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Comment by xeeeeeeeeeeenu | Hacker News Reader

It seems likely that hydrogen will replace diesel in trains. Companies like Alstom[1], PESA[2] and Talgo[3] are developing hydrogen trains. Germany has already started deploying them on a small scale[4], while Poland is planning to[5].

[1] - https://en.wikipedia.org/wiki/Alstom_Coradia_LINT#iLint

[2] - https://fuelcellsworks.com/news/poland-pesa-presented-a-hydr...

[3] - https://www.railwaypro.com/wp/talgo-to-launch-hydrogen-train...

[4] - https://constructionreviewonline.com/news/construction-of-hy...

[5] - https://www.orlen.pl/en/about-the-company/sustainable-develo...

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Bad idea in mi opinion, this is a solved problem, overhead wires, the amount of energy lost between the converting water into hydrogen and then back into water to get electricity can be as high as 70%, it's just a bad idea when you can use that energy directly using wire to get the same job done

Overhead wires are not a solution on a large scale, and also an eyesore.

Overhead wires are most definitely a solution on a large scale, and are used as such all over the world. And especially in Europe.

0% chance that Germans would tolerate these in their landscapes. Also, how do you think this would work with a train going 400kmh+?

They already do, and yes.

How about looking at the facts first?

How do you come to this conclusion? All high speed lines in Germany (ICE) are powered by overhead wires.

Okay I was wrong. I thought it meant something different.

> All high speed lines in Germany (ICE)

I suppose almost all:

https://en.m.wikipedia.org/wiki/ICE_TD

Interesting. That one diesel HST wasn't very successful. It's been taken out of service again and the line is now operated by a slower train again. This seems to suggest that electric trains are more suitable for high-speed lines, although it's not clear why exactly this diesel train didn't perform the way it should.

It was a 'tilting' train(leaning into the curve). Some part of that mechanism was constructed in wrong ways (too thin), which led to partial cracks, which led to partial derailing, trailing sparks. Which led to investigations of all of them, showing more cracks in development. So they have been "grounded" for a while, conventional trains taking over. Then it was deemed safe to operate them in non-tilting, conventional modes, which led to delays. So Deutsche Bahn wanted their money back, and got it. But no tilting diesel-trains.

Better inform the Germans. A little over half of the German rail network is electrified.

Oh dude, I'm all ears. What else do you think we (germans) think? I'm genuinely interested.

I am German. Most of us hate cables that aren't underground (hence the bad internet connectivity, because it's expensive to upgrade the network underground). Based on that I extrapolated. I presumed the same to be the case for these overhead cables, as I don't usually see them where I live.

https://www.bahnausbau-nordostbayern.de/files/img/Bahnstrom/...

It seems to be a lot more concentrated on the worse side of the rhine river. ;)

I'm surprised I must say. I have never ever heard of anyone talking about 'Oberleitungen' being something that we should get rid of. It wouldn't have come to my mind to question them, so that's why I was so baffled (and maybe a bit harsh in my expression).

Overhead wires would involve a significant infrastructure investment. Not too much of an issue with more densely populated areas like Europe - and countries like France and Japan already do use overhead wires - but it is not cost competitive in sparse locations like much of North America.

It's true that it's contingent on a carbon-free source of hydrogen. But if something like thermochemical hydrogen production through nuclear [1] or solar takes off, hydrogen fuel represents an energy-dense fuel that could be used in lieu of fossil fuels in many applications.

1. https://www.iaea.org/sites/default/files/gc/gc57inf-2-att1_e...

> "Countries like France and Japan already do use overhead wires"

Don't most countries already use these? World wide, a third of all rails is electrified in some way, and for long-distance rail, that's bound to be overhead.

Most European rail is electrified. So hydrogen or any other diesel replacement is only relevant for very rural, very sparsely used lines.

If a third of all rail is electrified then two thirds are not. Most of North America's railways are not electrified. Be cautious when looking at statistics on electrification: many results specifically only show electrification of passenger railways.

Yeah, the statistics on that are very interesting. Many European countries, but also countries like India, have 70+% of their rail network electrified Even Russia has 51% electrified, but in the US it's only 0.92%, Canada 0.20%, and Mexico 0.12%. No idea why North America is so adverse to electrification.

https://en.wikipedia.org/wiki/List_of_countries_by_rail_tran... claims to include both passenger and non-passenger networks.

