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This is so disingenuous. The total energy input from fossil fuels is several fold less than the energy output since most of it is derived from the sun. [1](See

This is so disingenuous. The total energy input from fossil fuels is several fold less than the energy output since most of it is derived from the sun. [1](See figure 3) Around 50% of the input is indeed from nitrogen, but it need not be derived from fossil fuels since you could source energy elsewhere and use water electrolysis derived hydrogen in the nitrogen production process. That it is currently more economical to use fossil fuels is a separate issue. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2935130/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2935130/

time_to_smile 5y ago
> more economical In the same way that bunker fuel powered ships are just "more economical" than transporting goods by sail powered ships. People throw this term around like making it "less economical" to produce food is some minor detail. Things being their current level of "economical" is what drives our global economy at the current scale it runs at. We could not have our current lifestyle using sail powered ships to transport goods from China any more than we could maintain anything like our current lifestyle if we had to produce all of our nitrogen fertilizer through electrolysis. Making food "less economical" means mass starvation.
- deleted 5y ago
  [deleted]
- kragen 5y ago
  It sounds like you disagree with the calculations Robotbeat presented in https://news.ycombinator.com/item?id=29842105 https://news.ycombinator.com/item?id=29842105, but it is unclear whether that is because you have done calculations of your own. Please elaborate. Robotbeat's calculations seem to show that producing all of the US's nitrogen fertilizer through electrolysis would use something like 5% of US electricity production, which would not be a major obstacle to "maintaining anything like our current lifestyle", and presumably the numbers in other countries are even better, except for the Netherlands.
  - time_to_smile 5y ago
    > 5% of US electricity production, which would not be a major obstacle to "maintaining anything like our current lifestyle" I don't think there's any point in arguing if you think 5% of electricity (of which, as Robotbeat pointed out is 60% fossil fuel generated) is "not a major obstacle" while we also have to reduce/eliminate fossil fuel use in every sector. It also doesn't touch on the price increase in food production. Where in the world is all of this extra energy going to come from if you remove fossil fuels from the equation? Robotbeat's analysis there is terrifying to me, rather than reassuring. But you can put works like "just" and "only" as modifiers to whatever you want if it makes it sound more achievable.
    - kragen 5y ago
      I take it you agree with the calculations, then, but disagree with their implications? Increasing electricity production 5% would not mean mass starvation. China increased electricity production 5% every six months throughout the 02010s. The US did it every year in the 01960s. It's not some kind of impossible obstacle to "maintain[ing] anything like our current lifestyle".
      - time_to_smile 5y ago
        All of those gains are from an increase in the usage of fossil fuels. Yes China is making big growth in renewables but they're making even bigger growth in coal. This is the problem with our intuitions about energy, we're so used to abundant, high energy density, relatively cheap energy that we can't even get our heads around not having it. You quote me but miss the point where I say that this is fine so long as we have unlimited fossil fuels and there are no serious externalities with fossil fuel usage. Both of these conditions are false, but even your reasoning here is assuming these are true. If for some non-fossil fuel related reason we had to switch to primarily electrolysis hydrogen production, then yea, we'd be fine. We haven't even come close to really solving just replacing our current energy demands with entirely renewable energy (which, even assuming perfect battery solutions, also requires growing the overall output of our grid by a factor proportional to intermittent power needs), let alone additional energy requirements that start popping up all over the place once you start removing fossil fuels. This has been a problem that has been well studied and understood for years, but because it leads to the scary conclusion that our current way of life is unsustainable it is brushed off.
- jay_kyburz 5y ago
