Time to rethink ethanol mandates for gasoline.

I just checked the price of corn. On May 7, the May 21, 2021 contract closed at $ 7.72 a bushel. A year ago, the price was a little over three dollars per bushel.
One bushel of corn makes 2.5 gallon of ethanol
That makes the feedstock price to make ethanol $3.08 a gallon. Add to that 50 cents to make the stuff and distribute it and the price per gallon is $ 3.58.
Since the heat content of ethanol is 67% of regular gasoline (no ethanol), the gasoline equivalent price of ethanol is $ 5.34 per gallon.
Over five bucks a gallon for ethanol! And that is before profit, blending, selling and taxes!
That’s the good news.
For the people that are worried about CO2 the bad news is:
To make corn you have to use 150 pounds of nitrogen fertilizer per acre. It takes the equivalent of 0.15 gallons of gasoline to produce one pound of nitrogen fertilizer. That comes to the equivalent of 22.5 gallons of gasoline to fertilize one acre. One acre of corn yields about 150 bushels of corn.
The fuel spent to produce one bushel of corn is therefore more than 0.15 gallons of gasoline. Since it also involves sowing, preparing the soil, cultivating, pesticides, phosphate fertilizer and harvesting it takes 0.25 gallons of fuel to produce one bushel of corn.
Here comes the kicker: When you ferment sugar into alcohol half the weight disappears as CO2! Let us examine the formula: C6H12O6 + Zymase → 2C2H5OH + 2CO2
The molecule weight of C2H5OH is 46 and the molecule weight of CO2 is 44.
Well almost half anyway.
Let us assume you have a car that gets 25 miles to the gallon and you drive 100 mile on pure gasoline. You have used 4 gallons of gasoline.
Now take the same car and drive 100 miles with a 10% ethanol mix, mandated by the EPA. Remember, they are concerned about CO2.
The ethanol has only 67% of the heat content of gasoline so the gas mileage will be lower. It will be consuming 0.04 x 0.9 +0.1 x 1.5 x 0.04 = 0.042 gallons per mile, 5% more or a total of 4.2 gallons for the 100 mile trip.
So you consumed 3.78 gallons of gasoline and 0.42 gallons of ethanol, for a total of 4.2 gallons. We have all experienced this increase in gas consumption. And this is best case.
What about CO2 up in the air? In the pure gasoline case we produced 4 gallons worth of CO2.
In the ethanol mix case we produced 4.2 gallons worth of CO2.
Add to that another .4 gallons equivalence of CO2 from the fermentation, and another .04 gallons worth of CO2 to produce the corn in the first place.
The sum total is 4.64 gallons worth of CO2, or about 16% more than in the gasoline only case.
But corn does absorb CO2 when it grows! Doesn’t that count?
Corn is one of the worst crops for soil erosion and uses up other nourishments that will not be used if you make ethanol from it. Granted the cattle are happy for the cakes that are left when the sugar and oil is removed.
In this age of looming food shortages nearly any other use of available tillable soil is to be preferred over ethanol production.
Oh, and one more thing. Assume that pure gasoline is 3 dollars a gallon at the pump, which includes 50 cents in taxes.
Unsubsidized ethanol blend should be $5.34 a gallon, before taxes
But we subsidize the ethanol production so the price is still 3 dollars a gallon at the pump.
If we used pure gasoline the hundred mile trip would cost twelve dollars.
If we paid full price for the ethanol blend we would pay $ 13.79 for the trip and produce 16% more CO2.
We are really paying $ 13.79 for the trip, produce 16% more CO2 and leave a bill of $1.79 for our grandchildren to pay, the subsidy of 0.42 gallons of ethanol.
This is EPA legislation at work, trying to combat the coming “climate catastrophe.”

There is a better way. remove ethanol subsidy guarantees and let the corn be used to produce more chicken and pork, and use some of the acreage to produce grain for a hungry world. This will help to prevent food prices inflation.

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Retired engineer, graduated from Chalmers Technical University a long time ago with a degree in Technical Physics. Career in Aerospace, Analytical Chemistry, computer chip manufacturing and finally adjunct faculty at Pennsylvania State University, taught just one course in Computer Engineering, the Capstone Course.

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