I wasn’t referring to a specific fuel, I meant per amount of energy used it emits 66% percent less co2 since ethanol production in the US has a ~3x return on fossil fuel investment. I am basing the figure on the same source on the energy return on energy invested balance I used in my other comment in the thread. Here is the source.

It doesn’t matter the mix it is in, since it takes the equivalent of 1 gallon of fossil energy and outputs 3x as much cleanish bioenergy. If it is E10 it would take 10 gallons before 1 gallon of ethanol was used, but that 1 gallon of ethanol would result in a third of the CO2 emissions compared to gasoline fuel.