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Distillers Grains Displacement Ratios for Corn Ethanol Life Cycle Analysis – Limitations and Uncertainties
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Distillers Grains Displacement Ratios for Corn Ethanol Life Cycle Analysis – Limitations and Uncertainties

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Invited presentation at the CRC Workshop on Life Cycle Analysis of Biofuels, Oct 20-21, 2009. More info at: http://www.crcao.org/workshops/LCA%20October%202009/LCAindex.html

Invited presentation at the CRC Workshop on Life Cycle Analysis of Biofuels, Oct 20-21, 2009. More info at: http://www.crcao.org/workshops/LCA%20October%202009/LCAindex.html

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Distillers Grains Displacement Ratios for Corn Ethanol Life Cycle Analysis – Limitations and Uncertainties Presentation Transcript

  • 1. Distillers Grains Displacement Ratios for Corn Ethanol Life Cycle Analysis – Limitations and Uncertainties Salil Arora, May Wu, Michael Wang Salil Arora, May Wu, Michael Wang Center for Transportation Research Argonne National Laboratory Presented at the CRC Workshop on Life Cycle Analysis of Biofuels Argonne National Laboratory, October 20‐21, 2009 A N ti lL b t O t b 20 21 2009
  • 2. U.S. Corn Ethanol and Distillers Grains production By 2015, with 15  Billion gallon of Corn  Ethanol, approximately  Ethanol approximately 37 Million Metric Tons  of  Distillers Grains will  be produced be produced Source: EIA/DOE Annual Energy Review 2008; RFA, 2009 Source: EIA/DOE Annual Energy Review 2008; RFA 2009 2
  • 3. U.S. Distillers Grains consumption – Domestic use  Beef and Dairy are major consumers, all WDGS consumed by beef and dairy cattle  Market share of Swine and Poultry animals is increasing, but can only consume DDGS DDGS/WDGS split (%) Market Animal Type Share DDGS WDGS Beef 40% 58% 42% Dairy 41% 58% 42% Swine 13% 100% 0% Poultry 6% 100% 0% Total T t l 100% 66% 34% Source: RFA, 2009 3
  • 4. All of Exported-U.S. Distillers Grains consumed as DDGS  In 2008, 20% of U.S. distillers grains production was exported I 2008 20% f U S di till i d ti t d  Mainly to Mexico, Canada, EU+Turkey, and Southeast Asia  In near future, export market can absorb 20% or more of the total U.S. Distillers Grains  production  Distillers Grains exported as DDGS  Assumed market share by animal type similar to U.S. Domestic consumption Source: US Grains Council, 2009 4
  • 5. U.S. Distillers Grains – Market Size  U.S. Distillers Grains market size large enough to absorb projected increase in DGS  production by 2015 production by 2015 Feed per GCAU GCAU Market penetration Animal type (metric tons/unit/yr.) (million units) (1,000 metric tons) 50% 100% y Dairy 3.95 10.55 10% 4,331 8,662 DGS Inclusion 20% 8,662 17,324 Beef 2.1 21.22 20% 4,456 8,912 DGS Inclusion 30% 6,684 6 684 13,369 13 369 Swine 2.1 26.24 10% 2,755 5,510 DGS Inclusion 20% 5,510 11,021 Poultry 2.1 30.44 10% 3,196 6,392 DGS Inclusion 15% 4,794 9,589 Total Market Size at current inclusion levels 17,493 34,987 GCAU = Grain Consuming Animal Unit Source: USDA-ERS 2009  Significant proportion of U.S. Livestock Industry categorized as Concentrated Animal  Si ifi t ti f U S Li t k I d t t i d C t t dA i l Feeding Operations (CAFOs), thus making it easier to incorporate Distillers Grains: – 262 Beef‐feedlots handle 60% of US Beef cattle sales – 40 Swine operations account for 75% of 100 million hogs marketed annually 40 Swine operations account for 75% of 100 million hogs marketed annually – 36% of Dairy operations have at least 1,000 head 5
