Greenhouse gas emissions and energy balances in bio-ethanol production and utilization in Brazil (1996)

Abstract Production of sugar cane in Brazil in the 1996/97 season was 273 million t (harvested wet wt)/year, leading to 13.7 million m 3 ethanol and 13.5 million t of sugar. Emissions of greenhouse gases were evaluated for the agronomic/industrial production processes and product utilization including N 2 O and methane. Up-dating the energy balance from 1985 to 1995 indicated the effect of the main technological trends; apparently, fossil fuel consumption due to the increasing agricultural mechanization is largely off-set by technological advances in transportation and overall conversion efficiencies (agricultural and industrial). Output/input energy ratio in ethanol grew to 9.2 (average) and 11.2 (best values). Net savings in CO 2 (equivalent) emissions, due to ethanol and bagasse substitution for fossil fuels, correspond to 46.7×10 6  t CO 2 (equivalent)/year, nearly 20% of all CO 2 emissions from fuels in Brazil. Ethanol alone is responsible for 64% of the net avoided emissions.