China’s New 100 MPH Train Runs On Hydrogen And Supercaps

Electric cars are very much en vogue right now, as the world tries to clean up on emissions and transition to a more sustainable future. However, these vehicles require huge batteries as it is. For heavier-duty applications like trucks and trains, batteries simply won’t cut the mustard.

Normally, the solution for electrifying railways is to simply string up some wires and call it a day. China is trying an alternative solution, though, in the form of a hydrogen-powered train full of supercapacitors.

Hydrogen Rides The Rails

CRRC is a Chinese state-owned company in the rolling stock business. It’s at the forefront of rail projects in the country, and has invested heavily in conventional high-speed rail and even mag-lev technologies. It’s latest hydrogen-powered project isn’t built for speed, with a cited top speed of just 160 km/h, along with a range of 600 km on a full tank. That might not be quick by modern rail standards, but it’s enough to make it the fastest hydrogen-powered train in the world. It’s also equipped with self-technology for automatic operations without a driver or crew. The train operates as a four-car consist, and is charged with passenger duty.

The train relies on fuel cells to make electricity from its hydrogen fuel. Fuel cells are generally considered an emissions-neutral power source, as their sole output is water. Of course, sourcing hydrogen in a clean fashion can still be difficult, but fuel cells themselves don’t directly contribute harmful emissions to the atmosphere.

It’s impossible to deliver a fuel cell transport project without plastering it with hydrogen-themed decals. CRRC

Notably, the train pairs the hydrogen fuel cells with a bank of supercapacitors. Fuel cells on their own are not great at responding to high instantaneous power demands. A design could obviously be built with a larger bank of fuel cells to serve peak power demands, but this would be expensive and inefficient.

Instead, supercapacitors are used as a power bank to cover off any spikes in power demand. The supercapacitors can be charged slowly over time by the fuel cells, and then deliver high power when it is needed most. The other benefit of adding supercapacitors is that they can store energy captured by regenerative braking. This can be particularly beneficial when a train is travelling down a long grade. That gravitational potential energy can be captured and stored as electrical energy for later use.

The CRRC effort compares ably with other hydrogen-powered rail projects overseas. German railways already operate a fleet of 14 Alstom trains on hydrogen fuel. The Alstom Coradia iLint passenger trains entered a pre-service trial back in 2018, and have since entered mainstream public service. They have a lower top speed, at just 140 km/h, though this is more than enough for the usual 80-120 km/h travel speeds on the EVB rail network. The German trains do offer longer range, with 64 on-board hydrogen tanks able to propel the trains up to 1,000 km. A single fill of the hydrogen tanks is enough for a full day’s service along typical routes. The new trains replaced a fleet of 15 diesel units, reportedly saving 1.6 million liters of diesel and 4,400 tonnes of CO2 annually. Alstom plans to ship more hydrogen train sets to other German cities, as well as France and Italy in future.

Research and development is also ongoing in the freight arena. An Australian project is exploring whether freight trains in remote mining areas could run on hydrogen instead of diesel. These long routes are unelectrified, and are currently plied by conventional diesel-powered locomotives. Freight trains tend to require much beefier locomotives, and so the challenge is somewhat greater than producing a hydrogen-powered passenger train. However, if this heavy haulage could run on hydrogen, there’s huge scope to cut emissions to a drastic degree.

Hydrogen fuel cells may seem like a curious choice for trains. Spending resources to create hydrogen, only to turn it back into electricity, is obviously less efficient than simply powering trains with electricity directly. The many overhead-wire and third-rail electric railways around the world indicate that this is a solved technology.

However, in certain circumstances, fuel cell trains do make sense. The trains can run on conventional, non-electrified railways in place of diesel trains, but without the usual greenhouse gas or particulate emissions. Employing a fuel-cell train eliminates the need to install overhead wires on many thousands of kilometers of track. This cuts up-front infrastructure expenditure. However, the trains do come with some expenses of their own. Maintenance of fuel cell trains is likely to be higher than that of conventional electric trains. There is also a need to establish hydrogen refuelling infrastructure along the train’s route. With a limited number of stops, it’s less onerous than providing hydrogen stations for road vehicles, but the infrastructure is still far from free. There’s also the need to provide hydrogen to the various refuelling stations throughout the network, whether via tanker trucks, tanker trains, or pipeline networks.

Fuel cell trains do offer a unique opportunity to cut emissions from railway transport. To achieve this properly, several factors must be considered. The trains should serve on routes currently inaccessible to regular electric trains, and must be fueled with hydrogen sourced as cleanly as possible. The entire supply chain of that hydrogen should also be taken into account, so as not to generate excessive emissions hauling it from production facilities to refueling stations. Costs should also be weighed up as to whether it would be cheaper, easier, and cleaner to simply install a caternary electric supply instead.

