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Ha! As an avid gardener who who got solar panels recently, I've seriously considered looking deeper into this. When I spec'd out my system, I did some back of

Ha! As an avid gardener who who got solar panels recently, I've seriously considered looking deeper into this. When I spec'd out my system, I did some back of the napkin math on mining bitcoin with surplus pixies during the day, and it came something on the order of 10x more profitable than what my utility is willing to give me for those same pixies. However, I don't really use bitcoin. I do however, have an ongoing need for nitrogen fertilizers. I've been digging about into what it would take to drive the Haber Bosch process at a home scale. A couple of 10's of kg of fixed nitrogen a month would be more valuable to me than what my utility is willing to pay, and I could put it right to work in the garden beds.

ciconia 4y ago
There are so many alternatives to chemical fertilizer: manure (cow, horse, chicken, human), compost, planting nitrogen fixers, sowing ground cover plants... Depending on where you live each may be easier or harder to produce or procure. In addition there are generative techniques that concentrate on soil fertility: permaculture, cover crops, syntropic agroforestry to name a few. I have never used a chemical fertilizer in my garden, and am striving towards a completely autonomous fertilization cycle, where my garden's fertility grows each year without any external input.
- jvanderbot 4y ago
  Imagine throwing 50kg of manure into the back of your tesla every spring.
  - RosanaAnaDana 4y ago
    50kg? Try more like 500kg. I usually get a 5 yard load dropped off once a year, and that isn't nearly enough.
    - 082349872349872 4y ago
      HN readers may be amused to learn that "New Idea" is a brand name of manure spreaders.
- RosanaAnaDana 4y ago
  > There are so many alternatives to chemical fertilizer: manure (cow, horse, chicken, human), compost, planting nitrogen fixers, sowing ground cover plants... Cool. And which of those can I generate using excess electrical energy from my solar panels? >I have never used a chemical fertilizer in my garden, and am striving towards a completely autonomous fertilization cycle That is great. I don't have the time or interest in managing animals, and I manage my space for food production because it gives me a sense of control and independence over my food-supply. Over the last 3 years I've imported almost 5000kg of animal manures into my gardens. Its incredibly expensive, and even with that additional fertility, I need more. Its more important for me to have the independence and control over my food-supply than it is to hold to a particular relgiosity around where my N comes from. If I have animal manures, I'll use them. If I have chemical fertilizers, I'll use them. When I have pest issues, I try to use IPM. When that fails, I'll use a pesticide.
  - empyrrhicist 4y ago
    Are you sure you aren't over-fertilizing? Or are you doing something else silly that causes you to lose all your N? That's a crazy amount of nutrient for even a very large garden.
    - RosanaAnaDana 4y ago
      >That's a crazy amount of nutrient for even a very large garden. Its really not. Cattle manure is around 2% nitrogen. If we call a yard of composted manure 450 kg, that's around 9 kg of nitrogen. Say I'm going through 5 yards annually, which is about right, so 45kg. I'd say some where between 1/2- 1/4th of that actually reaches the plants (22kg). I've got substantial gardens, and I garden them very intensively. I've got about 1000m2 of gardens. In my climate I can crop continuously. High fertility for corn would be around 280 kg/ha. If I'm at 220kg/ha on my 1000m2, that seems about right.
      - zafka 4y ago
        Where are you located. I am in south Florida, treasure coast. I am hoping to step up my farming on 5 acres over the next few years.
- sandworm101 4y ago
  Good luck with eating lettuce fertilized with pig/human manure. There is a reason we have health codes. It is the same reason why people in the middle ages boiled all thier food, never ever eating "fresh" vegitables. And if anyone is worried about antibiotics in meat, have a look at how many different drugs are found in human poop. There are a thousand little ancient diseases out there that we in the west have largely forgotten about. Start pooping near where we grow food and they will all start comming back. https://www.cbc.ca/radio/asithappens/as-it-happens-friday-edition-1.5166570/brain-surgeons-went-looking-for-a-tumour-but-found-a-tapeworm-instead-1.5166571 https://www.cbc.ca/radio/asithappens/as-it-happens-friday-ed...
bbojan 4y ago
If you have excess electricity, I always thought it would make sense to use the Birkeland–Eyde process [1]. From what I understand it is very energy inefficient, but scales down well. [1] https://en.m.wikipedia.org/wiki/Birkeland%E2%80%93Eyde_process https://en.m.wikipedia.org/wiki/Birkeland%E2%80%93Eyde_proce...
- RosanaAnaDana 4y ago
  Hmm. Very interesting. So many great industrial processes out there that got pushed aside by market forces. I don't suppose they've got a home unit that can run on 120?
  - bbojan 4y ago
    If not, there's a business idea!
sandworm101 4y ago
>> A couple of 10's of kg of fixed nitrogen a month And for any other nitrogen uses. Haber-Bosch was originally conceived as a process for making cheaper explosives. Wikipedia: "Allies had access to large deposits of sodium nitrate in Chile (Chile saltpetre) controlled by British companies. Germany had no such resources, so the Haber process proved essential to the German war effort. Synthetic ammonia from the Haber process was used for the production of nitric acid, a precursor to the nitrates used in explosives."
Fordec 4y ago
Would subscribe to this newsletter if you were to pursue the problem. Have lots of interest in the space but zero of the resources, access to sun, space or chemistry skillset so can only live vicariously on the topic.
KMag 4y ago
The Haber-Bosch reaction is exothermic, but requires elevated temperatures, so I suspect that there are significant economies of scale when scaling up the reaction vessel size due to reduced surface area to volume ratio.
staticautomatic 4y ago
When I think cryptocurrency and making nitrogen compounds, I think about the FBI and ATF showing up.

