10 ms·

Hydrogen is a stupid fuel. There, I said it. It's hard to store. It leaks away. It has poor energy density by volume (and much of the energy simply goes to com

• HWR_14 5y ago
  50% round-trip efficiency and 3x the density of li-ion sounds pretty good, actually. Assuming your efficiency number is the entire cost of water -> compressed H2.
  • DaiPlusPlus 5y ago
    Toyota's hydrogen tanks looked promising: 300mi range and 3 minute refill time. It's disappointing it never went anywhere.
    • s5300 5y ago
      >It's disappointing it never went anywhere. There's probably a sound reason for that
    • Tade0 5y ago
      It's 3 minutes assuming the fuelling station is at peak pressure - 700 bars. After the first fill up it needs several minutes to pressurize. Also such a facility costs at least $1mln and is unlikely to ever get much cheaper.
      • AnimalMuppet 5y ago
        > Also such a facility costs at least $1mln and is unlikely to ever get much cheaper. How much does a conventional gas station cost? I would expect several hundred thousand, at least.
        • Retric 5y ago
          A more relevant question is how much does a single gas pump or EV charging station cost. A gas station can easily have a dozen pumps for ~500k.
          • cma 5y ago
            Hydrogen tanks can also have multiple outlets (I get that they are more expensive than gas outlets, but the tank is presumably a large part of the hydrogen station cost).
            • Retric 5y ago
              If a 1 million dollar instillation can’t keep up with continuous 3 minute fill ups then it’s going to need significant extra hardware to have enough throughput for multiple pumps.
          • DaiPlusPlus 5y ago
            > EV charging station cost. A commercial-grade Level 1 charger (US domestic 110V 15 amp), if they even exist anymore, is probably on the order of $1000 or less - if it breaks buy a no-name replacement from Alibaba until it catches fire. A professionally-installed Level 2 charger without any payment system infrastructure - so one that's basically free-to-use and taps directly off your AC service-panel at 240V 50-90A will cost about $750-2000 including installation by an electrician - most states offer generous tax-deductions for this btw. A Level 2 charger that's part of some charger network, like Chargepoint... I've no idea. The hardware looks nice (i.e. expensive) but I'm unsure who pays the cost of the hardware and installation (is it the landowner or is there a cost-sharing deal with the network operator?) Level 3 chargers... we're talking a minimum 5-figure amount for even a single-stall set-up: as you need a huge (literally: easily 3x3x6 foot) DC transformer appliance for each pair of charging stalls (hidden behind a fence around the corner), connections to seriously high-power mains electricity (imagine a 16-stall Supercharger: that's 8 DC transformers doing ~120kW each: that's 2MW!) in addition to the aesthetically designed car-connector party. According to this article from 2013 (so it's already 8 years out-of-date) Tesla pays $100-200k towards a station, I'm unsure what the cost-split is, but I'd be surprised if the total cost overall was under $250k imo - I also wouldn't be surprised (still) if simply land-use-rights was the majority share: https://techcrunch.com/2013/07/26/inside-teslas-supercharger-partner-program-the-costs-and-commitments-of-electrifying-road-transport/ https://techcrunch.com/2013/07/26/inside-teslas-supercharger...
      • darksaints 5y ago
        Why would you assume that? Electrochemical compressors, as well as high pressure vessels, are rapidly declining in cost. Fuel station grade electrochemical compressors were ~$1M ten years ago, $300k five years ago, and about $150k today.
        • AtlasBarfed 5y ago
          Compare that to hooking up to a grid, costwise. All the H2 equipment is 20x more I'd guess than a charging station for an EV. All the other H2 issues aside, you're competing with a good, established logistic network in EVs: the grid. H2 is like any new nuke: you're 10 years out with a ton of subsidy and investment from being a player against the EVs of TODAY. Your price targets to compete will have to anticipate 5-10 years of accumulated economies of scale, tech improvements, etc in EV/grid/alternative energy/storage. I'd be shocked if a bank would float capital to support that given the uncertainty. Just like I'd be shocked if a bank would float financing to a new major fossil fuel development. It might be BANNED in under a decade.
