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This could be a boon for aquatic dead zones that suffer from hypoxia (low dissolved oxygen). The oxygen released during electrolysis could be reintroduced into

This could be a boon for aquatic dead zones that suffer from hypoxia (low dissolved oxygen). The oxygen released during electrolysis could be reintroduced into the water to bring it back up to safe levels. Obviously some efforts need to be made to make sure that the salt and oxygen levels don't get too high.

moloch-hai 4y ago
It would suffice to dissolve oxygen in river water on its way out. All the dead zones are at river outlets. The hydrogen freed would need to be sequestered to burn later, because hydrogen is insoluble in water, and is a 200x greenhouse gas (when counting secondary effects). There will be a hell of a lot of spare oxygen available to dissolve in water and flush to rivers, after we start producing green hydrogen. But just bubbling regular air through should suffice to saturate it, no electrolysis needed. A big perforated plate, with water running over it and air pushed under, does the job without fuss.
- seunosewa 4y ago
  > a 200x greenhouse gas I had no idea. So much for the hydrogen economy.
  - AnimalMuppet 4y ago
    Just don't leak. Burning it produces water vapor, which is pretty generally available in the atmosphere. [Edit: Yes, I know "just don't leak" is the goal, and is never 100% achieved.]
    - seunosewa 4y ago
      Preventing leaks is especially hard with hydrogen because its molecules are very tiny.
    - moloch-hai 4y ago
      Hydrogen is produced and used in the hundreds of millions of tons, today. People say it is mostly produced on demand at the site of use because of the difficulty of storing and transporting it. If it becomes an important part of the energy economy, it will need great care in preventing unavoidable leaks from escaping into the atmosphere. Of course for most uses, hydrogen will continue to be produced on the spot, by electrolysis instead of from natural gas as today. In places where it is not used immediately (e.g. to synthesize ammonia for transport), it will often be stored deep underground where leakage is less a worry. As aviation transitions to liquid hydrogen fuel, probably after 2040, hydrogen produced at major airports may be stored liquified in underground tanks, at a pressure close to ambient. Hydrogen leakage is minimal at low pressure. In general, for safety, installations that handle much hydrogen must continually flush air through indoor places with hydrogen plumbing, to prevent buildup of what would be an exceedingly dangerous mixture of hydrogen and air in confined spaces. It might be that sites handling much hydrogen will need to feed such air into an incinerator. A way to recognize significant hydrogen leaks, as we have for methane, probably will be needed.

moloch-hai 4y ago

It would suffice to dissolve oxygen in river water on its way out. All the dead zones are at river outlets. The hydrogen freed would need to be sequestered to burn later, because hydrogen is insoluble in water, and is a 200x greenhouse gas (when counting secondary effects). There will be a hell of a lot of spare oxygen available to dissolve in water and flush to rivers, after we start producing green hydrogen. But just bubbling regular air through should suffice to saturate it, no electrolysis needed. A big perforated plate, with water running over it and air pushed under, does the job without fuss.

seunosewa 4y ago
> a 200x greenhouse gas I had no idea. So much for the hydrogen economy.
- AnimalMuppet 4y ago
  Just don't leak. Burning it produces water vapor, which is pretty generally available in the atmosphere. [Edit: Yes, I know "just don't leak" is the goal, and is never 100% achieved.]
  - seunosewa 4y ago
    Preventing leaks is especially hard with hydrogen because its molecules are very tiny.
  - moloch-hai 4y ago
    Hydrogen is produced and used in the hundreds of millions of tons, today. People say it is mostly produced on demand at the site of use because of the difficulty of storing and transporting it. If it becomes an important part of the energy economy, it will need great care in preventing unavoidable leaks from escaping into the atmosphere. Of course for most uses, hydrogen will continue to be produced on the spot, by electrolysis instead of from natural gas as today. In places where it is not used immediately (e.g. to synthesize ammonia for transport), it will often be stored deep underground where leakage is less a worry. As aviation transitions to liquid hydrogen fuel, probably after 2040, hydrogen produced at major airports may be stored liquified in underground tanks, at a pressure close to ambient. Hydrogen leakage is minimal at low pressure. In general, for safety, installations that handle much hydrogen must continually flush air through indoor places with hydrogen plumbing, to prevent buildup of what would be an exceedingly dangerous mixture of hydrogen and air in confined spaces. It might be that sites handling much hydrogen will need to feed such air into an incinerator. A way to recognize significant hydrogen leaks, as we have for methane, probably will be needed.