Hydrogen is the future, not BEVs?
Discussion
anonymous said:
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And if you want the source of the 24% figure, it's in section 3.1 here - https://www.riagb.org.uk/RIA/Newsroom/Publications... . Seems that Mykola Zasiadko has quoted from the submissions by the "voice of the UK rail supply community" (to quote their website). An organisation with over 300 members and whose board includes the MD of Alstom UK, Balfour Beatty's Rail and Utilties CEO, VolkerRail's MD, etc. So would appear to represent the majority of the companies actually working in this field.
anonymous said:
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I've given you the source of the figures - if you have questions about their workings, go ask them. Their submissions don't distinguish between battery and battery-catenary trains, probably because the majority of battery trains trialled here are actually battery-catenary. I'd guess for the simple reason that the charging infrastructure for them either already exists or can be implemented relatively easily., just as they're doing in Germany.
They've ordered battery-catenary trains to replace diesel in some areas. Trains have a 150km range, but the longest section without electrification is only 80km and they're adding additional small electrified sections to charge them -https://www.globalrailwayreview.com/news/84300/stadler-wins-tender-to-supply-battery-operated-flirt-akku-trains/
Seems like a really sensible idea - there's no need for massive ranges when it's more cost effective (and weight effective) to have smaller range to easily get between charging sections.
rscott, any mention of electrification there means conventional electrification with cables as we now have. That doesn't mean pure battery or hybrid battery -electrical. The article isn't saying battery based trains are the optimal solution.
The point being our rail electrification costs are massively higher than those in Germany.
What may be thought of as cost effective to them isn't near as cost effective to us.
With regards weight, the battery trains such as the Talent 3 have the extra impact of the additional 7.5 tonnes of battery and the charging system and cooling system up on the roof, the added weight for the extra reinforcement that will be needed to support this and whatever they'll need to do to mitigate that weight so high up.
So it's looking like hydrogen, and it's production and delivery infrastructure, will be needed for trains, for HGVs, for shipping, for industry, maybe for homes.
That will make the option for this to be used in passenger cars more viable.
Edited by anonymous-user on Thursday 3rd December 12:40
anonymous said:
[redacted]
The RIA say hydrogen may be effective for some trains, but not for high speed routes or mainline freight trains though. They also point out that hydrogen trains need far more space for the fuel than the equivalent diesel (8 times the storage space), so there are design compromises with that too.The Talent 3 won't be coming to the UK (it doesn't fit our infrastructure). We'd be likely to get something based on the Aventra, which is designed to be either battery or diesel.
Or the Stadler Flirt, which is available with combinations of battery, overhead and diesel power, using a separate power car, i believe, which avoids the issue of overhead weight.
If anyone wants to binge-read about all the various aspects of producing and using hydrogen, there's lots of interesting articles here:
https://www.thechemicalengineer.com/tags/clean-ene...
https://www.thechemicalengineer.com/tags/clean-ene...
I have been quite vocal on the hydrogen threads about safety.
The problem I foresee is the ever increasing probability of accidents with thousands or millions of privately-owned vehicles in circulation, particularly as they start to age. I believe that it will be almost impossible to prevent accidental leakage for ageing or poorly maintained equipment. The type of equipment that is bound to have problems at some point are valves, hoses, pipes, connectors, etc. Preventative maintenance does not necessarily solve the problem, as it can also be the root cause, if the replacement is not correctly fitted (see Norway 2019). Maintenance standards are likely to become more variable with age, due to a wide range of owner affordability/decision making. At a minimum, I think it will be necessary to consider restricting maintenance to licensed operators, rather than a free-for-all.
If you then add in usage profiles that includes multiple vehicles in confined spaces, e.g. tunnels, underground car parks, the scenario of a single vehicle leakage combined with an ignition source and multiple other hydrogen vehicles in close proximity, it's not impossible to envisage something like the desert hotel scene in Quantum of Solace.
Limiting both the ownership and maintenance responsibility to licensed commercial operators would go some distance to addressing this, along with the fact that the number of vehicles in circulation would be vastly reduced. Given that batteries aren't currently feasible for some larger commercial vehicles, trains, ships and aircraft, is seems obvious that these are the better applications for its use, with a much lower the probability of multiple hydrogen vehicles being co-located in a confined space.
