Bio-Ethanol Production in Brazil

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Abstract

In this chapter the history and origin of the Brazilian program for bioethanol production (ProÁlcool) from sugarcane (Saccharum sp.) are described. Sugarcane today covers approximately 7 Mha, with 357 operating cane mills/ distilleries. The mean cane yield is 76.6 Mg ha-1 and almost half of the national production is dedicated to ethanol production, the remainder to sugar and other comestibles. The mean ethanol yield is 6280 L ha-1. An evaluation of the environmental impact of this program is reported, with especial emphasis on a detailed and transparent assessment of the energy balance and greenhouse gas (CO2, N2O, CH4) emissions. It was estimated that the energy balance (the ratio of total energy in the biofuel to fossil energy invested in its manufacture) was approximately 9.0, and the use of ethanol to fuel the average Brazilian car powered by a FlexFuel motor would incur an economy of 73% in greenhouse gas emissions per km travelled compared to the Brazilian gasohol. Other aspects of the environmental impact are not so positive. Air pollution due to pre-harvest burning of cane can have serious effects on children and elderly people when conditions are especially dry. However, cane burning is gradually being phased out with the introduction of mechanised green-cane harvesting. Water pollution was a serious problem early in the program but the return of distillery waste (vinasse) and other effluents to the field have now virtually eliminated this problem. Soil erosion can be severe on sloping land on susceptible soils but with the introduction of no-till techniques and green-cane harvesting the situation is slowly improving. The distribution of the sugar cane industry shows that reserves of biodiversity such as Amazônia are not threatened by the expansion of the program and while there may be no great advantages of the program for rural poor, the idea that it will create food shortages is belied by the huge area of Brazil compared to the area of cane planted. Working conditions for the cane cutters are severe, almost inhuman, but there is no shortage of men (and women) to perform this task as wages and employment benefits are considerably more favourable than for the majority of rural workers. The future will bring expansion of the industry with increased efficiency, more mechanisation of the harvest, lower environmental impact along with a reduction in the number of unskilled workers employed and an increase in wages for the more skilled. This biofuel program will not only be of considerable economic and environmental benefit to Brazil, but also will play a small but significant global role in the mitigation of greenhouse gas emissions from motor vehicles to the atmosphere of this planet.