Presentation on theme: "Switchgrass for Biomass Energy"— Presentation transcript:
1Switchgrass for Biomass Energy Rob MitchellUSDA-ARSGrain, Forage, and Bioenergy Research UnitLincoln, Nebraska
2Where are We Going? Background Establishment Production, Harvest and StorageSwitchgrass Production EconomicsSwitchgrass Energy ProductionLand Requirements and FeedstocksAnswer Biorefinery Questions
3Native to Tallgrass Prairie Ecologically functions as a monoculture
4Switchgrass Biomass Energy Current Goals & Research Tools and ProductsWeed control, no-till planting, seed qualityBreeding - Biomass specific cultivars & F1 hybrids, improved conversion, NIRSMolecular biology, cell walls, conversion & seed qualityC sequestration, entomologyGoalsFull establishment in 1 year with 50% yieldBe at full production (5 t/a) second yearGoal of 10 t/a in Midwest; increase ethanol yield/tonFully document environmental benefits
5Establishing Switchgrass How do you get from this……to this?
6Switchgrass Establishment Recipe Is switchgrass feasible for the area?Suitable for dryland corn = suitable for switchgrassPlant 2 to 3 weeks either side of optimum corn planting dateDevelop a good seedbedNo-till seed into soybean stubbleClean till and pack to leave a faint footprintUse high quality certified seed of adapted materialPlant at least 30 PLS per ft2 ¼ to 1/2” deepManage weeds ASAP!Pre-emergent application of 1 qt. of atrazine plus 8 oz of quinclorac/acreMow or spray broadleaves with 1-2 qt./a of 2,4-D in summerSpend money on quality seed & weed control
7Switchgrass seedling morphology, seedbed firmness, and planting depth Soft seedbed with packer wheel depressionSeedlings develop adventitious roots at soil surface not at seed.Planting depth.} = 1/2”} = 1/2”Seed Seed < 1/2” deepFirst rain fills the depression.} = 1”Seed The seed is too deep and will have problems emerging
8Worst-Case Scenario for Switchgrass Establishment 6 October 20062.5 tons/acre5 May 2006No-till seeded 57 acres into soybean stubble on 5 May 2006Pre-emergent application of 1 qt. of atrazine plus 8 oz of quinclorac/acreReceived 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 JulyProduced 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
9Worst-Case Scenario for Switchgrass Establishment 27 September 20074 tons/acre2 tons/acre regrowth31 July 20074 tons/acre
10Worst-Case Scenario for Switchgrass Establishment 17 October 20085-6 tons/acre~1 ton/acre regrowth7 August 20086 tons/acreAveraged over 4 tons/acre for the planting year and the first 2 production years
13Switchgrass Harvest & Storage 24% DM loss in 12 months3 or 4 wraps reduces spoilageBig squares rapidly degrade outsideChopping reduces density
14Major 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 $35/barrel oil.)Are perennial biomass energy crops net energy positive?New Question: Are they greenhouse gas neutral or negative?
15Northern Plains Field Scale Production and Economics Trial 15”-17” Annual PrecipitationOn-Farm ProductionTrials: acre (6-9 ha) fieldsCooperating farmers paidto manage fields as biomassenergy crops.31”-33” Annual Precipitation
16USDA switchgrass study 10 locations for 5 years165 acres seededSeeded with commercial drillsDryland sitesHarvested entire field with commercial hay equipment
17Switchgrass Average Annual Production Costs Cost Item$/Acre$/TonPlanting12.745.74Herbicide Applied12.955.84Fertilizer Applied15.046.78Harvest32.6514.72Total Operating Costs73.3833.08Land Rent59.7026.91Total Cost133.0859.99Costs are annualized at 10%.Perrin et al. 2008
18Previous Switchgrass Producer vs. New Crop Producer Five Year Average Cumulative CostsTotal costs$/tonCosts (no land $)Experienced (2)$43.13$26.42New crop producer (8)$69.16$37.28Experience helped producers reduce production costs by $10.86/ton during the 5 production years.Perrin et al. 2008
19Extension Efforts Will Pay Dividends Field of Jerry Roitsch near Bristol, South Dakota5-year average yield of 4.2 tons/acreAverage cost of $38/t including land & laborFarm gate feedstock cost was $0.48/galBased on 80 gallons of ethanol per ton, each big bale equals 50 gallons of ethanol
20Paramount Herbicide vs. No Paramount in Establishment Year Five Year Average Cumulative CostsTotal costs$/tonCosts (no land $)Paramount used (4)$44.06$28.35No Paramount (6)$77.22$39.62Applying Paramount in the establishment year reduced production costs by$11.27/ton for 5 production years, a $124/a return on a $20/a investment.Perrin et al. 2008
21Year 1 Harvests vs. No Year 1 Harvest Comparisons Five Year Average Cumulative CostsTotal costs$/tonCosts (no land $)Year 1 Harvest (3)$44.22$27.61No Year 1 Harvest (7)$72.41$38.32Harvestable yields in the establishment year reduced production costs by$10.71/ton over the 5 production years.Perrin et al. 2008
22On-farm Switchgrass Production in the Great Plains – Energy Previous models over-estimated the energy inputs for switchgrass production by as much as 2XSwitchgrass produced 13X more energy as ethanol than was required as energy from petroleumSwitchgrass produced 540% more renewable than non-renewable energy consumed on marginal land when properly managedSwitchgrass biofuel production systems are economically feasible, and energetically positive on marginal cropland in the central USA east of the 100th MeridianResults from ARS & UNL economic study. Manuscript in review.Schmer et al – Proceedings of the National Academy of Science
23USDA switchgrass study 10 locations67 ha seededSeeded with commercial drillsDryland sitesHarvested entire field with commercial hay equipmentMan-made prairiesOne locationSmall-plotsHand-seededIrrigated during establishmentHand-weededHand-harvested - 10cm wide strips
24Managed switchgrass produced 97% more ethanol yield than man-made prairies USDA studyTilman et al., 2006Higher yielding farms, a result of following best management practices produced 140% more ethanol than man-made prairies. Switchgrass managed as a bioenergy crop had similar ethanol yields as statewide corn grain yields from Nebraska, South Dakota, and North Dakota. Caution should be made in making direct ethanol yield comparisons with cellulosic sources and corn grain at present because corn grain conversion technology is mature while cellulosic conversion efficiency technology is a predicted value. However, mean corn grain yield is based on irrigated and rain-fed fields on both marginal and fertile soils. Switchgrass will likely be established on rain-fed, marginal soils where row crop yields are generally lower and more variable than crop yields on irrigated or rain-fed, fertile soils. Even with a more conservative cellulosic conversion value, switchgrass from this study is much closer to current corn grain ethanol yields than man-made prairies for this geographic region.
