Now here’s an a-peeling idea for a cellulosic fuel source. Researchers at the Agricultural Research Service Citrus and Subtropical Products Laboratory in Winter Haven have been looking at the possibility of using citrus peels to make ethanol. According to this ARS story, citrus waste materials are rich in pectin, cellulose and hemicellusic polysaccharides, which can be hydrolyzed into sugars and fermented into alcohol. Most of this dried peel residue — a total of 1.2 million tons annually in Florida alone — is currently marketed as low-value cattle feed, despite its relatively high processing cost. They estimate that Florida’s citrus peel waste could yield up to 80 million gallons of ethanol per year.