First generation feedstocks includes those that are already widely grown and used for some form of bioenergy or biofuel production. The vast majority of these crops are also used for food and feed production, which means that there are possible food versus fuel conflicts.
Sugars and starches
Sugars and starches are a primary source of energy for animals and are easily convertible into alcohols or other types of biofuels.
Alcohols, including ethanol (drinking alcohol) and butanol (“wood” alcohol), have been used as a source of bioenergy for thousands of years. Henry Ford designed his first cars to run on ethanol. Alcohols are produced by the fermentation of sugars, so the higher the yield of sugar in a feedstock the higher the yield of ethanol. Starches can be broken down into sugars with the use of enzymes and then converted into alcohols for fuel, although this extra step means that processing starches is somewhat less efficient than processing sugars
While enzymes that can break down starches have been well commercialized, the enzymes and other technologies for producing cellulosic ethanol (see below)are still relatively expensive.