83 thoughts on “China’s New 100 MPH Train Runs On Hydrogen And Supercaps

    1. Did you not read the article?

      “Of course, sourcing hydrogen in a clean fashion can still be difficult, but fuel cells themselves don’t directly contribute harmful emissions to the atmosphere.”

      1. “Difficult”? That’s a great way to evade the “where do you get the H2 from?”

        NG Reformation is the primary way, because its the economical way. It consumes NG to produce about 1/3 as much energy as was in the NG. The major outputs of the reformation are H2 and CO2. See

        Partial Oxidation is another, even less efficient way. Outputs are H2 and — wait for it — CO2

        The reason we engineers are not excited by H2 are numerous. The above is only one of the giant issues.

    2. Thank you for your comment. I am interested in microgrids and have learned how easily H2 can evolve from reactive metals. Is there any research on using that instead of pressure swing, or is that what steam reforming is?

    3. Sunhydrogen (hysr)has developed a technological that produce hydrogen directly from sunlight and any source of water and can be produced on location without needing to transport.

  1. Thanks for the article ! Two more reasons why hydrogen fuel cells are a lot better than any other solution,overhead lines or batteries:

    – Electrified lines are very costly to build,and after that to maintain depending of the length ,the topography the geography and the frequency of the trafic.Fuel cell trains may apparently cost a little more,but you will make so much savings subsequently…No need to say that between wind,extreme cold and extreme heat,
    the cost of maintenance of overhead line systems are going up sharply.

    – The classic efficiency match : “Spending resources to create hydrogen, only to turn it back into electricity, is obviously less efficient than simply powering trains with electricity directly ” .t’s true if you consider separately each journey while forgetting that a catenary system for electric train will require
    a complete electric grid with all the electricity losses it implies.You use the grid as your “storage system”.

    With hydrogen fuel cell trains,you don’t have to rely on the grid and have the risk of power outages.On an operational basis of one year,all in all,even if you have to turn electricity to hydrogen and then back to electricity,with all the impressive breakthroughs we are seeing now in electrolysis making hydrogen cheaper and cheaper,all in all,the hydrogen system is more efficient.

    Actually for an electric line to work you need both :

    1/ and overhead line with all its substations and its outage issues
    2/ a whole electric grid on which to connect ,which has also its efficiency costs…
    And it does not comme cheap ! To make a fair comparison ,all these costs must be added.

    With hydrogen fuel cells trains you only have the wires inside the locomotive and a few hydrogen refueling stations and you save on the millions of miles of the electric grid and overhead line wires and their permanent maintenance and repairs.

    And I don’t even talk of batteries which are completely outclassed in heavy duty because of recharging for hours,”vampire phenomenon” ,and cold weather.

    Best regards and thanks for site !

    1. Overhead, Hydrogen, and Battery all have a place if you want to actually make a working zero carbon rail network, with wide coverage.
      Overhead is most efficient and economic for busy long haul routes with big altitude changes or very high speeds.
      Hydrogen for routes that aren’t busy enough, but still long. For hydrogen you will be building hydrogen refuelling plants.
      Batteries for short spur routes, and to allow overhead trains to extend beyond the current end of line. Battery+Overhead trains need no extra charging infrastructure at all. Also when you have batteries onboard, you don’t have to build some of the difficult parts of the overhead wiring like through existing tunnels, over roadways, over switch yards etc. This lowers electrification costs in urban areas especially.

    2. Lots of assumptions based on looking backward, not forward. There will soon be 42% efficient thin film, printed roll-to-roll, which could be deployed along the length of a rail line, within the right-of-way. It feeds stationary batteries which will soon store 5 to 8 times more electricity per kilogram than today’s batteries. They feed the traction batteries on the train, with the same specific energy. The batteries will cost about half of today’s battery cost, and those made in the US with North American materials will get $45/kwh of that taken off, per the IRA announcements. The solar will cost about 20 cents a Watt, paying for itself quickly, as will the rest of the system.

        1. What the heck is kw/hr? Do you mean kWh?

          20 cents per (peak) watt is the (predicted) cost of the solar panels. I.e., a one kilowatt array is purported to cost just $200. Which is a pretty neat trick if you include mounting hardware, cabling and power conditioning.

          With normal capacity factor, it ends up being around $1 per usable watt.

  2. I wonder why bother with the hydrogen and fuel cell step?
    Batteries are *good* in a locomotive. Like GE uses in the Evolution locomotive, the extra weight contributes to the traction necessary.

    Maybe the distributed motors in passenger rail don’t benefit as much?

    It would be nice to see numbers. It still seems like batteries will win over hydrogen tank+fuelcell+supercap for volume, cost, total system efficiency, and maybe even rolling weight.

