Brazil stands as the second largest producer of ethanol obtained from sugarcane in the international market, having similar energy potential and much lower cost vis-a-vis ethanol from corn of countries such as the USA, and regions such as the European Union (EU), from beet and starch. Table 1 presents the global ethanol production between 2007 and 2012.

In Table 1, it is observed that the USA, Brazil, and Europe account for over 90 % of global ethanol production. The first two countries had similar production scale at the beginning of the period mentioned, occurring an expressive shift in favor of the USA during the period. In turn, EU has doubled its production with­out, however, reducing the difference to the first two significantly.

Brazil is pointed out as a tropical country with continental dimensions, in which the supply of biomass has great potential for use in power generation by Castro and Dantas (2008). In 2007, biomass was the second source of energy used in Brazil, with 31.1 % of the energy matrix, preceded by oil and its derivatives. Considering the national supply, biomass, along with other sources of internal origin, accounted for 3.7 % of the offer, according to the National Energy Balance (NEB) (ANEEL 2008).

According to Tolmasquim (2012), a great part of the Brazilian territory is within the most thriving region of the planet for the production of biomass, not only due to the high degree of sunlight on its territory, but also for its environ­mental conditions. In bioenergy, sugarcane stands out owing to technological advances, both in the agricultural and industrial phases, making ethanol and bio­electricity competitive products internally and externally.

The technological advance was not only due to the energy offer. The flex-fuel vehi­cle, whose engines work on any proportion of ethanol or gasoline, has already been consolidated in the market. Such was the acceptance of the Brazilian consumer that only 9 months after its release in 2003, the fleet of flex-fuel vehicles accounted for 57 % of the national fleet of light vehicles, i. e., about 18 million units (UNICA 2013b).

According to the Center for Sugarcane Technology (CTC) (2005), the biomass of sugarcane may become more important in energetic, economic, and environ­mental terms, with the increasing search for improvements in the production sys­tems of the sugarcane industry.

According to Dias et al. (2009), this highlight is due to the relevance of etha­nol production, its by-products, bagasse (cogeneration of electricity), and straw, as well as most of the biomass residues obtained in the agricultural and industrial activities, which become raw material capable of producing energy.

Among the sources of biomass for electricity generation in the country, sug­arcane is an alternative with great potential through the use of bagasse and straw. The participation of the cane is not only important for the diversification of the electric matrix, but also because the harvest coincides with the dry season in the Southeast and Midwest regions, where the greatest capacity of hydropower in Brazil is concentrated (ANEEL 2008).

Table 2 presents the main secondary sources, being expressively featured the electricity, produced mainly from hydropower and biomass, which have the sus­tainable characteristics due to the low GHG generation.

1.1.1 The Sugarcane Biomass

Both in Brazil and in the international market, biomass has been considered one of the main alternatives for diversification of energy sources and reduction of the use of fossil fuels (ANEEL 2008).

According to UNICA (2013a), there are 64.7 millions of hectares fit to sugar­cane plantation, i. e., 7.5 % of Brazilian cultivable area. However, sugarcane plan­tation occupied only 1 % of cultivable area in 2012. The sugarcane productivity in 2011/2012 harvest was 58.25 ton/ha for an area of 9.6 millions of hectares. The sugarcane production for milling was of 559.2 millions of tons, of which 297 mil­lions of tons of sugarcane were earmarked for the production of ethanol and the rest were earmarked for the production of sugar. It was produced a total of 22.7 millions of m3 of ethanol (8.6 million m3 of anhydrous ethanol and 14.1 million m3 of hydrated ethanol), i. e., about 6.8 m3/ha (UNICA 2013b) (Fig. 1).

In Brazil, there are 327 mills and distilleries allowed to operate for sugar and ethanol production, in which average capacity is about 810 m3/day. These mills are distributed in most Brazilian states, but their concentration is in Middle-South region. The total quantity of workers in these mills and distilleries was 160,984 in 2011 (Portal da Cana 2013; RAIS 2012). According to Shikida (2013), ‘1 ton of sugarcane produces, simultaneously, 120-135 kg of sugar and 20-23 l of ethanol, or if only produce ethanol, the amount is 80-86 l of ethanol’ (oral information).

The Brazilian areas suitable for the cultivation of sugarcane are concentrated in the Central-South region of Brazil (Fig. 2).

The sugarcane production is not adequate to the biome of the Brazilian Amazon or Pantanal, not only because they are protected areas by environmental legisla­tion, but also because they do not have edaphoclimatic conditions for sugarcane cultivation. It is noted that most of the sugarcane units, i. e., mills and distilleries are located in the Central-South and the northeastern coast of the country.

Veiga Filho (2008:3) reinforces this statement saying:

Rodrigues, [coordinator of the Agribusiness Center of Getulio Vargas Foundation] and Marcos Jank, [former] president of UNICA [Sugarcane Industry Union], say that 75 % of the sugar cane expansion occurs in pasture areas, which disallows another aspect of the offensive mounted against Brazilian ethanol. They say that the cane does not represent a real threat to the environmentally critical areas, such as the Amazon.

Chagas (2012) points out that in Brazil, ethanol is used in three sectors of the economy: transport, the chemical industry, and beverage manufacturing. Regardless of its allocation, Brazilian ethanol is more competitive than that pro­duced in other countries due to the large scale, which provides low production cost and low GHG emission, among other factors.

Table 3 depicts the volume of primary sources of biomass used in Brazil in 2011, highlighting the by-products of cane, which represent for more than 78 % of the primary sources.

In Brazil, there is no importation and exportation of sugarcane by-products. These by-products are consumed in the same mills and distilleries which they are produced because their transportation is infeasible. The transport of sugarcane also is infeasible for distance about 50-80 km from the mills (Rangel et al. 2008).