Experts are looking at the fuel potential of watermelons as millions of tons of the fruit not sold in the market can be converted to clean-burning ethanol to power cars and airplanes.

Researchers at the United States Department of Agriculture in Lane, Oklahoma made the finding in a study published in the journal "Biotechnology for Biofuels" Tuesday.

Chemist Wayne Fish, who led the study, found in experiments that 1.4 pounds of sugar can be extracted from the flesh and rind of a 20-pound watermelon. From that amount of sugar, seven-tenths of a pound of ethanol can be derived.

Fish estimated that 2.5 million gallons of ethanol can be extracted from the 360,000 tons of deformed and blemished watermelons left spoiling in fields across the U.S. every year.

He also said that water and nitrogen in leftover watermelon juice can be a good substitute for corn and molasses in the production of ethanol.