Update in Dec 2016:
The margin for ethanol is going back up. I can't find the article I saw that said our exports have increased to northern Brazil because southern Brazil is keeping its sugar cane to make more sugar. US ethanol crush margin reaches nearly two-year high. An interesting fact in that article is that one bushel of corn makes 2.8 gallons of ethanol. This also reinforces my theory that the price of ethanol follows the price of gasoline, not the price of corn.
2/20/2019: Kinder Morgan to expand Chicago ethanol hub to calm glut concerns barge terminal
"Currently, Argo can unload roughly 120 to 150 tank cars of ethanol each week, or roughly 4 million gallons, and can load two barges, or roughly 1.2 million gallons, at a time." ADM is sending a bunch of ethanol there to drive prices down. "ADM can produce roughly 1.6 billion gallons of ethanol annually, about 10 percent of U.S. capacity. Despite its massive production, it has often been a buyer on the cash market to supplement its long-term supply deals or to support a market view, dealers said. The Illinois-based global commodities powerhouse accounted for roughly 70 percent of the ethanol sold at the Chicago hub late last year, according to the data reviewed by Reuters."