New research has come out that indicates watermelon could make a good biofuel additive. Now, I know you're immediately cringing because watermelon is a food crop and that spells disaster, but the good news is that no one is proposing that we start taking over arrable land with watermelon patches.
It turns out that 20 percent of every annual watermelon crop is unused because, well, it's ugly. Misshapen or bruised fruit doesn't sell, so farmers leave them in the field and take a loss. Those extra watermelons could be processed for their juice, which could then be made into biofuel.
What makes these disfigured melons biofuel-worthy? Watermelon juice contains seven to ten percent directly fermentable sugars or easy ethanol. While the juice would have to be almost triple concentrated to be the sole feedstock in a biofuel, it would make a great additive to other biofuel blends that need to be supplemented or diluted. Farmers could process the juice on-site and use it as an alternative fuel or sell it to biofuel-makers and make revenue on what would usually be wasted fruit.
Of course, a feedstock's potential to make ethanol isn't everything. We'll have to see how watermelon-blended biofuels perform compared to other feedstocks and gasoline to know if harvesting their juice is worthwhile.