Environmental Management

, Volume 46, Issue 4, pp 565–578

Comparative Life Cycle Assessment of Lignocellulosic Ethanol Production: Biochemical Versus Thermochemical Conversion

  • Dongyan Mu
  • Thomas Seager
  • P. Suresh Rao
  • Fu Zhao
Article

DOI: 10.1007/s00267-010-9494-2

Cite this article as:
Mu, D., Seager, T., Rao, P.S. et al. Environmental Management (2010) 46: 565. doi:10.1007/s00267-010-9494-2

Abstract

Lignocellulosic biomass can be converted into ethanol through either biochemical or thermochemical conversion processes. Biochemical conversion involves hydrolysis and fermentation while thermochemical conversion involves gasification and catalytic synthesis. Even though these routes produce comparable amounts of ethanol and have similar energy efficiency at the plant level, little is known about their relative environmental performance from a life cycle perspective. Especially, the indirect impacts, i.e. emissions and resource consumption associated with the production of various process inputs, are largely neglected in previous studies. This article compiles material and energy flow data from process simulation models to develop life cycle inventory and compares the fossil fuel consumption, greenhouse gas emissions, and water consumption of both biomass-to-ethanol production processes. The results are presented in terms of contributions from feedstock, direct, indirect, and co-product credits for four representative biomass feedstocks i.e., wood chips, corn stover, waste paper, and wheat straw. To explore the potentials of the two conversion pathways, different technological scenarios are modeled, including current, 2012 and 2020 technology targets, as well as different production/co-production configurations. The modeling results suggest that biochemical conversion has slightly better performance on greenhouse gas emission and fossil fuel consumption, but that thermochemical conversion has significantly less direct, indirect, and life cycle water consumption. Also, if the thermochemical plant operates as a biorefinery with mixed alcohol co-products separated for chemicals, it has the potential to achieve better performance than biochemical pathway across all environmental impact categories considered due to higher co-product credits associated with chemicals being displaced. The results from this work serve as a starting point for developing full life cycle assessment model that facilitates effective decision-making regarding lignocellulosic ethanol production.

Keywords

Life cycle assessment Lignocellulosic ethanol Biochemical conversion Thermochemical conversion Greenhouse gas emission Fossil fuel consumption Water consumption 

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Dongyan Mu
    • 1
  • Thomas Seager
    • 2
  • P. Suresh Rao
    • 3
  • Fu Zhao
    • 4
  1. 1.School of Civil Engineering and Ecological Science and Engineering Interdisciplinary Graduate ProgramPurdue UniversityWest LafayetteUSA
  2. 2.Golisano Institute for SustainabilityRochester Institute of TechnologyRochesterUSA
  3. 3.School of Civil EngineeringPurdue UniversityWest LafayetteUSA
  4. 4.School of Mechanical Engineering and Division of Environmental and Ecological EngineeringPurdue UniversityWest LafayetteUSA

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