August 19, 2022

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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 percent 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.

As the name suggests, E15 is a mix of 15 percent ethanol and 85 percent gasoline. It’s much less common in the US due to the EPA’s restriction on summer sales (because of the greater evaporation during hot weather), but in 2019, former President Donald Trump approved its use year-round. In 2021, the US Court of Appeals for the DC Circuit ruled that the EPA had exceeded its authority in doing so.

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The White House says that it is making the move “to address the pain Americans are feeling at the pump as a result of Putin’s Price Hike,” despite a 15 percent fall in oil prices over the past three weeks. The administration also says that “E15 can save a family 10 cents per gallon of gas on average,” although the reduction in fuel efficiency due to the lower energy density of E15 might make it difficult for anyone to actually notice.

It’s also bad news for anyone concerned about climate change. Although biofuel blends were supposed to save us, growing energy-intensive corn to dilute gasoline is probably worse than just burning the gas itself, as Ars’ Tim de Chant covered in February. Last week, the Intergovernmental Panel on Climate Change published its latest report with the finding that we have to massively cut carbon emissions within the next three years if we want to have a chance at limiting warming to even just 2°C globally.