Agrofuels in Sub-Saharan Africa: Decision-making Criteria for Sustainability - Implementing Environmental and Resource Management - page 199

trial ways in which they are produced (Biofuelwatch et al. 2007). Agrofuels can be
made from (FAO 2008b):

• Sugar crops e.g. sugarcane, sugar beet, sweet sorghum;
• Starchy crops e.g. maize (corn), wheat, barley, rye, potatoes, cassava;
• Cellulosic materials e.g. switchgrass, Miscanthus , willow, poplar, stover;
• Oil crops e.g. rapeseed, oil palm, soybean, sunflower, peanut, Jatropha;
• Algae and animal fats.

The most common types of agrofuels are biodiesel and bioethanol. From figure
17.1 , it is evident that there has been a rapid and continuing increase in the pro-
duction of agrofuels, with bioethanol constituting the larger composition by vol-
ume. The same rapid increase can be seen in Sub-Saharan Africa (GRAIN 2008).
In 2009, the United States and Brazil accounted for 88 percent of global bioetha-
nol production whilst the European Union produced nearly 50 percent of the bio-
diesel (REN21 2010). Bioethanol is produced mainly by the fermentation of sug-
arcane or starch (mainly corn), while biodiesel is mainly produced as a result of
chemical conversion of fat or oil.

Global bioethanol and biodiesel production (estimates)

140000

120000

100000

80000

Bioethanol
Biodiesel

60000

40000

20000

0

1980 1985 1990 1995 2000 2005 2010 2015 2020

Ye a r s

Fig. 17.1. Rapid increase in global production of bioethanol and biodiesel (adopted from:
Dufey et al. 2007)

Four broad categories of agrofuels have been identified (UN 2007a) i.e.:

• 'First-generation' agrofuels, commonly biodiesel and bioethanol made from
feedstock;
• 'Second generation' agrofuels, mainly cellulosic ethanol made from lignocellu-
lose and other non-food materials, such as waste biomass, stalks of wheat, corn,
wood, special energy or biomass crops, such as Miscanthus ;
• 'Third generation' agrofuels, are low-input/high-yield and derive from algae;
• ' Fourth generation' agrofuels, are made using genetically engineered micro-
organisms designed to capture large amounts of carbon and efficiently produce
fuel.