Next stop, hydrogen-powered trains | Hacker News Reader

Next stop, hydrogen-powered trains

bbc.com

48 pointshhs55 comments

It might decarbonise the railway but not the supply chain. Currently the only practical large scale source of hydrogen is methane, mostly by steam reforming:

Steam-methane reforming reaction

CH4 + H2O (+ heat) → CO + 3H2

Water-gas shift reaction

CO + H2O → CO2 + H2 (+ small amount of heat)

See https://www.energy.gov/eere/fuelcells/hydrogen-production-na... and https://en.wikipedia.org/wiki/Hydrogen_production.

There are possible methods to produce hydrogen without releasing CO2 but they are not in widespread use, for instance, https://www.sciencedaily.com/releases/2017/12/171208171749.h....

So this looks like it is a way to keep the petro/gas industry in business instead of electrifying the network. One of the justifications in the article was avoiding the expense of electrifying rail routes that had few passengers; perhaps a more rational response would be to close the line and use buses instead (which could also be hydrogen if necessary but which can already be battery electric).

Replacing rural train links with buses invariably means significantly reducing mobility for a lot of people. It is also akin to a signed death-warrant for a locality that prospers from tourism and/or houses commuting families. That can be a valid choice for some localities, but it is a choice with far-reaching consequences.

Travelling with a pram or a wheelchair using public transport is doable by train. By bus it is fine for a short ride (up to a few kilometres), but with increasing distance it becomes undoable for more and more people.

Another group of people heavily affected are those with incontinence or bowel diseases. Trains usually have accessible toilets on-board (usable with wheelchairs as well), buses don't.

A rational response is to explore all possibilities for keeping a train link operational in a sustainable manner.

> signed death-warrant for a locality that prospers from tourism

If it is prospering from tourism by rail then why is the rail line not profitable enough to warrant electrification?

> Travelling with a pram or a wheelchair using public transport is doable by train. By bus it is fine for a short ride (up to a few kilometres), but with increasing distance it becomes undoable for more and more people.

Perhaps my perspective is skewed because I no longer live in the UK. Where I do live (Norway) travel by medium distance bus with a pram or wheel chair is not a problem because buses have powered lifts and dedicated spaces for both. Buses are also more flexible, new routes are vastly easier to set up than new routes for trains.

> If it is prospering from tourism by rail then why is the rail line not profitable enough to warrant electrification?

Sometimes the line is profitable as it is, but not profitable enough for electrification. It's a big investment with high maintenance costs. There are a bunch of lines like these in the Netherlands (Harlingen Haven — Leeuwarden is one I am quite familiar with).

Tourism is often seasonal, so while it does add up in terms of profit (or breaking even), for electrification to be a sensible investment you are talking double or triple the amount of passengers.

> buses have powered lifts and dedicated spaces for both.

But no accessible toilets (big issue for many disabled people, and anyone travelling with kids), and travelling with an infant in a pram really limits your bus-range (I have an infant son and avoid buses if at all possible). Also, the dedicated spaces are great, but if there is a wheelchair there already you have to take the next bus instead (unless you have a collapsible stroller, but then the kid is older already). This is fine for incidental travelling, but not for a frequent commute. In trains you can almost always make do; in a bus you're not even allowed on when the dedicated spaces are taken, because of (valid) safety concerns.

Buses are great if that's all that's available and all that ever has been available, but shutting down a train line impacts the lives of many people — some of whom wouldn't have chosen to live in town without a train link in the first place.

Exactly. I would say it was better to go the other way: use the syngas reaction to turn H2 from electrolysis into convenient CH4. Also absorbs some carbon from the atmosphere or other processes.

Of course, that only makes sense if there isn't cheap fracked gas out there ...

At the moment, all H2 power schemes are greenwashing for natural gas.

> So this looks like it is a way to keep the petro/gas industry

Yeah that also was my thought.

