted context omitted.

I thought they all had AVAS fitted? Are there markets where this isn’t the case?

Maybe? Problem is either that it can be and is always disabled by driver, or it's very quiet, because I as a healthy man in their 20s, hear the pavement tire noise before any other noise, and the car is already really close at that point

In the EU and UK markets we don’t have an option to disable the AVAS noise generator.

It self disables above something like 10kmh when, as you say, tyre roar is the predominant sound a car makes (unless someone is revving the engine I suppose).

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#113

Post by nautilius »

philjohn wrote: post #92
mmooss wrote: post #85

Earlier quoted context omitted.

If people followed that reasoning, there would be few EVs now because EVs had been tried for decades without success; so were airplanes and AI. If people quit as easily as you say hydrogen car manufacturers should, we wouldn't have much of anything.

Yes - but Hydrogen vehicles have not proven to match or even beat EV's in a lot of key metrics that matter. The biggest one is efficiency. 40% efficient is one figure I saw, versus 80% for EV's. Yes, you can refill quicker, but time to "refuel" EV's is dropping precipitously as well, and it's just all around safer than tanking around highly combustible liquid gas.

Efficiency is the standard red herring of the battery crowd - if efficiency was the prime motivation, we would all be driving bicycles and SUV or sportscars would not exist.

What are your other metrics? It’s an electric drivetrain with all advantages, but with the range of a gasoline car. Refueling cNG or LNG is standard in Europe, LH2 works just fine.

Google “burning Tesla” for that ridiculous take on why batteries would be inherently safe.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#114

Post by elif »

Besides those working in the technology keeping themselves employed, I'm really confused who is supporting hydrogen.

The infrastructure to support it is far more complex than our current petroleum network, and hydrogen is less safe than petroleum, while at the same time, electric is safer and requires just 10% of the infrastructure as petroleum.

It reaaalllly just feels like scientists and fossil fuel grifters still propping up hydrogens dead xorpse

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#115

Post by hnaccount_rng »

m101 wrote: post #102

I think there's a risk of "it's too soon to say here" when deciding on fuel vs battery Vs hydrogen. The problem is that this is a highly complex dynamic system with different people experiencing different externalities. Reasons answering this question is difficult are, for example: - given the demands for highly valuable electricity and alternative use cases, why do we insist on using it in locomotion? - given margin…

I think this "debate" is largely irrelevant: China has decided that locomotion will be (battery) electric. That is the largest scale you can get, so any effects of scale for an alternative will at best be as large as the battery electric one.

And then there are the variety of other disadvantages that come with hydrogen: - significant leakage and high greenhouse factor - heavy support equipment need (both for storage and for usage)

About the only advantage of hydrogen (vs. lithium-ion batteries) is gravimetric energy density (where it's about a factor of 300). But even volumetric energy density differs only be a factor of 5-10. (Both numbers ignore that the storage thing will add significant weight). And those are _already_ not limiting for locomotion needs.

- how sure are we that we are solving a co2 climate crisis with the actions we are taking?

The thing here is yes: Even if we would generate the energy for the locomotion completely with fossil fuel! Large plants are significantly more efficient (10-35% vs up to 60%) and it would be _much_ simpler to, e.g. think about carbon capture if we had tens of thousand CO2 emitters rather than a billion. But we are not doing that!

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#116

Post by hylaride »

nine_k wrote: post #54
m463 wrote: post #49

Earlier quoted context omitted.

I wonder if diesel electric locomotives are efficient at all. I think the electric is for infinite torque to get lots and lots of cars moving. But to slow down, "electric" brakes are to bleed off power into resistor banks, not re-capture the electricity. Meanwhile an electric bus actually has to be efficient, which means batteries and regenerative braking.

A diesel electric locomotive has no serious batteries, and no room for enough batteries to consume the energy of slowing down a train. At least it can dump it as heat without also producing fine dust, like mechanical brakes do.

They can (and do) have room if they're designed from the ground up for it. The engines for diesel electric trains are so large because they need to be sized to drive power for peak energy (usually accelerating and hills). If the energy can be stored, the engines for hybrid locomotives themselves can (and are) smaller.

So far you're only seeing hybrid locomotives for trains that stop/start a lot (shunting trains and passenger rail). The cutover for freight will likely take decades because A) locomotive lifetimes are measured in decades and B) longer range freight usually has less stop/start, making it's economical delta less.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#117

Post by bluGill »

adgjlsfhk1 wrote: post #37
martinald wrote: post #19

Earlier quoted context omitted.

Not really. Buses need to be charged whenever, not just overnight (it creates enormous logistical problems otherwise). A typical bus route running 5am to midnight say is not going to last with one charge, depending on length. Also, if it is a cold night and everyone leaves electric heating/heat pumps on, what happens then? Noone can get to work the next day? Regardless most urban transformers are not going to have 15…

Lots of busses are split shift. i.e. they drive from ~6:30am to ~9:30am and ~4pm to 7pm. This means that a significant portion of your bus fleet will be able to charge during the middle of the day when energy demand is relatively low and there's a ton of solar power. As an aside, we have so far really dropped the ball on level 1 electric vehicle chargers at offices. As solar power and EV numbers increase, it's pretty…

Split shift is a stupid idea that needs to die. It only works for people who always work '9 to 5'. Work a different shift and you drive. Need to go shopping - just drive. Have a day off - drive to whatever you do. Going to church one sundap - drive. Have a kid who might get sick at school - you better drive everyday.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#118

Post by bluGill »

jillesvangurp wrote: post #67
occz wrote: post #20

Electric buses in the form of trolleybuses seems like the better option than either of these, although I do agree that battery buses beat hydrogen every day of the week.

Batteries are cheap. Installing lots of copper lines for trolley buses isn't. That's why trolley buses are pretty rare. Old idea, didn't really take that well. There are a handful of cities that have them. And they've had them for decades. Most of those cities now also have battery electrical buses to service all the areas where the cables don't go. Expanding the network of cables doesn't seem to have a very high pri…

Trolly wires generally work out cheaper than batteries if you are running frequent service. Batteries work out better anyway though because they allow you to go around obsticals (roadwork, cars illegally parked in the land...)

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#119

Post by wolfram74 »

elif wrote: post #114

Besides those working in the technology keeping themselves employed, I'm really confused who is supporting hydrogen. The infrastructure to support it is far more complex than our current petroleum network, and hydrogen is less safe than petroleum, while at the same time, electric is safer and requires just 10% of the infrastructure as petroleum. It reaaalllly just feels like scientists and fossil fuel grifters still…

My impression is it's auto and fuel companies putting out this unworkable alternative to current technologies so they can appear to be concerned about climate change without having to actually stop making money, also if it does work they can crack the petro chemicals to get hydrogen out and people who point out it's basically as dirty as ICE engines will look like pedants.

The scientists are just there because if you give them the opportunity to work on hard technical challenges, they'll take it. The morality is much greyer than the ones being paid to contrive models with the initial goal of "higher CO2 is actually good for everybody."

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#120

Post by [deleted] »

kleiba wrote: post #83
spacebanana7 wrote: post #61

Earlier quoted context omitted.

Still, their point was directionally correct. London has 1397 electric buses and Moscow has over 2300. https://en.m.wikipedia.org/wiki/Low_emission_buses_in_London https://en.m.wikipedia.org/wiki/Electric_buses_in_Moscow

Germany has this recurring fixation on hydrogen for whatever reason. Even when Tesla had already long hit the mainstream market, German car manufacturers were still arguing against EVs in favor for hydrogen-powered cars that would theoretically be vastly superior. Well, we all know how that turned out for Mercedes, BMW, and the so on.

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