[plaidfuji]

Right. It also makes it sound like they’re not using the Haber Bosch process… but then:

> Electrolyzers are located on-site. They use wind energy to split water into hydrogen and oxygen gas.

> Additionally, nitrogen gas is directly harnessed from the atmosphere using an air-separation unit.

> Hydrogen and nitrogen are combined under pressure, resulting in carbon-free ammonia fertilizer.

That sounds a lot like the Haber Bosch process to me. So they’re just saying, rather than divert excess generation to a battery, you could instead build a micro H-B plant on site to produce ammonia.

I doubt this makes any sense in the grand scheme of things as you achieve major efficiencies at scale for chemical plants. Makes more sense to just electrify existing ammonia plants and ensure they use renewable electricity sources.

The green chemistry industry is full of penny-wise pound-foolish concepts like this and it drives me absolutely nuts.

[tonyarkles]

From doing a bit of digging into this myself after hearing it being promoted on the radio, I both agree and disagree. Working through the $/acre for on-site produced ammonia using locally-generated electricity (I forget if I was looking at PV or Wind, doesn’t matter) the payback period was surprisingly quick, like 2 or 3 years. One of the big reasons is that you don’t actually need a very big system; you only need on-farm ammonia a few days a year but you have all year long to harvest and store enough for those few days.

[everforward]

Then you have 1,000 separate ammonia generation systems that need upkeep, repairs, etc. It is doing chemical reactions under pressure to produce presumably ammonium nitrate which is explosive. The engineers you would need probably aren’t cheap, and storing large quantities of ammonium nitrate all year is sort of sketchy. Timothy McVeigh took out an entire federal building with about 4800 pounds of the stuff mixed with car fuel.

It’s usually a lot cheaper and safer to condense all that demand into a purpose-built facility where they can hire an engineer to look after all the generation, have centralized container storage, backup parts, etc.

None of that prevents putting the panels or windmills on farmer land, though. You could imagine some sort of “get a discount on ammonia if we can put a solar panel in your field” scheme. Or, even more simply, put up your own panels, sell the power back to the grid, use that money to buy fertilizer from the factory buying your power off the grid.

[tonyarkles]

I don’t know the exact process but I don’t think ammonium nitrate actually gets involved. The system I was looking at (Green Lightning) actually doesn’t make ammonia but rather liquid nitrogen fertilizer

Plasma to take N2 + O2 -> NO2 and NO gas

The NO and NO2 are dissolved in water to become HNO2 and HNO3, which then become NO2- and NO3- ions in the water.

It’s a low pH solution which stabilizes it and then you dilute right before application so that you don’t burn the crops.

[Lichtso]

I am curious what kind of plasma is used, as there are many ways to create plasma under various conditions, with very different efficiencies, selectivity, yield, etc.

Among the worst is the Birkeland-Eyde process, hot plasma by electric arcing, like it happens naturally during a thunderstorm. Even microwaving the air is more energy efficient. And amongst the most promising are transient non-equilibirum / cold plasma approaches using ns pulse generators.

Edit: So according to this video "Green Lightning" is indeed using the Birkeland-Eyde process. In other words, there is no way they even come close to their energy efficiency and yield claims. https://youtu.be/8TOnyAwJyvg?si=D9hat_XAfvuAAmpB&t=165

[LM358]

That is the Birkeland-Eyde process, which was superceded by the Haber-Bosch process because it is much more energy effective.

As far as I understand, the reasons for using methane as the hydrogen source in industrial processes is because of costs and the difficulty in scaling electrolysis industrially.

[tonyarkles]

Right, makes perfect sense.

So this is pretty far outside of my area of expertise, but https://pmc.ncbi.nlm.nih.gov/articles/PMC8133363/ suggests that there may be an evolution of Birkeland-Eyde that isn’t nearly as bad as the original process was. I haven’t gone through this in detail and even if I had I probably don’t have the background to do it justice.

[inigyou]

That sounds like the Birkland-Eyde process. It's cool because it uses only electricity and air and seems to produce something from nothing, but it's not as efficient as Haber-Bosch.

[scythe]

>That sounds a lot like the Haber Bosch process to me.

Well, kinda. But Haber-Bosch uses an iron catalyst. This is cheap, but it requires very high temperatures and pressures. There has been some recent work on ruthenium catalysts (particularly a Japanese company Tsubame BHB) which are more expensive, but allow the reaction to proceed under milder conditions. A particular goal is to have smaller facilities which can then be colocated with power generation. So you are exchanging a higher fixed cost for hopefully lower variable costs. I don't know if that's actually what they're doing here, though.

[inigyou]

One presumes the temperature and pressure can also be created renewably.

[llm_nerd]

It is literally the Haber-Bosch process, without question. The school actually calls it that in their own paper, https://cbsi-asabe.org/wp-content/uploads/2024/06/Harvesting..., because that is what it is.

I assume what confused the article is that ammonia plants often use natural gas, but that's purely as a convenient energy source and a source of hydrogen, so they cover both angles. But that isn't remotely a necessity.

[hvb2]

There's a lot of places in the world where there's room for wind but the grid can't transport it to a user. In that case consuming it locally would make sense, and especially fertilizer is a very energy heavy product.

So it might be easier to pipe the ammonia to wherever it's needed? When it's in ammonia form the energy is essentially stored for a long time.

[everforward]

I don’t think this is true, but it’s not my forte.

