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Life cycle assessment of biofuels from an integrated Brazilian algae-sugarcane biorefinery

Author:
Souza, Simone P., Gopal, Anand R., Seabra, Joaquim E.A.
Source:
Energy 2015 v.81 pp. 373-381
ISSN:
0360-5442
Subject:
Monte Carlo method, algae, algae culture, biodiesel, biorefining, carbon, carbon dioxide, developmental stages, electricity, energy, ethanol, fermentation, fuel production, glycerol, greenhouse gas emissions, heat, juices, life cycle assessment, petroleum, sugarcane, sugarcane bagasse, uncertainty, Brazil
Abstract:
Sugarcane ethanol biorefineries in Brazil produce carbon dioxide, electricity and heat as byproducts. These are essential inputs for algae biodiesel production. In this paper, we assessed ethanol's life cycle greenhouse gas emissions and fossil energy use produced in an integrated sugarcane and algae biorefinery where biodiesel replaces petroleum diesel for all agricultural operations. Carbon dioxide from cane juice fermentation is used as the carbon source for algae cultivation, and sugarcane bagasse is the sole source of energy for the entire facility. Glycerin produced from the biodiesel plant is consumed by algae during the mixotrophic growth phase. We assessed the uncertainties through a detailed Monte-Carlo analysis. We found that this integrated system can improve both the life cycle greenhouse gas emissions and the fossil energy use of sugarcane ethanol by around 10% and 50%, respectively, compared to a traditional Brazilian sugarcane ethanol distillery.
Agid:
6036060