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Why is it such a terrible idea? In theory you can generate it via electrolysis in places with plentiful renewable energy, and then you've got a very high-densit

Why is it such a terrible idea? In theory you can generate it via electrolysis in places with plentiful renewable energy, and then you've got a very high-density, lightweight fuel. On the surface, it seems ideal for things like cars or planes where vehicle weight matters. Batteries are huge and heavy and nowhere near as energy dense as gasoline.

CamperBob2 8mo ago
Besides being expensive to generate unless you already happen to have an electrolysis plant handy, hydrogen is awkward and hazardous to store. Once generated, it costs yet more energy to liquefy, and then it seeps right through many common metals, weakening them in the process. It's just not a good consumer-level energy source, and nobody could figure out why Toyota couldn't see that. Interestingly, liquid hydrogen is nowhere near the most energy-dense way to store and transport it. I don't recall the exact numbers but absorption in a rare-earth metal matrix is said to be much better on a volumetric basis. [1] Still not exactly cheap or convenient, but it mitigates at least some of the drawbacks with liquid H2. 1: https://www.fuelcellstore.com/blog-section/what-hydrogen-storage-is-best-for-me https://www.fuelcellstore.com/blog-section/what-hydrogen-sto...
- smcin 8mo ago
  Remember that China briefly embargoed Japan for rare earth metals in 2010, and Toyota launched the Mirai in 2014. My theory was that it was developed as a national fallback for Japan in case that embargo continued or got worse. Think 1930s Volkswagen. Anyone can comment on that?
  - seanmcdirmid 8mo ago
    Japan went heavy into hydrogen for a couple of decades ago. The only reason we are even talking about hydrogen passenger vehicles now is because Japan thought it was the future, they made a mistake.
    - smcin 8mo ago
      I'm pointing out that the timeline of continuing funding it, to the point of a major model design and launch, and nationwide network of hydrogen stations, might well be linked to China's emergent REE dominance and that Japan doesn't have those raw materials. (In some future decade/century, people might conclude that car dependency on fossil fuels, after electric from renewable became viable, was a mistake.)
      - seanmcdirmid 8mo ago
        I think Japan made their plans in the 2000s, maybe starting to gain traction in 2010, this is long before China became an EV power house or even had a dominant share of rare earth processing.
        smcin 8mo ago
        Independent of that. I'm saying there was some wisdom to continuing to fund it in Japan post-2010 as a hedge in case REEs were unavailable. (Separate to whether the idea originally made sense back in the 2000s.)
        seanmcdirmid 8mo ago
        Rare earths aren’t really that rare though. China has been the only country to invest in refining, sure, but any other country, including Japan or USA could have made similar investments and simply didn’t, because Chinese refiners were cheap and they couldn’t compete. Yes, the market failed to solve the REE problem at us, but it is not because we don’t have access to the inputs and we don’t know how to refine them. Japan could have simply started their own refining business if they were really worried about REEs in 2010. Yes, it would take them until 2015 or so to ramp up, but that was still 11 years ago.
- fuzzfactor 8mo ago
  The rare earth metal matrix can be a bit more optimized and I think progress is being made. Why wait though ;) With common metals hydrogen fits in between the matrix naturally to an extent. Not like for efficient storage though, just the embrittlement, which gives researchers even more challenging things to be careful about.
stephen_g 8mo ago
It’s horrible to work with - dangerous, embrittlement issues etc., and very energy intensive to compress into very heavy cryogenic storage containers…
- credit_guy 8mo ago
  > dangerous It is actually less dangerous than other fuels, for the simple reason that it is extremely light and buoyant. A gasoline fire is bad, because the gasoline stays where it is until it fully burns. A hydrogen fire is less bad, because it will tend to move upwards.
  - jiggawatts 8mo ago
    Hydrogen mixed with air has a very wide range of concentrations where it is explosive. It accumulates inside containers or just the roof of the car… where the passengers are. It takes just one lit cigarette for it to go boom.
    - jcgrillo 8mo ago
      And it burns really hot
  - chongli 8mo ago
    That's assuming the hydrogen is just loose in the area, like it'd been released from a balloon in a chemistry classroom. That amount of hydrogen is extremely small, from an energy standpoint. Equivalent to a teaspoon of gasoline or so. If you assume a realistic fuel capacity for a hydrogen vehicle, the hydrogen tank will be both much larger than a gas tank and the hydrogen will be under extreme pressure. A tank like that in your car would be extremely dangerous even if it were filled only with inert gas.
- amelius 8mo ago
  Yeah it is so bad that it is common that rockets are launched with a hydrogen leak here or there.
Rygian 8mo ago
Check out the "Clean Hydrogen Ladder" document. Hydrogen wastes a large amount of energy.
- cbmuser 8mo ago
  Unless you produce it using the Sulfur-Iodine cycle in a high-temperature nuclear reactor. See: https://en.wikipedia.org/wiki/Sulfur%E2%80%93iodine_cycle https://en.wikipedia.org/wiki/Sulfur%E2%80%93iodine_cycle and: https://www.jaea.go.jp/04/o-arai/nhc/en/research/hydrogen_heat/heat/heat_httr.html https://www.jaea.go.jp/04/o-arai/nhc/en/research/hydrogen_he...
  - Rygian 8mo ago
    According to the Wikipedia article, it is still significantly worse than Just Using the Electricity (~21 to 48% efficiency just on the hydrogen production part, not counting distribution and consumption).
SideburnsOfDoom 8mo ago
