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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 o
by 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 agoThank you! Where are your production figures from?
- Robotbeat 5y agoAmmonia 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 agoThis is great, thanks!
- deleted 5y ago[deleted]
- yholio 5y agoThe 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.
- Robotbeat 5y agoThanks for the clarification! We are in violent agreement.