“In practice, though, ethanol is actually worse for the environment than traditional gasoline. And while ethanol is cheaper than gasoline, it also contains less energy by volume. Depending on the age of your vehicle, it can also be bad for your engine.
One thing ethanol is good for, though, is corn farmers. A 2021 report by Taxpayers for Common Sense called the Renewable Fuel Standard “the largest current subsidy for corn ethanol.” A 2022 study found, as Reuters put it, that “as a result of the mandate, corn cultivation grew 8.7% and expanded into 6.9 million additional acres of land between 2008 and 2016.”It therefore makes perfect sense for two candidates desperate for votes in Iowa—the state that produces more corn than any other—to pledge fealty to a federal mandate that requires more people to buy corn-based ethanol. But just because something makes political sense doesn’t make it good policy.”
https://reason.com/2024/01/10/haley-and-desantis-pander-to-iowans-by-praising-ethanol-mandate/