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

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: 1)Raw material cost (60-70% of total) 2)Processing cost (the remainder)

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”

Cost of Biomass vs Petroleum

Some Perspectives and Premises on Agriculture as a Producer & Consumer of Energy Inexpensive plant raw materials will catalyze the very large 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

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

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 allocate environmental costs among all products-(no environmental burdens assigned to wastes) Perform sensitivity analysis: how much do results vary if assumptions or data change?

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”

ALL BIOMASS IS LOCAL

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

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

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

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

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

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

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.

Allocation Procedures Corn oil Corn grainCorn gluten meal Corn gluten feed PHA Soybean oil Conventional polymer Soybean millingSoybean culture Corn culture Polymer production Products Alternative product systems Crude oil Nitrogen in ureaAmmoniaNatural gas Driving by E10 fueled vehicle Driving by gasoline fueled vehicle Crude oilGasoline Ethanol production system PHA production system Surplus electricityElectricityCoal-fired power plantCoal Coproduct systems in both production systems

Primary Products from Biorefineries

Crude Oil Consumption Negative environmental impact represents an environmental credit.

Nonrenewable Energy

Global Warming

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

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

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