Life Cycle Greenhouse Gas Emissions of Brazilian Sugar Cane Ethanol Evaluated with the GREET Model Using Data Submitted to RenovaBio

Brazil is the second-largest ethanolproducer in the world, primarilyusing sugar cane as feedstock. To foster biofuel production, the Braziliangovernment implemented a national biofuel policy, known as RenovaBio,in which greenhouse gas (GHG) emission reduction credits are providedto biofuel producers based on the carbon intensities (CI) of the fuelsthey produce. In this study, we configured the GREET model to evaluatelife cycle GHG emissions of Brazilian sugar cane ethanol, using datafrom 67 individual sugar cane mills submitted to RenovaBio in 2019/2020.The average CI per megajoule of sugar cane ethanol produced in Brazilfor use in the U.S. was estimated to be 35.2 g of CO2 equivalent,a 62% reduction from U.S. petroleum gasoline blendstock without consideringthe impacts of land use change. The three major GHG sources were on-fieldN(2)O emissions (24.3%), sugar cane farming energy use (24.2%),and sugar cane ethanol transport (19.3%). With the probability densityfunctions for key input parameters derived from individual mill data,we performed stochastic simulations with the GREET model to estimatethe variations in sugar cane ethanol CI and confirmed that despitethe larger variations in sugar cane ethanol CI, the fuel provideda robust GHG reduction benefit compared to gasoline blendstock. Life cycle analysis using data from 67individual plantscollected through Brazil's National Biofuel Program, RenovaBio,demonstrates greenhouse gas mitigation potential from Brazilian sugarcane ethanol production for use in the United States.