The US looks set to use so-called “E15” gasoline throughout the summer. On Tuesday, President Joe Biden will announce that the US Environmental Protection Agency will issue a national emergency waiver allowing the use of the ethanol-gasoline blend between June 1 and September 15 as Americans complain about high fuel prices. Currently, the use of that fuel is illegal because of smog regulations.
Ethanol-gasoline blends became popular during the 2000s as a potential panacea for solving US energy dependence on the Middle East as well as a way to clean up the climate. It also always played well in the Iowa caucuses, as it gives us something to do with our immense corn surplus.
E85 fuel—a mix of 85 percent ethanol and 15 percent gasoline—rapidly fell out of favor. But 98 percent of US gas stations offer E10, a blend of 10 percent ethanol and 90 % gasoline, according to the Environmental Protection Agency . At this concentration, the ethanol oxygenates the fuel and increases its octane rating; it also stretches the country’s supply of gasoline by diluting it.