          • darksaints 5y ago
            You can't just "use the grid"...existing grid connections can't handle the load. You have to have high voltage lines run direct. Just the equipment to receive and distribute a high voltage connection, you're talking ~$150k. Then another $60k per charger. And before you can even consider installing anything, you have to have lines run specifically for your station, which can often be several miles. That's definitely not cheap. So no...hydrogen infrastructure is not 20x more. It's probably slightly more expensive than an urban charging station, but significantly cheaper than a rural charging station. And remember: electrical infrastructure is mature...it's not going to get significantly cheaper any time soon. Batteries are the innovation driving EV growth, not the grid. The only thing that is unambiguously more expensive is the fuel. And it always will be more expensive...but prices are going down constantly. If it costs $100 to drive a truck across the US, why would it matter if it costs $200 to do the same with hydrogen, especially if it means not having to stop for hours at a time to recharge?
            • 5y ago
    • rootusrootus 5y ago
      We really aren't that far from a plausible charging setup that can do 300 miles in 10 minutes. And that would be perfectly adequate. The infrastructure to support it would certainly be less difficult than trying to get hydrogen available everywhere.
      • iainmerrick 5y ago
        That’s not adequate at all! The lines at gas stations would be massive. Charging via electric at home or in a parking spot seems a lot more convenient, even if it takes a few hours.
        • rootusrootus 5y ago
          10 minutes isn't that far off what people routinely spend today to fill a tank of gas. Especially people with trucks, which is a large part of the US. Over half the population probably has the infrastructure to home charge right now, so this does not need to replace gas station pumps 1 for 1. I was not suggesting that all of us charging at home need to start using public chargers.
          • DaiPlusPlus 5y ago
            > 10 minutes isn't that far off what people routinely spend today to fill a tank of gas. I don't want to "uhm, acktually", but it's less than 5 minutes: https://www.quora.com/How-much-time-does-the-average-person-spend-filling-up-at-gas-station-during-the-ownership-or-lease-of-their-particular-car https://www.quora.com/How-much-time-does-the-average-person-... - and that's including time spent faffing around with the awful pay-at-pump machines' UX.
            • rootusrootus 5y ago
              I admit my experience is non-typical, as the only gasoline vehicle I own is a truck with a big tank, but 10 minutes is well within normal. For cars with 15 gallon tanks, 5 minutes is probably reasonable. But in any case, 10 minutes is fine no matter what. If you are willing to spend 4x as much for fuel in order to save less than 10 minutes per week when you stop for fuel, then the problem isn't the charge time.
    • neaanopri 5y ago
      Combination of needing lots of infrastructure, and lack of political will. If US decided that instead of waiting for green tech to emerge, we would just simply stop burning fossil fuels and revert to an Amish standard of living until clean fuels are developed, we could have converted to Hydrogen already
      • jxidjhdhdhdhfhf 5y ago
        That or violent overthrow.
        • behringer 5y ago
          That's what's coming now.
          • jxidjhdhdhdhfhf 5y ago
            Could be
      • labster 5y ago
        As long as Jeff Bezos gets to keep his new half a billion dollars yacht, I’m sure the elite would be happy to see the rest of us finally return to serfdom where we belong.
      • foxpurple 5y ago
        We don’t have to convert to an armish standard. We could have just massively reduced car transport and improve electric rail and walkability. I’m always amazed at how Americans consider driving to be a simple fact of life where you either drive daily or go back to throwing spears in the jungle.
