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Switchgrass for Biomass Energy

Switchgrass for Biomass Energy. Rob Mitchell USDA-ARS Grain, Forage, and Bioenergy Research Unit Lincoln, Nebraska. Background Establishment Production, Harvest and Storage Switchgrass Production Economics Switchgrass Energy Production Land Requirements and Feedstocks

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Switchgrass for Biomass Energy

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  1. Switchgrass for Biomass Energy Rob Mitchell USDA-ARS Grain, Forage, and Bioenergy Research Unit Lincoln, Nebraska

  2. Background • Establishment • Production, Harvest and Storage • Switchgrass Production Economics • Switchgrass Energy Production • Land Requirements and Feedstocks • Answer Biorefinery Questions Where are We Going?

  3. Native to Tallgrass Prairie Ecologically functions as a monoculture

  4. Goals Full establishment in 1 year with 50% yield Be at full production (5 t/a) second year Goal of 10 t/a in Midwest; increase ethanol yield/ton Fully document environmental benefits Tools and Products Weed control, no-till planting, seed quality Breeding - Biomass specific cultivars & F1 hybrids, improved conversion, NIRS Molecular biology, cell walls, conversion & seed quality C sequestration, entomology Switchgrass Biomass EnergyCurrent Goals & Research

  5. Establishing Switchgrass How do you get from this… …to this?

  6. Switchgrass Establishment Recipe • Is switchgrass feasible for the area? • Suitable for dryland corn = suitable for switchgrass • Plant 2 to 3 weeks either side of optimum corn planting date • Develop a good seedbed • No-till seed into soybean stubble • Clean till and pack to leave a faint footprint • Use high quality certified seed of adapted material • Plant at least 30 PLS per ft2 ¼ to 1/2” deep • Manage weeds ASAP! • Pre-emergent application of 1 qt. of atrazine plus 8 oz of quinclorac/acre • Mow or spray broadleaves with 1-2 qt./a of 2,4-D in summer • Spend money on quality seed & weed control

  7. Switchgrass seedling morphology, seedbed firmness, and planting depth Soft seedbed with packer wheel depression Seedlings develop adventitious roots at soil surface not at seed. Planting depth . } = 1/2” } = 1/2” Seed  Seed < 1/2” deep First rain fills the depression . } = 1” Seed  The seed is too deep and will have problems emerging

  8. Worst-Case Scenario for Switchgrass Establishment 6 October 2006 2.5 tons/acre 5 May 2006 • No-till seeded 57 acres into soybean stubble on 5 May 2006 • Pre-emergent application of 1 qt. of atrazine plus 8 oz of quinclorac/acre • Received 5 in of rain for the first 90-days after planting (40% of LTA) • Mowed & sprayed with 2 qt./acre of 2,4-D to control broadleaf weeds in July • Produced 2.5 tons/acre near Mead, NE in the establishment year (50% of our yield goal) • Seed quality & weed control are critical to economical switchgrass production

  9. Worst-Case Scenario for Switchgrass Establishment 27 September 2007 4 tons/acre 2 tons/acre regrowth 31 July 2007 4 tons/acre

  10. Worst-Case Scenario for Switchgrass Establishment 17 October 2008 5-6 tons/acre ~1 ton/acre regrowth 7 August 2008 6 tons/acre Averaged over 4 tons/acre for the planting year and the first 2 production years

  11. Switchgrass Harvest & Storage

  12. Switchgrass Harvest & Storage

  13. Switchgrass Harvest & Storage 3 or 4 wraps reduces spoilage 24% DM loss in 12 months Big squares rapidly degrade outside Chopping reduces density

  14. Major Questions for Perennial Herbaceous Bioenergy Crops • Can perennial herbaceous biomass energy crops be produced at a cost which makes their use for biomass energy economically feasible? (Initial goal was to compete with $35/barrel oil.) • Are perennial biomass energy crops net energy positive? • New Question: Are they greenhouse gas neutral or negative?

  15. Northern Plains Field Scale Production and Economics Trial 15”-17” Annual Precipitation 2000-2005 On-Farm Production Trials: 15-20 acre (6-9 ha) fields Cooperating farmers paid to manage fields as biomass energy crops. 31”-33” Annual Precipitation

  16. USDA switchgrass study 10 locations for 5 years 165 acres seeded Seeded with commercial drills Dryland sites Harvested entire field with commercial hay equipment

  17. Switchgrass Average Annual Production Costs Costs are annualized at 10%. Perrin et al. 2008

  18. Previous Switchgrass Producer vs. New Crop Producer Experience helped producers reduce production costs by $10.86/ton during the 5 production years. Perrin et al. 2008

  19. Extension Efforts Will Pay Dividends Field of Jerry Roitsch near Bristol, South Dakota • 5-year average yield of 4.2 tons/acre • Average cost of $38/t including land & labor • Farm gate feedstock cost was $0.48/gal • Based on 80 gallons of ethanol per ton, each big bale equals 50 gallons of ethanol

  20. Paramount Herbicide vs. No Paramount in Establishment Year Applying Paramount in the establishment year reduced production costs by $11.27/ton for 5 production years, a $124/a return on a $20/a investment. Perrin et al. 2008

  21. Year 1 Harvests vs. No Year 1 Harvest Comparisons Harvestable yields in the establishment year reduced production costs by $10.71/ton over the 5 production years. Perrin et al. 2008

  22. On-farm Switchgrass Production in the Great Plains – Energy • Previous models over-estimated the energy inputs for switchgrass production by as much as 2X • Switchgrass produced 13X more energy as ethanol than was required as energy from petroleum • Switchgrass produced 540% more renewable than non-renewable energy consumed on marginal land when properly managed • Switchgrass biofuel production systems are economically feasible, and energetically positive on marginal cropland in the central USA east of the 100th Meridian Schmer et al. 2008 – Proceedings of the National Academy of Science

