3 ms·

Correct me if I am wrong, but did the author make a calculation error? The number of required energy comes in at the order of 10^20 J or 90000TWh: https://www

Correct me if I am wrong, but did the author make a calculation error? The number of required energy comes in at the order of 10^20 J or 90000TWh: https://www.wolframalpha.com/input?i=300+quadrillion+BTU+in+TWh https://www.wolframalpha.com/input?i=300+quadrillion+BTU+in+... but if I multiply the energy return from biofuels with these alleged 1billion hectares of land, I get much, much more energy, billions of TWh: https://www.wolframalpha.com/input?i=582Mwh%2Fm%5E2+*+1billion+hectares++in+TWh https://www.wolframalpha.com/input?i=582Mwh%2Fm%5E2+*+1billi... So unless there's a mistake somewhere, only a marginal fraction of land would be needed to cover all needs. So what went wrong here? I think it's the MWh per square meter number. 500MWh in PV would be a 500kW solar installation in Germany. I am quite sure you cannot fit that into a square meter. But even if we assume 580MWh per hectare per year, the output from 1billion hectares would be 580000TWh. So there's probably more wrong in that post.

fsh 4y ago
Your units are completely off. From the article: > According to Google, the world’s total arable land is about 1.38 billion hectares. Using the biomass LUIE figure of 580 m²/MWh/y, we get a total potential electricity production of 23,793 TWh / year. This is correct: https://www.wolframalpha.com/input?i=%281.38+billion+hectares%29%2F%28580+m%C2%B2%2F%28MWh%29%29+to+TWh https://www.wolframalpha.com/input?i=%281.38+billion+hectare...
snewman 4y ago
[Author here] The LUIE figure we found for dedicated biomass is 580 m²/MWh/y: 580 square meters to generate one megawatt-hour per year. You multiplied this by hectares, meaning you multiplied area times area. If you want to determine the amount of energy you can produce from a given area (e.g. 1 billion hectares), you need to divide by 580, not multiply by 580.
- choeger 4y ago
  Ah, it's 1/580 MWh per square meter, I completely misread the unit there. Meter per MWh is somewhat unusual in these discusst.

fsh 4y ago

Your units are completely off. From the article: > According to Google, the world’s total arable land is about 1.38 billion hectares. Using the biomass LUIE figure of 580 m²/MWh/y, we get a total potential electricity production of 23,793 TWh / year. This is correct: https://www.wolframalpha.com/input?i=%281.38+billion+hectares%29%2F%28580+m%C2%B2%2F%28MWh%29%29+to+TWh https://www.wolframalpha.com/input?i=%281.38+billion+hectare...

snewman 4y ago

[Author here] The LUIE figure we found for dedicated biomass is 580 m²/MWh/y: 580 square meters to generate one megawatt-hour per year. You multiplied this by hectares, meaning you multiplied area times area. If you want to determine the amount of energy you can produce from a given area (e.g. 1 billion hectares), you need to divide by 580, not multiply by 580.

choeger 4y ago
Ah, it's 1/580 MWh per square meter, I completely misread the unit there. Meter per MWh is somewhat unusual in these discusst.