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

cleantechnica.com

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

#151

Post by mixermachine »

pjscott wrote: post #136
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…

Do you have actual knowledge of their motives? Or is this speculation, confidently stated as fact? Another possible motive, mentioned in the the paragraph you quote, is that the oil companies see an energy transition coming and are trying to get aboard the hydrogen train to diversify their future revenue sources. And that sounds like a reasonable motive; the sort of thing that people who don't see themselves as evil…

One can extract hydrogen from fossil fuels. So if a hydrogen break through is coming, they already have a cheap source for the material. Not really green though...

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

#153

Post by myself248 »

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.

Exactly. Flying the airplane is the first 90% of flying, managing the engine is the other 90%. So it helps to set one aside while you work on the other.

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

#154

Post by fraserharris »

AtlasBarfed wrote: post #149
fraserharris wrote: post #119

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 tha…

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.

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

#155

Post by bobthepanda »

KeplerBoy wrote: post #144
bombcar wrote: post #31

Earlier quoted context omitted.

Seattle also has (or had) trolley busses which fixed that problem. Everything is cost, it's all cost, not the ability to actually solve the problem.

I wonder if trolley busses will make a great comeback now. Seems so obvious to just put the overhead lines near a few central bus hubs, so buses can recharge during the shift.

The main issue with trolleybuses is that they are subject to a lot of NIMBYism, so you'll run into issues siting trolley hubs.

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

#156

Post by jeffbee »

fraserharris wrote: post #119

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 tha…

They're much quieter however.

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

#157

Post by AnthonyMouse »

adrian_b wrote: post #110
AnthonyMouse wrote: post #82

Earlier quoted context omitted.

That's efficiency, not range. Suppose hilly terrain reduces range by a third for electric vehicles and half for diesel. The diesel bus just fills up twice as often. The electric bus needs a 50% bigger battery in order to finish the same route without stopping to charge, and then it becomes 70% because it has to lug the bigger battery up the hills. You can just... do that, but that doesn't mean it's not a thing you ha…

It is impossible for a hilly terrain to reduce the range by a third for well-designed electric buses. The efficiency of regenerative braking increases with the power of the vehicle. The electric efficiency should be well over 90%, perhaps even 95%. The mechanical losses will lower the total efficiency to much smaller values, but even so, the total efficiency should be over 80%. A bus with an ICE will consume 5 times…

> The efficiency of regenerative braking increases with the power of the vehicle. The electric efficiency should be well over 90%, perhaps even 95%. The mechanical losses will lower the total efficiency to much smaller values, but even so, the total efficiency should be over 80%.

It's not just about conversion efficiency. Moving a vehicle up a hill requires several times as much power as traveling on level terrain, which heats the battery. Reaching the top of the hill and starting regen when going back down again, also heats the battery. On normal terrain that isn't all hills there will be level sections in between that allow the battery to cool. If the terrain doesn't have that then the battery gets too hot and the vehicle will disable regenerative braking and use friction braking to allow the battery to cool off. The steeper the hills are, the more heat is generated per unit time.

Batteries also have charge curves. In the extreme case you start at a higher elevation, go down a hill and can't use regen at all because the battery is full and there is nowhere to put it, but then you have to spend energy later to get back to where you started. The same is true even if the battery isn't fully charged, because extreme charge levels require charging to be done gradually and the battery might not be able to take as much power right now as a heavy bus would generate descending a steep grade.

> A bus with an ICE will consume 5 times more extra energy for climbing the hill and it will also consume energy while going downhill.

Modern engines will cut fuel entirely when descending a grade.

> the presence of hills in any city can only make electric buses more advantageous, not less advantageous, due to much greater cost savings for fuel and maintenance.

That doesn't contradict the point that they'll need to have larger batteries to achieve the same range on hilly terrain.

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

#158

Post by AnthonyMouse »

bluGill wrote: post #115
AnthonyMouse wrote: post #104

Earlier quoted context omitted.

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, hal…

You would then be subjecting people to indirect paths with multiple transfers. Instead of going from A to B you'd have to go from A to the first bus depot to the second bus depot to B, waiting for another bus at each transfer. If the trip was 30 minutes to begin with, now you've made it 45 (at best).

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

#159

Post by neRok »

cf100clunk wrote: post #39

Look into propane (a.k.a. LPG or Autogas). If the goal is anything-but-diesel-or-gasoline/petrol, the use of propane (a fossil fuel that is a byproduct of oil and gas refining) is a well-understood, well-implemented practice. I am not advocating for propane as a primary solution, but rather as part of the journey towards truly clean vehicle emissions and the ramp-down of heavily polluting fossil fuel refining. Propan…

LPG had its chance here in Australia in the 2000's, but it didn't work out [1]. Subsidised conversions were offered back then, which many people took up on their 80's+90's model cars, but it probably led to the early demise of many of those cars. By the late 2000's there were factory cars selling with LPG "gas" systems, but they weren't as good as the petrol variants [2]. By 2011 you could get "liquid injection" models, which were as good [3]. But like the first article states, people with "large" cars were shifting to SUV's and dual cabs by that stage, and a lot of them were 4cyl petrol/petrol-turbo/hybrid/turbo-diesel, so their fuel efficiency was comparatively decent.

Also in 2011, the government introduced fuel-tax on to LPG, which it had been exempt/discounted on previously. So the price went up, and all of a sudden it wasn't as economical. So that put it in to a death-spiral, especially when many servo's started getting rid of it due to low demand. Now people with LPG cars have "range anxiety" [4]. Where I live (Perth, Western Australia), you are basically stuck in the metro area if you are LPG only. It also means there's a ton of ~2008-2012 LPG Falcons for sale second-hand at good price, but no one wants to buy them.

Out of curiosity, I just went and looked up some data for where I live - the Perth metro (source [5]);

  Year  Month  Fuel  c/L avg  Servos  $cost / 100km for Ford Falcon sedan (UNO)
  -----------------------------------------------------------------------
  2010  Dec    LPG     69.4   216     @ 15L = $10.4  (gas model)
               ULP    128.0   298     @ 10L = $12.8  (petrol model)
  2019  Dec    LPG     89.0   147     @ 15L = $13.4  (gas model)
               LPG     89.0   147     @ 12L = $10.7  (LPi model)
               ULP    144.9   387     @ 10L = $14.5  (petrol model)
  2024  Dec    LPG    133.9    46     @ 12L = $16.1  (LPi model)
               ULP    172.7   436     @ 10L = $17.3  (petrol model)
               ULP    172.7   436     @  6L = $10.4  (Falcon Ecoboost 4cyl 2L turbo)
               Dsl    178.5   437     @  9L = $16.1  (Ford Territory SUV 2.7L TD)
[1] https://www.fleetcare.com.au/news-fleettorque/fuel-cards/wha... [2] https://www.smh.com.au/national/running-the-rule-over-lpg-op... [3] https://www.drive.com.au/reviews/ford-falcon-ecolpi-lpg-revi... [4] https://www.abc.net.au/news/2023-04-19/lpg-cars-disappearing... [5] https://www.fuelwatch.wa.gov.au/retail/historic
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