About steam reforming, it seems it still emits CO2, so it's far from being green.

So the greenest transport there is, is train and trams powered by nuclear energy, including merchandise.

This small train would seem pretty relevant in certain cases https://en.wikipedia.org/wiki/London_Post_Office_Railway for example in places where you want to diminish truck traffic, in dense areas. But overall electrified rail was always a green transport until auto companies lobbied to remove rail.

But again, those are long term investments, and capitalism never likes it.

What I often don't see mentioned in the discussion about using hydrogen power is solving the volumetric capacity problem of storing hydrogen.

One potential solution is to instead use formic acid as stable energy storage. There have been recent advances in catalysts that make it feasible to convert hydrogen to formic acid and back again. Formic acid is stable, not very toxic, and has an energy capacity of 1.77 kWh/L.

The only party I know of that is trying to bring this to market is Dens [1], formed out of a student group at the University of Eindhoven [2]. Their website is a bit high on the rhetoric (including trying to coin "hydrozine"), and their mockups looks like, well, mockups, but there are real technology advances behind this, for example their trial with a city bus [3] (Dutch).

[1] https://dens.one/our-products/

[2] https://teamfast.nl/technology/

[3] https://www.volkskrant.nl/nieuws-achtergrond/deze-stadsbus-i...

Formic acid, being more oxidized, has lower energy density than methanol. In what way is it better than methanol?

It isn't purely about the (energy density of the) chemicals themselves, but also about the available reformation / hydrogenation processes. As far as my limited knowledge goes, the processes for methanol have seen more development, but formic acid has a potential for simpler and smaller systems in less demanding circumstances (pressure, heat). [1] was the first comparison I stumbled upon.

[1] https://doi.org/10.1515/9783110536423-002

Another option to expensive full electrification is partly electrifying the tracks, and running on battery in between

That’s the current Norwegian plan for electrifying the Northern Norway line as its the cheapest option

https://www.railjournal.com/technology/norway-to-replace-die...

They're still considering hydrogen too, however hydrogen production/distribution is really inefficient and as of today not very carbon neutral [1].

When you count the whole supply chain it has about the same efficiency as a diesel.

Pumping hydro electricity into a battery is much more efficient.

I guess there would also be issues transferring the hydrogen to the trains, we already struggle (struggled, the H-stations for cars are closed after an explosion here) with multiple cars filling up in turn. The pumps would just freeze and you had to wait for half an hour to fill up the next car.

[1] https://en.wikipedia.org/wiki/Hydrogen_production

> In 2016, Germany unveiled the Coradia iLint, the world’s first hydrogen-powered train, which can run for 600 miles on a single tank of fuel – on par with the distances that traditional trains achieve on a tank of diesel

> The train’s hydrogen power system produces sufficient power to take the train 50 to 75 miles. The train, called Hydroflex, is the UK’s first to be powered by hydrogen

The iLint seems to be much further advanced. In this Industry, what does a Team in the Hydroflex's position normally do next in this position?

Long distance tracks are mostly already electrified in most places. In Germany & the Netherlands, diesel trains are limited to the edges of the rail network and there have been plenty of experiments with replacing those with hydrogen, gas and even battery trains. Mostly those trains service short routes.

That's not so true in the UK, here is a map of electrification from 2010 [0]. The only major difference is the Great Western Mainline (from London to Wales) is now electrified as far as Cardiff. A lot of passenger trains are still powered by diesel, and for freight trains I believe diesel is used in even higher proportions.

[0] https://ichef.bbci.co.uk/news/410/media/images/46102000/gif/...

Here in Ontario, Canada, all regional rail is diesel.

What keeps all the tracks from be electrified? If it's just cost, what would make it cheaper to use fuel cells?

Electrifying rarely used tracks makes little economic sense. There is a huge up-front cost and you have significantly increased maintenance costs. Hydrogen powered trains can be rolled out incrementally.

Makes perfect sense, thanks.

