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Do hydrides have any advantages at all over synthetic hydrocarbons or biofuels? It seems like an effort to shoehorn hydrogen in there somewhere instead of just

Do hydrides have any advantages at all over synthetic hydrocarbons or biofuels? It seems like an effort to shoehorn hydrogen in there somewhere instead of just admitting that it has literally no place at all in the energy economy

kortex 7y ago
Carbon-free. Synthetic hydrocarbons and biofuels still give off carbon dioxide. Hydrides are just a vector for hydrogen. The advantage of hydrides over hydrogen is you don't release all the flammable gas at once, improving safety.
- extropy 7y ago
  Giving off carbon dioxide might be fine if it's collected back from atmosphere in the manufacturing process.
- dTal 7y ago
  Is that a problem, though? CO2 emissions aren't locally toxic. The main issue with it today is the fact that the carbon comes from the ground and doesn't get put back. Water vapor is a greenhouse gas too!
  - petra 7y ago
    Water vapor is a greenhouse gas, but it is always kept in balance and the air cannot hold more than it is. All that will happen is that it rains. And no amount of water vapor from hydrogen cars compares to what all the oceans contribute to the water vapor. It will basically have no effect. Source:https://www.reddit.com/r/explainlikeimfive/comments/3qhj31/eli5wont_hydrogen_cars_produce_a_lot_of_water/ https://www.reddit.com/r/explainlikeimfive/comments/3qhj31/e...
    - dTal 7y ago
      Right, I wasn't actually suggesting that water vapor emissions from hydrogen vehicles would be a climate issue - on the contrary, I was drawing the comparison to illustrate that greenhouse gas emissions aren't necessarily a problem, if part of a closed loop (or other stabilizing influences like you point out).
  - kortex 7y ago
    Entropy. It's easier to just not involve carbon at all via some hydrogen cycle than to burn it and have to capture it, or extract it from the air/water. As I mention elsewhere in this thread, hydrocarbons will dominate the air travel industry long after most others have converted. The less carbon in flux, the better.
    - dTal 7y ago
      Is it easier, though? Both hydrogen and carbon cycles react atmospheric oxygen with some other element, creating a low-energy molecule that is released into the environment. To be sustainable, the feedstock atom must be segregated from that same waste low-energy molecule, an inherently energy-intensive procedure. This energy must be sustainably sourced by either nuclear or energy ultimately from the sun. Separating hydrogen from water requires electricity, a very low-entropy form of energy. Creating combustible carbon from atmospheric CO2 is as simple as planting something that grows fast - it will use sunlight directly. And that's not even getting in to how much more tractable carbon is to work with than hydrogen. Really, it doesn't matter whether we burn hydrogen or carbon. How much carbon is in flux is irrelevant. The main thing - the only thing - is to stop digging it up. The cycle must be closed. After that, it's safe to let the market decide the most efficient energy cycles.
CamperBob2 7y ago
The problem we face isn't fuel storage and delivery, it's waste disposal. "Hydrogen economy" advocates miss that point entirely. Moving and transporting hydrogen gas is a total dead end, and I can't believe that hydrides would be much better. I've always thought that the best approach would be to find a way to take advantage of the hydrogen delivery infrastructure that already exists in the form of gas stations on every other corner. If we could just come up with a scalable way to split hydrocarbon molecules without actually burning them, we'd be able to turn most CO2 emission sources into harmless water sources. Might as well wish for flying cars and unlimited fusion power while I'm at it, I guess...
- Nasrudith 7y ago
  Reminds me of the theoretical concept of a "digester" of hydrocarbons which kept the carbon and other toxic wastes like say heavy metals bound into a "slag" instead of releasing it atmospherically. Granted by the time we could manage something like that there would be far better options out there including using excess power generation to synthesize fuel from the air and water - let alone batteries which may use the energy more efficiently.

kortex 7y ago

Carbon-free. Synthetic hydrocarbons and biofuels still give off carbon dioxide. Hydrides are just a vector for hydrogen. The advantage of hydrides over hydrogen is you don't release all the flammable gas at once, improving safety.

extropy 7y ago
Giving off carbon dioxide might be fine if it's collected back from atmosphere in the manufacturing process.
dTal 7y ago
Is that a problem, though? CO2 emissions aren't locally toxic. The main issue with it today is the fact that the carbon comes from the ground and doesn't get put back. Water vapor is a greenhouse gas too!
- petra 7y ago
  Water vapor is a greenhouse gas, but it is always kept in balance and the air cannot hold more than it is. All that will happen is that it rains. And no amount of water vapor from hydrogen cars compares to what all the oceans contribute to the water vapor. It will basically have no effect. Source:https://www.reddit.com/r/explainlikeimfive/comments/3qhj31/eli5wont_hydrogen_cars_produce_a_lot_of_water/ https://www.reddit.com/r/explainlikeimfive/comments/3qhj31/e...
  - dTal 7y ago
    Right, I wasn't actually suggesting that water vapor emissions from hydrogen vehicles would be a climate issue - on the contrary, I was drawing the comparison to illustrate that greenhouse gas emissions aren't necessarily a problem, if part of a closed loop (or other stabilizing influences like you point out).
- kortex 7y ago
  Entropy. It's easier to just not involve carbon at all via some hydrogen cycle than to burn it and have to capture it, or extract it from the air/water. As I mention elsewhere in this thread, hydrocarbons will dominate the air travel industry long after most others have converted. The less carbon in flux, the better.
  - dTal 7y ago
    Is it easier, though? Both hydrogen and carbon cycles react atmospheric oxygen with some other element, creating a low-energy molecule that is released into the environment. To be sustainable, the feedstock atom must be segregated from that same waste low-energy molecule, an inherently energy-intensive procedure. This energy must be sustainably sourced by either nuclear or energy ultimately from the sun. Separating hydrogen from water requires electricity, a very low-entropy form of energy. Creating combustible carbon from atmospheric CO2 is as simple as planting something that grows fast - it will use sunlight directly. And that's not even getting in to how much more tractable carbon is to work with than hydrogen. Really, it doesn't matter whether we burn hydrogen or carbon. How much carbon is in flux is irrelevant. The main thing - the only thing - is to stop digging it up. The cycle must be closed. After that, it's safe to let the market decide the most efficient energy cycles.

CamperBob2 7y ago

The problem we face isn't fuel storage and delivery, it's waste disposal. "Hydrogen economy" advocates miss that point entirely. Moving and transporting hydrogen gas is a total dead end, and I can't believe that hydrides would be much better. I've always thought that the best approach would be to find a way to take advantage of the hydrogen delivery infrastructure that already exists in the form of gas stations on every other corner. If we could just come up with a scalable way to split hydrocarbon molecules without actually burning them, we'd be able to turn most CO2 emission sources into harmless water sources. Might as well wish for flying cars and unlimited fusion power while I'm at it, I guess...

Nasrudith 7y ago
Reminds me of the theoretical concept of a "digester" of hydrocarbons which kept the carbon and other toxic wastes like say heavy metals bound into a "slag" instead of releasing it atmospherically. Granted by the time we could manage something like that there would be far better options out there including using excess power generation to synthesize fuel from the air and water - let alone batteries which may use the energy more efficiently.