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That growing corn and then turning it into ethanol to burn in your cars is unlikely to be sustainable or more energy-efficient than extracting fossil fuels. Ba

That growing corn and then turning it into ethanol to burn in your cars is unlikely to be sustainable or more energy-efficient than extracting fossil fuels. Basic matter of thinking in terms of conversion losses. It probably helps to know that currently every calorie produced by Western agriculture costs about ten calories worth of fossil fuels, but still. EDIT: I realised just now that I took Michael Pollan's word on that 10:1 number without checking it, mea culpa. Quick search on the web gives me this though: http://people.uwplatt.edu/~dalecki/newperspectives.pdf http://people.uwplatt.edu/~dalecki/newperspectives.pdf and that graph on the sixth page (or "page 184") does look pretty damning on ethanol as a fuel (I'm making no statements on its qualities as an oxidizer).

Turing_Machine 9y ago
"Basic matter of thinking in terms of conversion losses. " While it is true that Western agriculture uses a lot of fossil fuels, that isn't necessarily the case for all possible models of agriculture. Plants get their energy from the sun. They don't drink it from a gas pump. Yeah, there'll be "conversion losses" (i.e., less energy will show up in the plant than was produced by fusion in the core of the sun), but it's hard to see why that matters in any realistic sense.
- vanderZwan 9y ago
  > that isn't necessarily the case for all possible models of agriculture. No, but then we change the discussion: we were talking about the (in)efficiencies of corn ethanol. Hence my Western agriculture qualifier, because that is the context in which it is generated as a biofuel. If we look more broadly, then a whole lot of alternatives look a lot better obviously.
  - maxerickson 9y ago
    The 10:1 likely rolls in animal products and low calorie vegetables, which aren't corn either.
    - vanderZwan 9y ago
      Ah, fair point there. I had not considered that.
- vanderZwan 9y ago
  Also, conversion losses do matter, because a lot of efficiency calculations cheat by forgetting (or perhaps "forgetting") to include them, as a hidden form of externalising energy costs. For example: > [If we compare] the thermal efficiencies from modern cooking stoves with those from stoves used in poorer households, we see that the improved biomass stoves in developing countries beat our "high-tech" cooking technology with a factor of two to three (graphic below). > The main discrepancy with these figures is caused when one doesn't take into account that electricity first needs to be produced in power plants which sometimes convert less than a third of the primary energy into electricity. This is not an issue with gas or biomass stoves, where a primary fuel is directly converted into heat for cooking. > Evidently, there is something wrong with the western approach to sustainability. Converting heat into electricity which is then converted back into heat, at 20-40% efficiency, is similar to building a Rube Goldberg machine; it's a needlessly complex operation compared to simply converting the primary fuel into heat to boil water. Essentially, any electric cooking device is an insult to the science of thermodynamics. http://www.lowtechmagazine.com/2014/06/thermal-efficiency-cooking-stoves.html http://www.lowtechmagazine.com/2014/06/thermal-efficiency-co... ... huh, I guess that's last sentence where I got my thermodynamics remark from.
  - Turing_Machine 9y ago
    "Also, conversion losses do matter" Not when it comes to the fusion reactions occurring in the sun. Cooking stoves aren't really relevant here at all, but of course the reason we use these so-called "Rube Goldberg" methods is so that we don't have to go chop wood and then attempt to regulate the temperature of a wood-burning range. If you haven't done that, you (and the author of your linked article) should try it sometime. Hint: it's not easy. Both of my great-grandmothers could bake fancy cakes in a wood-burning oven, to take just one example, but that's a skill I will never have.
    - vanderZwan 9y ago
      Are you wilfully trying to not see the point I'm making or something? Electric cooking is always sold as more energy efficient than the alternatives, while it turns out that gas is by far the most energy efficient option for Western cooking if you do the actual calculations. And you still don't have to chop your own wood that way. When it comes to growing corn: of all the sunlight that comes in, how much of that is converted into potential energy by growing corn? How much external energy and resources does it cost to grow corn otherwise? How much energy and resources does it cost to turn that corn into biofuel? By comparison, how much sunlight can be converted to electricity by photovoltaics? How much of that energy is lost when getting that electricity into an electric vehicle? How much extra overhead do the batteries have compared to fossil fuels due to extra weight, given their lower energy density? Those are all questions of conversion losses. If you honestly want to say that they are not, or that they don't matter, I would like to know why. Because I do not understand what the comparison with the Sun's generated energy has to do with anything.

