Hacker News new | past | comments | ask | show | jobs | submit login

The comments here are focused on how much energy it would take to turn this into fuel. The real story here is decentralized fertilizer production, buried at the end of the article:

> this innovation could fundamentally reshape fertilizer manufacturing by providing a more sustainable, cost-effective alternative to centralized production

The high energy cost of Haber-Bosch, plus the additional cost of transportation from manufacturer to farmer could potentially be eliminated by distributed, passive fertilizer generators scattered around in the fields.

I'm no expert, but assuming sufficient local production, low concentration could potentially be overcome by continuous fertilization with irrigation throughout the growing season.

Let's find out. Some quick fiddling with a molarity calculator and an almanac:

-- 100 uM ammonia -> 1.7 mg / L ammonia

-- 82% nitrogen -> 1.4 mg / L nitrogen

-- My lawn needs around 1 lb / 1000 sq ft, or around 5 g / m2

-- So my lawn needs about 3500 L / m2 of fertilized irrigation total for the season

-- Ballpark farming irrigation is around 0.2 inches per day, or around 5L/m2

I would need to water my lawn about 700 days in the year, or more realistically up my irrigation rate by about a factor of 4, AND source all of the water from the fertilizer box.

I'm a little skeptical that I can allocate space for enough production and still have a lawn left to fertilize. The tech probably isn't ready for the big time on an industrial farm yet, but for research demo, this seems like a promising direction! Much more than concentrating it for fuel.






Interesting idea.

So, farms are definitely setup already to accomplish this. Most farms have moved to central pivots for irrigation, and they already inject fertilizer into the pivot [1]. If fertilization could be generated onsite, then you could theoretically have everything plumbed together to "just work" without much intervention or shipping of chemicals.

[1] https://www.farmprogress.com/farming-equipment/chemical-fert...


Rain will wash nitrogen away (down to streams, rivers, and then the ocean creating lots of problems) so you want to apply nitrogen with an eye on when it will rain so your fertilizer stays on the field where you want it. Your link doesn't specify what fertilizer is being applied, I would guess nitrogen is not one.

Ammonia should be applied to the soil - in the air it is a hazard that can kill people and harm the plants (farmers wear lots of protective gear when working with ammonia, with more other things they don't bother).

As such I'm not convinced that is the right answer. You want a system that will apply nitrogen


> I would guess nitrogen is not one.

It's the main fertilizer applied.

Here's another site talking about common problems with this technique (from a farmer's perspective). [1]

[1] https://www.valleyirrigation.com/blog/valley-blog/2022/06/13...


Farmers use anhydrous ammonia that bounds with water in the soil and then bonds to the soil.

I don't know that farmers wear anything special when applying it, but there are safety procedures. I work with a farmer and he was telling me about one time he forgot to switch one of the valves off and when he disconnected a hose, the fumes knocked him out. Luckily it was just the fumes from the hose and not the whole tank or he likely would have died instead of just being knocked out.


Farmers already do keep an eye when it will rain before applying fertilisers. So, this is already part of their calculation. Although, yes , this means they will not apply it everyday. Depending on their location this means that a lot of weeks are out of the picture.

A somewhat passive fertiliser generator scattered around your fields is also known as a "cow" and a "chicken".

Cows and chickens cannot fix nitrogen from the air. They eat the nitrogen-fixing plants. So in a sense they don't "generate" fertiliser, they only concentrate it.

The cows also “stack shit up”, building a thick layer of soil: “carbon sequestration”.

All in all, cows are around zero emissions when held outside and fed grass only.


In Western Europe at least, cows are kept in pastures, which are permanently dedicated to that use and not used as fields to grow crops. All in all, cows are probably only low carbon in premodern rural contexts in West Africa and Asia for instance.

And distribute it across acreage.

Of course you can't have cows wandering through your corn or soybeans, they'll eat and/or crush it. But if you had fields that you could rotate between pasture and planted that could work.

You don't need soy or corn if you have cows on grass instead: much less carbon dioxide and more nutritious.

Until big fertilizer lobbies to make decentralized fertilizer illegal. Insert national security, wrong hands blah blah

> Insert national security, wrong hands blah blah

That isn't a big reach.

Ammonium nitrate is already controlled in several parts of the world

https://en.wikipedia.org/wiki/ANFO


ANFO is explosives made with ammonium nitrate(Ammonium Nitrate Fuel Oil), however ammonium nitrate is by itself rather energetic and will explode when store improperly. The most recent memorable incident would be 2020 Beirut: https://en.wikipedia.org/wiki/2020_Beirut_explosion

Imagine one of these units left somewhere, slowly filling a tank that has not been sealed, water evaporating back out leaving a nice ammonium nitrate powder behind....


I'm no chemist so someone will have to explain to me how ammonia sitting around by itself, without water, just becomes ammonium nitrate.

There's a ton of water in the air for it to react with

NGL, it would be an easy sell. You are just a hop/skip and a quack away from turning that decentralized fertilizer into a decentralized bomb making system.

A hop, skip, quack, jump, and fairly obvious high-energy distillation process away. The national security angle probably isn't a concern here for the same reason that this process doesn't produce good fuel.

Ammonium nitrate is made from ammonia and nitric acid (which is also made from ammonia). Therefore, ammonia is the only necessary direct precursor to ammonium nitrate, which is probably the most relevant oxidizer in improvised explosives today.

Not saying that it should be regulated on the basis of national security, but it’s not like there isn’t a potential security concern.


What happens when your decentralized fertilizer mixes with someone's copyrighted/trademarked fertilizer? Do you have to pay them their dues?

If you think this is outlandish, you must not be familiar with Monsanto


That is an exaggeration. The only time Monsanto did anything was cases of intentional mixing.

> you must not be familiar with Monsanto

It has been out of business for almost seven years now. Who is putting any energy into remembering them at this point?


It's not out of business. It merged with Bayer. It's a change in ownership, and to some degree a change in upper management, but large swathes of the company are unchanged.

Its assets were sold to Bayer and BASF and some former Monsanto workers may have begun working at those other businesses, that is true. That kind of scenario is true of all businesses that close down, though, at least unless they truly have no remaining assets to sell or workers wanting new jobs, both of which are unlikely for anything beyond the simplest of sole proprietorships. By your logic, there is almost no business in history that has ever gone out of business.

I mean, you can vertically scale these, right? It isn't solar powered.

Also while I understand the local delivery aspect, why waste arable soil on this, use desert. Hm, do you need moist air? They were testing it near water. Maybe on the Pacific side of the Rockies? That air is moist enough to drop feet of snow at once.


I mean, the extended headline suggests it is producing fuel, which is wrong.

Ammonia has a lot of uses, and fuel is one of them.

It's a recent use. I'm still not convinced it's a good use case. I think it's mostly greenwashig (bluewashing?) to avoid the explicit release of CO2, but probably biodiesel is a more ecological friendly alternative.

Would it be suitable for Mars atmosphere?

Plenty of nitrogen in Mars' atmosphere.



Consider applying for YC's Spring batch! Applications are open till Feb 11.

Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: