Task 2.10:
Life Cycle Assessment of Fermentable
Carbohydrates for Biofuels and Commodity
Chemicals
Edgardo Ortiz-Reyes
Graduate Student
Prof. Robert P. Anex
Advisor
Research Task
Develop Sustainability Metric
Greenhouse Gas Emissions
Energy use (total & fossil)
Eutrophication
Build life cycle inventory data
Feedstock Production
Research Question:
Feedstock Transportation
How do fermentable carbohydrates
from energy cane and sweet sorghum
grown in LA compare with that from US
corn syrup, US sugar beets, and
Brazilian sugar cane?
Processing
Final Conversion
Production System and LCA Goal and Scope
Our Emphasis
Co-Products
Emissions to air, water and/or soil
Collaboration with
industry partners
Boundary
Agriculture
Production
Transportation
Processing
Milling /
Cogeneration
Energy and Material inputs
Functional Unit:
1 Tonne F.C.
LCA
Scope
Agriculture to Final Conversion
Cradle to Gate Analysis
F.C. = fermentable carbohydrates
Conversion
Functional Unit:
One MJ of Fuel
Goal
discussed
today
Greenhouse Gas emissions [kg CO2 eq]
Resource Depletion [MJ-Fossil Fuel]
Eutrophication Potential [kg PO4 eq]
GHG Emissions of F.C. Allocated by Energy
Energy Cane
Environmental Burden
GHG = greenhouse gas
83% beets
70% energy cane
83% sorghum
85% sugar cane BR
66% US corn
Fermentable Carbohydrates
17%
30%
17%
15%
34%
Co-products
GHG Emissions of F. C. Allocated by Market Value
Environmental Burden
91%
90%
95%
95%
65%
F.C. = fermentable carbohydrates, GHG = greenhouse gas
Fermentable Carbohydrates
9%
10%
5%
5%
35%
Co-products
GHG Emission Contribution by Input
Nitrogen
Fuel
Agricultural Phase
GHG = greenhouse gas
Total Fossil Energy Use
Brazilian sugar cane
GHG Emission from Virent Drop-in Biofuels
45% Reduction in GHG emission per MJ
Scenario with H2 from biomass
Conclusions
 The major source of GHG emissions in Sweet Sorghum and
Energy Cane production comes from Nitrogen Fertilizer,
Field emissions (N2O), and fossil fuel use
 Sweet Sorghum and Energy Cane GHG emissions are
similar to Brazilian Sugar Cane
 Fermentable Carbohydrates from Sweet Sorghum and
Energy Cane have the lowest GHG emissions
Future Work
Compare economic assessment of Fermentable Carbohydrates from Energy
Cane and Sweet Sorghum with their environmental assessment
Estimate Greenhouse gas emission, Eutrophication Potential and Energy use
for the production of Isoprene