Hydrogen is the minimum viable atom: one proton, one electron. H2 is a tiny molecule. "hydrogen embrittlement" is when it's small enough to diffuse into solid metal, because it's that much smaller than iron atoms. It's hard to work with because of this, and what's the point? For most uses, electricity supply is already everywhere.
- Qwertious 8mo ago
  >Hydrogen is the minimum viable atom: one proton, one electron. Wait until you hear about H+
  - antonvs 8mo ago
    That’s a type of ion, or of course a proton. An ion with no electrons is not considered an atom normally. GP is correct. (Atoms must have electrons - the definition in physics and chemistry is a structural one.)
  - SideburnsOfDoom 8mo ago
    Yes, hydrogen will ionise into loose protons. The basic point is that a material that is highly flammable, needs to be compressed to high pressure in order to be useful, but also will seep through and damage steel containers because of the fundamental fact that the atoms and charged ions are just too small, is never going to be easy to work with. Compared to electrical battery tech now being widely and cheaply rolled out. This goes some way to answering the "Why is it such a terrible idea?" question. Or at least it's an idea whose time has passed, due to the abovementioned battery tech maturing.
L-four 8mo ago
The cheapest way to make hydrogen is to use fossil fuels.
loeg 8mo ago
It's hell to store. The energy density is terrible and as a tiny molecule it escapes most seals. When it transitions from a liquid to a gas, it expands manyfold (i.e., explodes).
ssl-3 8mo ago
Ignoring some of the other issues: Imagine we have this electrolysis plant, splitting up water to produce the hydrogen we need for an area. That's fine. But it needs fed electricity to keep the process going. Lots of it. It needs more electrical power to split the water than combining it again produces. So it starts off being energy-negative, and it takes serious electricity to make it happen. Our grid isn't necessarily ready for that. And then we need to transport the hydrogen. Probably with things like trucks and trains at first (but maybe pipelines eventually). This makes it even more energy-negative, and adds having great volumes of this potentially-explosive gas in our immediate vicinity some of the time whether we're using it individually or not. Or: We can just plug in our battery-cars at home, and skip all that fuel transportation business altogether. It's still energy-negative, and the grid might not be ready for everyone to do that either. But at least we don't need to to implement an entirely new kind of scale for hydrogen production and distribution before it can be used. So that's kind of the way we've been going: We plug out cars into the existing grid and charge them using the same electricity that could instead have been used to produce hydrogen. (It'd be nice if battery recycling were more common, but it turns out that they have far longer useful lives than anyone reasonably anticipated and it just isn't a huge problem...yet. And that's not a huge concern, really: We already have a profitable and profoundly vast automotive recycling industry. We'll be sourcing lithium from automotive salvage yards as soon as it is profitable to do so.)
- aunty_helen 8mo ago
  It’s not even the grid, by the time you’ve done the electrolysis you’d be better off just charging a battery. Also, compressing and cooling a gas takes another huge hit at the efficiency. Electrolysis comes out at atmospheric pressures. Oh and the platinum electrodes you need… I’m also just now visualising a hydrogen pipeline fire… terrible terrible idea.
  - ssl-3 8mo ago
    It's the everything, yeah. There's a lot working against using hydrogen as the local energy source for automotive propulsion in the world that we presently have. Some advantages are that a fuel cell that accepts hydrogen and air at one end and emits electricity and water at the other can be lighter-weight than a big battery, and it can [potentially] be refueled quickly for long trips. Some disadvantages: We need a compressed hydrogen tank -- which isn't as scary to me as it may be for some people, but that's still a new kind of risk we need to carry with us wherever we drive. And we still need a big(ish) battery and the controls for it in order for regen braking to do its thing (which hybrids have shown to be very useful). And, again, the grid: If it were cheaper/better/efficient to move energy from electrical generating stations to the point of use using buckets [or trucks or trains] of hydrogen, we'd already be doing that. But it isn't. So we just plug stuff in, instead, and use the grid we already have. A quick Google suggests that a regular 120v US outlet might charge EVs at a rate somewhere in the range of 3 to 5 miles per hour. So a dozen or so hours sitting, plugged in at home every day, is enough to cover most folks' every-day driving. There's far faster methods, but that's something that lots of regular people with a normal commute and normal working hours can already accomplish very easily if they have private parking with an outlet nearby. For most folks, with most driving, that's all they ever have to do. It shifts concerns about refueling speed from "Yeah, but hydrogen is fast! I waste hardly any time at all while it refills!" to "What refueling stops? I just unplug my car in the morning and go. I haven't needed to stop at gas station in years." The main advantages of hydrogen are real, but they just aren't very useful compared to other things that we also have.
nkoren 8mo ago
Zubrin's "Hydrogen Hoax" from 2007[1] is basically an ironclad critique. The physics are inescapably poor, and always will be. (Zubrin makes other points in that article which should probably be taken with more salt, but his critique of hydrogen stands). 1: https://www.thenewatlantis.com/publications/the-hydrogen-hoax https://www.thenewatlantis.com/publications/the-hydrogen-hoa...
fuzzfactor 8mo ago
>you've got a very high-density, lightweight fuel. Correction, a very low density, lightweight fuel. Burns clean though with no carbon in the exhaust. But the upstream carbon emissions have not come close to zero when you look at total hydrogen use in the real world so far.