  The rts website below suggests that "30-40 percent of the entire US food supply" is wasted. We could start by fixing that. I suspect those of us in wealthy countries also eat _alot_ more that than we should. We are a very long way from mass starvation. [1] https://www.rts.com/resources/guides/food-waste-america/ https://www.rts.com/resources/guides/food-waste-america/
hn_throwaway_99 5y ago
> That it is currently more economical to use fossil fuels is a separate issue. That's not a separate issue. That's the WHOLE issue. The first 2 words in the quote were "Modern agriculture". The point is not that there are many types of farming that can be done without using fossil fuels as an input, nor that in the future we couldn't transition away from fossil fuels for fertilizer. The point is that the output of modern agriculture would, at present, completely collapse if the energy input from fossil fuels wasn't available.
- Robotbeat 5y ago
  That latter point is false, though except in a trivial sense. Hydrogen can be and is easily made with electricity. There is plenty of clean electricity available to do it. Also, 50% of the energy does not come from fixed nitrogen. Majority is from the Sun.
  - TheSpiceIsLife 5y ago
    There currently aren’t enough green hydrogen > ammonia manufacturing plants on the planet to do this though. Building the necessary renewable energy and ammonia plants and infrastructure is technically trivial in that we needed approximately no innovation as the tech already exists. The scaled of the problem is immense.
    - Robotbeat 5y ago
      It’s not immense compared to almost anything else we’ve done (such as the transition to air conditioning… air conditioners consume about 6% of US electricity). To replace all US ammonia production would require less than 5% of US electricity (see my other post: https://news.ycombinator.com/item?id=29842105 https://news.ycombinator.com/item?id=29842105). Heck, you can get about halfway there just on the nuclear power plants in the US that have been shut down in the last couple decades! (Works well with intermittent renewables, too, as hydrogen production can be throttled without much penalty.)
      - 5y ago
legutierr 5y ago
If you are saying that 50% of the energy input is from nitrogen, and if the most economical means of supplying nitrogen is from fossil fuel sources, such that the vast majority of it originates from fossil fuels, then wouldn't it be the case that nearly 50% of the energy input of the system is from fossil fuels? How would this input be "several fold less" than the energy output of the system?
- kragen 5y ago
  50% of the marketed energy input, that is, which someone bought on the market, is from nitrogen (though I read the same article and I thought it said 90%). But that marketed energy input is only about 20% of the total energy input of the system; the other 80% is the sunlight that falls on the fields.
  - legutierr 5y ago
    A very important distinction! So, maybe fossil-fuel inputs to the system correspond to less than 10% of the total energy output? Would that be accurate?
    - Enginerrrd 5y ago
      YES, that was exactly my point.
Robotbeat 5y ago
50% from (FIXED) nitrogen is wrong, though. Fixed nitrogen, ie ammonia (for instance), is made from gaseous nitrogen and hydrogen. 3kg of hydrogen makes 17kg of ammonia. 200 pounds of ammonia (16kg of hydrogen) will make about 250 bushels of corn. 1 bushel of corn is about 370MJ. 1kg of hydrogen is 142MJ. So 2.3GJ of hydrogen makes 92GJ of corn. That’s about 3%, not 50%. BTW, the US produces about 17 megatonnes of ammonia per year, or 3 Megatonnes of hydrogen per year. At 60% efficiency, that would require about 22 Gigawatts of average electricity, or less than 5% of average US electricity usage. The US grid is about 40% clean, so that’s still only about 10% of US’a clean electricity usage.
- kragen 5y ago
  Thank you! Where are your production figures from?
  - Robotbeat 5y ago
    Ammonia per bushel of corn from: https://www.canr.msu.edu/news/nitrogen-rate-trial-results-in-michigan-s-thumb https://www.canr.msu.edu/news/nitrogen-rate-trial-results-in... US Ammonia production per year: https://www.eia.gov/naturalgas/weekly/archivenew_ngwu/2021/04_01/ https://www.eia.gov/naturalgas/weekly/archivenew_ngwu/2021/0...
    - kragen 5y ago
      This is great, thanks!
  - deleted 5y ago
    [deleted]
- yholio 5y ago
  The hero we need, he did the math.
- Enginerrrd 5y ago
  >1 bushel of corn is about 370MJ. 1kg of hydrogen is 142MJ. So 2.3GJ of hydrogen makes 92GJ of corn. That’s about 3%, not 50%. This was basically my point. >50% from (FIXED) nitrogen is wrong, though. Sorry, I wasn't clear. I was saying that 50% of the artificial energy input (i.e. excluding free sunlight to the plants) IS from the nitrogen, rather than farming equipment, transportation, etc.

