4 ms·

Well, I don't think hydrogen is the answer for all these reasons. It seems, that sodium (Na) can under certain conditions (very thin film, e.g. when applied to

Well, I don't think hydrogen is the answer for all these reasons. It seems, that sodium (Na) can under certain conditions (very thin film, e.g. when applied to a surface with great speed of 10s of m/s) react directly with water and produce stable electric current. That is not so hard to do, e.g. hard disks, regular turbines etc. pretty much would provide such conditions :-) The patents for such use in Lockheed-Martin rockets expired long ago but it seems based on the details, that it worked reasonably well. Sodium is very easy to handle. There is no need for large pressure or any bonding elements. The hydroxide can be turned into sodium again by well known processes that were used on industrial scale more than 100 years ago already. This process and the "burn" of sodium with water both release hydrogen as a by-product. This could solve the winter energy storage issue. Also you could quite likely safely transport sodium in former oil tankers or by pipe if heated to a bit more than 100 °C/ or in the form of concentrated hydroxide (the "waste")... so the infrastructure is mostly there. As you all well know, original sodium can be extracted from regular NaCl salt that we have plenty of in sea water and salt mines. Best of all, sodium reacts so rapidly, it could under minor adjustments replace diesel in +- regular engines too. (That is also the contents of one of the patents.) That is of course not so efficient, but there is a large installed base.

petre 6y ago
> Sodium is very easy to handle. It only blows up when it touches water.
- eru 6y ago
  From an engineering point of view, that might still count as easy. Especially compared to hydrogen.
  - Brian_K_White 6y ago
    You can carry gasoline in an open pail, spill it all over yourself, and even throw a lit cigarette right in the pail, all without harm, all while having very high energy density. Sodium is not remotely in that class.
s0rce 6y ago
Doesn't most of what you said also apply to magnesium? Seems like we'll never run out (2.5% of earth's crust), there are well established methods to refine it and you just react the hydride with water to generate hydrogen.
- alexchamberlain 6y ago
  Hehe never run out. Like we never ran out of IPv4 addresses or crude oil... I think any solution needs to be cyclic.
  - s0rce 6y ago
    Looks like there is ~10^−8 earth masses of oil and coal [1]. I can't seem to find the mass of magneisum on earth but its 2.5% of the earth's crust, which is apparently <1% of the earth's volume, lets estimate 0.1% of the total mass to be conservative, not sure how reasonable this is but seems ok for this back of the envelope calculation [2]. This gives about ~10^-5 earth masses of magnesium, still orders of magnitude more than the oil and coal and this process won't consume it, its just for hydrogen storage/transport. More numbers on the mass of the crust in [3]. [1] https://osf.io/dkmwy/download https://osf.io/dkmwy/download [2] https://en.wikipedia.org/wiki/Earth%27s_crust https://en.wikipedia.org/wiki/Earth%27s_crust [3] ttps://ui.adsabs.harvard.edu/abs/2007AGUFM.V33A1161P/abstract
DennisP 6y ago
If we were to use sodium on such massive scale, I'm wondering what we would do with all the chlorine.

petre 6y ago

> Sodium is very easy to handle. It only blows up when it touches water.

eru 6y ago
From an engineering point of view, that might still count as easy. Especially compared to hydrogen.
- Brian_K_White 6y ago
  You can carry gasoline in an open pail, spill it all over yourself, and even throw a lit cigarette right in the pail, all without harm, all while having very high energy density. Sodium is not remotely in that class.

s0rce 6y ago

Doesn't most of what you said also apply to magnesium? Seems like we'll never run out (2.5% of earth's crust), there are well established methods to refine it and you just react the hydride with water to generate hydrogen.

alexchamberlain 6y ago
Hehe never run out. Like we never ran out of IPv4 addresses or crude oil... I think any solution needs to be cyclic.
- s0rce 6y ago
  Looks like there is ~10^−8 earth masses of oil and coal [1]. I can't seem to find the mass of magneisum on earth but its 2.5% of the earth's crust, which is apparently <1% of the earth's volume, lets estimate 0.1% of the total mass to be conservative, not sure how reasonable this is but seems ok for this back of the envelope calculation [2]. This gives about ~10^-5 earth masses of magnesium, still orders of magnitude more than the oil and coal and this process won't consume it, its just for hydrogen storage/transport. More numbers on the mass of the crust in [3]. [1] https://osf.io/dkmwy/download https://osf.io/dkmwy/download [2] https://en.wikipedia.org/wiki/Earth%27s_crust https://en.wikipedia.org/wiki/Earth%27s_crust [3] ttps://ui.adsabs.harvard.edu/abs/2007AGUFM.V33A1161P/abstract

DennisP 6y ago

If we were to use sodium on such massive scale, I'm wondering what we would do with all the chlorine.