6 ms·

I love the idea of hydrogen, batteries seem toxic to me, to be able to crack water and then burn it later (or use in a fuel cell) seems much more natural. One

by zz865 5y ago

I love the idea of hydrogen, batteries seem toxic to me, to be able to crack water and then burn it later (or use in a fuel cell) seems much more natural. One thing though if released Hydrogen will escape the earth's atmosphere right? Seems kinda risky to slowly lose all our water...

jvanderbot 5y ago
Escaped hydrogen will probably turn to water fairly rapidly. And by that I mean it will explode.
- fphhotchips 5y ago
  Depends on the environment that you're in. In an enclosed space: yeah. In open air, unlikely, because the density difference means it rises (and disperses) quickly.
  - pfdietz 5y ago
    In open air the halflife of hydrogen to oxidation is just a few years, which is much faster than the timescale for hydrogen to be convected up to the homopause.
fphhotchips 5y ago
Some quick research indicates that while we won't lose our water per se, there are potentially other issues along that line of thinking: https://www.caltech.edu/about/news/hydrogen-economy-might-impactearths-stratosphere-study-shows-722 https://www.caltech.edu/about/news/hydrogen-economy-might-im... (2003) Edit: you might be thinking of helium, which is inert, and so I believe does escape the atmosphere more easily.
- Ratalala 5y ago
  Hydrogen escapes the atmosphere because it is extremely light and the planet's gravity cannot hold on to it.
  - jhgb 5y ago
    That just means you've invented a new fancy way to combat rising oceans! (No, in reality, we have nowhere near the power to make appreciable amounts of hydrogen escape. Even if you electrolyzed water continuously with 2.5 TW of power, which is roughly global average electricity generation, you'd lose something like 4 cubic kilometers of water per year. The Earth meanwhile has over a billion cubic kilometers of water in its oceans, so you'd need over 250 million years to make them disappear.)
  - pfdietz 5y ago
    Only if the hydrogen is very high up. Hydrogen released at ground level will almost entirely be oxidized before it can get that high.
- zz865 5y ago
  Yes Helium is the other gas that does this too - but Hydrogen is lighter than Helium.
elihu 5y ago
Batteries vary a lot. Lithium iron phosphate seems pretty reasonable to me: they're made of lithium, iron, copper, aluminum, plastic, fertilizer, carbon, and probably a few more things I'm not aware of. Nothing particularly toxic or hard to recycle, and they tend to have very good longevity. https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery
simonh 5y ago
Hydrogen escape from our atmosphere is diffusion limited, so this isn't a concern. https://en.wikipedia.org/wiki/Diffusion-limited_escape https://en.wikipedia.org/wiki/Diffusion-limited_escape
- pfdietz 5y ago
  Hydrogen released into the atmosphere will mostly be turned to water by oxidation with OH radicals before it can escape. This is not entirely a good thing, as an OH radical consumed by reaction with hydrogen will not be available to react with methane -- and we want that methane scrubbed out of the atmosphere as quickly as possible.

by zz865 5y ago

jvanderbot 5y ago

Escaped hydrogen will probably turn to water fairly rapidly. And by that I mean it will explode.

fphhotchips 5y ago
Depends on the environment that you're in. In an enclosed space: yeah. In open air, unlikely, because the density difference means it rises (and disperses) quickly.
- pfdietz 5y ago
  In open air the halflife of hydrogen to oxidation is just a few years, which is much faster than the timescale for hydrogen to be convected up to the homopause.

fphhotchips 5y ago

Some quick research indicates that while we won't lose our water per se, there are potentially other issues along that line of thinking: https://www.caltech.edu/about/news/hydrogen-economy-might-impactearths-stratosphere-study-shows-722 https://www.caltech.edu/about/news/hydrogen-economy-might-im... (2003) Edit: you might be thinking of helium, which is inert, and so I believe does escape the atmosphere more easily.

Ratalala 5y ago
Hydrogen escapes the atmosphere because it is extremely light and the planet's gravity cannot hold on to it.
- jhgb 5y ago
  That just means you've invented a new fancy way to combat rising oceans! (No, in reality, we have nowhere near the power to make appreciable amounts of hydrogen escape. Even if you electrolyzed water continuously with 2.5 TW of power, which is roughly global average electricity generation, you'd lose something like 4 cubic kilometers of water per year. The Earth meanwhile has over a billion cubic kilometers of water in its oceans, so you'd need over 250 million years to make them disappear.)
- pfdietz 5y ago
  Only if the hydrogen is very high up. Hydrogen released at ground level will almost entirely be oxidized before it can get that high.
zz865 5y ago
Yes Helium is the other gas that does this too - but Hydrogen is lighter than Helium.

elihu 5y ago

Batteries vary a lot. Lithium iron phosphate seems pretty reasonable to me: they're made of lithium, iron, copper, aluminum, plastic, fertilizer, carbon, and probably a few more things I'm not aware of. Nothing particularly toxic or hard to recycle, and they tend to have very good longevity. https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery

simonh 5y ago

Hydrogen escape from our atmosphere is diffusion limited, so this isn't a concern. https://en.wikipedia.org/wiki/Diffusion-limited_escape https://en.wikipedia.org/wiki/Diffusion-limited_escape

pfdietz 5y ago
Hydrogen released into the atmosphere will mostly be turned to water by oxidation with OH radicals before it can escape. This is not entirely a good thing, as an OH radical consumed by reaction with hydrogen will not be available to react with methane -- and we want that methane scrubbed out of the atmosphere as quickly as possible.