5 ms·

Corn ethanol _is_ an inefficient biofuel. It uses more energy to produce than it generates, but thanks to the federal government there's a mandate to include it

Corn ethanol _is_ an inefficient biofuel. It uses more energy to produce than it generates, but thanks to the federal government there's a mandate to include it in gasoline, so we keep producing it.

vanderZwan 9y ago
Yeah, I still remember the basic laws of thermodynamics ;). If only they taught those in high school too. Aside: sometimes I wonder if spending some time to teach more advanced concepts of science in more "conceptual" ways wouldn't be a lot more useful for the general public than the current style of education. You can get a perfectly fine intuition and "first-principle" understanding of laws of nature running the world around you, without ever worrying about calculus, and it's quite useful.
- maxerickson 9y ago
  What do the basic laws of thermodynamics and intuition do to inform you about the EROI of biofuels?
  - vanderZwan 9y ago
    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.
maxerickson 9y ago
Using it as an oxidizer, even at some energy loss, likely makes lots of sense. It's relatively easy to handle, not that nasty, etc. It's probably not an energy loss though: http://www.energytrendsinsider.com/2016/02/23/a-critical-review-of-the-2015-energy-balance-for-corn-ethanol/ http://www.energytrendsinsider.com/2016/02/23/a-critical-rev... (But still not enough of an energy gain to be acting like it is a good energy source)
- sbierwagen 9y ago
  >Using it as an oxidizer, even at some energy loss, likely makes lots of sense Ethanol is C2H6O. Two carbons, six hydrogens, one oxygen. Not a lot of oxygen in that molecule. Calling it an oxidizer akin to LOX or N2H4O3 is unusual.
  - maxerickson 9y ago
    Yes, oxygenate is the correct term.
sliverstorm 9y ago
Please see Wiki about oxygenates in gasoline: https://en.wikipedia.org/wiki/Oxygenate https://en.wikipedia.org/wiki/Oxygenate
simias 9y ago
AFAIK the argument is that the CO2 is produces during combustion was captured from the atmosphere while the plant was growing, so it's neutral in terms of CO2 emissions (not taking into account other sources of CO2 emissions during the fabrication of the ethanol). Fossil fuels on the other end take carbon that was sleeping in the ground and leave it in the atmosphere after combustion. At least that's what I hear over here in Europe, maybe motivations are different in the US.
- wahern 9y ago
  It takes a lot of energy to cultivate corn and produce ethanol. Think of all the trucks, tractors, and other machinery involved; and energy-intensive fertilizers like ammonia. In many cases it take's more energy (i.e. fossil fuel energy) than you can recover, and even when there's a net gain it's far too little compared to the alternatives. See vanderZwan's post below.
- AnimalMuppet 9y ago
  But if autarch is right, that it uses more energy to produce then it generates, is that energy to produce it carbon neutral? If not, then using ethanol as fuel is not carbon neutral, because of the carbon of the energy used to produce the ethanol.
- yourapostasy 9y ago
  > At least that's what I hear over here in Europe, maybe motivations are different in the US. The real reason corn-based ethanol is politically supported in the US is because of an artifact of the US federal political process. Iowa is the first state to hold caucuses [1], to a first approximation explanation. This exerts an effect similar to first mover advantage: their outcomes have a disproportionate effect upon other states' primaries [2] (linked article gives a better, more nuanced explanation than a glib "they're first"). Not coincidentally for this topic, Iowa grows a lot of corn [3], the most of any state in the US, and more than all of Mexico combined. The two major parties are terrified of pissing off Iowa voters who personally depend upon the corn economy in Iowa. So corn-based ethanol stays encrusted into the US federal political landscape, until an Alexander-like politician cuts it in half, Gordian Knot-mythos-like [4]. Either that, or until Iowa's shortsighted monocropping causes them to irretrievably lose their topsoil, and they can't grow anything at scale, and removing the subsidies becomes moot; at the macro scale, they're eroding their topsoil with no end in sight. I SWAG a few more decades before we reach an inflection point, where input costs to prop up poor topsoil corn growing start to negate the subsidies' artificial boost. That's going to really suck for our food supply system, if it comes down to that. [1] https://en.wikipedia.org/wiki/Iowa_caucuses https://en.wikipedia.org/wiki/Iowa_caucuses [2] https://people.howstuffworks.com/iowa-caucus.htm https://people.howstuffworks.com/iowa-caucus.htm [3] https://en.wikipedia.org/wiki/Corn_production_in_the_United_States https://en.wikipedia.org/wiki/Corn_production_in_the_United_... [4] https://en.wikipedia.org/wiki/Gordian_Knot https://en.wikipedia.org/wiki/Gordian_Knot

