Doing the math
Sorry to harp on the peak oil thing. I think I lose half my audience every time I bring this up. When did I turn into an activist? I'm just having a hard time shaking the idea of the end of life as we know it...
Eleutheros had a post titled "Do the Math", in which he stated that if every kernel of corn* grown worldwide were turned into ethanol, it would amount to about four days' worth of fuel for the US. He didn't include his calculations, so I thought I'd try to "do the math" myself.
"The math" in this case is just some back-of-the-napkin stuff - mostly unit conversions. Nothing fancy. If you trust my math skills, feel free to skip to the end. Note that my math skills are pretty shaky...
My sources are just whatever came up first on Google.
So here goes:
According to this link, there were 598 million metric tons of corn produced globally in 2002. (That was the first year I came across. Let's assume it's typical.)
598 million metric tons * (2204.6 lbs/metric ton)
...converts to 1.3 billion lbs of corn.
A bushel of corn is currently defined as 56 lbs.
1.3 billion lbs * (1 bushel/56 lbs)
...converts to about 23.5 million bushels of corn.
According to this article, a bushel of corn can produce 2.7 gallons of ethanol.
23.5 million bushels * (2.7 gallons/bushel)
...tells us that 63.5 million gallons of ethanol could theoretically be made from all the corn grown globally in one year.
According to this, a barrel of petroleum has 42 gallons. After refining, it could be made into about 19.5 gallons of gasoline.
So if we say that 1 gallon of ethanol can replace one gallon of gasoline, then
63.5 million gallons * (1 barrel / 19.5 gallons)
comes to 3.2 million barrels.
(The 1-to-1 ethanol-to-gasoline ratio is likely flawed, but this is
getting too complicated. Let's just say 1-to-1.)
According to this source, the United States currently uses 20 million barrels of oil per day.
3.2 million barrels * (1 day / 20 million barrels)
amounts to 0.16 days.
So if we can stop using corn for livestock feed, corn starch, corn syrup, corn oil, corn chips, corn stoves, corn bread, popcorn, candy corn**, corn on the cob, corn dogs, creamed corn... er... sorry, I was channeling Forrest Gump for a second...
If we use all of the corn grown in one year for making ethanol, and production is still propped up by using current (petroleum-heavy) farming practices, it would keep the U.S. running for just under four hours. Or, if you prefer, Argentina could last almost a week. Or we could supply Togo with their fuel needs for the entire year.
Feel free to check my math. I'm sure this must be due to rounding error.
* - Corn = maize. I know in some places "corn" is a generic grain term.
** - I checked. Corn syrup is an ingredient in Candy Corn