time_to_smile 5y ago

> more economical In the same way that bunker fuel powered ships are just "more economical" than transporting goods by sail powered ships. People throw this term around like making it "less economical" to produce food is some minor detail. Things being their current level of "economical" is what drives our global economy at the current scale it runs at. We could not have our current lifestyle using sail powered ships to transport goods from China any more than we could maintain anything like our current lifestyle if we had to produce all of our nitrogen fertilizer through electrolysis. Making food "less economical" means mass starvation.

deleted 5y ago
[deleted]
kragen 5y ago
It sounds like you disagree with the calculations Robotbeat presented in https://news.ycombinator.com/item?id=29842105 https://news.ycombinator.com/item?id=29842105, but it is unclear whether that is because you have done calculations of your own. Please elaborate. Robotbeat's calculations seem to show that producing all of the US's nitrogen fertilizer through electrolysis would use something like 5% of US electricity production, which would not be a major obstacle to "maintaining anything like our current lifestyle", and presumably the numbers in other countries are even better, except for the Netherlands.
- time_to_smile 5y ago
  > 5% of US electricity production, which would not be a major obstacle to "maintaining anything like our current lifestyle" I don't think there's any point in arguing if you think 5% of electricity (of which, as Robotbeat pointed out is 60% fossil fuel generated) is "not a major obstacle" while we also have to reduce/eliminate fossil fuel use in every sector. It also doesn't touch on the price increase in food production. Where in the world is all of this extra energy going to come from if you remove fossil fuels from the equation? Robotbeat's analysis there is terrifying to me, rather than reassuring. But you can put works like "just" and "only" as modifiers to whatever you want if it makes it sound more achievable.
  - kragen 5y ago
    I take it you agree with the calculations, then, but disagree with their implications? Increasing electricity production 5% would not mean mass starvation. China increased electricity production 5% every six months throughout the 02010s. The US did it every year in the 01960s. It's not some kind of impossible obstacle to "maintain[ing] anything like our current lifestyle".
    - time_to_smile 5y ago
      All of those gains are from an increase in the usage of fossil fuels. Yes China is making big growth in renewables but they're making even bigger growth in coal. This is the problem with our intuitions about energy, we're so used to abundant, high energy density, relatively cheap energy that we can't even get our heads around not having it. You quote me but miss the point where I say that this is fine so long as we have unlimited fossil fuels and there are no serious externalities with fossil fuel usage. Both of these conditions are false, but even your reasoning here is assuming these are true. If for some non-fossil fuel related reason we had to switch to primarily electrolysis hydrogen production, then yea, we'd be fine. We haven't even come close to really solving just replacing our current energy demands with entirely renewable energy (which, even assuming perfect battery solutions, also requires growing the overall output of our grid by a factor proportional to intermittent power needs), let alone additional energy requirements that start popping up all over the place once you start removing fossil fuels. This has been a problem that has been well studied and understood for years, but because it leads to the scary conclusion that our current way of life is unsustainable it is brushed off.
jay_kyburz 5y ago
The rts website below suggests that "30-40 percent of the entire US food supply" is wasted. We could start by fixing that. I suspect those of us in wealthy countries also eat _alot_ more that than we should. We are a very long way from mass starvation. [1] https://www.rts.com/resources/guides/food-waste-america/ https://www.rts.com/resources/guides/food-waste-america/

hn_throwaway_99 5y ago

> That it is currently more economical to use fossil fuels is a separate issue. That's not a separate issue. That's the WHOLE issue. The first 2 words in the quote were "Modern agriculture". The point is not that there are many types of farming that can be done without using fossil fuels as an input, nor that in the future we couldn't transition away from fossil fuels for fertilizer. The point is that the output of modern agriculture would, at present, completely collapse if the energy input from fossil fuels wasn't available.

