4 ms·

In reality ethanol is not used as a renewable fuel, although it is touted as such. It is simply used to increase the octane rating of gasoline. Without ethanol

In reality ethanol is not used as a renewable fuel, although it is touted as such. It is simply used to increase the octane rating of gasoline. Without ethanol we'd need lead. Or some stuff that would be worse. Or, we'd put up with the lower octane rating, and so less efficient engines, and fewer mpg, and more CO2 emissions.

olliej 3y ago
I was at least 20 before I realized the 87, 95, etc weren't release years (I think at least in part because I only became aware of them when NZ banned leaded gas in 96, and at the same time "unleaded 95" became something being advertised as the advertisers started advertising fuel grades like super)
- bombcar 3y ago
  Unleaded 98 SE was the best gas.
  - olliej 3y ago
    If only there were a DLC version :D
    - bombcar 3y ago
      I always consider DEF (diesel exhaust fluid) is basically DLC for diesel.
jerrysievert 3y ago
that doesn't make sense. there is clear gas with 110 octane, and most clear gas is 92 octane. clear gas does not have ethanol nor lead. there are other octane boosters that don't raise the price of food. editing to add that other octane boosters don't drop mpg efficiency nearly as much as ethanol does. ethanol also has a much lower energy content, meaning a much lower mpg.
- credit_guy 3y ago
  Petroleum contains many hydrocarbons, with chains of different lengths. Octane (C8H18) is one. Refineries separate various hydrocarbons. In principle a refinery can separate pure octane. If sold at the pump, that would be by definition gasoline with 100 octane rating. The majority of the hydrocarbons are worse than octane, but some are slightly better. So you could have gasoline without any additives that has an octane rating slightly higher than 100. The problem is that most chains have octane rating significantly lower than 100. What do you do with them? You throw them? Of course not. People create different blends, and add some additives so they can sell as much of the original petroleum as gasoline with a decent octane rating. Yes, there are some other octane boosters. The main ones today are 3: ethanol, MTBE and ETBE. MTBE and ETBE are derived from methanol and ethanol respectively [1]. I don't know if there is anything wrong with MTBE or ETBE, but the ethanol lobby managed to push the idea that ethanol is good, so it is widely mixed in gasoline in the US. According to the DOE [2]: Lower-octane gasoline is blended with 10% ethanol to attain the standard 87 octane. [1] https://en.wikipedia.org/wiki/Methyl_tert-butyl_ether#Alternatives_to_MTBE_as_an_anti-knock_agent https://en.wikipedia.org/wiki/Methyl_tert-butyl_ether#Altern... [2] https://afdc.energy.gov/fuels/ethanol_fuel_basics.html https://afdc.energy.gov/fuels/ethanol_fuel_basics.html
  - jabl 3y ago
    MTBE/ETBE is banned in many places due to groundwater contamination. But ethanol-less gasoline wouldn't be a disaster either, it would mean the refiners would have to do more processing (alkylation, reformation etc.) to increase the octane of the gasoline, which would increase costs. But OTOH without an ethanol mandate there might be less cost via agricultural subsidies etc., so it wouldn't surprise me if the total cost to society would be less. There are also some other octane boosters that could be used (which aren't environmental disasters like lead, or arguably corn ethanol), like aromatic amines.
  - jerrysievert 3y ago
    it's not the hydrocarbons or the fact that ethanol provides higher octane that I'm disagreeing with, it's this: > and so less efficient engines, and fewer mpg ethanol, while providing a higher octane rating (which if you drive a car that requires a higher octane rating for its immediate power might matter), actually lowers the mean mpg quite a bit, since it has much lower energy density. that, and the fact that we're literally burning food, are some of my issues with ethanol. I drive a car that knocks if I put less than 91 octane in, but if that octane is obtained from ethanol, it reduces the mpg by 25% (for 10% ethanol, higher if the ethanol percentage is raised). that's a problem. sure, I too want to get off of hydrocarbons that produce co2 for energy, but making that energy less efficient is not the way to do it, especially when we're burning our food and destroying the soil to achieve that.

olliej 3y ago

I was at least 20 before I realized the 87, 95, etc weren't release years (I think at least in part because I only became aware of them when NZ banned leaded gas in 96, and at the same time "unleaded 95" became something being advertised as the advertisers started advertising fuel grades like super)

bombcar 3y ago
Unleaded 98 SE was the best gas.
- olliej 3y ago
  If only there were a DLC version :D
  - bombcar 3y ago
    I always consider DEF (diesel exhaust fluid) is basically DLC for diesel.

jerrysievert 3y ago

that doesn't make sense. there is clear gas with 110 octane, and most clear gas is 92 octane. clear gas does not have ethanol nor lead. there are other octane boosters that don't raise the price of food. editing to add that other octane boosters don't drop mpg efficiency nearly as much as ethanol does. ethanol also has a much lower energy content, meaning a much lower mpg.

credit_guy 3y ago
Petroleum contains many hydrocarbons, with chains of different lengths. Octane (C8H18) is one. Refineries separate various hydrocarbons. In principle a refinery can separate pure octane. If sold at the pump, that would be by definition gasoline with 100 octane rating. The majority of the hydrocarbons are worse than octane, but some are slightly better. So you could have gasoline without any additives that has an octane rating slightly higher than 100. The problem is that most chains have octane rating significantly lower than 100. What do you do with them? You throw them? Of course not. People create different blends, and add some additives so they can sell as much of the original petroleum as gasoline with a decent octane rating. Yes, there are some other octane boosters. The main ones today are 3: ethanol, MTBE and ETBE. MTBE and ETBE are derived from methanol and ethanol respectively [1]. I don't know if there is anything wrong with MTBE or ETBE, but the ethanol lobby managed to push the idea that ethanol is good, so it is widely mixed in gasoline in the US. According to the DOE [2]: Lower-octane gasoline is blended with 10% ethanol to attain the standard 87 octane. [1] https://en.wikipedia.org/wiki/Methyl_tert-butyl_ether#Alternatives_to_MTBE_as_an_anti-knock_agent https://en.wikipedia.org/wiki/Methyl_tert-butyl_ether#Altern... [2] https://afdc.energy.gov/fuels/ethanol_fuel_basics.html https://afdc.energy.gov/fuels/ethanol_fuel_basics.html
- jabl 3y ago
  MTBE/ETBE is banned in many places due to groundwater contamination. But ethanol-less gasoline wouldn't be a disaster either, it would mean the refiners would have to do more processing (alkylation, reformation etc.) to increase the octane of the gasoline, which would increase costs. But OTOH without an ethanol mandate there might be less cost via agricultural subsidies etc., so it wouldn't surprise me if the total cost to society would be less. There are also some other octane boosters that could be used (which aren't environmental disasters like lead, or arguably corn ethanol), like aromatic amines.
- jerrysievert 3y ago
  it's not the hydrocarbons or the fact that ethanol provides higher octane that I'm disagreeing with, it's this: > and so less efficient engines, and fewer mpg ethanol, while providing a higher octane rating (which if you drive a car that requires a higher octane rating for its immediate power might matter), actually lowers the mean mpg quite a bit, since it has much lower energy density. that, and the fact that we're literally burning food, are some of my issues with ethanol. I drive a car that knocks if I put less than 91 octane in, but if that octane is obtained from ethanol, it reduces the mpg by 25% (for 10% ethanol, higher if the ethanol percentage is raised). that's a problem. sure, I too want to get off of hydrocarbons that produce co2 for energy, but making that energy less efficient is not the way to do it, especially when we're burning our food and destroying the soil to achieve that.