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There's a real prospect of a worse is better outcome. Hydrogen is way more energy dense than oil-based fuel, never mind battery tech, and can be refilled just a

There's a real prospect of a worse is better outcome. Hydrogen is way more energy dense than oil-based fuel, never mind battery tech, and can be refilled just as fast. But it's a bigger technical leap, and people won't be able to refuel at home. If most vehicles are used for commutes, I can see battery tech winning the war, except perhaps for trucks, which today may take LPG and can more easily live with bigger distances between refuels. Hydrogen fuel cells may be the solution to aviation though.

ISL 7y ago
Water and electricity flow to many homes. It isn't certain that people can't refuel at home.
darksaints 7y ago
Hydrogen can be refueled at home. Electrolysis is pretty damn easy.
- masklinn 7y ago
  Currently the best electrolysis can do is 50kWh/kg of hydrogen, which is about equivalent to a gallon of gas. That's 7c/kWh to match a $3.6 gallon (as found in CA or HI). And that's before the storage issue is even considered.
  - darksaints 7y ago
    That's the best that PEM electrolysis can do. Solid oxide cells have been >93% efficient for over a decade now, and some research cells are 99% efficient. If you are willing to supply heat to run in endothermic mode, they are >100% efficient on an electricity basis (meaning they take less than 39kwh of electricity to make a kg of hydrogen, with the rest made up via heat). I personally have made hydrogen with SOECs for $2.72/kg using industrial rates for electricity. After a 60% efficient conversion back to electricity, that comes out to $0.116/kWh, which is better than the residential rates for nearly any state.
- wcoenen 7y ago
  Electrolysis may be easy, but pressurizing the hydrogen to 700 bar is not. That would probably require a relatively bulky and noisy multistage compressor system.
  - darksaints 7y ago
    https://en.m.wikipedia.org/wiki/Electrochemical_hydrogen_compressor https://en.m.wikipedia.org/wiki/Electrochemical_hydrogen_com... They're pretty efficient, compact, and also no moving parts and no noise.
unchocked 7y ago
Depends on how you view density. Energy per unit mass - better than hydrocarbons. Energy per unit volume - worse.
- masklinn 7y ago
  They're technically wrong as energy density is per volume, "specific energy" or "massic energy" is per mass. Also while the specific energy of hydrogen is good, you have to account for the weight of the container. You can store fuel in a bucket, not so hydrogen.
  - darksaints 7y ago
    Compressed hydrogen containers are pretty heavy and that's a bummer, but they're still better than lithium ion by an order of magnitude.
- darksaints 7y ago
  Compressed hydrogen at 700 bar is 2x better volumetric energy density than the best lithium ion batteries on the market today. It's a 4-5x worse than hydrocarbons, but still workable.
  - nimish 7y ago
    2x better than a technology that benefits from the enormous, monstrous economies of scale that lithium ion batteries do is a folly. Every portable electronic device benefits from lithium ion improvements. That's how Tesla was able to launch: use the commodity 18650s from laptops as a relatively low cost cell. There's a fundamentally better argument to shifting everyone to hybrids (extreme bang for buck for CO2 emission reduction) than FCEVs.
    - darksaints 7y ago
      I think for most electric vehicles, batteries are good enough, and probably the better choice. But if you're going hybrid for the extra range, fuel cell technology is basically already there and makes a great range extender.
matthewdgreen 7y ago
Battery tech has already won for general automotive applications, even though the number of cars sold is still small. The problem is that while Toyota is a big company, they’re not big enough to deploy the massive hydrogen distribution and fueling infrastructure that would be required in order to make their cars commercially viable around the world. To make this work, they’d need basically every other major auto manufacturer to commit to hydrogen fuel cells as their future non-ICE alternative. Unfortunately for Toyota, virtually every other auto manufacture has already bet heavily on BEV, and against hydrogen. Even if the bet ultimately proves to be a bad one on technical grounds (and I don’t think it is), it seems very unlikely that any set of circumstances can undo it at this point.
- deleted 7y ago
  [deleted]
ncmncm 7y ago
Aviation, yes. Aviation is particularly sensitive to mass density, not so much to volume, and the number of joules available per kilogram of hydrogen is nothing short of spectacular. Unfortunately, while storing hydrogen in a much bigger tank makes economic sense, the lead time on designing, approving, and deploying new lifting-body airframes is too long to help much with the current crisis. Boeing is not about to start studying lifting-body designs when they are unsure they can survive at all. Airbus, meanwhile, has reason to be complacent now, same reason. Starting a new airliner company is extremely risky. A hydrogen bizjet would be safer, but wouldn't generate the investment to get hydrogen refueling infrastructure in enough places. It's too bad, because the room for innovation in a hydrogen-powered air transport is inspiring. Imagine electric-only launch, and a jet engine that only needs to operate above 300 knots. Electric motor propellers mounted anywhere convenient, because of small size and disinclination to explode. Lifting-body designs with enormously more cargo space.