Aviation is in interesting one. My understanding is that CO2 emissions at high altitudes aren't necessarily a problem (compared to those same emissions occurring at ground level), but that NOx at high altitude is quite bad. Airbus are suggesting that it might be 15 years before we see hydrogen-powered aircraft in service.
https://www.airbus.com/newsroom/press-releases/en/...
I'm not sure yet how I feel about travelling in hydrogen-powered vehicles or craft. Trains are probably the one that I feel the most comfortable with, as I'd imagine that an accident would be survivable for most of the passengers.
It may seem like I'm over-egging this issue, however, I'd hazard a guess that 99% of people currently have very little knowledge or experience of actually working with large quantities of it. I'm slightly uneasy with the 'clean/safe/healthy living' picture being painted by the stakeholders, I'd much rather see an honest approach to assessing the benefits and risks, and recognising that hydrogen does not represent a society-wide energy utopia. Here is a link to the wikipedia page that gives some examples of what happens when it goes wrong. I'd also recommend googling images of hydrogen accidents to get a scale of the damage and blast radius that can occur.
https://en.wikipedia.org/wiki/Hydrogen_safety
How do others feel about travelling in hydrogen-powered aircraft or vehicles?
The problem I foresee is the ever increasing probability of accidents with thousands or millions of privately-owned vehicles in circulation, particularly as they start to age. I believe that it will be almost impossible to prevent accidental leakage for ageing or poorly maintained equipment. The type of equipment that is bound to have problems at some point are valves, hoses, pipes, connectors, etc. Preventative maintenance does not necessarily solve the problem, as it can also be the root cause, if the replacement is not correctly fitted (see Norway 2019). Maintenance standards are likely to become more variable with age, due to a wide range of owner affordability/decision making. At a minimum, I think it will be necessary to consider restricting maintenance to licensed operators, rather than a free-for-all.
If you then add in usage profiles that includes multiple vehicles in confined spaces, e.g. tunnels, underground car parks, the scenario of a single vehicle leakage combined with an ignition source and multiple other hydrogen vehicles in close proximity, it's not impossible to envisage something like the desert hotel scene in Quantum of Solace.
Limiting both the ownership and maintenance responsibility to licensed commercial operators would go some distance to addressing this, along with the fact that the number of vehicles in circulation would be vastly reduced. Given that batteries aren't currently feasible for some larger commercial vehicles, trains, ships and aircraft, is seems obvious that these are the better applications for its use, with a much lower the probability of multiple hydrogen vehicles being co-located in a confined space.
Aviation is in interesting one. My understanding is that CO2 emissions at high altitudes aren't necessarily a problem (compared to those same emissions occurring at ground level), but that NOx at high altitude is quite bad. Airbus are suggesting that it might be 15 years before we see hydrogen-powered aircraft in service.
https://www.airbus.com/newsroom/press-releases/en/...
I'm not sure yet how I feel about travelling in hydrogen-powered vehicles or craft. Trains are probably the one that I feel the most comfortable with, as I'd imagine that an accident would be survivable for most of the passengers.
It may seem like I'm over-egging this issue, however, I'd hazard a guess that 99% of people currently have very little knowledge or experience of actually working with large quantities of it. I'm slightly uneasy with the 'clean/safe/healthy living' picture being painted by the stakeholders, I'd much rather see an honest approach to assessing the benefits and risks, and recognising that hydrogen does not represent a society-wide energy utopia. Here is a link to the wikipedia page that gives some examples of what happens when it goes wrong. I'd also recommend googling images of hydrogen accidents to get a scale of the damage and blast radius that can occur.
https://en.wikipedia.org/wiki/Hydrogen_safety
How do others feel about travelling in hydrogen-powered aircraft or vehicles?
Back in the real world where EVs are the future, we have this just opened, amazing elegance, efficiency and simplicity.
https://www.youtube.com/watch?v=FoN4WCpuxHY
Trying to do something like this with hydrogen would be a total inefficient mess.
https://www.youtube.com/watch?v=FoN4WCpuxHY
Trying to do something like this with hydrogen would be a total inefficient mess.
