The most well-known first-generation biofuel is ethanol made by fermenting sugar extracted from sugar cane or sugar beets, or sugar extracted from starch contained in maize kernels or other starch-laden crops. Similar processing, but with different fermentation organisms, can yield another alcohol, butanol. Commercialization efforts for butanol are ongoing, while ethanol is already a well-established industry. Global production of first-generation bio-ethanol in 2006 was about 51 billion litres, with Brazil (from sugar cane) and the United States (from maize) each contributing about 18 billion litres, or 35 per cent of the total. China and India contributed 11 per cent to global ethanol production in 2006, and production levels were much lower in other countries, with feedstocks that include cane, corn, and several other sugar or starch crops (sugar beets, wheat, potatoes). Many countries are expanding or contemplating expanding their first-generation ethanol production, with Brazil and the United States having by far the largest expansion plans. Ethanol production is expected to more than double between now and 2013 in Brazil, and production capacity in the United States will double from the 2006 level once new plants currently under construction are completed.

From the perspective of petroleum substitution or carbon emissions mitigation efficiencies, the potential for most first-generation biofuels is limited. The United States is projected to produce about 34 billion litres of ethanol in 2007 by using 27 per cent its corn crop. On an energy basis, this ethanol will still account for less than 4 per cent of United States gasoline plus ethanol consumption in 2007. In addition, the significant amount of fossil fuel used to produce this ethanol substantially offsets the carbon emissions reductions from photosynthetic uptake of carbon by the corn plants.