Byproduct

A byproduct of biofuels production is any product, substance, or chemical compound created as a result of the process. Industry usage of the word is usually narrower, distinguishing byproducts from coproducts, where byproducts are waste products or products for which a commercial use has not yet been found. Alternately, byproducts reflect a cost of production. An example of a biofuels byproduct is glycerol from biodiesel production.