The answer to our fuel woes might be monster sweet potatoes

By Jess Zimmerman

Corn ethanol is a good idea in theory — what’s more renewable than a fuel source you plant and harvest every year? But corn is such an inefficient energy source that if we wanted to meet our biofuel goals with corn ethanol alone, they’d have to shoulder out every other crop. You know what yields more ethanol per acre than corn, though? Sweet potatoes.