How dare you argue against the "electrification is too expensive to do in the US!" crowd with facts like "most of the rest of the world does it"!

In the US, the east coast line is electrified from Boston to DC (possibly further? Can't remember.)

In total less than 2,000 miles of track are electrified out of 140,000 miles of track [1]. Boston to DC is electrified only on a specific passenger rail line (along with one route to Philadelphia). The only other electric rail lines are short coal-haulers moving coal from mines to coal power plants.

Europe's lines are economical to electrify because of greater density. Electrifying a rail line costs the same regardless of how many trains use it, so it breaks even in dense and frequently traveled routes but not on sparse lines. Guess which is more common in a less densely populated continent like North America?

1. https://en.wikipedia.org/wiki/Railroad_electrification_in_th....

Yet even Russia has 51% of its rail network electrified.

Even in Japan, about 30% of rail (by distance) is not electrified. It’s more than 40% in France. Generally these are lower usage, so electrification isn’t justified. Hydrogen might be a good option in cases where the route is too long for batteries.

Given that trains need tracks, why is it significant added infrastructure to have wires?

You have to put up wires and a bunch of posts. Googling around, cost estimates are $4.8 million per track-mile [1]. At 140,000 track miles in the US that's $672 billion to electrify the railway network.

Especially if hydrogen becomes very cheap through something like generation through waste-heat from nuclear power plants, hydrogen propulsion may make more sense.

1. https://www.freightwaves.com/news/is-electrifying-the-freigh...

> $4.8 million per track-mile

The study you quote is for southern california so that probably is on the high end of an estimate. Probably a different budget for West Virginia.

That's $10K per foot of track, there's no way that is dominated by parts or the actual installation labor.

In other news, one of the maintenance roads for the Golden Gate Bridge was recently completed. Adjusted for inflation, it cost more and took

longer than the bridge itself. If I remember right, one of the bus stops in SF also cost more than the Golden Gate Bridge.

Peanuts. Just one wasted war less, and it is there.

> Overhead wires would involve a significant infrastructure investment.

Yeah building dozens of large scale hydrogen plants, trenching and welding pipelines, building massive excess of necessary renewable energy, figuring distribution networks, deciding storage & container standards, house retrofits etc to run our society will be much easier than ...(checks notes)... Hanging wires

A hydrogen economy is likely going to be developed anyway, to decarbonize air transport and maritime shipping. Piggy backing on top of this maybe be cheaper than the ~$700 billion (probably closer to a trillion if we include Canadian rail) required to electrify North American rail transport.

Most rail stations are wired for water and electricity already, and small scale hydrogen crackers are already being deployed commercially in the US.

That addresses all your concerns, except maybe that people will want to produce hydrogen at home from their own solar arrays. That's expensive, but arguably unnecessary, since the hydrogen would mostly just be used to power cars.

I think the vast majority of trains will go electric. This is already a mainstream technology (unlike electric cars). Overhead wires or 3rd rails in most places, with batteries where that's not possible or economic. Perhaps hydrogen will have it's niche though (perhaps on low-use railways?).

Hydrogen fuel cells and batteries are roughly comparable technologies.

The main difference is that you can use the power grid to "charge" the fuel cell while it's in motion. You simply generate hydrogen at its destination, then rapidly pump the hydrogen into tanks when it stops.

So, the higher the duty cycle of the vehicle, the more sense hydrogen makes. Also, hydrogen has higher energy density (volume and weight per unit energy are both lower).

For those two reasons, I'd guess long haul, heavy use lines would be the first use case for hydrogen, and that batteries won't ever be particularly competitive for those use cases.

Hydrogen also requires quite a bit of infrastructure that hasn't been built out, whereas railways generally have an electrical supply already. I suspect that will make batteries a lot more competitive in the short term. Hydrogen could make sense if it can overcome those hurdles. But with improvements in battery technology (solid state lithium batteries seem to be coming soon) I wonder if it will ever be better enough to gain adoption.

I'm not against using Hydrogen but the problem is always what are they producing Hydrogen with and how is it more efficient energetically and emission wise?

Most Hydrogen is produced from Methane by steam reforming

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

That will change, obviously.

> what are they producing Hydrogen with and how is it more efficient energetically and emission wise?

