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Brazilian Biofuels Programmes from the WEL Nexus Perspective

Brazilian Biofuels Programmes from the WEL Nexus Perspective

Brazilian Biofuels Programmes from the WEL Nexus Perspective

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Brazil’s biofuel programmes viewed <strong>from</strong> <strong>the</strong> <strong>WEL</strong>-nexus perspectiveTable 4.6 Energy balance of ethanolFossil energy consumption in sugar cane production, harvesting and transportation (MJ tc -1 )Item 2005/06 Scenario 2020Agricultural operations 13.3 14.8Harvesting 33.3 46.9Sugar cane transportation 38.6 44.8Inputs transportation 10.9 13.5O<strong>the</strong>r activities 38.5 44.8Fertilisers 52.7 40.0Lime, herbicides, insecticides 12.1 11.1Seeds 5.9 6.6Machinery 6.8 15.5Total 210.2 238.0Fossil energy consumption in <strong>the</strong> production of ethanol (MJ tc -1 )Item 2005/06 Scenario 2020Chemicals and lubricants 19.2 19.7Building 0.5 0.5Equipments 3.9 3.9Total 23.6 24.0Energy balance, external flows (MJ tc -1 )2005/06 Scenario 2020Fossil inputSugar cane production/transportation 210.2 238.0Production of ethanol 23.6 24.0Total fossil input 233.8 262.0Renewable outputEthanol 1926.4 2060.3Bagasse surplus 176.0 0.0Electricity surplus 82.8 972.0Total renewable output 2185.2 3032.3Renewable output/fossil input (ethanol + bagasse + electricity) 9.3 11.6Source: The authors based on Macedo et al., 2008.Table 4.6 suggests that a considerable increase is expected in <strong>the</strong> fossil-fuel energyconsumption in <strong>the</strong> 2020 scenario (<strong>from</strong> 210.2 MJ in 2008 to 238 MJ in 2020), mainly due todiesel consumption associated to <strong>the</strong> growth of mechanical harvesting, trash recovering andincrease in <strong>the</strong> use of machinery (this item more than doubles for <strong>the</strong> 2020 scenario) (Macedoet al., 2008). Burning cane fields, still a common practice in Brazil, is a major concern becauseof <strong>the</strong> associated environmental and health hazards. This issue is being treated by <strong>the</strong>environmental agencies and will probably be resolved in <strong>the</strong> medium term through laws andagreements between government authorities and <strong>the</strong> sugar cane industry, increasingmechanical harvesting and <strong>the</strong> use of machinery. For example, in São Paulo, State Law no.11.241/2002 forbids <strong>the</strong> burning of straw for <strong>the</strong> purpose of manual sugar cane harvesting<strong>from</strong> 2021 (IEA, 2002).Higher use of residues in ferti-irrigation would significantly reduce <strong>the</strong> demand for mineralfertilisers. Macedo et al. (2004) also explain <strong>the</strong> slight changes in energy consumption for <strong>the</strong>production of ethanol (Table 4.6) for <strong>the</strong> 2020 scenario by <strong>the</strong> improvement of ethanol yield.The results of Macedo et al. (2008), as well as o<strong>the</strong>r results found in <strong>the</strong> literature review,show that <strong>the</strong> energy balance of ethanol is extremely positive. Fossil energy ratio was 9.3 for2005/2006 and may reach 11.6 in 2020 using existing commercial technologies (ibid.).Urquiaga et al. (2004) found <strong>the</strong> value of 8.06 for <strong>the</strong> fossil energy ratio for ethanol in 2004.According to Coelho et al. (2006), <strong>the</strong> production costs of ethanol <strong>from</strong> sugar cane are low notonly because of geographic conditions but also because of <strong>the</strong> favourable energy balance.35

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