        • robocat 5y ago
          You are regurgitating a clichéd argument. > massively reduced car transport How the hell could enough people be convinced to spend say 10% of their income on public transport instead of their car and petrol/charging? https://www.statista.com/statistics/748911/us-average-per-capita-vehicle-spending-by-category/ https://www.statista.com/statistics/748911/us-average-per-ca... > improve electric rail and walkability. So click your fingers and you have cheaply and immediately magically redesigned the distribution of residential and commercial property to suit public transport and/or pedestrian/bike access? Finally, ignoring the above, building out that infrastructure and other changes would cost trillions, which indirectly causes trillions of dollars worth of extra CO2… Your argument is as trite as saying “why don’t we just stop producing CO2?”. Edit: disclaimer: yes I own a car and I also use public transport when convenient (I was even 100% carless for a few years, by living close to work and bus route was accessible).
  • dTal 5y ago
    I'm not an expert in fuel cell efficiency, I'd read that number somewhere and a quick google confirms it: https://www.sciencedirect.com/topics/engineering/round-trip-efficiency https://www.sciencedirect.com/topics/engineering/round-trip-... The energy density situation looks less attractive when you include the beefy 350-bar storage tanks, and the fuel cell itself. A battery just has two wires sticking out and that's it.
    • jfim 5y ago
      > A battery just has two wires sticking out and that's it. What about thermal management, the outer shell that can hold the battery cells and modules, and the battery management system?
      • dTal 5y ago
        Sure, but a hydrogen fuel cell system has most of that too. My point was just that hydrogen can't be directly compared to batteries because it's just the fuel, while batteries are the complete system. I guess I worded it badly.
    • nightfly 5y ago
      > A battery just has two wires sticking out and that's it. Considering the heating/cooling mechanisms required for EV batteries this is a pretty disingenuous statement. Not even considering the highly-toxic fire risk with Li-ion.
      • dTal 5y ago
        Well okay, but if we're bringing those things into it, hydrogen requires cryogenic storage and is, ah, famously flammable, even when it's not pressurized to 350 bar. I wasn't saying Li-ion is perfect - all I was trying to say was that if you want to compare like with like, you can't compare batteries with just hydrogen - the hydrogen is just the fuel, while the battery is both the fuel and the generator.
        • darksaints 5y ago
  • FabHK 5y ago
    Yes, also given that electric motors have an efficiency of 90%+ (or thereabouts) and internal combustion engines only of 20-30% IIRC.
    • busterarm 5y ago
      Modern ICE are hitting 40%.
      • diarrhea 5y ago
        I don't know why you are being downvoted. You are correct, and some ICEs (large, maritime) are hitting 50% even. For a thermal engine, that's incredibly good (it's not about the gap to 100%, but the gap to Carnot efficiency).
        • busterarm 5y ago
          There's a strong contingent here on HN that believes tha continued used of ICEs equates to the imminent death of the human race. It's also a likely wealthy contingent that imports all of its food, flies everywhere, etc.
          • dTal 5y ago
            On what grounds do you draw that connection?
            • busterarm 5y ago
              Previous threads, comments & votes.
      • AtlasBarfed 5y ago
        ... except the cost of the ICE drivetrain, certainly to hit 40% (that takes turbos and other complexities to the basic ICE, correct?) is about to lose to the cost of the EV drivetrain. It's basically at price parity based on what I see out of Tesla and what Lucid/Rivian/VW/GM are targeting. In three years? Less. And a decade from now? EVs will probably be half the cost of an ICE.
• belorn 5y ago
  Green hydrogen is the only realistic alternative to nuclear in areas which rely on wind power for renewable energy. Li-ion batteries can not economically create weeks long capacity of stored energy with a charge cycle of a few times a year. Wind does not have a day cycle as solar has. What green hydrogen need to do is become economical, and to my knowledge it is even more expensive per w/h then nuclear is.
  • ars 5y ago
    Methane is a better fuel for that than hydrogen, you can make it from air plus energy (although not easily - there's not enough CO2 in the air for that). Or, more practically, coal and water and energy.
  • the8472 5y ago
    "only realistic alternative" isn't quite right since it's one of several grid-scale storage options none of which have yet proven themselves to be economical.