Even if it is just Blue hydrogen being burnt here, the splitter plants can have some carbon capture in it which would be impossible to install on a moving train (beats diesel and also direct LNG burning).

That said, with trains there's no real argument against electrification. The wheels have been electrically driven for a few decades now. It's not like they need to come up with motors or work out batteries.

Hydrogen can be produced electrically from water. A positively stupendous amount of electrolysis equipment will need to be built out, but there will be demand for as much as can be produced. Burning hydrogen produces mainly water. Burned in an engine, it also produces nitrous oxides, so probably some ammonia would be dissolved in to scavenge that.

Liquid hydrogen takes up a lot more room than kerosene. The insulated liquid-hydrogen tank is quite a lot bigger than the kerosene tank -- maybe it is a whole other car -- but so what? Room on a train is cheap. What matters is weight. The tank is light, and the weight of LH2 needed to go the same distance is much less. The difference is weight that doesn't itself need to be transported.

Furthermore, the LH2 can be produced and banked on-site at the railyard, and during peak-production hours, so cheaply.

So, a win all around. Not as big a win as LH2-powered aircraft, but better, and much easier to retrofit.

Just because the tank is light, doesn't mean that a completed fuel carriage will be much lighter than any other car.

A tanker that holds 80,000 pounds of kerosine will hold about 8000 pounds of LH2 in the same dimensionality. 0.07 = density of LH2, Density of water 1.0, kerosine 0.7 +/- varies with grade. So it take 10 times the cubeage plus Dewar grade insulation. At a permeant depot they will have a super refrigerator to condense boil off into LH2. They are trying to get a viable clathrate hydrate to hold a higher density form of bound but not reacted Hydrogen

The measure of fuel you need to carry is not weight, but energy content. It takes a much smaller weight of LH2 to match the energy content of diesel. So, correspondingly less than 10x volume. It is this better "gravimetric energy density" that makes LH2 an attractive fuel in many cases. You end up needing only about 2-3x tankage space, including the insulation.

Better gravimetric energy density doesn't make so much difference for a train, so its other advantages -- production on-site, zero emissions, carbon-neutral -- are more important.

At the trainyard, the LH2 would be banked in an underground tank where insulation is easy. It is not necessary to refrigerate it after it is liquified. It will gradually boil off, so you just make more anytime the level goes down, whether from boil-off or pumping out to a locomotive tank.

There is truth in that energy density. but it is still cheaper energetically to chill boil off to liquid back to the tank that to make new hot hydrogen you then chill to liquid back to the tank. The end game of clathrate storage will solve many of these problems.

True, keeping the LH2 below its boiling point is, energetically, strictly cheaper than producing as much new hydrogen as would have boiled off, and then chilling that... But, it incurs the added complexity cost of building refrigeration plumbing into the tank, and maintaining that. That could mean the tank has to be above ground, for easy access (which might be needed anyway).

My expectation was that native electrical energy will be cheap enough that wasting some is better than complicating your system. Each tradeoff will be an engineering analysis. In this case it will all depend on how good your insulation is, which is of course better in an underground tank. Many old conventions will be overturned as the marginal cost of electrical power at peak times gets cheaper.

Both will be tried, so we will see.

Yes, flow batteries, gravity batteries and high water storage will all make their presence felt. Those ~~20-50 tonne bricks they haul and drop would be costly, but I expect them to make them as strong walled brick shapes, with a lower cost fill - be wise to add salt to limit freezing in cold weather.

The bricks, anyway, will not happen. It's the dumbest idea I have run across.

> Hydrogen can be produced electrically from water.

Which adds three energy transformation steps (Electricity for H2O to H2 + compression, H2 + 02 to water and heat, water and heat to mechanical movement) as opposed to electricity to motor.

Hydrogen is a meme.

Solar panels on the train car roofs would utterly fail to propel the train, even at noon. So, the energy has to be concentrated somehow. Batteries are heavy, and also involve a pair of chemical transformations. Hydrogen is the single most energy-dense (per unit mass) medium.

But hydrogen is not best compressed, but liquified. There might be some value in compressing it on the way to liquifaction. Liquifying hydrogen consumes some energy too.

How would you argue to convince someone that it's more likely than not?

The existence of r&d initiatives is a signal but doesn't seem sufficient to make the case.

Never understood how this makes sense.

Just make they hydrogen into methanol or whatever and use mostly existing tech instead.

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