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Comment by fraserharris | Hacker News Reader

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

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The maintenance costs are only marginally higher per the report at $1.33 FCEB vs $1.15 BEB , $2.37 for Hybrids and $1.28 for Diesel (with additional public health costs for respiratory illnesses), the sample size(5x5) is too small to draw any meaningful conclusion on infrastructure costs or even reliability given the limited experience in operating anything not diesel.

Economics of hydrogen in CA are also complicated given our on-off approach to hydrogen infrastructure[2] for both personal and commercial vehicles but there is some progress on commercial side at least last year [1].

Hydrogen is not everyone but there are use cases for it.

The uptime (i.e. the refueling time) is an key factor [4]. Battery operated vehicles need a lot of downtime for charging thus you will need more vehicles for the same coverage. Fast charging can help but impacts battery life and thus TCO.

All green public transit are expensive. It is not a easy choice for administrators, should they improve coverage/ service frequency etc for their residents who need transit the the most or better air quality and less noise pollution for all of them.

Remember Fuel Cells are far cleaner for the air much more than BEV also, because it needs oxygen from the air FCs purify the air to do so. Kind of like having a big vacuum on the road in addition to not emitting direct pollutants[3]

[1] https://www.portofoakland.com/port-of-oakland-celebrates-hyd...

[2] https://www.energy.ca.gov/data-reports/energy-almanac/zero-e...

[3] Ignoring tire dust, it is problem for all vehicles of course, that is independent of propulsion systems

[4] Even for personal vehicles it can be a decision factor when considering going green, as an owner of a Mirai with no easy access to EV charging stations I have benefited from being to refuel like a gar car.

If I'm reading that right the Battery Electric busses had the lowest maintenance costs? The need to charge is a potential issue, but at the same time busses do lots of low speed stop and go where battery systems are most efficient. As long as the bus has enough capacity for an entire day and can be recharged overnight it seems like an ideal solution, minus of course the up-front cost of the bus. Lower fuel costs, no noxious pollutants, less noise, lower maintenance, there is a lot to love.

An other option BEV busses give is hybrid trolleys, that way once a popular line gets fixed you can add overhead lines to it and later upgrade it to tram more easily.

It also means charge is a matter of having overhead lines which can be added as hoc (as overhead docking stations) to end-of-line stops, letting the bus juice up for some time before it runs the route back.

It is likely that new models had higher costs, including maintainers becoming familiar. Long-term, electric is unquestionably cheaper to fuel and maintain, assuming they are built to the same standards and scale as outgoing diesel models

I wonder about the added wear on roads that comes with so much added weight. That is the kind of cost that is easy to put in someone else's bucket until it impacts everyone. One of the roads near here was closed for a while putting a large amount of truck traffic on another road. It is impressive how quickly ruts have formed in a relatively short period of time from what I assume is a combination of increased traffic and the increased weight.

A typical diesel or natural gas city bus has a curb weight between 20,000 and 33,000 lbs[1]. An electric bus I found lists a curb weight of 28,000 lbs[2]. It doesn't seem like extra road wear is going to be a major issue.

[1] https://onlinepubs.trb.org/onlinepubs/tcrp/docs/TCRPJ-11Task...

[2] https://www.fotonmobility.com.au/electric-city-bus-12-5m

Lowest short term maintenence cost. Until the battery is destroyed in a couple of years.

Charging a fleet of 100 buses overnight looks like a huge infrastructure issue to me. 100 charging ports, huge grid connection, substation etc. That is if the local grid even has capacity. Anyone who has tried to open a factory will know that is not always the case.

>Until the battery is destroyed in a couple of years

BYD are doing one guaranteed for a million km.

EV batteries have been performing much better than dying after just 700 cycles. Also, power is generally cheapest overnight when there is excess grid capacity. People with variable electricity pricing and battery banks make money by charging overnight and releasing power to the grid during peak hours. Commercial vehicles typically get more like 6,000 cycles out of a battery pack.

I think the case for using hydrogen today is pretty weak, but a lot of the details for why it's a bad choice are (as you say) exacerbated by the one-off deploys of the technology. If you were testing gas busses and needed to truck gasoline in just for your busses you would expect the numbers to get worse too.

My view is that if you want a clean alternative today you'd go with electric and also the tech seems worth continuing to develop for other applications. I also think that public transit doesn't seem like it plays to the strengths (such as they are) of hydrogen.

I get the impression they've had similar results in London. They've had ~20 hydrogen busses for a while but apparently are expensive like £500k per bus plus you need to find hydrogen.

On the other hand battery seems to be cracking along: "over 1,600 zero-emission buses currently in service, and TfL aims to have a fully zero-emission bus fleet by 2030, accelerating plans with increased government funding."

Only two years? They operated hydrogen buses from 2006 to 2010 and then got some more in 2011 and 2019. There are budget line items for new buses in 2023 and 2024 that I assume got bought

I'm not going to dispute your numbers with diesel versus EV reliability, but I have to think the simplicity of an EV drivetrain will win that battle in the next version or two.

The reliability speaks to the technology immaturity. I agree with the inevitability of the EV drivetrain + charging off the existing distribution network being more reliable than competing technologies.

idk these sound like very specific problems they had. The chargers had an availability of only 23% because of a recurring issue with the power modules failing. In a later volume they also again attribute a lot of unavailability to the same chargers:

> The BEB fleet operated at 66% availability with more than half of the total days related to retrofit of the charger cabling and programming by the OEM.

I guess you could say this is due to immature technology but honestly I don't see 75% of HPC chargers being offline for maintenance at any given time. This is probably just bad luck with a vendor.

If you look at the road calls the BEB is by far the most reliable one, causing one road call out of 45. It was also the cheapest per mile by a long stretch.

It’s hard to imagine it not. And also kudos and crazy respect for all the thousands of engineers that poured their work into making combustion engines as efficient and reliable as they are. A true marvel of humanity, and something to be respected even as we leave it behind.

I see your point, but at best you're getting 40% thermal efficiency with IC. It's not great.

Relative to EVs it’s not. But relative to ICE engines from 50 years ago it’s great. EVs are obviously going to take over ICE, my only point is that we shouldn’t discount all the work and ingenuity that went into ICE engines simply because a disruptive technology came about.

No one cares about thermal efficiency. What matters is the economic efficiency.

And yet, how much earlier could we have had better solar panels and EVs?

Certainly wind power was viable as soon as fiberglass was invented.

The mass engineering should have also been directed at that which would have saved us a billion tons of carbon.

Based on personal experience my guess is that the unreliability would be in the battery not the drive train.

Or more precisely put, batteries are a sort of black box they ether work or they don't work but either way you are not going to be able to open one up and find out why. that is, they are a high cost unrepairable item on the vehicle and this is a huge liability.

Batteries aren't unrepairable; you wouldn't open one up in the middle of the road to try fix it but at the bus depot with enough volume of battery electric vehicles, they'll have reason to hire repair technicians that can refurbish and repair batteries.

Obviously anything has a bunch of single points of failure, or catastrophic means of failure, but a battery isn't like "one engine". It's basically hundreds of little power modules wired in parallel, so an individual battery cell loss shouldn't bring down the whole pack.

So a battery pack should actually be heavily redundant ... assuming the pack has enough modules for a loss of vehicle to get to some charging station.

They're much quieter however.

Limerick City in Ireland has electric double decker buses. They are dead quiet and it's a total treat to be a pedestrian without the buses passing by and blowing my ears off.

I note that their electric buses are made by a different company than their diesel buses, which would make reliability comparisons a bit questionable.

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