Strewth! If you guys can't agree, what hope do we mere mortals have?

Sure, keep in mind: this is a real-world, for all practical purposes type calculation.

First: I used 2.96 gallons/bu. If you noticed in my link some refineries are reaching this level. I'm sure many, many more will be in the future.

Now, to the "Cattle Feed." Remember, almost 90% of all field corn goes to feed livestock, mostly cattle. This is a very important concept to keep in mind.

When you process a bushel of corn you get back 17.5 lbs of distillers grains. This is, for all practical purposes, corn with the starch, and CO2 removed. All of the vitamins, nutrients, and protein is still there. A ration that's 65% corn, and 30% dgs will actually yield 10% More weight on a cow than a ration with 95% corn.

For that reason, I, normally, figure that we've used 60% of the corn to realize our 2.96 gallons of ethanol, and retained 40% - .30 + .33(.30) of our cattle feeding ability.

*in the above calculation I used 33% instead of 40% because I knew that 17,706 btus signified that it was the Corn Plus Plant, and that they gassified some of their "syrup" thus cutting back, slightly, on the "feed" returned.

Anyway, let's take 3 gal/by (it's easier than using 2.96) and multiply by 3/2 (remember, we only used 2/3 of our corn for the ethanol) to get 4.5 gal/bu. Now, we'll multiply that by 150 bu/acre, and come out with 675 gal/acre.

Now, I adjust the tilling, planting, harvesting, and fertilizer production, and seed drying inputs accordingly; but I don't mess with the Refinery inputs since that process would never be undertaken absent the need to make ethanol.

Here's where I, really, take a "Liberty." I've given several links of real, honest to goodness, real-world tests that show that ethanol in ten, twenty, or thirty percent blends are basically mileage-neutral compared to gasoline. So, for a little "shock" value I used the 116,000 btu content of gasoline, not the 76,000 btus of ethanol. It's shady, of course; but, it's also "real-world" accurate, inasmuch as ethanol's 30% Higher Octane compensates where it really matters - at the gas pump.

Hey, PUD

Read it when I was young; don't remember much about it.

I'm just interested in the "Real" World. BTUs don't mean a thang if you can't get the energy out. In the Real World you need Octane. Ethanol has gobs of it. 113 - 116, depending on how you measure.

Throw some compression to it, and you can knock gasoline's socks off. At low to medium blends you don't need too much compression to equal gasoline's performance. Two Links: First one on "Efficiency," Second on on EPA cycle test using midlevel blends.

http://www.methanol.org/pdf/ISAF-XV-EPA.pdf

http://www.mda.state.mn.us/news/publications/renewable/ethanol/e20drivab...

Again, a Hershy Bar has a thousand btus, or so; but you can't burn it in an ICE. BTUs, without considering Octane, is a worthless metric. In the "Real" world you can do as much work with ethanol as with gasoline.