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Hydrogen vs. Battery Buses: A European Transit Reality Check

cleantechnica.com

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

#51

Post by hakfoo »

m463 wrote: post #49
01HNNWZ0MV43FF wrote: post #40

Earlier quoted context omitted.

I'm surprised hybrids are so under-represented in this considerations. Maybe I'm missing something but I would think at the scale of a bus, a hybrid is even more appealing than at the scale of a sedan. Even locomotives and one or two earthmoving off-highway trucks have electric transmissions, making them series hybrids (With very small batteries not used for traction)

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.

As I understand it, straight electric locomotives would use the 'dynamic' braking to send current back up the wires. Apparently this would make for entertaining economics-- a section of the rail network where most of the tonnage went downhill could produce a net negative power bill.

With diesel-electrics, there was nowhere to the braking power, so resistor grids were the order of the day. I wonder if it would be possible or worthwhile to outfit them with battery tenders to recapture the current with modern batteries and power-management circuitry.

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

#52

Post by deepsun »

vegavis wrote: post #45
Kirby64 wrote: post #9

Earlier quoted context omitted.

> you would need a whole new infrastructure for hydrogen powered buses, while keeping a lot of the downsides of fossil fueled air breathing vehicles (eq. air filters filters regardless of if you burn the hydrogen or use it in fuel cells). Unless you burn the hydrogen, you aren't producing any emissions... unless you count water as an emission. Fuel cells don't produce any emissions. Burning hydrogen though, does prod…

Fuel Cells have a lot in common to ICE. They require a significant balance of plant that helps provide air to the fuel cell, coolant for many of the components, electronics controller and significant electrical harnessing, bracketry for support, filters, coolant pump, air source, radiator... etc. in one way it is a downside since its more parts and complication than maybe a pure EV architecture, but the similarities…

I drove hydrogen Mirai, and it feels pretty much electric in every way but fueling. It drives off battery, no hybrid transmission, hydrogen is only there to charge the battery.

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

#53

Post by morsch »

m463 wrote: post #49
01HNNWZ0MV43FF wrote: post #40

Earlier quoted context omitted.

I'm surprised hybrids are so under-represented in this considerations. Maybe I'm missing something but I would think at the scale of a bus, a hybrid is even more appealing than at the scale of a sedan. Even locomotives and one or two earthmoving off-highway trucks have electric transmissions, making them series hybrids (With very small batteries not used for traction)

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.

On the other hand, pure electric trains seemingly have had regenerative braking for a hundred years.

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

#54

Post by nine_k »

m463 wrote: post #49
01HNNWZ0MV43FF wrote: post #40

Earlier quoted context omitted.

I'm surprised hybrids are so under-represented in this considerations. Maybe I'm missing something but I would think at the scale of a bus, a hybrid is even more appealing than at the scale of a sedan. Even locomotives and one or two earthmoving off-highway trucks have electric transmissions, making them series hybrids (With very small batteries not used for traction)

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.

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

#55

Post by Rygian »

vegavis wrote: post #44

Yeah this only reveals a snapshot of the current situation. The truth is that lithium ion has a few more decades of serious R&D and successfully mass produced commercial products on the market. Hydrogen fuel cells arent as fortunate; they still have a high production cost due to low volume, the supply chain has had a fraction of the investment of ICE and EV, and the regulatory environment is even less clear than EV a…

Why so much waste?

Why would a factory invest in hydrogen fueled forklifts and their associated refueling infrastructure if they can get electric ones that just plug into a wall socket?

Unless research on hydrogen manages to upturn our foundational understanding of thermodynamics, hydrogen will be a waste of useful energy in most applications.

For further reference, check the "clean hydrogen ladder"

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

#56

Post by mmooss »

rsynnott wrote: post #4

I think battery buses have comprehensively won this one, to be honest. The biggest hydrogen bus fleet seems to be 35 vehicles; there are many BEV bus fleets in the hundreds and some in the thousands. As a certified old person, I'm having trouble getting used to them. It is unnatural for a double-decker bus to pull up near-silently, and then move off smoothly when you get on. They are _supposed_ to vibrate violently a…

> The biggest hydrogen bus fleet seems to be 35 vehicles

From the OP:

Cologne is one of the few relatively good news stories for hydrogen bus fleets. Regionalverkehr Köln (RVK) has become the largest operator of hydrogen fuel cell buses in Europe, with a fleet that reached 101 vehicles by late 2024 and is expected to grow to 160 by the end of 2025.

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

#57

Post by f_devd »

kumarski wrote: post #35

Hydrogen buses limp at an EROI of 0.5 to 1.5. Losses via Gibbs free energy (237 kJ/mol to split H2O) and compression (20% of H2’s 120 MJ/kg.) Barely cash in on the H2-O2 reaction (ΔH = -285.8 kJ/mol). Battery buses, powered by lithium-ion cells, hit EROI of 2 to 4. Redox heavy lithium mining (150 MJ/kg) drags it all down. Charge-discharge losses (90% Coulombic efficiency)+ 5-10% capacity fade after 1000 cycles. All t…

By your own calculation EROI of Battery buses should be about 15-30 (taking diesel EROI as given as it has no source) if you actually apply the vehicle's efficiency; ~85% efficiency for E2E diesel-generator-to-EV. While diesel bus would be around ~21% effiency.

Source/explainer: https://youtu.be/6c94vRmbM6Y?si=WmCvyB6uKJT7TWZ7&t=444

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

#59

Post by amsha »

There is a very to-the-point diagram called the Hydrogen Ladder [0] that classifies the usefulness of hydrogen by domain. The author makes a good case that, despite its versatility, hydrogen is almost always worse than some other clean technology for any use case. It’s hard to make, store, and use in a scalable/cheap way, and even generous estimates of future progress show a cost curve that requires subsidies basically forever.

Buses are classified as a “Most Uncompetitive” category. Electricity, whether wired or battery powered, is cheaper and easier to scale for the predicable everyday energy use of a city bus.

0: https://www.liebreich.com/hydrogen-ladder-version-5-0/

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

#60

Post by dangerlibrary »

j_4 wrote: post #58

Often overlooked but electric buses are very heavy. Here in my small hometown they visibly started decaying the road infrastructure super fast in many places since they got introduced. Not impossible to patch up, but not a negligible cost of moving to the tech.

The US Government did a study in the 1950s and discovered that the damage done to a roadway by a car is proportional to the fourth power of its axle weight.

https://en.wikipedia.org/wiki/Fourth_power_law

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