Turing_Machine 9y ago

"Basic matter of thinking in terms of conversion losses. " While it is true that Western agriculture uses a lot of fossil fuels, that isn't necessarily the case for all possible models of agriculture. Plants get their energy from the sun. They don't drink it from a gas pump. Yeah, there'll be "conversion losses" (i.e., less energy will show up in the plant than was produced by fusion in the core of the sun), but it's hard to see why that matters in any realistic sense.

vanderZwan 9y ago
> that isn't necessarily the case for all possible models of agriculture. No, but then we change the discussion: we were talking about the (in)efficiencies of corn ethanol. Hence my Western agriculture qualifier, because that is the context in which it is generated as a biofuel. If we look more broadly, then a whole lot of alternatives look a lot better obviously.
- maxerickson 9y ago
  The 10:1 likely rolls in animal products and low calorie vegetables, which aren't corn either.
  - vanderZwan 9y ago
    Ah, fair point there. I had not considered that.
vanderZwan 9y ago
Also, conversion losses do matter, because a lot of efficiency calculations cheat by forgetting (or perhaps "forgetting") to include them, as a hidden form of externalising energy costs. For example: > [If we compare] the thermal efficiencies from modern cooking stoves with those from stoves used in poorer households, we see that the improved biomass stoves in developing countries beat our "high-tech" cooking technology with a factor of two to three (graphic below). > The main discrepancy with these figures is caused when one doesn't take into account that electricity first needs to be produced in power plants which sometimes convert less than a third of the primary energy into electricity. This is not an issue with gas or biomass stoves, where a primary fuel is directly converted into heat for cooking. > Evidently, there is something wrong with the western approach to sustainability. Converting heat into electricity which is then converted back into heat, at 20-40% efficiency, is similar to building a Rube Goldberg machine; it's a needlessly complex operation compared to simply converting the primary fuel into heat to boil water. Essentially, any electric cooking device is an insult to the science of thermodynamics. http://www.lowtechmagazine.com/2014/06/thermal-efficiency-cooking-stoves.html http://www.lowtechmagazine.com/2014/06/thermal-efficiency-co... ... huh, I guess that's last sentence where I got my thermodynamics remark from.
- Turing_Machine 9y ago
  "Also, conversion losses do matter" Not when it comes to the fusion reactions occurring in the sun. Cooking stoves aren't really relevant here at all, but of course the reason we use these so-called "Rube Goldberg" methods is so that we don't have to go chop wood and then attempt to regulate the temperature of a wood-burning range. If you haven't done that, you (and the author of your linked article) should try it sometime. Hint: it's not easy. Both of my great-grandmothers could bake fancy cakes in a wood-burning oven, to take just one example, but that's a skill I will never have.
  - vanderZwan 9y ago
    Are you wilfully trying to not see the point I'm making or something? Electric cooking is always sold as more energy efficient than the alternatives, while it turns out that gas is by far the most energy efficient option for Western cooking if you do the actual calculations. And you still don't have to chop your own wood that way. When it comes to growing corn: of all the sunlight that comes in, how much of that is converted into potential energy by growing corn? How much external energy and resources does it cost to grow corn otherwise? How much energy and resources does it cost to turn that corn into biofuel? By comparison, how much sunlight can be converted to electricity by photovoltaics? How much of that energy is lost when getting that electricity into an electric vehicle? How much extra overhead do the batteries have compared to fossil fuels due to extra weight, given their lower energy density? Those are all questions of conversion losses. If you honestly want to say that they are not, or that they don't matter, I would like to know why. Because I do not understand what the comparison with the Sun's generated energy has to do with anything.