  • 6. Distillers Grains use by Animal Type – Survey and Feedback from Animal Science Experts p  In our original study we relied on a 2007 NASS‐USDA survey reporting Distillers Grains  use in Beef, Dairy, and Swine  2007 Texas Tech University surveyed nutritionists consulting Beef cattle feedlots,  2007 Texas Tech University surveyed nutritionists consulting Beef cattle feedlots survey representative of 69% of total U.S. beef cattle population in 2007  2009 Univ. Nebraska survey reported distillers grains use in beef feedlot cattle in the  State of Nebraska State of Nebraska  For other animal types feedback received from Industry and University feed  nutritionists Inclusion rate (%) Beef cattle Dairy Swine Poultry Survey DDGS WDGS DDGS WDGS DDGS DDGS NASS-USDA 2007 23% ─ 8% ─ 10% ─ Texas Tech 2007 16.5% 16.5% ─ ─ ─ ─ UNL 2009 ─ 35.5% ─ ─ ─ ─ Industry Nutritionists dust y ut t o sts *15% 5% *15% 5% 10% 0% 10% 0% 20% 0% 10% 0% Argonne Study 17% 25% 10% 10% 20% 10% *For DGS inclusion in SFC diets for Beef Cattle 6
  • 7. Feeding of Distillers Grains in Beef Feedlot Cattle & Corn Processing Methods g  2007 Texas Tech survey reported steam‐flaking of corn (SFC) as the most common  processing method in US Beef feedlots – Dry rolled corn / High moisture corn (DRC/HMC): Midwest – Steam flaked corn: High Plains, Southwest, other regions – For current study, we assumed market share of  SFC and DRC/HMC to be 62% and 38%  Reasons for using SFC: – Better animal performance compared Better animal performance compared to DRC/HMC based diets – Energy intensive: high Natural gas and Electricity use  Impact of introducing Distillers grains in Beef feedlot cattle diets – DRC/HMC + DGS diets have equivalent animal performance compared to SFC + DGS diets – Energy savings due to switch from SFC to DRC/HMC diets gy g / 7
  • 8. What does Distillers Grains displace in Animal Diets?  Distillers Grains generally displace equal amounts of corn & SBM, because of high protein  content (~30%, DM basis)   Beef cattle: mainly replace corn, and small amounts of SBM and urea – Improved animal performance (weight gain) when fed in combination with DRC/HMC diets – 75% of the 2009 UNL survey respondents reported improved animal performance, 23.6%‐no  change – No change in performance when fed in combination with SFC diets   Dairy cattle: replace equal amounts of corn and SBM – Improved milk production reported in scientific studies – NASS‐USDA reported 8% inclusion, no survey data on animal performance available  Swine: replace equal amounts of corn and SBM – Animal performance remains unchanged – NASS‐USDA reported 10% inclusion, recently because of drop in DDGS prices, higher inclusion  between 20‐30% b 20 30%  Poultry: replace equal amounts of corn and SBM – No change is animal performance  Enteric fermentation credit: due to improved animal performance for Beef cattle fed  DRC/HMC diets and Dairy cattle 8
  • 9. Distillers grains Displacement ratios  Displacement ratio for the entire US DGS production Di l t ti f th ti US DGS d ti Displacement ratio kg feed displaced  Enteric  per kg DGS (wet basis)** Fermentation Credit Corn Soybean  Urea CO2 savings  Meal (g/mmBtu EtOH) DGS sold as DDGS DGS sold as DDGS 0.770 0 770 0.390 0 390 0.021 0 021 ‐1,808 1 808 DGS sold as WDGS 0.925 0.407 0.023 ‐4,576 US DGS production* 0.793 0.398 0.020 ‐2,449 *Includes Domestic Consumption & Exports  **Displacement ratio presented as DDGS with 11% moisture  Uncertainties in determining future displacement ratios – Whi h i l f d Which animal feed markets will absorb future increase in DGS production? k t ill b b f t i i DGS d ti ? – Beef and Dairy feed markets are saturated at current inclusion levels of 20% and 10% – Increase in inclusion levels for beef and dairy diets will keep displacement ratios unchanged – Increase in market share of swine and poultry will decrease displacement ratios but above unity Increase in market share of swine and poultry will decrease displacement ratios, but above unity – Increase in Exports market share will decrease overall displacement ratios 9