  23. USDA switchgrass study 10 locations 67 ha seeded Seeded with commercial drills Dryland sites Harvested entire field with commercial hay equipment Man-made prairies One location Small-plots Hand-seeded Irrigated during establishment Hand-weeded Hand-harvested - 10cm wide strips

  24. Managed switchgrass produced 97% more ethanol yield than man-made prairies USDA study Tilman et al., 2006

  25. What about soil carbon?

  26. Switchgrass grown for bioenergy:Soil carbon storage in 5 years: 0-30 cm

  27. Switchgrass Soil Carbon Sequestration when grown and managed as a biomass energy crop • C storage for field at left: - 1 Mg SOC/ha/y in the top 30 cm of soil - 3.7 Mg SOC/ha/y in the top 120 cm of soil Liebig et al. 2008 (in press) Field near Douglas, Nebraska

  28. Grass to crops – what happens to the soil carbon? • Searchinger et al, Science 2008 – sequestered carbon from perennial bioenergy crops is lost due to plowing and crop production. • Fact: plowing is not necessary and not recommended. Too expensive and sod-seeding is easier. • What happens to sequestered C under no-till farming? • Mitchell et al., 2005. Renovating pastures with glyphosate tolerant soybeans. Online. Forage and Grazinglands doi:10.1094/FG-2005-0428-01-BR. Soybeans in big bluestem sod Soybeans in indiangrass sod Soybeans in fescue and bluegrass sod

  29. Change in soil C – bromegrass sod to no-till corn: 10-30 cm for 6 years. Mead, NE Data from R. Follett et al., in review.

  30. Switchgrass for BioenergyEconomics and Environmental Issues • Switchgrass grown for biomass energy is net energy positive • Evidence is accumulating that indicates switchgrass is greenhouse gas neutral or negative (that is good!) • Switchgrass has wildlife & other benefits • Switchgrass fits the landscape and can be profitable

  31. Long-term Study of Corn & SwitchgrassMead, NE • 10-year experiment established in 1998 on marginal site in eastern NE • In 2000, corn plots were split & 50% of stover removed on half of plots • Evaluate PV & no-till corn on marginal sites for: • Corn stover removal effects on yield • Response to applied N • Ethanol Production • C sequestration • Switchgrass competition • Sustainability of PV harvest & corn stover removal

  32. Effect of 50% stover removal on corn grain yields in eastern NE fertilized with 120 kg N/ha. Mean Yields in kg/ha for first 5 years. Varvel et al. 2008 Biomass & Bioenergy.

  33. Removing ½ of stover reduced grain yield by 7.2% ½ stover removed - 7.2% grain

  34. Removing ½ of stover reduced biomass yield by 5% ½ stover removed - 5% biomass

  35. Switchgrass Harvested Post Frost was Greater than August * * * *

  36. Switchgrass Biomass Increased as N Increased

  37. Corn Biomass was Greater than Switchgrass in August ½ stover removed

  38. Corn Biomass was Similar to Switchgrass Post Frost ½ stover removed

  39. In an 84-month period, 62 months (74%) were in drought Seeding year

  40. When Should Switchgrass be Harvested? Switchgrass biomass curve developed from first growth ‘Cave-in-Rock’ switchgrass harvested at 7-day intervals from 5 production environments in August, September, October, and November in 2004, 2005, 2006, and 2007 at Mead, NE.

  41. Where Are We Going?Conventional Breeding ProgressYield Trial Mead, NE 2003-2005

  42. Hybrid Switchgrass • Improved hybrid cultivars with modified cell walls could improve ethanol yields & reduce costs. Vogel & Mitchell, Crop Sci. 2008, In press.

  43. High-input low-diversity polycultures, currently-available switchgrass, and hybrid switchgrass are feasible feedstocks

  44. Biorefinery Investor Questions • How soon can switchgrass be supplied to the biorefinery? • Can adequate biomass be produced and delivered to the biorefinery in a timely manner? • Is production system information available, verified and sustainable? • Bottom Line: Can the area provide a reliable & affordable feedstock supply for the long-term?

  45. How soon can switchgrass be supplied to the biorefinery?Answer: Full scale switchgrass production could occur in as little as 5 years. Question 1

  46. Large-scale switchgrass production will require a 2-year lead time before initiating biorefinery construction, assuming Foundation Seed is available for planting Certified Seed fields.

  47. Can adequate biomass be produced and delivered to the biorefinery in a timely manner?Answer: Using the above seed production timeline, adequate biomass can be produced and delivered to the biorefinery in as little as 5 years. Question 2

  48. Potential dry matter (DM) yield for herbaceous perennial feedstocks in the Great Plains and Midwest. A 50-million gallon cellulosic ethanol plant will require 625,000 tons of feedstock per year, assuming 80 gallons of ethanol are produced per DM ton. 1Low-input, high-diversity mixtures (Tilman et al. 2006). 2Upland forage-type switchgrass cultivar released in 1995. 3Lowland Bioenergy-specific switchgrass in the cultivar release process. 4F1 hybrid of Summer and Kanlow switchgrass cultivars that will likely reach field-scale production in 10 years (Vogel and Mitchell 2008).

  49. Is production system information available, verified and sustainable? Answer: Switchgrass has been grown and managed since the 1930’s. Based on more than 70 years of research, switchgrass production is feasible, verified, and sustainable. Question 3

  50. Can the area provide a reliable & affordable feedstock supply for the long-term? Answer: Switchgrass can provide a reliable and affordable feedstock supply for many areas in the Central and Northern Great Plains, but the preferred feedstock will vary by locations within agro-ecoregions. Question 4

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