Do you sit at the drive-through with your engine running, even though the line isn’t moving? Does your car idle in the school pick-up lane? Do you warm up your car for 15 minutes on chilly mornings because you just can’t stand to sit on a cold car seat?

Despite its long history as a fuel, ethanol’s popularity has waxed and waned. Since ethanol — also known as ethyl alcohol, grain alcohol and drinking alcohol — became a banned substance with the advent of Prohibition in 1920, Henry Ford’s preferred fuel fell out of favor. It didn’t make a comeback until the oil embargo of the ’70s, and then, after gasoline supplies returned to normal, was quickly forgotten until motor fuel prices began to climb in the late 1990s...