    1. On the whole I agree Battery seem like a more natural fit for most rail use. However…

      Battery vs fuel cell is a debate with no single right answer even just from the most basic in use criteria – fuel cell can be refilled quicker and in theory anyway have much longer lifespans than a chemical battery. Where on the flip side operating a Battery system is often easier as the existing infrastructure to ship electrons around can be used largely as is and from primary energy source to consumption aught to be more efficient so quite possibly cheaper.

      And its the same give and take all the way down in every use case – for instance you put lots of battery in the locomotive to get the range required it gets better traction, but it also increases the loading on the track perhaps beyond its tolerance. So then you have have to ask if you need to distribute battery along the entire train to get enough range is that adding too much complication to the operator, or too many connectors and points of failure?

      1. Also: fuel cells generate heat. Batteries don’t work (well) below freezing and will spend a considerable portion of their capacity just to keep warm. It’s the same problem with cars: range can drop 50% when the temperature goes below zero. Fuel cells, no difference.

        1. Sure, fuel cells do generate heat. That comes from the fact that they are really not very efficient, converting only 40-60% of the available energy to output power. The rest is wasted as heat. This is true whether the weather is hot or cold.
          I’m not seeing how a fuel cell is better in this aspect.

          1. It’s that variable range that forces you to over-provision the battery system for the worst case, and then over-provision it some more to account for capacity loss over time. It’s cheaper to waste fuel than waste extra batteries you don’t really use all that much because batteries go bad over time whether you use them or not.

          1. Only relevant to cars, where you have a small thin battery pack hanging underneath the car in the ambient temperature.
            Completely irrelevant to any big battery system that will have cooling and heating and insulation if it needs it.

          2. A train runs all day in the ambient temperature, and the batteries are located in a rail car that requires heating from the batteries themselves.

            Most of the lost capacity in the case of the Leaf is exactly because of the need to generate heat for the cabin and the battery. This is no different for the train. They can’t afford to add a foot of insulation everywhere.

        2. Indeed and battery vs fuel cell self discharge is a question as well – in the case of hydrogen its going to have a higher rate than some other fuel cell energy sources and in the case of battery the same thing different techs with different self-discharge.

          Or volume consumed – energy density vs extraction efficiency of the battery vs fuel cell systems are different as well and will favour one or other for some situations.

          There are so many criteria for how its used and the environment its used in that there can never be one right answer, and for some snapshots of time any system exposed that to volatile thing called the outside would be better off being a different technology. In the same way air-source heat pumps are really bad when its cold and humid outside as they ice over, but a ground-source heat pump won’t. Yet as the air is rather more mobile than the ground air-source are often going to be better as they can quickly be exposed to and exchange energy with a much much larger volume…

          1. Lithium battery self-discharge is essentially negligible. It’s the battery monitoring or management system and “vampire loads”, such as always-on DC-DC converters, that keep draining the batteries in your portable devices.

          2. Yes Dude, but there is a reason you have the BMS stuff with a lithium cell – the cell itself might hold power quite well, but you really can’t go without battery management on most if not all lithium chemistries, so that point is entirely moot. And not all batteries are lithium either, and with how expensive and flammable a lithium battery can be compared to other techs there are many reasons to use other chemistries.

    2. For a passenger train in EMU form, more weight is bad. Passenger trains rarely suffer from lack of adhesion. Adding more weight means that at every stop, more potential energy is lost (regenerative braking is never more than 30% efficient)

      1. “(regenerative braking is never more than 30% efficient)” sounds like a number made up on the spot.

        Similar to how the sentiment that all internal combustion engines are 30% efficient, same for the whole drive train of a car. Or a wind turbine capturing energy from the wind. 30% is a common figure that rarely seems true if one digs deeper.

        To return to regenerative breaking, it is mostly limited by the efficiencies of the components in the system. This being the motors ability to act as generators, but also the train’s ability to handle and store that energy. (Or to load it off onto the grid if such a connection is available.)

        Now yes, induction motors are abhorrent generators.
        But nothing states that one must use an induction motor.

        1. >sounds like a number made up on the spot.

          It’s in the right ballpark, if not too optimistic.

          The recovery system works the best when slowing down from high to low speed. It works poorly, or with negative energy return, going from a low speed to a stop. This is because the motors need an excitation current (consume energy) to act as generators. The slower it turns, the more energy you have to put in to get energy out. There is a cut-off point where the regenerative brake is no longer useful.

          The trick is, when the train is traveling longer distance at high speed, it rarely stops. When it is traveling at low speeds between local stops, it frequently stops. The regenerative system is forced to operate in non-optimal conditions and the average return efficiency is poor indeed. With hybrid and electric cars on the roads, it is often just 5-10%.

          >But nothing states that one must use an induction motor.