  • Hermitian909 5y ago
    For context, I'm a software developer who works with a lot of battery researchers. My understanding from them is that while Li-ion batteries cannot create weeks long capacity, rust batteries may be able to in the future. Check out Form Energy[0] for an early version of this, they're claiming ~100 hours of storage right now and if they're right about the science and can manage the engineering it could grow past a month. These batteries are challenging to run, a bit like a mini-chemical plant, but they do actually seem plausible. (No personal association with the company, some of my coworkers know the founders though) [0] https://formenergy.com/ https://formenergy.com/
    • elihu 5y ago
      Interesting. Is the idea just that they're optimizing for cost, rather than optimizing for watt-hours per kilogram? I.e. if it doesn't matter how much it weighs, you can use a simple, cheap sort of battery that wouldn't be practical in a phone or a car?
• thescriptkiddie 5y ago
  Any idea about the round trip efficiency for other synthetic fuels like methane or propane? It's probably awful but may be worth the increased density over hydrogen.
  • rootusrootus 5y ago
    Or liquid fuels like gasoline or kerosene that don't just boil off if you don't keep them compressed. I'd like to see that analysis.
  • dTal 5y ago
    You can synthesize gasoline, for that matter. You can't really do much better than that for a liquid fuel. I'm surprised there's not more of a market for "green gasoline". It's not that hard to make.
    • cogman10 5y ago
      IIRC, wasn't the price point for a bio-gas (made from atmospheric CO2) something like $4/gallon?
      • dTal 5y ago
        If that's true then it's revolutionary. I'm sure that price point makes Americans clutch their pearls, but in Europe gas already costs a lot more than that.
        • cogman10 5y ago
          This article [1] says the cost point is closer to $34 per gallon (back in 2009). [1] https://www.greentechmedia.com/articles/read/algae-biodiesel-its-33-a-gallon-5652 https://www.greentechmedia.com/articles/read/algae-biodiesel...
          • dTal 5y ago
            I mean... vegetable oil is 5 bucks a gallon at Wal-Mart and you can run diesel vehicles on it almost unmodified. I'm struggling to see the problem here.
• unpolloloco 5y ago
  It's not a stupid fuel in cases where you need massive amounts of energy and can't spare the weight... Like rockets and... rockets
  • cogman10 5y ago
    Maybe airplanes and boats?
  • dTal 5y ago
    Yes, I concede it's a good engineering solution there. Especially when you also need water!
    • amluto 5y ago
      If you’re burning hydrogen to power a rocket, you don’t get to keep the exhaust. If, on the other hand, you use hydrogen and oxygen to power a fuel cell, keep the water, and use the power output to power an ion thruster or similar device, I suspect you end up with worse overall results than simply using a rocket and carrying some water.
      • dTal 5y ago
        Apollo used fuel cells to good effect. Their constraints lined up perfectly - they already needed oxygen tanks, and a supply of water, and they didn't have li-ion batteries back then either. Also, the weight cost of the fuel cells themselves amortizes nicely when you need power for an entire week - and hydrogen is light. And once it had been used, the water was flushed, saving further weight. The big downside to batteries is they weigh the same empty and full.
  • Gwypaas 5y ago
    Not even rockets. Lose too much from the low density leading to a larger structure and isolation required to handle it as a liquid, and not freeze the oxygen. Meaning worse performance than the pure numbers would imply. Not to mention cost of handling it. Case in point, SpaceX going larger rocket with less efficient kerosene first and now methane to increase efficiency and reduce soot, while still keeping everything simpler than hydrogen.
• unchocked 5y ago
  Yet it's absolutely required for synthesizing hydrocarbons from CO2 so, there's that. I mean, pick any fuel you want, their utility as stores of energy are all based on hydrogen content. So we're going to kick the fossil habit and still have fuel of _any_ sort, we're going to have to learn to produce and utilize hydrogen at scale. Grey and blue hydrogen are transition fuels. They build a market for green hydrogen to fill. It's going to be a little messy along the way.
