Biodiesel scams are puny compared with Medicare and Social Security fraud. For sheer moxie, though, it’s hard to beat Phil Rivkin. ... He started Green Diesel in October 2005, two months after President George W. Bush signed legislation creating the Renewable Fuel Standard program. The law directed the EPA to oversee a regulatory regime designed to foster production of alternative transportation fuels, including corn-based ethanol, as well as biodiesel derived from vegetable oils, animal fats, and used cooking grease. ... The statute was a boon to renewable fuel makers—and an irritant to gasoline and diesel refiners—because it required refiners to blend at least 4 billion gallons of ethanol (for gasoline) and biodiesel (for diesel fuel) into their products in 2006, with the amount rising to 7.5 billion gallons by 2012. The program now calls for 36 billion gallons in 2022, with varieties of ethanol representing the bulk of the requirement. Each year, the EPA sets obligations for individual refiners. Most years, ExxonMobil is on the hook to blend the largest amounts of renewables. ... Making biodiesel is simple enough that high school students do it in chemistry class. In a process called transesterification, producers use a chemical catalyst such as methanol to separate methyl esters—the scientific name for biodiesel—from glycerin in such feedstocks as poultry fat. ... Per EPA rules, each gallon of ethanol or biodiesel produced is assigned a 38-digit number—a renewable identification number, or RIN—that travels with the product as it moves from producer to refiner to end user. Ethanol RINs generally remain fixed to their respective gallons throughout the process. But the EPA allows biodiesel makers to strip RINs off their product and sell them separately as tradable credits. Refiners who fall short of blending the statutory minimum of biodiesel into their refined products must buy RINs to make up the difference or pay penalties. ... It isn’t hard to see how Rivkin was able to snooker Fortune 100 companies. To them, Green Diesel—or some equally innocuous broker that had bought RINs from it—was merely an entry on a computer offering to make a problem go away. The refiners needed RINs, Rivkin was selling, and the price was trifling.