          PMDC motors face different but similar problems. Low speed = low voltage, which requires you to boost the voltage up to the battery, which multiplies the current drawn from the generator and increases the I2R losses disproportionately. It’s an impedance matching problem either way – you get high output, or high efficiency, but not both at the same time.

          1. Besides, adding mass adds rolling resistance in direct proportion, which in the long haul will dominate over any kinetic energy you might recover.

            A passenger rail car has a resistance of about 0.002. If the added normal force is 1 ton or 10 000 Newtons, you lose an additional 20 kJ per kilometer regardless of your speed. Meanwhile, accelerating 1 tons to 100 kph takes about 365 kJ. The energy lost to rolling friction, that you cannot recover, starts to dominate the calculation after 18 kilometers.

            At low speeds, say 50 kph, the rolling friction loss takes over after 4 km. At that distance, you cannot recover more than 50% of the energy you spent by adding 1 tons more to your train. Realistically, you’re not getting more than half of the half back, or about 25%.

        2. Thx for the trust. This is a number I researched a few years back, I don’t know my sources anymore but a quick google search I find results from 6-28% efficiency. Also a few 80% figures though from system producers, but I think they mean only one specific system.
          28% efficiency means 28% of the kinetic energy can be recovered to stored (or distributed) power. That figure might have gone up with the innovation in power electronics of the last few years.
          Regenerative braking is still way more efficient than old-school braking (with 0% recovery), but I often encounter people who think it’s a magical thing that can almost fully recharge your battery. Instead, if you can, it’s better to not regen and coast when you need to get to a standstill.

    3. I don’t like trains that run on batteries. My kids have trains that run on batteries, those batteries are always empty on the most silly moments. Back when I was a kid, I had a wooden train, you moved it with your hands, placed it on the top of the bridge and then it ran allllllllll the way down the bridge by itself, now that was fun. Who needs batteries, we need more bridges!

    4. The smaller the total energy capacity the better a fit batteries are.
      Here e-bikes now have 80% of the pushbike market.
      The thing about fuel tanks and internal combustion engines, is that the material used does not scale linearly with energy and power. Batteries and electric motors both scale linearly. This means that at some power/range point, more difficult solutions like hydrogen can become more economic.
      And conversely, we can safely say that the low end, batteries and electric motors are compelling. This has already happened with ebikes. It will soon happen with small short range urban cars which will be 90% electric within a decade, because they will be compellingly cheaper to own.

      1. Batteries are most economical when they’re just large enough to get you there and back, and you use them to the maximum capacity every time, often.

        This is because batteries cost energy to make – a lot of energy – equivalent to about 200-400 full charge cycles of the battery itself. They last for 2000-4000 full charges when fresh, but deteriorate over time regardless of use.

        If you maximize your use of the battery, then the manufacturing cost approaches about 10% of the energy you put through it. Translated to efficiency, you can approach 90% energy efficiency.

        If you do not maximize your use of the battery – let’s say you have 80 km range and you only ever cycle 8 km per day and never end up using more than 10% of the potential charge cycles before the battery dies of old age, well your energy efficiency then is just 50%

        It’s not that e-bikes are necessarily better or a more suitable application for batteries – it’s just that they’re smaller and cheaper to the point that you won’t care about efficiency.

        1. Mind, that’s just the efficiency of the battery. Small electric motors also run at shockingly poor efficiency, especially when driven at low speeds to produce torque rather than power. The total system efficiency of your e-bike can be very similar to a conventional scooter.

          1. E-bike motors can be quite efficient brushless rare earth pm motors. My chinese mid-drive one appears to be ~90%, from actual thermal measurements made in the motor – the motor is quite small and must be efficient or it would burn out. The gear train after the motor (two helical sets) probably has lower efficiency that the motor.

            If you mean a petrol motor scooter, then you are way, way off. In urban transport an ebike is >12x energy efficiency over 110cc 4 stroke scooter (Honda cub). They have very similar journey times.
            Other research has ebikes as ~4x better CO2 efficiency than push bikes (allowing for food). However, that assumes that I actually eat fewer pies if I don’t ride my bike. I personally see no evidence that is true.

          2. >the motor is quite small and must be efficient or it would burn out.

            Or current limited at lower RPM. The motor drive is usually smart enough to count the thermal constant of the motor and limit heat dissipation. Small BLDC motors achieve peak efficiency at mad speeds – at lower RPMs they’re just terrible. Small motors also have the advantage of geometry: it’s easier for the heat to get out, so they can tolerate higher proportional losses.

            >If you mean a petrol motor scooter, then you are way, way off. In urban transport an ebike is >12x energy efficiency over 110cc 4 stroke scooter

            That’s a different calculation. They are similarly efficient in their energy use, but the scooter uses more energy overall – because it is more powerful, faster, heavier, higher drag etc. This is obvious: the e-bike is limited at 250 Watts and the scooter about 2.5 kW or 10x more.

