New Data on Ethanol Plant Energy Consumption and Co-products Presented by: Steffen Mueller, PhD University of Illinois at Chicago Energy Resources Center Fuel Ethanol Workshop St. Louis, MO June, 2010
A) New Energy Use and Co-Product Data
What is current ethanol plant energy use: UIC 2008 Plant Energy Survey The sample frame consisted of the entire population of dry mill ethanol plants operating during the 2008 In total the survey was sent to 164 plants. The survey instrument was developed with industry input and Argonne National Laboratory. The survey instrument was issued to the respondents via a web-based template. Survey Research Laboratory located at U of I Urbana- Champaign created web-based survey template and issued secure survey links to each respondent.
Survey Instrument Screen Shot
Survey Response Characteristics In total, 90 dry mill plants of 150 operating plants during 2008 responded to the survey This represents 6.1 billion gallons of 9.27 billion gallons of operating capacity or a 66% response rate Two response tests were performed to assess potential bias. The first test assured that the vintage of responses matched the plant vintage of the population The second test assured that the geographic location of the responses matched the geographic location of the population
Bias Test: Plant Vintage 40 35 30 25 20 15 10 5 0 Population Survey Responses Number of Ethanol Plants 1996 1994 1991 1985 1981 2008 2006 2004 2002 2000 1998 Year
Bias Test: Geographic Location
Results: Process Technologies and Ethanol Yield Process technologies plant has installed : Corn Fractionation Unit Process technologies plant has installed : Backend Corn Oil Separation Unit Process technologies plant has installed : Carbon Dioxide Extraction Unit Process technologies plant has installed : Cold Cook Process Count 2 23 8 27 % 2.7 30.7 10.5 37.0 N 73 75 76 73 Ethanol Yield: Anhydrous Ethanol Yield: Denatured Weighted gallons/bushel 2.78 2.85 Avg 2.80 2.87 STD 0.12 0.13 N 77 78
Results: Energy Use All Thermal Feedstock Plants Natural Gas Plants Only (Btu/gal) Anhydrous (Btu/gal) Anhydrous Weighted Average (HHV) 28,692 29,118 Average (HHV) 28,590 29,177 STD (HHV) 4,471 3,416 Weighted Average (LHV) 25,859 26,206 N 78 73 Weighted Average 0.74 0.73 Average 0.76 0.75 STD 0.24 0.23 N 75 70
Results: Co-Products DDGS (lbs/gal) WDG (lbs/gal) Corn Oil (gal/gal) Weighted Average 5.30 2.15 0.006 N 53 53 53 Moisture content: DDGS 10.8%; WDG 57.2% Co-products combined, on a bone-dry basis amount to 5.68 lbs/gal
Co-Product Diversification Co-Product # of Plants Syrup 3 Modified Distillers Grains 3 Carbon Dioxide 1 Bran, Germ Syrup 1 Syrup, Carbon Dioxide 1 Condensed Distiller Solubles 2 Solubles 1
Results: Water Use Fresh Water Water Discharge Weighted gal/gal (anhydrous) 2.72 0.46 Avg 2.69 0.43 STD 0.88 0.63 N 48 55
2008 Ethanol At a Glance The last comprehensive survey of energy consumption at corn ethanol plants dates back to 2001 The 2001 survey was conducted by BBI International and it was commissioned by the Office of Energy Policy and New Uses, US Department of Agriculture The 2001 survey finds that, on average, dry mill plants use 36,000 Btu per gallon and 1.09 kwh per gallon of ethanol and produce 2.64 gallons of ethanol per bushel We find that ethanol produced in 2008 requires 28% less thermal energy per gallon and requires 32.1% less electricity per gallon but produces 5.3% more ethanol per bushel Peer Reviewed Paper currently in Print with Biotech Letters
B) Future Co-Products
Quantifying the Impact of New Technologies: Life Cycle Analysis The GWI of Corn Ethanol (aka carbon intensity) for the purpose of this study is defined as the sum of the emissions of Carbon Dioxide (CO 2 ), Nitrous Oxide (N 2 O), and Methane (CH 4 ) emitted on a life cycle basis weighted by the global warming potential of each gas as defined by the Intergovernmental Panel on Climate Change (IPCC). Unit: gco 2 e Unit related to fuel: gco 2 e/mj (gco 2 e/mmbtu)
Co-Product Credits Current Co-Product Credit: DDGS based on displacement of corn as animal feed. Life Cycle Credit for equivalent greenhouse gas emissions to produce that amount of corn Now: Additional Co-products I) Ethyl Lactate: Biobased ethyl lactate holds particular promise as an organic solvent. If a biobased chemical is identical to the petrochemical product (such as biobased PTT and petrochemical PTT) the technical substitution potential is 100% or if it can replace a chemically different product (such as ethyl lactate replacement of ethyl acetate) the substitution potential is lower II) Yield Enhancing Technologies Controlled Flow Cavitation and Cellulose Conversion