Electrication in more rural areas means over head lines. That's so you can use high voltage and not suffer power loss over long distances. Those are hard and expensive to setup and much more likely to break during extreme weather. So they're not really suitable for places with weather or low numbers of trains (as all rail costs are ultimately per passenger).

It has to be said that adding overhead cabling above train-tracks is far from trivial.

Back in 1996, or so, I was on a work-placement with British Rail and our project was auditing the bridges and tunnels along various routes. In order to fit overhead cables over the tracks, and over the trains, there were are lot of bridges that had to be raised, adjusted, or replaced to give clearance room.

It is expensive, see https://en.wikipedia.org/wiki/21st-century_modernisation_of_...

That doesn't answer my question.

Oh well.

> Long distance tracks are mostly already electrified in most places.

That's certainly not true in the US.

Classic britian: out electric train is 4 years later than the German one, with a tenth the range for double the price.

If that can make you feel better, Germany also has its own classic clusterfuck :)

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

AFAIK this is good because some renewable energy sources cannot produce continuously (solar, wind), and therefore storing their production is a major challenge. As stated in this article generating hydrogen can be done with electricity. Moreover fuel cells may also power trucks and even cars.

The main issue is the overall efficiency of the process. Creating hydrogen by electrolysis is about 80% and then a fuel cell electric efficiency is 60-70%. So overall the whole process is not very good.

How's the energy storage density on Hydrogen though? One of the main problems with Lithium is it's heavy and requires a lot of space to store energy.

I think that you can get good energy density with Hydrogen which will allow long train journey, but this will degrade further the overall efficiency as high compression of the gas is needed, and this energy is likely lost during usage.

Extremely good for weight and extremely poor for volume. To reduce the gasses volume storage is usually either highly compressed (200-700bar) or cryogenic (30K), like in the space shuttles tank.

In both cases the volumetric density is still quite poor, cryogenic is about 70g/l, which is actually less than the weight of hydrogen chemically bound in a liter of gasoline.

There exists some concepts of storing hydrogen chemically bound, e.g. to hydrocarbons or metal hydrites which release the gas on high temperatures (100-200°C).

Formic acid might be a possible solution for the volumetric capacity problem, although it is still very much in its infancy. See [1].

[1] https://news.ycombinator.com/item?id=22449894

How is better than methanol?

Other parameters: a renewable energy source produces without any combustible, risk, or pollution/waste.

Even 48% of a no-string-attached gift is a gift.

There are a lot of sectors looking at hydrogen from excess renewables, some of them will require huge quantities (e.g. low-carbon steel production). And to start, the very first thing to do with hydrogen produced from excess renewables is to replace the industry-used hydrogen that currently comes from natural gas.

I think hydrogen will play some role in the future, but it should really only be used where no other, more efficient technology is available. For trains a well established technology is available: Electric trains with overhead lines. Use that.

Efficiency is a parameter. There are other ones. An energy source able to continuously produce without any combustible, pollution, running cost, waste, risk... would indeed be adequate and supremely efficient.

Waiting for this miracle, we have to store energy.

What about a separate tanker car? Seems like that would solve the range issue.

What about biodisel or syngas made with renewable energy instead of hydrogen? Still carbon neutral operations.

Would be a nice comeback: https://en.m.wikipedia.org/wiki/Tender_(rail)

Biodiesel has absolutely terrible efficiency and uses up valuable land. Outside of very niche applications where demand can be satisfied with food waste we shouldn't use it at all.

Hydrogen production is not especially efficieby either and uses fossil natural gas (some of which escapes during handling and is a potent greenhouse gas).

I think what's needed is a systemic look at various liquid/gas fuel energy storage mechanisms for converting renewable energy for use in transport.

Batteries and transmission lines seem to be the clear winners in current usage, everything else is niche for one reason or another. An analysis of the tradeoffs and direction for potential research plus funding for that research is what's needed.