When you opt for hydrogen instead of helium to fill your party balloons....
https://www.youtube.com/watch?v=ndn1-StjA6I
https://www.youtube.com/watch?v=ndn1-StjA6I
anonymous said:
[redacted]
I'd be interested to see the data behind your comments above. Why would the relative well-to-wheel energy efficiency ratio be substantially different for trains than it is for cars? Is there some different way of obtaining the hydrogen for trains, or is there some other energy factor that affects one variant significantly over the other?And for clarity, I'm just talking about comparing when both variants are operating under their "own steam", because quite clearly when you factor in any catenary powered mileage, its no contest in favor of the batt-cat.
anonymous said:
[redacted]
His figures aren't that far off those quoted in this article - https://www.imeche.org/news/news-article/could-hyd..."Typical efficiencies for electrolysis and fuel cells are respectively 68% and 52%. Compressing hydrogen for storage, typically at 350bar, requires 6% of its chemical energy. So the overall cycle efficiency is 33%. Hence hydrogen traction requires 3kW of electricity to deliver 1kW of power to the wheel. An electric train has no on-board energy conversion so only needs 1.2kW.
This low overall cycle efficiency potentially undermines the green credentials of hydrogen trains as they require 2½ times the electrical energy of a comparable electric train, especially if hydrogen is delivered by the much cheaper CO2-producing reforming process. However, if otherwise surplus overnight wind-turbine generating capacity is used to produce and store hydrogen, this low efficiency is not an issue. Used in this way, hydrogen production also addresses intermittency issues associated with electrical generation from renewables.
A further constraint is hydrogen’s low energy density. At 350bar, the volumetric energy density of hydrogen is 4.6MJ/litre, compared with 35.8MJ/litre for diesel. So a hydrogen train requires fuel storage eight times the size of a diesel train’s fuel tank"
rscott, none of those figures relate to BATTERY CATENARY TRAINS.
A battery catenary train is not as efficient as a pure electric train.
Dave is talking about BATTERY Vs FUEL CELL, not fuel cell versus pure, cable powered electric.
When a hydrogen train uses 0.25kg to travel 1km that equates to approx 8kwh per km.
Look at some of the battery kWh to battery driven range (km)ratios of battery-catenary trains.
300/40
500/50
500/60.
They equate to a consumption of 7.5 to 10kWh per km.
That is the vehicle efficiency. You need to look beyond just the drivetrain efficiency. The drivetrain efficiency measures totally exclude every other factor in the nature of that vehicle as if they didn't exist. In the real world there are other factors that affect the vehicle efficiency other than just the powertrain, quite evidently so with these trains.
Can you think what one of those things might be?
Now you might push those figures back through the old Bossel chart (pre tank, mind you, we've already dealt with any of the efficiencies within the vehicle) but you won't get to 1:2 or 1:3.
And be sure to factor in the losses when rapidly charging the batteries on the battery-catenary train.
Note the comment in your quote though:
"However, if otherwise surplus overnight wind-turbine generating capacity is used to produce and store hydrogen, this low efficiency is not an issue".
A battery catenary train is not as efficient as a pure electric train.
Dave is talking about BATTERY Vs FUEL CELL, not fuel cell versus pure, cable powered electric.
When a hydrogen train uses 0.25kg to travel 1km that equates to approx 8kwh per km.
Look at some of the battery kWh to battery driven range (km)ratios of battery-catenary trains.
300/40
500/50
500/60.
They equate to a consumption of 7.5 to 10kWh per km.
That is the vehicle efficiency. You need to look beyond just the drivetrain efficiency. The drivetrain efficiency measures totally exclude every other factor in the nature of that vehicle as if they didn't exist. In the real world there are other factors that affect the vehicle efficiency other than just the powertrain, quite evidently so with these trains.
Can you think what one of those things might be?
Now you might push those figures back through the old Bossel chart (pre tank, mind you, we've already dealt with any of the efficiencies within the vehicle) but you won't get to 1:2 or 1:3.
And be sure to factor in the losses when rapidly charging the batteries on the battery-catenary train.
Note the comment in your quote though:
"However, if otherwise surplus overnight wind-turbine generating capacity is used to produce and store hydrogen, this low efficiency is not an issue".
Edited by anonymous-user on Thursday 3rd December 20:05
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