  • xyzzyz 5y ago
    > I mean, pick any fuel you want, their utility as stores of energy are all based on hydrogen content. OK, I pick black coal. No hydrogen content. What do I win?
    • j_walter 5y ago
      Actually it does have hydrogen... https://en.wikipedia.org/wiki/Bituminous_coal https://en.wikipedia.org/wiki/Bituminous_coal >The carbon content of bituminous coal is around 45–86%;[1] the rest is composed of water, air, hydrogen, and sulfur, which have not been driven off from the macerals.
      • joecool1029 5y ago
        >Actually it does have hydrogen... Shitty coals like lignite and bituminous coal do. The real chad coal, anthracite, is up to 98% carbon.[1] [1]https://en.wikipedia.org/wiki/Anthracite https://en.wikipedia.org/wiki/Anthracite
  • dTal 5y ago
    Sure, but when people say "hydrogen fuel" they usually mean pure H2. Trouble is, those carbon atoms everyone's so keen to get rid of are damn useful, chemically speaking. I actually think there's a lot more mileage in synthesizing hydrocarbons from biowaste. There's nothing inherently wrong with burning hydrocarbons - the problem is that we're lazily digging historical supplies out of the ground, instead of keeping the carbon cycle closed. Really, we should just put massive tax levies on fossil fuel extraction operations and call it a day. The market will sort the rest out.
• MengerSponge 5y ago
  Also it's odorless, is flammable in air from 4% to 74%, and has an invisible flame during the day when it does. It's a nightmare.
  • c_o_n_v_e_x 5y ago
    Don't forget low ignition energy and hydrogen embrittlement
    • jessaustin 5y ago
      We will know that "green" hydrogen is nearly feasible when they stop talking about hydrogen and just admit that ammonia, which doesn't cause embrittlement and stores energy more densely than hydrogen, is what they meant all along.
      • dnhz 5y ago
        But hydrogen is the prerequisite for ammonia, and ammonia still needs cryogenic infrastructure?
        • jessaustin 5y ago
          No it just has to be pressurized in order to stay in liquid state. The pressures involved at normal ambient temperatures are less than 300 psi, which is not extreme. Scuba tanks, for example, handle pressures of 3000 psi or sometimes more.
• AYBABTME 5y ago
  It has much better energy density than batteries, which is useful when mass is at a premium (in specific circumstances because it also requires heavy apparatus), or when you need some backup power supply to supplement a worst case scenario that would require a prohibitively large battery to handle.
  • kjksf 5y ago
    I'm pretty sure it's not true when you account for the wight of the hydrogen tank (as opposed to just looking at hydrogen). Toyota Mirai is heavier, more expensive, has less range and cargo space than Tesla Model 3. So it's definitely not true when we're talking about batteries vs hydrogen for passenger cars. Maybe when you scale the tank to the size of a semi it might edge out batteries, but at the moment there's no data to support this. Hydrogen is worse than gasoline / diesel. The hydrogen that is only slightly more expensive than diesel is just as much (if not more) damaging to environment. That's the hydrogen made from natural gas. The "clean" hydrogen i.e. the one made by electrolysis, is way more expensive than gasoline which is why it's almost non-existent, commercially speaking. Not to mention all the "but electric cars are not clean because coal plants!" arguments apply 3x as much to hydrogen, because due to losses you need 3x time electricity (and therefore cost) for hydrogen compared to just putting it in a battery.
    • coderenegade 5y ago
      A Mirai is much bigger car than a Model 3. The better comparison would be the Model S, which has almost identical dimensions to the Mirai; when you do that comparison, the Mirai is around 300kg lighter and goes further. It doesn't matter which way you cut it, even with all of its disadvantages, hydrogen with a tank still has 3-5 times the energy density of lithium ion, and it scales better with larger vehicles. This is also the reason why industrial drones are moving to hydrogen. They've been using batteries for more than a decade now, and it's been the big limitation holding back a number of applications. Hydrogen gets you double-to-triple the endurance, even at relatively low pressurizations, which makes things like surveying easier, and delivery services possible. Military-grade platforms are supposedly already looking into using liquid hydrogen, with a number of platforms having already been converted over the past decade.