        2. That cost to make is an artifact of how batteries are made today. We’re working on a totally different way, requiring less refining of raw materials, hence far less energy, raw materials, and capital equipment — the factories may cost 30 times less per million kWh of battery capacity produced per year.

  3. I think Hydrogen will be the future.and all this wiring cars to chargers is a waste of time..and too many countrys jumped on the EV bandwagon without thinking…and im sure that hydrogen will also be used on petrol and diesel engines soon…

    1. Hydrogen as a wholesale replacement for fossil fuels doesn’t fly – efficiency from primary source to load is pretty awful, cost to produce that much hydrogen fuel in an at all green way is likely to be ruinously high, the energy density and therefore high pressure or liquification required and the massive complexity and inefficiency that will add to the fuel transport network. It just isn’t that magic fix all.

      Hydrogen makes a good longer term energy store. Hydrogen generation a good bulk load for absorbing the excesses of renewable energy generation. It is probably better for some road users than battery – those that really need to pack on heaps miles all the time with short downtime, and likely wins out in cases where high energy capacity for relatively little weight is important. But Battery for your personal car is likely to remain the winner for almost everyone – hundreds of miles of range so way more than needed 99.9% of trips, and it can be filled up by the magic pixies while you shop/sleep/work so its way more convenient for most than having to divert to a petrol station to buy go juice. Not the solution for every user, but being much more efficient and convenient for most the one that is rather likely to remain hugely dominant and is arguably the best choice for even commercial drivers if nations are to meet their climate change goals.

    2. I highly doubt that. The end of hydrogen cars is already in sight. In the US they removed a lot of pumps. Hydrogen is in theory possible, in reality it’s a disaster.

      Storing it properly means you either have to cool it below -253C/-424F, or keep the tanks pressurized above 700 bar / 10152 PSI. Otherwise you have to store it in a gas state, which is far from perfect. A pump for gasoline/diesel is tens of thousands of dollars to place, but a hydrogen pump runs in the millions. Maintenance is crazy expensive too. Then you got production, which is only viable if you start investing in a bunch of nuclear plants. Then you got the dangers. Hydrogen is highly explosive, unlike gasoline, diesel etc, which can also explode, but aren’t nearly as dangerous as hydrogen.

      Hydrogen as is, is not the future. Ammonia though, looks to be the future. At work we are already working with a supplier to convert several ships to ammonia power. You split ammonia inside the vessel to create the needed hydrogen. So you bypass all the hydrogen parts and only create it on demand. Ammonia isn’t as dangerous as hydrogen (still don’t want to breath it in) and doesn’t need to be stored under pressure. Newer technologies might make this possible to use in cars. That also means you don’t have driving bombs on the road, don’t need to wait an hour to charge, no need for expensive pumps, just drive to the station, fill it up like a gasoline vehicle and drive off. Ammonia production can be used by reusing cow urine and from other sources, requiring only a little electricity.

      Another thing is the new e-gasoline by Porsche, which is oil free gasoline. Porsche is planning on starting production soon as they build a factory for it.

      1. Hydrogen is highly flammable, but actual detonation is much less likely than with gasoline.

        In mass production I doubt LH2 pumps will be much more expensive than LNG pumps. LNG is already in use for trucking. The liquefaction equipment significantly more expensive sure, but they already use it for road transport now over compressed hydrogen so it can’t be that expensive.

        Ammonia, now that’s a fun liquid in accidents.

  4. My company has for a few years led the way in electric buses in the Netherlands. New electric vehicles had a very distinct and futuristic look. The concession I work for got 62 new electric vehicles end 2019, with relatively little fanfare (They were a year and a half late and we didn’t want to draw too much attention to that) and the buses looked almost exactly like the diesel fleet we already had: No decals, no pantograph, no extra equipment on the roof. The best giveaway you’re looking at an electric bus is that the first window behind the driver (on the street side) is all black.

    I have witnessed several hobbyists (both in the wild and online) say “That’s not an electric bus, it has nothing on the roof”.

    It has since gained “This is an electric bus” stickers but quite subtle.

    1. Nice! Bus routes make a lot of sense for battery drivetrains: Plannable, fixed-route, in an urban environment so definitely emmissions sensitive. Shame about the lack of Pantographs though, I figure at least in Arnhem those would make sense to use the existing trolley bus network, no?

      If I may ask (not asking you to spill company secrets or anything): in your experience, how do the economics stack up vs. diesel drivetrains? Is the maintenance indeed less than for fossil models?