  • 10. New Corn Ethanol Processing Technologies  New technologies being adopted by new as well as existing Ethanol plants – Reduce energy costs – Improved profitability by producing more valuable co‐products Improved profitability by producing more valuable co‐products  Corn oil extraction: corn oil and de‐oiled DGS as co‐products – Modification to existing dry mills, using centrifuge to extract corn oil from DGS – DGS generally have fat content of 11%, while de‐oiled DGS have fat content of 2%  Dry mill corn fractionation: HPDDG, corn oil, and corn gluten feed as co‐products – Separates corn kernel into endosperm, germ, and bran Separates corn kernel into endosperm, germ, and bran – HPDDG has high protein content (35‐44%) and low fat content (3‐6%), used in dairy, swine  and poultry diets – Corn gluten feed (CGF) has a protein content of 20% used in beef and dairy diets typically Corn gluten feed (CGF)  has a protein content of 20%, used in beef and dairy diets, typically  replaces corn in animal diets 10
  • 11. Displacement ratios of coproducts from new technologies g  De‐oiled DDGS – no data available on inclusion in animal diets – assumed to have same displacement ratio as DDGS  Corn oil – displaces soybean oil  Corn gluten feed (CGF) – 1 kg CGF displaces 1 kg of corn in beef and dairy diets – recommended inclusion levels of 20% in beef diets, animal performance remains unchanged , p g  High Protein Dry Distillers Grains (HPDDG) Displacement ratio kg feed displaced per  – used in dairy, swine and poultry diets kg HPDDG (wet basis)* – displaces greater amounts of SBM than corn displaces greater amounts of SBM than corn Corn Soybean Meal Soybean Meal – animal performance remains unchanged 0.282 0.735 *Based on HPDDG inclusion in Swine diets,  Widmer et al. 2008, J of Animal Sci. 11
  • 12. Energy Consumption by Technology EtOH yield y DGS yield y Corn Oil HPDDG CGF Process (gal/bu) (lb/gal EtOH)* (lb/gal) (lb/gal)* (lb/gal)* Case A. GREET Avg. (80% NG, 20% Coal), DDGS 2.72 5.995 Case B. GREET Avg. (80% NG, 20% Coal), Wet-DGS 2.72 15.244 Case C. GREET Avg. (100% NG), DDGS 2.72 5.995 Case D. Corn oil extraction (100%NG), DDGS 2.73 5.333 0.28 Case E. Corn Fractionation (100% NG) 2.64 0.28 2.6 3.7 Source: GREET 2009, Mueller & C S 2009 M ll Copenhaver 2009 h *Yield *Yi ld as wet b i DDGS 11% moisture, W t DGS 65% moisture, t basis, DDGS: i t Wet-DGS: i t HPDDG & CGF: 10% moisture. EtOH yield as undenatured gallon 35,000 1.20 Thermal Energy Electricity 30,000 30 000 1.00 25,000 0.80 kWh/ga EtOH Btu/gal EtOH 20,000 al 0.60 0 60 15,000 0.40 10,000 0.20 5,000 5 000 0 0.00 Case A Case B Case C Case D Case E 12
  • 13. Methods of dealing with Co-products of Biofuels  Displacement method (System boundary expansion method or Substitution method)  Allocation methods – Mass based allocation Mass based allocation – Energy content/BTU based allocation – Market value/Economic revenue based allocation  Process‐purpose based method  European Union in its latest directive on renewable energy has selected: – Energy Allocation method for Individual biofuel manufacturers  – Displacement method in addition to Energy allocation method for policy analysis  CARB and EPA are using displacement method  Displacement method is the most conservative LCA approach Displacement method is the most conservative LCA approach  Energy Allocation most suitable when majority coproducts are used as fuels, e.g.  Petroleum refineries 13
  • 14. Choice of Co-product method has significant effect on WTW results for Corn Ethanol LCA 1,200,000 PTW Fossil Energy WTP Case Use Btu/mmBtu) 1,000,000 Coproducts Case 1 Case 2 Case 3 Case 4 Case 5 DM 13% 1 800,000 EA 37% DM 18% nergy Use (B 2 EA 37% 600,000 DM 13% 3 EA 37% 400,000 DM 17% Fossil En 4 EA 37% 200,000 DM 15% 5 EA 39% 0 DM EA DM EA DM EA DM EA DM EA DM = Displacement method EA = Energy Allocation Gasoline GREET GREET GREET New EtOH, New EtOH, Avg. EtOH Avg. EtOH Avg. EtOH Corn oil & Corn (80% NG, (80% NG, (100% NG), DDGS Fractionation ), 20% Coal), 20% Coal), ), DDGS ( (100% NG) ) ( (100% NG)) DDGS Wet-DGS 14
