As shown in Fig. 3.1, the life cycle of biofuels encompasses planting, growing and harvesting of biomass (if applicable), conversion to the biofuel and its use, also including all transportation steps used in the system. Each stage in the life cycle is associated with several sustainability issues, depending on the type of the feedstock and biofuel. Some of these issues are listed in Table 3.1 (Brigenzu et al., 2009; IDB, 2009; The Royal Society, 2008). Several of the environmental and social issues, particularly those associated with land use, food security and health impacts, have been discussed in chapter 2. Here, the focus is on the life cycle environmental impacts and economic costs.