  5. There is nothing that stops a hydrogen train (or a battery one) having a pantograph on the roof to use overhead power where it is available, and worthwhile.
    Unless there is a lot of heavy traffic every day, overhead lines are uneconomic. There are probably places where overhead wires would be economic for that part of the journey that has a significant change in altitude, but not for the flat parts or for the whole average journey. It is easy to envisage that there are many places, especially spur lines, where it will never be economic to put overhead wires up, even when the main trunk is electrified.

    When you open a new service, it can take years for usage to slowly build up on that route. It doesn’t make sense to bear the cost of electrifying the route, before you start getting a return on that route.
    In China (like the US) there are big distances in places, and that favours hydrogen. While it is true that hydrogen has ~25% efficiency, half of that of battery systems, it is important to realise that our current fossil fueled transport system runs at 10-30% system efficiency. The lack of efficiency hasn’t been an obstacle to petrol and diesel, so it’s not an intrinsic issue for hydrogen. Current diesel-electric (DE) locos are pretty much exactly that same architecture and efficiency as hydrogen-electric locos.

    As an aside, I see a pantograph/battery/hydrogen retrofit tender for DE locos becoming a thing. If you have a partly electrified rail system, you can reduce emissions by XX% without immediate replacement of all your locos

    1. The absolute system efficiency is not the deciding factor.

      Price is. The fact that diesel is still cheaper overall is why we don’t have replaceable battery cars on our trains already.

      1. Its not even price, its the lack of interest. Invest in such things and the train is more profitable for being much cheaper to run, but its going to cost lots upfront and make this short period of time’s numbers look bad… Or in the case of goverment owned railways its going to cost alot right now and not be ready to boost your election campaign as it can’t be doing any good that quickly.

      2. I’m just spitballing here and haven’t even scribbled on a napkin… but maybe the “replaceable battery cars” idea could have some merit in grid stabilisation? Like, if a freight train has a regular route through the desert, maybe collecting a few dozen battery cars along the way is logistically very cheap. Then those battery cars do to somewhere that needs the electricity (some big city in winter) then when the batteries are depleted, the next train takes them back to the desert where they can be recharged from cheap off-peak solar.

        Sure, it’s not as good as, you know, a robust national grid. But in the absence of robust continent-spanning infrastructure, maybe it could make sense. I mean, this hydrogen train also only makes sense in the absence of “better” infrastructure too.

  6. Do some more research and you may find that the high speed rail links in China are not economically viable and only continue to function due to financial support from the state.

    1. Ever considered that things like public transport is a thing countries do to keep working, and don’t necessarily have to be making a profit?
      The Dutch railway system rarely makes a profit, or breaks even at all. It’s a private company which is fully allowed to make a profit, although the state owns almost all shares in it.
      The country would be plunged into crisis without it, which is why the govt keeps all the shares to prevent a ‘Profit first people later’ owner from getting rid of important for humans, but unprofitable connections.
      It is an essential government service, just like road construction. Our tax on cars and fuel don’t even come close to covering the cost of car infrastructure and car-related health care cost. We can’t go without cars either, so road construction has to be taxpayer funded.

      1. I suggest that you actually look into what is really going on with the Chinese high speed rail network. The underutilisation even calls into question the environmental credentials of building such a system. It isn’t really a public transport system if the majority of people can’t afford to use it.

      2. Thank you for making this point, Laurens. Public infrastructure doesn’t need to turn a direct profit in order to still be a net benefit to society. Sure, boondoggles still exist, but the counter argument that any given infrastructure “sucks because it doesn’t make a profit!” is childish. Cities don’t have sewerage systems to make a profit on the pipes, they have a sewerage system because everything else works better if the streets aren’t knee-deep in shit. Just like society works better if goods and people can move around efficiently.

        Further to that point, if I am driving a car, I am unproductive while doing so. If I’m seated on a bus or train, on the other hand, I can read a book (or a datasheet), write an email, or even post here on Hackaday. This is usually ignored when the benefits of public transport are being analysed, I suspect because it would skew the numbers so spectacularly in favour of public transport that there would be no “debate” left to have.

  7. Just out of curiosity, and I defer to those more knowlegeable than myself, is why can’t solar panels be used at the top of this train to keep the super capacitors charged, and as the train uses the power from the super capacitors the solar panels can charge those? Now, provided that you don’t use more power going out than is going in, the train could run as long as the sun is shining on the panels or am I missing something here?