• darksaints 5y ago
  One of the dirty secrets of li-ion is that in order to use it for cars, you need high voltage batteries, and if your charging source isn't similarly high voltage, your charging efficiency tanks because you spend 30-40% of your energy stepping your voltage up to a level that will charge your batteries. For example, if you charge your Tesla with a 120v AC power supply, you're looking at 58% charge efficiency, which will put your end to end efficiency at the same level: ~50%.
  • Baeocystin 5y ago
    The numbers from my friends' Leaf point to a charging efficiency loss of 110V vs. higher rates at around 10%. FWIW. [edit] From https://www.mynissanleaf.com/viewtopic.php?f=31&p=545335#p545318 https://www.mynissanleaf.com/viewtopic.php?f=31&p=545335#p54... >Level 1 (120v, 12 amps): 78% efficient >Level 2 (240v, 16 amps): 91% efficient >Level 2 (208v, 30 amps): 91% efficient >CHAdeMO (500v DC, ~100 amps): 93% efficient
    • darksaints 5y ago
      Yeah, that's because of the lower nominal voltage of the battery: 350v vs Tesla's 450v. So you get higher charge efficiency, but you'll get lower motor efficency with it. Not sure if it comes out ahead in end to end efficiency.
  • avidiax 5y ago
    Why is it so hard to step up voltage efficiently? 120VAC is already AC, so a simple transformer can boost it to e.g. 480VAC easily, and then you have the same AC to DC problem that a native 480VAC charger would have. At least for li-ion, the infrastructure problem isn't too terrible, as most cars will have an endpoint with high-voltage, i.e. the workplace.
    • addaon 5y ago
      The size of a high-power 60 Hz transformer is prohibitive in weight, both directly (where are you going to put it?) and in impact on price (shipping, amount of metal). It ends up lighter, cheaper, and not much less efficient to do a high-frequency conversion instead, either as a boost directly from the 120V AC or as a DC-DC in the secondary.
• mrtnmcc 5y ago
  Last time I looked at hydrogen-electric, a huge limitation was the lifetime of the electrolyzer membrane. They are expensive and you have to replace regularly.
• swiley 5y ago
  Also it can damage your ears pretty badly if it burns in open air.
• pfdietz 5y ago
  Hydrogen energy storage capacity underground: $1/kWh Li-ion energy storage capacity: somewhere around $200/kWh? So, no, hydrogen is not "hard to store". It's vastly cheaper to store it at scale than it is to use shorter-term storage technologies. The disadvantage is low round trip storage efficiency (maybe 40% if used with a combined cycle power plant) but THAT'S OK for long term storage, which will have many fewer such iterations than diurnal storage. If you want to level grid energy use and demand over a year, batteries would be insane. Hydrogen, however, could be quite practical.
• ZeroGravitas 5y ago
  This is true, but probably could be stated better. Increased Green Hydrogen production is an essential and inevitable part of the response to climate change. But the people pushing it for personal transport (often putting more effort into talking down their battery equivalents than actually building and selling vehicles) and anyone suggesting blue hydrogen, as a stopgap because green hydrogen is so far away and expensive, is more pro-fossil than pro-hydrogen. If oil and gas majors aren't annoyed by your hydrogen strategy, then you're not doing it right.
• benhurmarcel 5y ago
  And yet hydrogen is the only realistic solution we have for 0-emission mid/long range aircraft.
  • FabHK 5y ago
    what about synthetic kerosene? Net-zero.
    • coderenegade 5y ago
      You need to make hydrogen as a precursor to making synthetic kerosene.