Life Cycle Assessment of Integrated Biorefinery-Cropping Systems: All Biomass is Local

1. Life Cycle Assessment of Integrated Biorefinery-Cropping Systems: All Biomass is Local Seungdo Kim and Bruce E. Dale Michigan State University June 24 - 25, 2004Arlington, Virginia

2. Biocommodities: A New Partnership between the U. S. Chemical Industry & U. S. Agriculture? Raw Materials + Processing = Value-Added Products Processing by Physical, Thermal, Chemical and/or Biological Means Cost to make mature, commodity products depends on: Raw material cost (60-70% of total) Processing cost (the remainder)

3. Features of a Mature Biocommodity Industry: Some Lessons from Petrocommodities • Yield of product(s) is the dominant techno-economic factor • Raw material cost & supply ultimately determines potential scale of industry • Product slate diversifies over time • Very broad plant raw material base (but compositionally materials are quite similar) • Agricultural productivity (“food vs. fuel”) is the ultimate constraint on production • “Sustainability” is the dominant socio-environmental constraint: soil fertility first of all • Industry will be influenced to an unprecedented degree by local issues: “all biomass is local”

4. Cost of Biomass vs Petroleum

5. Some Perspectives and Premises on Agriculture as a Producer & Consumer of Energy • Inexpensive plant raw materials will catalyze the verylarge scale production of fuels from “biomass” • “Consumer of energy” is straightforward • “Producer of energy” not so straightforward • Except for windpower, agriculture does not “produce” energy • Conversion facility (“biorefinery) makes the energy products • Systems questions addressed by “life cycle analysis” (LCA) integrating agricultural sector with biorefinery • Some critical issues: • all BTU are not created equal– “exchange rate” 3 BTU coal = 1 BTU electricity • all BTU do not have the same strategic importance • “All Biomass is Local” climate, soils, crops

6. What Are Life Cycle (LCA) Models? • Full system studies of material/energy inputs & outputs of both products & processes • Inventory environmental impacts of products & processes (many possible impacts, select “key” ones) • Objectives: • Benchmark, evaluate & improve environmental footprint • Compare with competition • Comply with regulations or consumer expectations? • Methods for doing LCA studies are not universally agreed upon—allocation issues in particular are both important and somewhat controversial

7. Some Life Cycle Analysis Standards: In Plain English • Use the most recent data possible • Make it easy for others to check your data and methods= transparency • Set clear system boundaries: what exactly are we comparing? • Multi-product systems must allocateenvironmental costs among all products-(no environmental burdens assigned to wastes) • Perform sensitivity analysis: how much do results vary if assumptions or data change?

8. Our Approach to Life Cycle Analysis • Be very specific about the location and particular cropping systems that support the biorefinery • Be very clear and careful about system boundaries • Defend/explain allocation of environmental burdens among products-including energy products • Formulate, ask and answer specific questions • Explore complete system (Industrial Ecology model) when possible • Remember: “All Biomass Is Local”

9. ALL BIOMASS IS LOCAL

10. Advantages of a Local Focus for Biobased Products LCA • Reduces opportunities for agenda-driven manipulation of data • Studies are more relevant to the actual situation faced by investors & innovators • Better application of agricultural & environmental policy instruments • Improves selection of crops & cropping systems for local biorefineries • Illuminates opportunities for system integration & “waste” utilization

11. Objectives • Environmental performance of biobased products • Integrated biorefinery-cropping systems • Ethanol • Polyhydroxyalkanoates (PHA) • Eco-efficiency analysis • Ethanol and PHA are produced from the same unit of arable land

12. Plant Raw Material Pre-processing Final Processing Functional Unit Recycle or Disposal Grains Products to Replace Petroleum Based or Petroleum Dependent Products Recycled within Product System or to Other Product Systems Fuels • Carbohydrates Chemicals, etc. • Protein Crop Residues Polymers • Feeds & Foods • Oil Oilseeds Monomers • Syngas Lubricants • Steam Electricity • • Sugar Crops Lignin Compost pile or Landfill Woody & Herbaceous Crops Ash Fertilizer • Concept of Biorefinery

13. Cropping Systems • Cropping site: Washington County, Illinois • No-tillage practice • Continuous cultivation (No winter cover crop) • 0 % of corn stover removed: CC • Average 50 % of corn stover removed: CC50 • Effect of winter cover crop • Wheat and oat as winter cover crops after corn cultivation with 70 % corn stover removal: CwCo 70

14. Products in a Biorefinery Agricultural process Biorefinery Products Use • Ethanol Wet milling Corn grain • Corn oil Liquid fuel • Corn gluten meal • Corn gluten feed If applicable Edible oil • Ethanol Corn stover Corn stover process • Electricity Animal feed Ethanol production system • Corn oil • Corn gluten meal Corn grain Wet milling • Corn gluten feed Export to power grid PHA fermentation & recovery • PHA Polymer If applicable • PHA Corn stover Corn stover process • Electricity PHA production system

15. Life Cycle Assessment Study • Functional Unit: One acre of farmland • Allocation: System expansion approach • Avoided product systems • Gasoline fueled vehicle for ethanol fueled vehicle • Polystyrene for PHA • Corn grain and nitrogen in urea for corn gluten meal/corn gluten feed • Soybean oil for corn oil • Electricity generated from a coal-fired power plant for surplus electricity • Inventory data sources: Literature • Soil organic carbon and nitrogen dynamics: DAYCENT model • Impact assessment: TRACI model (EPA) • Crude oil consumption, Nonrenewable energy, Global warming

16. Primary Assumptions • Ethanol yield • From corn grain: 2.55 gal/bushel (via wet milling) • From corn stover: 89.7 gal/dry ton • Ethanol is used as an E10 fuel in a compact passenger vehicle • a mixture of 10 % ethanol and 90 % gasoline by volume • PHA yield • From corn grain: 10.9 lb of PHA/bushel • From corn stover : 294 lb of PHA/dry ton • PHA replaces an equivalent mass of petroleum based polymer.

17. Allocation Procedures Products Alternative product systems Driving by E10 fueled vehicle Driving by gasoline fueled vehicle Gasoline Crude oil Ethanol production system Conventional polymer PHA Polymer production Crude oil PHA production system Surplus electricity Electricity Coal-fired power plant Coal Corn oil Soybean oil Soybean milling Soybean culture Corn gluten meal Corn grain Corn culture Corn gluten feed Nitrogen in urea Ammonia Natural gas Coproduct systems in both production systems

18. Primary Products from Biorefineries

19. Crude Oil Consumption Negative environmental impact represents an environmental credit.

20. Nonrenewable Energy

21. Global Warming

22. Eco-efficiency Definition A practice with a greater eco-efficiency would be more sustainable.

23. Eco-efficiency Analysis • Suppose ethanol and PHA are produced together from the same unit of arable land. Global warming (1,0) Crude oil used (0,0) Nonrenewable energy (0,0) X: Fraction of corn grain utilized for producing ethanol Y: Fraction of corn stover utilized for producing ethanol

24. Conclusions • Cropping systems play an important role in the environmental performance of biobased products. • Utilizing corn stover combined with winter cover crop production (CwCo70) is the most environmentally favorable cropping system studied here. • Both ethanol and PHA produced in CwCo70 provide environmental credits in terms of crude oil use, nonrenewable energy and global warming. • Considering only “sustainable utilization” of biomass (i.e., at maximum eco-efficiency), the fractions of corn grain and corn stover utilized for producing ethanol vary with the impact categories. • Sustainable, energy-producing approaches are available to produce commodity chemicals & fuels from plant raw materials