Corn ethanol _is_ an inefficient biofuel. It uses more energy to produce than it generates, but thanks to the federal government there's a mandate to include it in gasoline, so we keep producing it.

vanderZwan 9y ago

Yeah, I still remember the basic laws of thermodynamics ;). If only they taught those in high school too. Aside: sometimes I wonder if spending some time to teach more advanced concepts of science in more "conceptual" ways wouldn't be a lot more useful for the general public than the current style of education. You can get a perfectly fine intuition and "first-principle" understanding of laws of nature running the world around you, without ever worrying about calculus, and it's quite useful.

maxerickson 9y ago
What do the basic laws of thermodynamics and intuition do to inform you about the EROI of biofuels?
- vanderZwan 9y ago
  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.

maxerickson 9y ago

Using it as an oxidizer, even at some energy loss, likely makes lots of sense. It's relatively easy to handle, not that nasty, etc. It's probably not an energy loss though: http://www.energytrendsinsider.com/2016/02/23/a-critical-review-of-the-2015-energy-balance-for-corn-ethanol/ http://www.energytrendsinsider.com/2016/02/23/a-critical-rev... (But still not enough of an energy gain to be acting like it is a good energy source)

sbierwagen 9y ago
>Using it as an oxidizer, even at some energy loss, likely makes lots of sense Ethanol is C2H6O. Two carbons, six hydrogens, one oxygen. Not a lot of oxygen in that molecule. Calling it an oxidizer akin to LOX or N2H4O3 is unusual.
- maxerickson 9y ago
  Yes, oxygenate is the correct term.

sliverstorm 9y ago

Please see Wiki about oxygenates in gasoline: https://en.wikipedia.org/wiki/Oxygenate https://en.wikipedia.org/wiki/Oxygenate

simias 9y ago

AFAIK the argument is that the CO2 is produces during combustion was captured from the atmosphere while the plant was growing, so it's neutral in terms of CO2 emissions (not taking into account other sources of CO2 emissions during the fabrication of the ethanol). Fossil fuels on the other end take carbon that was sleeping in the ground and leave it in the atmosphere after combustion. At least that's what I hear over here in Europe, maybe motivations are different in the US.

wahern 9y ago
It takes a lot of energy to cultivate corn and produce ethanol. Think of all the trucks, tractors, and other machinery involved; and energy-intensive fertilizers like ammonia. In many cases it take's more energy (i.e. fossil fuel energy) than you can recover, and even when there's a net gain it's far too little compared to the alternatives. See vanderZwan's post below.
AnimalMuppet 9y ago
But if autarch is right, that it uses more energy to produce then it generates, is that energy to produce it carbon neutral? If not, then using ethanol as fuel is not carbon neutral, because of the carbon of the energy used to produce the ethanol.
yourapostasy 9y ago
> At least that's what I hear over here in Europe, maybe motivations are different in the US. The real reason corn-based ethanol is politically supported in the US is because of an artifact of the US federal political process. Iowa is the first state to hold caucuses [1], to a first approximation explanation. This exerts an effect similar to first mover advantage: their outcomes have a disproportionate effect upon other states' primaries [2] (linked article gives a better, more nuanced explanation than a glib "they're first"). Not coincidentally for this topic, Iowa grows a lot of corn [3], the most of any state in the US, and more than all of Mexico combined. The two major parties are terrified of pissing off Iowa voters who personally depend upon the corn economy in Iowa. So corn-based ethanol stays encrusted into the US federal political landscape, until an Alexander-like politician cuts it in half, Gordian Knot-mythos-like [4]. Either that, or until Iowa's shortsighted monocropping causes them to irretrievably lose their topsoil, and they can't grow anything at scale, and removing the subsidies becomes moot; at the macro scale, they're eroding their topsoil with no end in sight. I SWAG a few more decades before we reach an inflection point, where input costs to prop up poor topsoil corn growing start to negate the subsidies' artificial boost. That's going to really suck for our food supply system, if it comes down to that. [1] https://en.wikipedia.org/wiki/Iowa_caucuses https://en.wikipedia.org/wiki/Iowa_caucuses [2] https://people.howstuffworks.com/iowa-caucus.htm https://people.howstuffworks.com/iowa-caucus.htm [3] https://en.wikipedia.org/wiki/Corn_production_in_the_United_States https://en.wikipedia.org/wiki/Corn_production_in_the_United_... [4] https://en.wikipedia.org/wiki/Gordian_Knot https://en.wikipedia.org/wiki/Gordian_Knot