Can Bioenergy be Sustainable?

1. Can Bioenergy be Sustainable? Steven L. Fales Professor of Agronomy Iowa State University

2. Topics • Current situation • Technology options • Major hurdles • Building sustainable bioenergy systems

3. Supply Peak Oil 2007 ? Known oil reserves Time Confluence of Crises Demand

4. Is this acceptable?

5. What are the choices? • Control foreign sources of oil and gas • Increase domestic oil exploration • Improve efficiency of use • Power down, and radically change the way we live • Find short- and medium-term alternative energy sources

6. Corn ethanol: a logical initial step

7. Grain-to-Ethanol Plant (Biochemical Processing) EtOH CO2 Starch Enzymes Grain Mill Cooker DDGS/water Distillation Fermenter Separates ethanol from DDGS and water Releases starch from kernel Breaks starch into sugar Converts sugar into ethanol

8. Aggressive Goals and Timelines to Decrease Fossil Fuel Use

9. Limitations to Grain EthanolProduction • Feedstock supply • 5.5 million bu (15 billion gal EtOH by 2016*) • Net energy return • +30% • Food vs. Fuel • Land use issues • Direct • Indirect *NCGA, http://www.ncga.com/ethanol/pdfs/2007/HowMuchEthanolCanComeFromCorn0207.pdf

10. 12 Transgenic (Bt)insect resistance 10 Conservation tillage, soil testing, NPK fertilization 8 Double-x tosingle-x hybrids Grain yield (Mg ha-1) 6 4 Integrated pestmanagement y = 112.4 kg ha-1 yr-1(1.79 bu ac-1 yr-1)r2 = 0.80 Expansion of irrigated area,increased N fertilizer rates 2 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year How far can we go with corn? ? USA Corn Yield Trends, 1966-2005 Future? CAST. 2006. Commentary QTA 2006-3 (http://www.cast-science.org/publications.asp).

11. Filling the Gap October 2008 Capacity(7.9 billion gal) 25 x ‘25 Gap for “advanced biofuels” to fill 30 x ‘30 20 in 10 Energy Policy Act Ethanol from corn

12. Next generation biofuels

13. Biochemical: Cellulose-to-Ethanol Distillation Ethanol Fermenter CO2 Cellulose Enzymes Biomass Saccharification Preprocessing water Convert cellulose and hemicellulose to sugars Remove lignin

14. Cellulase action active site cellulose microfibril

15. Limitations to Biochemical Approach • Need to remove lignin • Enzyme specificity • Hemicellulose • Cellulose • Feedstock specificity

16. Thermochemical Processing • All kinds of feedstocks reduced to carbon monoxide (CO) and hydrogen (H2), which are then converted to other products.

17. Thermochemical Biorefinery Fuel CO2 Biobased fuels: green diesel, alcohols, hydrogen, ammonia Syngas Gas Cleaning Catalytic Upgrading Gasifier NH3 Biomass Ash Air Thermally breaks down all biomass into reactive gases

18. Gasification Integrated Processing Systems Ethanol Lignocellulosic feedstock collection and delivery beer slurry Fuels = (CO2, H2O, sunshine) Sugar fermentation Enzymatic Hydrolysis Pre-processing Pre-treatment de-water Fischer- Tropsch Synthesis FT Fuels Conditioning NH3 recovery Ammonia Ash

19. Production of NH4HCO3 Ash remaining after gasification of switchgrass Source: ORNL-DOE

20. Major investments being made…

21. What about the feedstock? Who will produce it and where? What will it cost?

22. Billion Ton Report (DOE, 2005)1.366 billion tons/year Estimated biomass (million tons/year) contribution by 2030 Perlack et al., 2005;http://bioenergy.ornl.gov

24. What does a billion look like? • If 1 ton = 1 sq. in., • 1 billion tons = 145 football fields • Stack of round bales (5 ft, 1000 lb, end-to-end) • 1.89 million miles (75 times around the earth) Source: Wally Wilhelm, USDA-ARS

25. Economic viability Sustainability

26. Crop Residues Feedstock Candidates

27. Impact of residue removal? • Loss of erosion protection • Loss of soil nutrients • Impact on water quality • Loss of soil carbon

28. Management Affects Soil Carbon Modern agriculture Stover harvest + Cover crops Green manure Increased efficiencies Innovative technologies Pre-cultivation steady-state Soil carbon Management change + No tillage? Stover removal Time ∆ SOC = input - output Source: W. Wilhelm

29. Opportunity to re-design agriculture • Maximize annual capture of solar radiation  High yields (8 to 20 tons/A) • Plant breeding for improved performance • Cropping systems • Annual • Perennial

30. Missed opportunities for resource assimilation and dry matter production Additional opportunities for resource losses Biomass production in annual cropping systems Dry matter production or resource loss (mass / time) Summer annual grain crop Winter Autumn Spring Summer

31. Reduced opportunities for resource losses Biomass production in double crop systems Dry matter production or resource loss (mass / time) spring crop summer crop Winter Autumn Summer Spring

32. Perennial Biomass Crops Environmental Services • Reduce soil erosion • Improve soil quality • Reduce water runoff • Water infiltration • Carbon sequestration • Used in crop rotations • Can reduce pesticide use • Can reduce mineral N loss • Wildlife habitat

33. Native Warm-Season Grasses Characteristics • Native to tallgrass prairie • Widely adapted in Iowa • Perennial growth habit • C4 photosynthesis • Relatively high yield potential • High N efficiency • High H2O use efficiency

34. Native Warm-Season Grasses 10 8 6 Dry matter (tons/acre) Big bluestem 4 Switchgrass Indiangrass 2 Eastern gamagrass 0 0 50 100 150 200 250 Nitrogen (lbs/acre)

35. Native Warm-Season Grasses Monoculture? Mixed Prairie?

36. Exotic species Miscanthus giganteus

37. Algae

38. Forest Products

39. Forest Products • Forest trimmings and thinnings • Short-rotation coppice • Willow • Poplar • Conifer plantations • Advantages & disadvantages

40. Some other big issues • Transportation

41. Storage

42. Putting it all together: linking fields and biorefineries Biogeochemical inputs Biological N fixation Plant biomass Deposition, weathering Biorefinery Crops Fuels Soil Fertilizer (minimize) Recycled Nutrients (ash) Nutrient losses (minimize)

44. Plants = Solar Energy Collectors 2% 12%

45. Energy densities of different feedstocks

46. Some Things to Keep in Mind • Recognize that bioenergy will be only part of a future energy portfolio • Establish social climate of conservation • Efficiency alone will not be the answer • Power down our lives • Recognize limits to infinite growth (e.g., Herman Daly)

47. Assignment • The Agricultural Committee of the U.S. Senate has been charged with the task of developing an incentive payments program to encourage adoption of sustainable biofeedstock production systems in the Corn Belt region. • In order to assist in this process, a hearing has been organized on Capitol Hill to help congressional representatives understand the pros and cons of different systems and select the optimal system for the program. • With your group, design a biofeedstock production system using an appropriate combination of annual crops, perennial herbaceous plants, and woody plants that maximizes the benefits obtained from both economic returns AND ecosystem services and sustainability (e.g., an “optimal compromise” between short- and long-term benefits). • Each group will present an argument supporting their system on Tuesday (10 min each). • The presentations will be followed by a full Senate discussion of the pros and cons and an attempt to reach consensus on which system should be selected for the biofeedstock incentive program.

48. Groups • 1 • Bill • Dan • Jessica • 2 • Michaeleen • Sami • Jarret • Rick • 3 • Robin • Dave • Justin