Pure ammonia is toxic to animals. At normal outdoor temperatures it also only becomes a liquid at ~100 PSI (it’s like 150 at 80F). The boiling point at STP is like -27F.

I’m doubtful running a power transmission line to these places is harder than maintaining pipes that transport either a toxic gas, or a toxic pressurized liquid.

If you could turn it into ammonium nitrate, that’s a solid at room temp and easier to transport. It’s explosive but insensitive so it shouldn’t without another explosion first. Even if it does, this sounds remote enough that it shouldn’t matter and ammonium nitrate is a no -toxic fertilizer. Wildlife shouldn’t even notice.

[hn_throwaway_99]

I didn't realize this previously but straight anhydrous ammonia can be used directly in the field as a fertilizer - specialized trucks just inject it directly into the soil where it dissolves in soil moisture.

Yes, it needs to be stored as a "toxic pressurized liquid" in steel tanks, but we store and use lots of toxic pressurized liquids all the time. Lots of people run all their energy needs off propane tanks, after all.

[everforward]

I think bacteria will convert it to ammonia nitrate, but I could be wrong. I do some hydro and the guidance is not to do it with hydro because the bacteria don’t grow as well so they won’t convert it into something plants can eat.

> we store and use lots of toxic pressurized liquids all the time. Lots of people run all their energy needs off propane tanks, after all.

That’s stored at rest, not being pumped through pipes. We could probably store it locally and send people to collect it, that might be cheaper than power lines.

I would be surprised if maintaining pipes to transport pressurized liquid or gas was cheaper than power lines. Power lines aren’t free, but super cheap relative to pipes that can leak everywhere.

[inigyou]

Probably not pipes. Unless you have a huge flow, pipelines in general don't make sense. You'd fill up some kind of container and haul it away when it's nearly full. What kind of container stores ammonia, I don't really know - which is why ammonium nitrate is often used, as it's a solid at room temperature and pressure.

[senthil_rajasek]

What if the Ammonia is used locally? Potentially, in that Minnesota farm.

It eliminates the need to connect the turbine to the grid.

[jijijijij]

Not to mention ammonia isn't the friendliest of chemicals and doesn't exactly beg for decentralized logistics.

I think, projects like these grew out of dunkelflaute moral panic regarding renewable energy. Meanwhile grid battery storage has becomes cheap enough to completely obliterate this concern.

And quite frankly, fertilizer needs in agriculture should be addressed by ecological means anyway. If we want to lower the impact of climate change, we need to get out of this "just throw more energy at it" technology mindset.

[0x000xca0xfe]

Here in Germany we have up to three months of almost zero solar production in winter due to foggy conditions (measured from my own solar inverter). It is not feasible to store summer electricity until winter in batteries. Batteries have self-discharge and would be hilariously expensive per KWh if they only cycle once a year. Chemical storage is probably the way to go here at least, and hydrogen can be used for many other useful things than just heating or running power plants.

Although there are many sunny countries where solar + one or two days of battery storage are probably enough for the full year.

[jijijijij]

Right, in winter there is less sun. However, there still is some sunlight and in winter you also still got wind energy. Maybe more wind, especially off-shore. Not to mention geothermal and water energy.

In any case, battery storage has been shown to be economically feasible already and are as of now operating at scale. And battery tech is only getting better. The worries about grid stability are therefore unwarranted. If you can manage the up and down of wind and solar, you don't need gas energy to stabilize the grid, you got better bad options and the seasonal variation becomes highly predictable. And of course you could e.g. reserve water potential energy generation for winter times.

And as I said, we also need to cut down our energy consumption. Building data centers to undress celebrities is not the direction of survival.

Hydrogen generation, storage, logistics and electricity conversion are all very lossy. Again battery/solar/wind tech is already there and is only getting better. We should absolutely not use hydrogen for anything, where direct electrification/battery storage is possible. We critically need it for things like steel production, but that's a special use case, where it should be made on-site. Let's be real, the only reason anyone in Germany is pushing for hydrogen is because the German "industry" historically sabotaged local solar and storage tech and now try to salvage their obsolete combustion tech. Hydrogen has a lobby, but no future. For similar reasons Russia and USA are putting propaganda efforts into climate denial: China owns battery and solar tech, China owns the energy future. It's sad, but true. There is no one to blame but those legacy economies being all inert, fat and complacent - they got a million chances to win this slow, slow race, which has been advertised a century ago.

[inigyou]

If you've ever played Factorio you'll know that everyone makes batteries because they are cheap, but you also have the option to have a separate power grid that just doesn't get powered at night and shut down your factory at night, which you would do if you modded it so that you couldn't make batteries so easily.

[WalterBright]

What I find funny is people that build machines that extract carbon from the atmosphere. None of the articles about it ever mention the energy cost in running the machine or howinell it could be scaled up to make a measurable difference.

But trees, for example, are 50% carbon, extracted from the atmosphere. And they're solar powered! And look nice.

[trollbridge]

“Plant more trees” won’t get you an IPO.

[adrianN]

Finding a way to make money by capturing CO2 will get you an IPO. The technology you use is only of secondary concern.

[inigyou]

I think that's called farming. But it doesn't work any more because the farmlords (landlords who own farms) extract 98% of your would-be profit. You know why so many farmers can't financially withstand a single bad year? That's why - not personal irresponsibility.

[trollbridge]

What are you talking about? Farmland usually leases for $50-$200 an acre per year.

[inigyou]

Equipment too?