CamperBob2 8mo ago

Besides being expensive to generate unless you already happen to have an electrolysis plant handy, hydrogen is awkward and hazardous to store. Once generated, it costs yet more energy to liquefy, and then it seeps right through many common metals, weakening them in the process. It's just not a good consumer-level energy source, and nobody could figure out why Toyota couldn't see that. Interestingly, liquid hydrogen is nowhere near the most energy-dense way to store and transport it. I don't recall the exact numbers but absorption in a rare-earth metal matrix is said to be much better on a volumetric basis. [1] Still not exactly cheap or convenient, but it mitigates at least some of the drawbacks with liquid H2. 1: https://www.fuelcellstore.com/blog-section/what-hydrogen-storage-is-best-for-me https://www.fuelcellstore.com/blog-section/what-hydrogen-sto...

smcin 8mo ago
Remember that China briefly embargoed Japan for rare earth metals in 2010, and Toyota launched the Mirai in 2014. My theory was that it was developed as a national fallback for Japan in case that embargo continued or got worse. Think 1930s Volkswagen. Anyone can comment on that?
- seanmcdirmid 8mo ago
  Japan went heavy into hydrogen for a couple of decades ago. The only reason we are even talking about hydrogen passenger vehicles now is because Japan thought it was the future, they made a mistake.
  - smcin 8mo ago
    I'm pointing out that the timeline of continuing funding it, to the point of a major model design and launch, and nationwide network of hydrogen stations, might well be linked to China's emergent REE dominance and that Japan doesn't have those raw materials. (In some future decade/century, people might conclude that car dependency on fossil fuels, after electric from renewable became viable, was a mistake.)
    - seanmcdirmid 8mo ago
      I think Japan made their plans in the 2000s, maybe starting to gain traction in 2010, this is long before China became an EV power house or even had a dominant share of rare earth processing.
      - smcin 8mo ago
        Independent of that. I'm saying there was some wisdom to continuing to fund it in Japan post-2010 as a hedge in case REEs were unavailable. (Separate to whether the idea originally made sense back in the 2000s.)
        seanmcdirmid 8mo ago
        Rare earths aren’t really that rare though. China has been the only country to invest in refining, sure, but any other country, including Japan or USA could have made similar investments and simply didn’t, because Chinese refiners were cheap and they couldn’t compete. Yes, the market failed to solve the REE problem at us, but it is not because we don’t have access to the inputs and we don’t know how to refine them. Japan could have simply started their own refining business if they were really worried about REEs in 2010. Yes, it would take them until 2015 or so to ramp up, but that was still 11 years ago.
fuzzfactor 8mo ago
The rare earth metal matrix can be a bit more optimized and I think progress is being made. Why wait though ;) With common metals hydrogen fits in between the matrix naturally to an extent. Not like for efficient storage though, just the embrittlement, which gives researchers even more challenging things to be careful about.