    1. As train motors are usually over 1000kW peak and double that and more wouldn’t be unusual to give some idea of the energy a train requires…

      The power you might be able to get off the roof of a train is going to vary by loading gauge – but for arguments sake lets take something around a small 3 car passenger train for UK loading gauge – each car is around 20m long by something like 3m wide but with a curved roof profile as tunnels and bridges in the UK tend to be rather small so the roof peak width is less. So say you can fit the fairly standard cell of around 1 meter by 2m on each train along its entire length 50 odd times – at noon on a clear day something perhaps up to 500w per panel, more likely 350w. So right then assuming you have no trees, tunnels or other occlusions you would get 17.5-25kW enough to run most lower speed light passenger rail probably – but when something like the British Rail 125 a 70mph ish train had peak power for a comparable size train of 710kW you might not even be able to keep it running for the slow stuff! But with modern electric motors being more efficient, for the slow stuff its perhaps plausible.

      However it gets worse, you then have to consider off axis illumination, which means a solar panel produces rather less, so the early morning rush hour on a clear day even under such ideal conditions you may only be getting 50 odd watt per panel – still sounds like alot on domestic terms but…

      And as trains also run at night, and often in revetment, though tunnels, with building and trees occluding them…

      A directly self powering solar train will never work, with current technologies anyway, and probably isn’t really plausible on Earth at all – modern solar panels are getting perhaps 40% efficiency if they are the cream of current crop and something like 20-30% is what you would normally have on your house. So even if you take the worst case and say that above example was 500w at only 20% sunlight to electric and assuming eventually we will manage some miracle and get 100% sunlight conversion – so a 5x bump that is still only turning that 25kW into 125kW on a train size that in service had a 710kW diesel…

    2. It is much more efficient to put those solar panels on the station building than to put them on the train. Less vibration damage, easier to point directly at the sun, and the surface area of the roof of a building is a lot larger than the surface area of a train roof.
      Regardless, as a test, the Byron Bay Railroad Company in Australia (very sunny there!) actually mounted panels to the roof of a small battery train. In their specific use case, it works – because it’s a heritage train route that takes 10 minutes to reach the end of the line, and runs very slowly. You give it one good shove at the start of the line, and then barely have to run the motors to keep rolling. It appears to do one up-and-down trip per hour. They have 6,5kW of generated solar energy on the train roof, and if necessary, another 30kW on their station building.

      Compared to ordinary trains (the Dutch VIRM trains draw about 150.000 watts to keep rolling at 140km/h, as well as some energy for heating or AC), you can see that it’s just not feasable to run a medium speed, 300-500 passenger train on solar power fitted to the roof of the train.
      Aforementioned VIRM draws multiple megawatts of power when accelerating, and draws that for about 2 minutes to get up to 140km/h in dry weather.

    3. In short: Good idea, but the enery requirements don’t work out by a couple orders of magnitude. Smaller stuff like auxilliary power (e.g. lights or so) might be served by the available surface, but I doubt it would be worth the added engineering effort.

      I’m mostly posting to link this handy solar panel reference chart (xkcd webcomic: ) that covers a surprisingly broad range of possible solarification projects, including trains.

  8. The problem with batteries is also simply that they can’t do most of the mobility jobs.According to Ford Motor Co. CEO Jim Farley “HYDROGEN TRUCKS WILL BEAT ELECTRIC”
    He says that the Ford Super Duty,a heavy-duty pickup truck with substantial capacity for heavy load and towing stands a better chance of being dethroned by a HYDROGEN FUE CELL hydrogen fuel cell vehicle than by an EV truck.

    On the compared efficiency of fuel cell systems against battery systems,we should do it from the electricity generator (wind turbines,solar panels…etc) to the electric motor in mobility.

    With battery electric vehicles,it goes directly from the wind turbines to the vehicle.Except that you loose near 10 % in the transmission…Then they loose some more when unused, depending of the temperature and the age of the battery.During winter it falls quickly to zero,and you have to recharge frequently,for along time.
    If you do it for a day trip,with the battery fully charged,in spring,we can estimate that the BEV is the winner.
    But if you calculate it for frequent journeys with frequent refueling ,it change it all.

    On a 24/24,7/7,365/365 days basis,let’s say a fleet of cabs or trucks,between the hours lost at recharging,the winter capacity shrinkage,even if you integrate the passage by electrolysis and hydrogen storage,before conversion to electricity ,hydrogen fuel cell system are a clear winner for trucks of any size,ships,planes…etc.

    On the whole cycle,they are more efficient simply because you can use hydrogen fuel cell vehicles,trains,ships,and planes almost 24 hours a day with an availability close to 100 %,which will never be the case with batteries.Where’s the efficiency when you have to leave your vehicle idle for hours a day at recharging.In a commercial operation,it’s a zero yielding asset when your powerful fuel cell truck or train is earning money all night and day long.

    For train,you make so much savings on the infrastructure,overhead lines and electric grid and their maintenance,particularly for mines in faraway places,when you can pack it all in your locomotive and maybe some kind of tender,that hydrogen fuel cells are also a winner.