I) Integrated Ethyl Lactate / Ethanol Production Fermentation Corn (11.2 M bu/yr) $23 Million/yr Raw ethanol 30 Mgal/yr Lactic acid (88%) (20 M lb/yr) $10 MM/yr Distillation EtOH/H 2 O recycle 2.3/0.1 Mgal/year Esterification process Azeotrope (EtOH/H 2 O) 30/1.0 Mgal/yr Absolute EtOH 3.8 Mgal/yr Azeotropic EtOH/H 2 O 32.3/1.1 Mgal/yr Ethanol purification Absolute EtOH 32.3 Mgal/yr H 2 O Ethyl lactate 25 M lb/yr ($28 Million/yr) Absolute EtOH 28.5 Mgal/yr ($60 Million/yr)
Life Cycle Modeling Results Pathway Component Base Ethanol Ethyl Lactate Case 1 Ethyl Lactate Case 2 gco2e/mj gco2e/mj gco2e/mj Farm Equipment 5.0 5.3 5.3 Farm Chemicals 7.9 8.3 8.3 Downstream N2O 15.6 16.4 16.4 Feedstock Transport 2.2 2.3 2.3 Plant Energy 29.4 32.8 32.8 DDGS Credit -13.0-13.6-13.6 Lactic Acid 0.0 4.7 10.7 Ethyl Lactate Credit Petr. Substitute 0.0-28.2-19.3 Ethanol T&D 1.4 1.4 1.4 Combustion (net) 2.9 2.9 2.9 Total Fuel Cycle 51.5 32.3 47.2 Reduction from Base Ethanol -37.2% -8.3%
Life Cycle Analysis: Ethyl Lactate Co-Produced with Corn Ethanol 100.0 100.0 90.0 90.0 80.0 80.0 gco2e/mj 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0-10.0-20.0-30.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0-10.0-20.0-30.0 Combustion (net) Ethanol T&D Ethyl Lactate Credit Petr. Substitute Lactic Acid DDGS Credit Plant Energy Feedstock Transport Downstream N2O Farm Chemicals Farm Equipment Total Fuel Cycle -40.0-40.0-50.0-50.0-60.0 Base Ethanol Ethyl Lactate Case 1 Ethyl Lactate Case 2-60.0 Modeling support provided by Life Cycle Associates
Summary: Ethyl Lactate Co-Product The result indicate that depending on the lactic acid production process and the petrochemical substituted by ethyl lactate, co-producing ethyl lactate at corn ethanol plants can reduce ethanol s life cycle greenhouse gas emissions by 8% to 37%
II) Controlled Flow Cavitation Controlled flow cavitation (CFC), a process enhancement developed by Arisdyne Systems, Inc., is currently utilized by 2 operating ethanol plants The process improvement routes the corn and enzyme slurry through a narrow nozzle, which reduces the particle size distribution and enhances starch accessibility to enzymes The resulting yield increases range between 3% to 5% Besides increased starch conversion, laboratory testing has shown that CFC also holds particular promise for corn kernel fiber to ethanol conversion, which would increase yield by an additional 3% to 5% We model both the additional starch conversion and a combined starch and fiber to ethanol case
Life Cycle Analysis: Controlled Flow Cavitation 70.0 70.0 65.0 65.0 60.0 60.0 55.0 55.0 gco2e/mj 50.0 45.0 40.0 35.0 30.0 25.0 20.0 15.0 10.0 5.0 50.0 45.0 40.0 35.0 30.0 25.0 20.0 15.0 10.0 5.0 Combustion (net) Ethanol T&D DDGS Credit Plant Energy Feedstock Transport Downstream N2O Farm Chemicals Farm Equipment Total Fuel Cycle 0.0 0.0-5.0-5.0-10.0-10.0-15.0 Base Case CFC CFC & Fiber 1 CFC & Fiber 2-15.0 Modeling support provided by Life Cycle Associates
Summary: Controlled Flow Cavitation The results indicate that CFC reduces greenhouse gas emissions on a life cycle basis by 2.3% and CFC combined with corn kernel fiber conversion reduces greenhouse gas emissions by 4.9%
C) Co-Products and Land Use DDGS Absolute Energy, St. Ansgar IA
Determine Corn Supply Area Start-up: February of 2008. From 11/2008 to 8/2009 plant produced 96 mg of ethanol using 35 million bushels of corn
Absolute Energy LLC, St. Ansgar, IA St Ansgar, IA Minnesota Iowa
DDGS and Land Use Year 2008 Area County Corn Yield (bu/acre) 172 Agricultural Acres 2,379,000 Ethanol Production (gallons) 95,674,000 Average ethanol yield per bushel (gal/bu) 2.78 Required Bushels 34,459,000 St. Ansgar Corn-Ethanol Area Harvested (acres) 200,052 Percent of Net Area Harvest of Total Ag Acres 8% DDGS Production (tons) 215,570 DDGS corn eq - area harvested credit (acre) 42,685 DDGS soy eq - area harvested credit (acre) 61,489 Total Credit (acres) 104,174 St. Ansgar Net Area Harvested 95,878 Percent of Net Area Harvest of Total Ag Acres 4%
Summary Substantial Reduction in Energy Use at Ethanol Plants Increase in Ethanol yields and Co-product diversification Advanced Co-products will further reduce environmental footprint Advanced Feed products will further reduce land use implications
Questions Steffen Mueller University of Illinois at Chicago 312-355-3982 Ken Copenhaver University of Illinois at Chicago 217-377-0071