  • 15. WTW GHG emissions 100,000 100,000 Case 1 Case 2 Case 3 Case 4 Case 5 GHG Case Emissions 80,000 80,000 Coproducts HG Emissions (g/mmBtu) GH Emission (g/mmBtu DM 17% 60,000 60,000 1 EA 37% DM 26% 40,000 2 40,000 EA 37% DM 19% 3 20,000 20,000 EA 37% DM 20% 4 0 0 EA 36% PTW DM 18% 5 -20,000 WTP EA 39% -20,000 WTP WTW -40,000 -40,000 -40 000 DM EA DM EA DM EA DM EA DM EA DM = Displacement method EA = Energy Allocation Gasoline GREET GREET GREET New EtOH, New EtOH, Avg. EtOH Avg. EtOH Avg. EtOH Corn oil & Corn (80% NG, (80% NG, (100% NG), DDGS Fractionation ), 20% Coal), 20% Coal), ), DDGS ( (100% NG) ) ( (100% NG)) DDGS Wet-DGS 15
  • 16. WTW GHG emissions 100,000 80,000 u) GH Emission (g/mmBtu 60,000 40,000 ns 20,000 HG 0 PTW -20,000 WTP WTW -40,000 DM DM DM DM DM DM = Displacement method Gasoline GREET GREET GREET New EtOH, New EtOH, Avg. EtOH Avg. EtOH Avg. EtOH Corn oil & Corn ( (80% NG, ( (80% NG, ( (100% NG), ) DDGS Fractionation 20% Coal), 20% Coal), DDGS (100% NG) (100% NG) DDGS Wet-DGS 16
  • 17. WTW GHG reduction relative to Gasoline GREET GREET GREET New EtOH EtOH, New EtOH EtOH, Avg. EtOH Avg. EtOH Avg. EtOH Corn oil & Corn (80% NG, (80% NG, (100% NG), DDGS Fractionation 20% Coal), 20% Coal), DDGS (100% NG) (100% NG) DDGS Wet-DGS DM = Displacement method DM EA DM EA DM EA DM EA DM EA EA = Energy Allocation gy 0% -10% ange ative GHG Emission Cha -20% -26.2% -30% 30% -32.4% -37.4% -40% -38.2% -42.4% Rela -43.6% 43 6% -50% -47.4% -50.5% -50.7% -53.4% -60% 17
  • 18. WTW GHG reduction relative to Gasoline GREET GREET GREET New EtOH, New EtOH, Avg. EtOH Avg. EtOH Avg. EtOH Corn oil & Corn (80% NG, (80% NG, (100% NG), DDGS Fractionation 20% Coal), 20% Coal), DDGS (100% NG) (100% NG) DDGS Wet-DGS DM DM DM DM DM DM = Displacement method Di l t th d 0% -10% Relative GHG Emissio Change -20% on -30% -26.2% -26 2% -32.4% -40% -38.2% -37.4% -42.4% 42 4% G -50% -60% 18
  • 19. Choice of Co-product methods: Benefits and Issues  Displacement method – Most conservative LCA method – Data intensive: need detailed understanding of the displaced product sector – Dynamic results: subject to change based on economic and market modifications – Results developed using this method will need to be revised regularly  Energy Allocation method – Easy to use – Frequent updates not required for mature industry, e.g. Petroleum refineries – Results not entirely appropriate, when coproducts are used in non‐fuel  applications 19
  • 20. Recommendations and Future Research requirements  Displacement method p Requirements – Need for regular surveys (annual/biennial) conducted by Independent organization reporting  yield of Corn Ethanol and Coproducts, energy consumption – Need for regular surveys reporting coproducts use by animal industry type, inclusion levels,  animal performance – Feedback/Survey of Professional Animal Industry Nutritionists regarding typical animal diets with  or without Coproducts ith t C d t Recommendations – Develop displacement ratio scenarios based on this information; can be used to calculate  Coproduct credit for individual biorefineries Coproduct credit for individual biorefineries  Energy Allocation method Requirements – Publish heating values of new coproducts (HPDDG Corn germ de‐oiled DDGS) Publish heating values of new coproducts (HPDDG, Corn germ, de oiled DDGS)  Reconcile Distillers Grains Displacement Ratios with GTAP/CARB  approach – GTAP/CARB considered 1 kg DGS displace 1 kg Corn – Should be modified to consider Distillers Grains additional displacement of SBM Urea Should be modified to consider Distillers Grains additional displacement of SBM, Urea 20
  • 21. Acknowledgements  We thank Zia Haq of DOE’s Office of Biomass Program for his  q g support of this effort. 21