Oil has lost a third of its value in two months, bringing U.S. drivers within pennies’ reach of $2.50 gasoline. But there’s at least one thing standing in the way of a steeper decline at the pumps: ethanol. While the crude rout dragged gasoline futures down about 60 cents a gallon, ethanol’s dropped a mere 15 cents — making it costlier than gasoline this week for the first time since January. Ethanol’s one thing that’ll keep gasoline prices from a total free fall. The biofuel’s value is being propped up by concern over yields for this year’s corn crop, its main feedstock. Meanwhile, refiners are required to blend the additive into gasoline to comply with the federal regulations. “Because they’re forced to blend, they’re blending a more expensive product,” Chris Knittel, professor of energy economics at the Massachusetts Institute of Technology in Cambridge, said by phone. “A large fraction […]