This could be an excellent way to use up excess solar power for completely off grid panels. Efficiency matters a lot less when the incremental cost of energy is almost zero.
This is a really interesting idea and the unit economics are great. However when I researched this (or rather Gemini 2.5 Pro researched this) the problem appears that Haber-Bosch produces ammonia, whereas Birkeland-Eyde produces nitrate, which then needs to be converted in nitric acid. Getting from nitric acid to ammonium nitrate (which dominates the fertiliser market) needs ammonia from somewhere, which destroys the economics.
However calcium nitrate, potassium nitrate production via B-E looks really interesting.
"Due to the emergence of low cost renewable electricity from solar and wind, there is renewed interest in decentralized opportunities for electricity-driven nitrogen fixation."
"This analysis shows that the energy consumption for NOX synthesis with plasma technology is almost competitive with the commercial process with its current best value of 2.4 MJ mol N−1, which is required to decrease further to about 0.7 MJ mol N−1 in order to become fully competitive"
Note that this measure of competitivity is based on energy, not cost. So the (intermittently) ultra-low cost of electrical energy generated by modern PV installations (where substantial overprovisioning is becoming normal) has not been taken into account.
An Agri-PV installation that produces all the fertilizer it needs from its own surplus electricity would be cool indeed.
Plants are happy with nitrate as the only nitrogen source.
Ammonium nitrate is preferred because it provides more nitrogen per weight, i.e. at similar transportation costs with the alternatives, and also because introducing a too great amount of metal cations together with the nitrate, e.g. potassium or calcium, can be detrimental for the soil and can make it too alkaline after the nitrate is consumed.
it's "less efficient" only because there is currently no meaningful externality priced into the natural gas supply chain. This might change in the future ;)
Where does the nitrogen go in a closed system? I'm not aware of a natural process that converts fixed nitrogen back to N2. Doesn't mean a process doesn't exist, I just don't know about it.
Andreas the Alchemist on Youtube has a scaled up machine that supposed can do about a gallon of nitric acid every 24 hours, somewhere near the fuming nitric concentration (at the cost of something insane like 5kW power consumption).
I wish he would publish plans for his machine, or someone would offer to build them. Wouldn't matter if it cost five times as much as retail, to be able to make fertilizer and prague salt with nothing but air and self-sufficient power would be a god-send.
Though, I gotta say that his fucking power supply gives me the heebie-jeebies just watching on Youtube. Electrical is one thing, but I know better than to look at high-voltage cross-eyed...
Probably not a great idea to release a step by step for this on YouTube? Isn't nitric acid a direct precursor to... some very heavily regulated and dangerous things?
I'm sure lots of off grid solar powered independent farmers need a way to nitrogen fix their soil other than just buying fertilizer or growing beans or whatever.
Wonder if Azolla is economical. Its a floating plant, uses its nitrogen fixing bacteria, doubles in mass every few days and is top vegetable source by essential amino acids.
This could be an excellent way to use up excess solar power for completely off grid panels. Efficiency matters a lot less when the incremental cost of energy is almost zero.
This is a really interesting idea and the unit economics are great. However when I researched this (or rather Gemini 2.5 Pro researched this) the problem appears that Haber-Bosch produces ammonia, whereas Birkeland-Eyde produces nitrate, which then needs to be converted in nitric acid. Getting from nitric acid to ammonium nitrate (which dominates the fertiliser market) needs ammonia from somewhere, which destroys the economics.
However calcium nitrate, potassium nitrate production via B-E looks really interesting.
This paper provides an in-depth analysis of the feasabilty of this idea: https://pubs.rsc.org/en/content/articlelanding/2021/ee/d0ee0...
"Due to the emergence of low cost renewable electricity from solar and wind, there is renewed interest in decentralized opportunities for electricity-driven nitrogen fixation."
"This analysis shows that the energy consumption for NOX synthesis with plasma technology is almost competitive with the commercial process with its current best value of 2.4 MJ mol N−1, which is required to decrease further to about 0.7 MJ mol N−1 in order to become fully competitive"
Note that this measure of competitivity is based on energy, not cost. So the (intermittently) ultra-low cost of electrical energy generated by modern PV installations (where substantial overprovisioning is becoming normal) has not been taken into account.
An Agri-PV installation that produces all the fertilizer it needs from its own surplus electricity would be cool indeed.
Plants are happy with nitrate as the only nitrogen source.
Ammonium nitrate is preferred because it provides more nitrogen per weight, i.e. at similar transportation costs with the alternatives, and also because introducing a too great amount of metal cations together with the nitrate, e.g. potassium or calcium, can be detrimental for the soil and can make it too alkaline after the nitrate is consumed.
> needs ammonia from somewhere, which destroys the economics.
Urine collection.
Very impressive, it could allow for closed-cycle systems to replenish the soil that normally requires https://en.wikipedia.org/wiki/Nitrogen_fixation
Since it's less efficient than modern processes I don't think it had any application besides the fun of a DIY project.
Though I guess it's an interesting way to obtain nitric acid for individuals, since access to it is quite restricted otherwise.
it's "less efficient" only because there is currently no meaningful externality priced into the natural gas supply chain. This might change in the future ;)
Is it? I can buy a pallet of 500ml bottles from a science supplier. Hell, I can buy a bottle from Amazon for $30.
Who in their right mind would deliver that?
Feel free to try that and report back lol
>since access to it is quite restricted otherwise.
There's a reason for that, of course.
That's what fertilizers are for. And the production of fertilizer was the point of Birkeland–Eyde process.
Where does the nitrogen go in a closed system? I'm not aware of a natural process that converts fixed nitrogen back to N2. Doesn't mean a process doesn't exist, I just don't know about it.
Andreas the Alchemist on Youtube has a scaled up machine that supposed can do about a gallon of nitric acid every 24 hours, somewhere near the fuming nitric concentration (at the cost of something insane like 5kW power consumption).
120 kwh * $0.13/kwh = $15.60/gallon near where I live. That's not too bad in and of itself.
I wish he would publish plans for his machine, or someone would offer to build them. Wouldn't matter if it cost five times as much as retail, to be able to make fertilizer and prague salt with nothing but air and self-sufficient power would be a god-send.
Though, I gotta say that his fucking power supply gives me the heebie-jeebies just watching on Youtube. Electrical is one thing, but I know better than to look at high-voltage cross-eyed...
Does it really need those long arcs? Why not make a fractal surface, that arcs and isolates?
Probably not a great idea to release a step by step for this on YouTube? Isn't nitric acid a direct precursor to... some very heavily regulated and dangerous things?
I'm sure lots of off grid solar powered independent farmers need a way to nitrogen fix their soil other than just buying fertilizer or growing beans or whatever.
Wonder if Azolla is economical. Its a floating plant, uses its nitrogen fixing bacteria, doubles in mass every few days and is top vegetable source by essential amino acids.
https://theazollafoundation.org/azollas-uses/for-food/
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