    Recently a Swiss and a French company (Nestlé and Engie) had the excellent idea to prepare a buffer rail-car ,some kind of “coal tender” behind the old electric locomotive which was still working very well.They will put the hydrogen fuel cell and the hydrogen fuel between the electric locomotive and the freight train.
    This way,they will save a lot and become zero emission without have to change immediately the locomotive.
    They will just branch it in the hydrogen fuel cell tender just behind.No need for new catenaries and substations with costly new connections to the grid.

    Batteries will be still very useful as a component,but they raise too much issues and they clearly don’t have the range of the capacity for heavy duty,without talking of specialized trucks like concrete trucks,waste trucks and snow plow trucks applications which can also tirelessly near 24 hours a day.You only have to change the driver three times and refuel at the same time in 8 minutes .This is what I call efficiency.
    With one hydrogen fuel cell truck,you do the job of four battery electric snow plow trucks,Worth considering
    by any city council when you know the price of these super heavy duty trucks !

  9. Absolutely stupid. Just build overhead electric lines, and where you cant do that, use third rail.
    This is a solved problem already, Nothing will be as efficient as that. And that way you dont have totally out of date obsolete tech built into the train that you have to maintain and upgrade every 10 years. You can keep the same lines and the same trains for decades, and the whole time you can upgrade the grid that powers it. It wont care if the power comes from coal or wind or nuclear or hydro. Ultimate flexibility.

    1. But how do you get any venture capital for a boring electric train? And where is the technical innovation with that well-known approach? Hybrid future train with super-caps + fuel cell is so much more exiting! I really like how this example demonstrates how the whole energy revolution is going.

    2. Really not that easy – pantographs are relatively expensive to build and do wear and get damaged by that storm etc – so have more significant maintenance costs and third rails are unsuitable to anywhere that is likely to get wet. Lots of places can benefit from something that replaces the rather loud and dirty diesel with a battery or fuelcell electric drive.

      Do you really want to spend billions putting in a pantograph system on some long stretch across the more empty parts of America AND then have to maintain it? Much much cheaper to have to refurbish or replace the trains more often than do that. Especially if your rail network gets as little use as the USA’s seems to (at least from a European perspective).

    1. From Wikipedia: “The high-speed rail (HSR) network in the People’s Republic of China (PRC) is the world’s longest and most extensively used – with a total length of 42,000 kilometres (26,000 mi) by the end of 2022. The HSR network encompasses newly built rail lines with a design speed of 200–350 km/h (120–220 mph). China’s HSR accounts for two-thirds of the world’s total high-speed railway networks.”

      Meanwhile, the USA has <50 route miles of high speed track where Acela reaches 150mph… So while China has 5 times the US population, it has 500 times the high speed mileage…

  10. Why would one use hydrogen locomotives in Europe where most lines are already electrified ?

    I don’t know about China, but Germany being a smaller country would benefit from electrifying the (few?) lines that are not electrified yet.

    I wonder what is the balance between electrifying new or existing lines (upfront cost + maintenance) compared to operating these kind of locomotives, which arguably are more complex to maintain as well.

    1. Don’t know about China, but in the case of Germany, it is money allocation more than engineering issues preventing electrification. Simply put, the costs for electrification are not borne by the same entity that buys the H2 trains, and therefore we get suboptimal results.

      The H2 trains that run now are in rural areas, on lines that aren’t electrified and probably never will be: The tracks are owned by DB, the state-owned railway company, but the concessions have been given to a competitor. DB has no incentive footing the bill for electrification of those lines, and public investments anyways are bound to strict cost-benefit analyses (making rural electrification exceedingly unlikely).

      Thus, the H2 train company has a cost-incentive to switch away from diesel trains (probably they get nice subsidies on top as a pilot project), but they can’t force DB to install overhead lines. DB couldn’t install overhead lines for rural lines even if it wanted to (cost-benefit negative), which they don’t anyways. Hence, the least bad everyone can do given the circumstances is introducing those trains and hope for the best. At least they run quieter than the diesels.

      (On top of that, DB is just emerging from a 20-year stretch of pretty severe underinvestment in their infrastructure, due to an ultimately abandoned attempt to make them look profitable for the stock market. The easiest way to make that happen was to neglect upkeep and close rural train lines, with crumbling infrastructure and mounting downtime as a result. Things are looking up now with renewed public investment, but the capacities have been reduced such that there isn’t even enough personnel to process all the repair permits, much less perform the actual repairs).

  11. “Cut the mustard.”

    It’s interesting how something misheard can come into common usage. “Cut the mustard” is silly. The original phrase is “cut the muster”, referring to selecting from an assembled group. Those selected “make the cut.”

  12. Dear rail equipment engineers: we already have a solution to clean rail transit. It’s called just powering the train off the existing power grid with a third rail or overhead lines.

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