stephen_g 8mo ago

It’s horrible to work with - dangerous, embrittlement issues etc., and very energy intensive to compress into very heavy cryogenic storage containers…

credit_guy 8mo ago
> dangerous It is actually less dangerous than other fuels, for the simple reason that it is extremely light and buoyant. A gasoline fire is bad, because the gasoline stays where it is until it fully burns. A hydrogen fire is less bad, because it will tend to move upwards.
- jiggawatts 8mo ago
  Hydrogen mixed with air has a very wide range of concentrations where it is explosive. It accumulates inside containers or just the roof of the car… where the passengers are. It takes just one lit cigarette for it to go boom.
  - jcgrillo 8mo ago
    And it burns really hot
- chongli 8mo ago
  That's assuming the hydrogen is just loose in the area, like it'd been released from a balloon in a chemistry classroom. That amount of hydrogen is extremely small, from an energy standpoint. Equivalent to a teaspoon of gasoline or so. If you assume a realistic fuel capacity for a hydrogen vehicle, the hydrogen tank will be both much larger than a gas tank and the hydrogen will be under extreme pressure. A tank like that in your car would be extremely dangerous even if it were filled only with inert gas.
amelius 8mo ago
Yeah it is so bad that it is common that rockets are launched with a hydrogen leak here or there.

Rygian 8mo ago

Check out the "Clean Hydrogen Ladder" document. Hydrogen wastes a large amount of energy.

cbmuser 8mo ago
Unless you produce it using the Sulfur-Iodine cycle in a high-temperature nuclear reactor. See: https://en.wikipedia.org/wiki/Sulfur%E2%80%93iodine_cycle https://en.wikipedia.org/wiki/Sulfur%E2%80%93iodine_cycle and: https://www.jaea.go.jp/04/o-arai/nhc/en/research/hydrogen_heat/heat/heat_httr.html https://www.jaea.go.jp/04/o-arai/nhc/en/research/hydrogen_he...
- Rygian 8mo ago
  According to the Wikipedia article, it is still significantly worse than Just Using the Electricity (~21 to 48% efficiency just on the hydrogen production part, not counting distribution and consumption).

SideburnsOfDoom 8mo ago

Hydrogen is the minimum viable atom: one proton, one electron. H2 is a tiny molecule. "hydrogen embrittlement" is when it's small enough to diffuse into solid metal, because it's that much smaller than iron atoms. It's hard to work with because of this, and what's the point? For most uses, electricity supply is already everywhere.

Qwertious 8mo ago
>Hydrogen is the minimum viable atom: one proton, one electron. Wait until you hear about H+
- antonvs 8mo ago
  That’s a type of ion, or of course a proton. An ion with no electrons is not considered an atom normally. GP is correct. (Atoms must have electrons - the definition in physics and chemistry is a structural one.)
- SideburnsOfDoom 8mo ago
  Yes, hydrogen will ionise into loose protons. The basic point is that a material that is highly flammable, needs to be compressed to high pressure in order to be useful, but also will seep through and damage steel containers because of the fundamental fact that the atoms and charged ions are just too small, is never going to be easy to work with. Compared to electrical battery tech now being widely and cheaply rolled out. This goes some way to answering the "Why is it such a terrible idea?" question. Or at least it's an idea whose time has passed, due to the abovementioned battery tech maturing.

