Greenhouse gas emissions and production cost of ethanol produced from biosyngas fermentation process

Abstract

Life cycle (LC) of ethanol has been evaluated to determine the environmental and economical viability of ethanol that was derived from biosyngas fermentation process (gasification-biosynthesis). Four scenarios [S1: untreated (raw), S2: treated (torrefied); S3: untreated-chemical looping gasification (CLG), S4: treated-CLG] were considered. The simulated biosyngas composition was used in this evaluation process. The GHG emissions and production cost varied from 1.19 to 1.32 kg-CO2 e/L and 0.78 to 0.90$/L, respectively, which were found to be dependent on the scenarios. The environmental and economical viability was found be improved when untreated feedstock was used instead of treated feedstock. Although the GHG emissions slightly reduced in the case of CLG process, production cost was nominally increased because of the cost incurred by the use of CaO. This study revealed that miscanthus is a promising feedstock for the ethanol industry, even if it is grown on marginal land, which can help abate GHG emissions.

Keywords: Biosyngas; Ethanol; GHG emissions; Life cycle assessment (LCA); Production cost.