Robotbeat 5y ago
That latter point is false, though except in a trivial sense. Hydrogen can be and is easily made with electricity. There is plenty of clean electricity available to do it. Also, 50% of the energy does not come from fixed nitrogen. Majority is from the Sun.
- TheSpiceIsLife 5y ago
  There currently aren’t enough green hydrogen > ammonia manufacturing plants on the planet to do this though. Building the necessary renewable energy and ammonia plants and infrastructure is technically trivial in that we needed approximately no innovation as the tech already exists. The scaled of the problem is immense.
  - Robotbeat 5y ago
    It’s not immense compared to almost anything else we’ve done (such as the transition to air conditioning… air conditioners consume about 6% of US electricity). To replace all US ammonia production would require less than 5% of US electricity (see my other post: https://news.ycombinator.com/item?id=29842105 https://news.ycombinator.com/item?id=29842105). Heck, you can get about halfway there just on the nuclear power plants in the US that have been shut down in the last couple decades! (Works well with intermittent renewables, too, as hydrogen production can be throttled without much penalty.)
    - 5y ago

legutierr 5y ago

If you are saying that 50% of the energy input is from nitrogen, and if the most economical means of supplying nitrogen is from fossil fuel sources, such that the vast majority of it originates from fossil fuels, then wouldn't it be the case that nearly 50% of the energy input of the system is from fossil fuels? How would this input be "several fold less" than the energy output of the system?

kragen 5y ago
50% of the marketed energy input, that is, which someone bought on the market, is from nitrogen (though I read the same article and I thought it said 90%). But that marketed energy input is only about 20% of the total energy input of the system; the other 80% is the sunlight that falls on the fields.
- legutierr 5y ago
  A very important distinction! So, maybe fossil-fuel inputs to the system correspond to less than 10% of the total energy output? Would that be accurate?
  - Enginerrrd 5y ago
    YES, that was exactly my point.

Robotbeat 5y ago

50% from (FIXED) nitrogen is wrong, though. Fixed nitrogen, ie ammonia (for instance), is made from gaseous nitrogen and hydrogen. 3kg of hydrogen makes 17kg of ammonia. 200 pounds of ammonia (16kg of hydrogen) will make about 250 bushels of corn. 1 bushel of corn is about 370MJ. 1kg of hydrogen is 142MJ. So 2.3GJ of hydrogen makes 92GJ of corn. That’s about 3%, not 50%. BTW, the US produces about 17 megatonnes of ammonia per year, or 3 Megatonnes of hydrogen per year. At 60% efficiency, that would require about 22 Gigawatts of average electricity, or less than 5% of average US electricity usage. The US grid is about 40% clean, so that’s still only about 10% of US’a clean electricity usage.

kragen 5y ago
Thank you! Where are your production figures from?
- Robotbeat 5y ago
  Ammonia per bushel of corn from: https://www.canr.msu.edu/news/nitrogen-rate-trial-results-in-michigan-s-thumb https://www.canr.msu.edu/news/nitrogen-rate-trial-results-in... US Ammonia production per year: https://www.eia.gov/naturalgas/weekly/archivenew_ngwu/2021/04_01/ https://www.eia.gov/naturalgas/weekly/archivenew_ngwu/2021/0...
  - kragen 5y ago
    This is great, thanks!
- deleted 5y ago
  [deleted]
yholio 5y ago
The hero we need, he did the math.
Enginerrrd 5y ago
>1 bushel of corn is about 370MJ. 1kg of hydrogen is 142MJ. So 2.3GJ of hydrogen makes 92GJ of corn. That’s about 3%, not 50%. This was basically my point. >50% from (FIXED) nitrogen is wrong, though. Sorry, I wasn't clear. I was saying that 50% of the artificial energy input (i.e. excluding free sunlight to the plants) IS from the nitrogen, rather than farming equipment, transportation, etc.