ciconia 4y ago

There are so many alternatives to chemical fertilizer: manure (cow, horse, chicken, human), compost, planting nitrogen fixers, sowing ground cover plants... Depending on where you live each may be easier or harder to produce or procure. In addition there are generative techniques that concentrate on soil fertility: permaculture, cover crops, syntropic agroforestry to name a few. I have never used a chemical fertilizer in my garden, and am striving towards a completely autonomous fertilization cycle, where my garden's fertility grows each year without any external input.

jvanderbot 4y ago
Imagine throwing 50kg of manure into the back of your tesla every spring.
- RosanaAnaDana 4y ago
  50kg? Try more like 500kg. I usually get a 5 yard load dropped off once a year, and that isn't nearly enough.
  - 082349872349872 4y ago
    HN readers may be amused to learn that "New Idea" is a brand name of manure spreaders.
RosanaAnaDana 4y ago
> There are so many alternatives to chemical fertilizer: manure (cow, horse, chicken, human), compost, planting nitrogen fixers, sowing ground cover plants... Cool. And which of those can I generate using excess electrical energy from my solar panels? >I have never used a chemical fertilizer in my garden, and am striving towards a completely autonomous fertilization cycle That is great. I don't have the time or interest in managing animals, and I manage my space for food production because it gives me a sense of control and independence over my food-supply. Over the last 3 years I've imported almost 5000kg of animal manures into my gardens. Its incredibly expensive, and even with that additional fertility, I need more. Its more important for me to have the independence and control over my food-supply than it is to hold to a particular relgiosity around where my N comes from. If I have animal manures, I'll use them. If I have chemical fertilizers, I'll use them. When I have pest issues, I try to use IPM. When that fails, I'll use a pesticide.
- empyrrhicist 4y ago
  Are you sure you aren't over-fertilizing? Or are you doing something else silly that causes you to lose all your N? That's a crazy amount of nutrient for even a very large garden.
  - RosanaAnaDana 4y ago
    >That's a crazy amount of nutrient for even a very large garden. Its really not. Cattle manure is around 2% nitrogen. If we call a yard of composted manure 450 kg, that's around 9 kg of nitrogen. Say I'm going through 5 yards annually, which is about right, so 45kg. I'd say some where between 1/2- 1/4th of that actually reaches the plants (22kg). I've got substantial gardens, and I garden them very intensively. I've got about 1000m2 of gardens. In my climate I can crop continuously. High fertility for corn would be around 280 kg/ha. If I'm at 220kg/ha on my 1000m2, that seems about right.
    - zafka 4y ago
      Where are you located. I am in south Florida, treasure coast. I am hoping to step up my farming on 5 acres over the next few years.
sandworm101 4y ago
Good luck with eating lettuce fertilized with pig/human manure. There is a reason we have health codes. It is the same reason why people in the middle ages boiled all thier food, never ever eating "fresh" vegitables. And if anyone is worried about antibiotics in meat, have a look at how many different drugs are found in human poop. There are a thousand little ancient diseases out there that we in the west have largely forgotten about. Start pooping near where we grow food and they will all start comming back. https://www.cbc.ca/radio/asithappens/as-it-happens-friday-edition-1.5166570/brain-surgeons-went-looking-for-a-tumour-but-found-a-tapeworm-instead-1.5166571 https://www.cbc.ca/radio/asithappens/as-it-happens-friday-ed...

bbojan 4y ago

If you have excess electricity, I always thought it would make sense to use the Birkeland–Eyde process [1]. From what I understand it is very energy inefficient, but scales down well. [1] https://en.m.wikipedia.org/wiki/Birkeland%E2%80%93Eyde_process https://en.m.wikipedia.org/wiki/Birkeland%E2%80%93Eyde_proce...

RosanaAnaDana 4y ago
Hmm. Very interesting. So many great industrial processes out there that got pushed aside by market forces. I don't suppose they've got a home unit that can run on 120?
- bbojan 4y ago
  If not, there's a business idea!

sandworm101 4y ago

>> A couple of 10's of kg of fixed nitrogen a month And for any other nitrogen uses. Haber-Bosch was originally conceived as a process for making cheaper explosives. Wikipedia: "Allies had access to large deposits of sodium nitrate in Chile (Chile saltpetre) controlled by British companies. Germany had no such resources, so the Haber process proved essential to the German war effort. Synthetic ammonia from the Haber process was used for the production of nitric acid, a precursor to the nitrates used in explosives."

Fordec 4y ago

Would subscribe to this newsletter if you were to pursue the problem. Have lots of interest in the space but zero of the resources, access to sun, space or chemistry skillset so can only live vicariously on the topic.

KMag 4y ago

The Haber-Bosch reaction is exothermic, but requires elevated temperatures, so I suspect that there are significant economies of scale when scaling up the reaction vessel size due to reduced surface area to volume ratio.

staticautomatic 4y ago

When I think cryptocurrency and making nitrogen compounds, I think about the FBI and ATF showing up.