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The photosynthesis isn't the end of the biofuel equation. Corn ethanol is energy negative (switchgrass, sugar cane or beets are better but still abysmal). If y
by Schroedingersat 4y ago
The photosynthesis isn't the end of the biofuel equation. Corn ethanol is energy negative (switchgrass, sugar cane or beets are better but still abysmal).
If you consider a hybrid PV-CSP plant, the H2 step can be done at 20% from air. CO2 capture is under 10%.
So you'd need to show that the ethylene step is under 5% efficient when you also had an available free low quality steam input (or high quality at 50% sunlight-efficiency).
- gus_massa 4y agoI almost agree. From https://en.wikipedia.org/wiki/Sugarcane#Ethanol https://en.wikipedia.org/wiki/Sugarcane#Ethanol > One hectare of sugar cane yields 4,000 litres of ethanol per year (without any additional energy input, because the bagasse produced exceeds the amount needed to distill the final product). This, however, does not include the energy used in tilling, transportation, and so on. Thus, the solar energy-to-ethanol conversion efficiency is 0.13%. but I'm still pessimistic about the efficiency of the new method.
- Schroedingersat 4y agoThe thing that will kill as an energy storage method it is capital and labour expenses more than efficiency. I'd expect something like it to be viable for chemical feedstock once the fossil fuel subsidies start to die out and less investment goes into extracting more and worse sources cheaply though.
- deleted 4y ago[deleted]