ISL 7y ago

Water and electricity flow to many homes. It isn't certain that people can't refuel at home.

darksaints 7y ago

Hydrogen can be refueled at home. Electrolysis is pretty damn easy.

masklinn 7y ago
Currently the best electrolysis can do is 50kWh/kg of hydrogen, which is about equivalent to a gallon of gas. That's 7c/kWh to match a $3.6 gallon (as found in CA or HI). And that's before the storage issue is even considered.
- darksaints 7y ago
  That's the best that PEM electrolysis can do. Solid oxide cells have been >93% efficient for over a decade now, and some research cells are 99% efficient. If you are willing to supply heat to run in endothermic mode, they are >100% efficient on an electricity basis (meaning they take less than 39kwh of electricity to make a kg of hydrogen, with the rest made up via heat). I personally have made hydrogen with SOECs for $2.72/kg using industrial rates for electricity. After a 60% efficient conversion back to electricity, that comes out to $0.116/kWh, which is better than the residential rates for nearly any state.
wcoenen 7y ago
Electrolysis may be easy, but pressurizing the hydrogen to 700 bar is not. That would probably require a relatively bulky and noisy multistage compressor system.
- darksaints 7y ago
  https://en.m.wikipedia.org/wiki/Electrochemical_hydrogen_compressor https://en.m.wikipedia.org/wiki/Electrochemical_hydrogen_com... They're pretty efficient, compact, and also no moving parts and no noise.

unchocked 7y ago

Depends on how you view density. Energy per unit mass - better than hydrocarbons. Energy per unit volume - worse.

masklinn 7y ago
They're technically wrong as energy density is per volume, "specific energy" or "massic energy" is per mass. Also while the specific energy of hydrogen is good, you have to account for the weight of the container. You can store fuel in a bucket, not so hydrogen.
- darksaints 7y ago
  Compressed hydrogen containers are pretty heavy and that's a bummer, but they're still better than lithium ion by an order of magnitude.
darksaints 7y ago
Compressed hydrogen at 700 bar is 2x better volumetric energy density than the best lithium ion batteries on the market today. It's a 4-5x worse than hydrocarbons, but still workable.
- nimish 7y ago
  2x better than a technology that benefits from the enormous, monstrous economies of scale that lithium ion batteries do is a folly. Every portable electronic device benefits from lithium ion improvements. That's how Tesla was able to launch: use the commodity 18650s from laptops as a relatively low cost cell. There's a fundamentally better argument to shifting everyone to hybrids (extreme bang for buck for CO2 emission reduction) than FCEVs.
  - darksaints 7y ago
    I think for most electric vehicles, batteries are good enough, and probably the better choice. But if you're going hybrid for the extra range, fuel cell technology is basically already there and makes a great range extender.

matthewdgreen 7y ago

Battery tech has already won for general automotive applications, even though the number of cars sold is still small. The problem is that while Toyota is a big company, they’re not big enough to deploy the massive hydrogen distribution and fueling infrastructure that would be required in order to make their cars commercially viable around the world. To make this work, they’d need basically every other major auto manufacturer to commit to hydrogen fuel cells as their future non-ICE alternative. Unfortunately for Toyota, virtually every other auto manufacture has already bet heavily on BEV, and against hydrogen. Even if the bet ultimately proves to be a bad one on technical grounds (and I don’t think it is), it seems very unlikely that any set of circumstances can undo it at this point.

deleted 7y ago
[deleted]

ncmncm 7y ago

Aviation, yes. Aviation is particularly sensitive to mass density, not so much to volume, and the number of joules available per kilogram of hydrogen is nothing short of spectacular. Unfortunately, while storing hydrogen in a much bigger tank makes economic sense, the lead time on designing, approving, and deploying new lifting-body airframes is too long to help much with the current crisis. Boeing is not about to start studying lifting-body designs when they are unsure they can survive at all. Airbus, meanwhile, has reason to be complacent now, same reason. Starting a new airliner company is extremely risky. A hydrogen bizjet would be safer, but wouldn't generate the investment to get hydrogen refueling infrastructure in enough places. It's too bad, because the room for innovation in a hydrogen-powered air transport is inspiring. Imagine electric-only launch, and a jet engine that only needs to operate above 300 knots. Electric motor propellers mounted anywhere convenient, because of small size and disinclination to explode. Lifting-body designs with enormously more cargo space.