Not mindless boosterism (like the article) for one particular fuel.

I believe the idea is to use renewable energy during surplus times for electrolysis.

I believe the idea is to use renewable energy during surplus times for electrolysis, which actually makes sense, as opposed to using agricultural land for biodiesel.

Carbon neutral is a fossil industry marketing gimmick. The climate does not care about provenance of CO2, it only cares about its presence.

We need to de-carbonize, and hydrogen produce by renewables such as wind qualifies.

Growing biomass removes co2 from atmosphere. Burning carbon from that biomass releases it back. Make the process efficient enough (with addition of external power) and you end up with no added co2 in atmosphere. That's not just a marketing gimmick.

Of course it is debatable if it is an efficient approach for doing things, but the concept is sound

There is no net reduction of co2 emissions here, that's why its marketing.

The fact that sequestration in plants happens first does not make it better for global warming if you then burn it right after.

Encouraging plant growth on top of a decarbonized energy cycle, now that will make a difference.

How is replacing fossil diesel with recycled atmospheric co2 not a net reduct of emissions?

I am not so sure that hydrogen is the best energy storage medium for using renewable energy for transport. The handling properties of biodiesel and synthetic gasoline likely outweigh and efficiency losses.

An advantage of fuel cells over biogas/biodiesel is that the former only produce water vapour while the latter, due to the fact that they use ambient air for combustion which contains 78% nitrogen also produce nitrogen oxides which in turn lead to smog, acidification, ozone and fine particle production.

3-car 200-passangers train going 160 km/h in Sweden uses 5.6 kWh per 1 km [1]. More than that when it accelerates, but it mostly happens near the stations where there is electric network.

Or if the train stops there you can just detach used batteries and attach freshly charged ones - should help if the charging is too slow (but it shouldn't be - after all if the electric network is sufficient for powering trains when they accelerate/decelerate and use several times more power than on cruise - then it should be also sufficient for charging batteries powering trains when they cruise).

That's 560 kWh or 112 of used Tesla battery modules 5 kWh each. You can buy one for 1300 USD [2]. That's a recyclable resource (from used electric car batteries) and it would cost about 150 000 USD to upgrade one train with these.

150 000 USD is peanuts compared to multi-million USD prices per car of most modern passanger trains [3].

It would also add 2.9 tonnes to the train, which isn't that much for 3 cars train that weighs 165 tonnes [4].

You could add it as a small aerodynamic car trailing the train that can be swapped on stations if needed (so you don't need to upgrade all the trains, just buy enough of these cars to serve the unelectrified lines).

This would bypass the need for new hydrogen supply chain, would have much better synergy with already electrified tracks, would allow to gradually improve the system, and wouldn't need any carbon emission (unlike hydrogen production).

It's also a proven technology unlike hydrogen power.

Sources:

[1] https://www.quora.com/How-much-electricity-is-used-by-a-trai...

[2] http://store.evtv.me/proddetail.php?prod=TeslaBattModule

[3] https://montrealgazette.com/business/local-business/bombardi...

[4] https://en.wikipedia.org/wiki/Regina_(train)

Anyone know of efforts to enhance the efficiency of electrolysis with RF resonance?

There is a relatively old patent, but I'm looking for recent scientific work. https://patents.google.com/patent/US4265721A/en

The only industrial-scale process for making hydrogen starts with carbon fuel. Come at me, Chevron lovers.

What's the net carbon emission from 1 kWh from a liquid hydrogen engine compared to a modern diesel engine?

Well, you need to burn a lot of diesel (or it’s equivalent) to produce, store, and transport the hydrogen so I think it goes without saying that hydrogen fuel is worse.

I suppose hydrogen-powered trains can make some sense. Provided that it's worth wasting the electricity (bc of inefficiency of hydrogen energy storage) for a lower cost of energy capacity (no expensive lithium-ion batteries).

I wonder how these would go in a heavy haulage scenario.

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