Why is the Energy Return on Investment (EROI) much lower for North American ethanol fuel than for Brazilian ethanol? Select one: a. Labour costs are lower in Brazil. b. Fermentation of sugar cane differs from that of corn. c. Ethanol in Brazil is made using sugar cane as the source crop. d. Sugar cane plantations rely primarily on human labour. SPOTLIGHT PRODUCING ETHANOL FROM SUGARCANE IN BRAZIL Brazilians have been growing sugarcane since early settlement days in the 1500s. Over the past 30 years, they have been able to apply the world's most efficient sugarcane cultivation technology to the production of ethanol (mostly for fuel), sugar (a valuable product), and bagasse (sugarcane waste that is burned to produce heat and electricity). The process involves growing productive fields of sugarcane, harvesting the crop, and transporting it to sugarcane-processing plants. There, the sug arcane is washed, shredded, and milled to collect a sweet juice called garapa and a fibrous residue called bagasse. The garapa is processed into sugar and a thick molasses that is later fermented to produce ethanol. Initially, the ethanol is hydrous-meaning that it contains about 5% water. Usually, the water is removed by chemical means, and this anhydrous ethanol is combined 25.75 with gasoline to be burned in car engines. However, an increasing number of Brazilian "flex" vehicles are being built that can use the cheaper anhydrous ethanol and can handle other mixtures besides 25% ethanol and 75% gasoline. Brazil has become the world's largest producer of ethanol fuel, while producing valuable sugar and harnessing the waste bagasse to power the sugar- cane industry and to generate surplus electricity. The process decreases their reliance on fossil fuels, and occupies only 1.5% of their farmland. It is no wonder that Brazil is considered to have the world's most sustainable biofuels economy (Smeets et al., 2006, Goettemoeller et al., 2007)