L-four 8mo ago

The cheapest way to make hydrogen is to use fossil fuels.

loeg 8mo ago

It's hell to store. The energy density is terrible and as a tiny molecule it escapes most seals. When it transitions from a liquid to a gas, it expands manyfold (i.e., explodes).

ssl-3 8mo ago

Ignoring some of the other issues: Imagine we have this electrolysis plant, splitting up water to produce the hydrogen we need for an area. That's fine. But it needs fed electricity to keep the process going. Lots of it. It needs more electrical power to split the water than combining it again produces. So it starts off being energy-negative, and it takes serious electricity to make it happen. Our grid isn't necessarily ready for that. And then we need to transport the hydrogen. Probably with things like trucks and trains at first (but maybe pipelines eventually). This makes it even more energy-negative, and adds having great volumes of this potentially-explosive gas in our immediate vicinity some of the time whether we're using it individually or not. Or: We can just plug in our battery-cars at home, and skip all that fuel transportation business altogether. It's still energy-negative, and the grid might not be ready for everyone to do that either. But at least we don't need to to implement an entirely new kind of scale for hydrogen production and distribution before it can be used. So that's kind of the way we've been going: We plug out cars into the existing grid and charge them using the same electricity that could instead have been used to produce hydrogen. (It'd be nice if battery recycling were more common, but it turns out that they have far longer useful lives than anyone reasonably anticipated and it just isn't a huge problem...yet. And that's not a huge concern, really: We already have a profitable and profoundly vast automotive recycling industry. We'll be sourcing lithium from automotive salvage yards as soon as it is profitable to do so.)

aunty_helen 8mo ago
It’s not even the grid, by the time you’ve done the electrolysis you’d be better off just charging a battery. Also, compressing and cooling a gas takes another huge hit at the efficiency. Electrolysis comes out at atmospheric pressures. Oh and the platinum electrodes you need… I’m also just now visualising a hydrogen pipeline fire… terrible terrible idea.
- ssl-3 8mo ago
  It's the everything, yeah. There's a lot working against using hydrogen as the local energy source for automotive propulsion in the world that we presently have. Some advantages are that a fuel cell that accepts hydrogen and air at one end and emits electricity and water at the other can be lighter-weight than a big battery, and it can [potentially] be refueled quickly for long trips. Some disadvantages: We need a compressed hydrogen tank -- which isn't as scary to me as it may be for some people, but that's still a new kind of risk we need to carry with us wherever we drive. And we still need a big(ish) battery and the controls for it in order for regen braking to do its thing (which hybrids have shown to be very useful). And, again, the grid: If it were cheaper/better/efficient to move energy from electrical generating stations to the point of use using buckets [or trucks or trains] of hydrogen, we'd already be doing that. But it isn't. So we just plug stuff in, instead, and use the grid we already have. A quick Google suggests that a regular 120v US outlet might charge EVs at a rate somewhere in the range of 3 to 5 miles per hour. So a dozen or so hours sitting, plugged in at home every day, is enough to cover most folks' every-day driving. There's far faster methods, but that's something that lots of regular people with a normal commute and normal working hours can already accomplish very easily if they have private parking with an outlet nearby. For most folks, with most driving, that's all they ever have to do. It shifts concerns about refueling speed from "Yeah, but hydrogen is fast! I waste hardly any time at all while it refills!" to "What refueling stops? I just unplug my car in the morning and go. I haven't needed to stop at gas station in years." The main advantages of hydrogen are real, but they just aren't very useful compared to other things that we also have.

nkoren 8mo ago

Zubrin's "Hydrogen Hoax" from 2007[1] is basically an ironclad critique. The physics are inescapably poor, and always will be. (Zubrin makes other points in that article which should probably be taken with more salt, but his critique of hydrogen stands). 1: https://www.thenewatlantis.com/publications/the-hydrogen-hoax https://www.thenewatlantis.com/publications/the-hydrogen-hoa...

fuzzfactor 8mo ago

>you've got a very high-density, lightweight fuel. Correction, a very low density, lightweight fuel. Burns clean though with no carbon in the exhaust. But the upstream carbon emissions have not come close to zero when you look at total hydrogen use in the real world so far.