26Switchgrass grown for bioenergy: Soil carbon storage in 5 years: 0-30 cm
27Switchgrass Soil Carbon Sequestration when grown and managed as a biomass energy crop Field near Douglas, NebraskaC 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 soilLiebig et al (in press)
28Grass 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., Renovating pastures with glyphosate tolerant soybeans. Online. Forage and Grazinglands doi: /FG BR.Soybeans in big bluestem sodSoybeans in indiangrass sodSoybeans in fescueand bluegrass sod
29Change 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.
30Switchgrass for Bioenergy Economics and Environmental Issues Switchgrass grown for biomass energy is net energy positiveEvidence is accumulating that indicates switchgrass is greenhouse gas neutral or negative (that is good!)Switchgrass has wildlife & other benefitsSwitchgrass fits the landscape and can be profitable
31Long-term Study of Corn & Switchgrass Mead, NE 10-year experiment established in 1998 on marginal site in eastern NEIn 2000, corn plots were split & 50% of stover removed on half of plotsEvaluate PV & no-till corn on marginal sites for:Corn stover removal effects on yieldResponse to applied NEthanol ProductionC sequestrationSwitchgrass competitionSustainability of PV harvest & corn stover removalCooperative work of ARS Lincoln, ARS Ft. Collins – Ron Follett, and USDA-NRCS National Soils Lab (John Kimble).
32Effect 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 Biomass & Bioenergy.
33Removing ½ of stover reduced grain yield by 7.2% ½ stover removed- 7.2% grainCooperative work of ARS Lincoln, ARS Ft. Collins – Ron Follett, and USDA-NRCS National Soils Lab (John Kimble).
34Removing ½ of stover reduced biomass yield by 5% ½ stover removed- 5% biomassCooperative work of ARS Lincoln, ARS Ft. Collins – Ron Follett, and USDA-NRCS National Soils Lab (John Kimble).
35Switchgrass Harvested Post Frost was Greater than August ****Cooperative work of ARS Lincoln, ARS Ft. Collins – Ron Follett, and USDA-NRCS National Soils Lab (John Kimble).
36Switchgrass Biomass Increased as N Increased Cooperative work of ARS Lincoln, ARS Ft. Collins – Ron Follett, and USDA-NRCS National Soils Lab (John Kimble).
37Corn Biomass was Greater than Switchgrass in August ½ stover removedCooperative work of ARS Lincoln, ARS Ft. Collins – Ron Follett, and USDA-NRCS National Soils Lab (John Kimble).
38Corn Biomass was Similar to Switchgrass Post Frost ½ stover removedCooperative work of ARS Lincoln, ARS Ft. Collins – Ron Follett, and USDA-NRCS National Soils Lab (John Kimble).
39In an 84-month period, 62 months (74%) were in drought Seeding year
40When 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.
41Where Are We Going? Conventional Breeding Progress Yield Trial Mead, NE 2003-2005 CultivarYear releasedBiomass yield -Ton/a(Mg/ha)IVDMD(%) (mature)Trailblazer19846.3 (14.1)52.5Shawnee19956.5 (14.5)54.8NE 2000C1In seed increase7.4 (16.6)53.8NE Late YD C47.0 (15.7)55.2
42Hybrid Switchgrass Strain Yield Tons/A (Mg/ha) Kanlow & Summer F1’s 9.4 (21)Kanlow7.1 (16)Summer6.1 (14)Vogel & Mitchell, Crop Sci. 2008, In press.Improved hybrid cultivars with modified cell walls could improve ethanol yields & reduce costs.
44Biorefinery 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?
45Question 1How soon can switchgrass be supplied to the biorefinery? Answer: Full scale switchgrass production could occur in as little as 5 years.
46Large-scale switchgrass production will require a 2-year lead time before initiating biorefinery construction, assuming Foundation Seed is available for planting Certified Seed fields.Year 1Year 2Year 3Year 4Year 5Harvest Foundation Seed# PLS/aPlant Certified Seed-2 # PLS/acreHarvest Certified SeedPlant Biomass Fields4 # PLS/acreHarvest Biomass Fields2 tons/acre4 tons/acreBiorefineryBeginConstructionFinishFullProduction
47Question 2Can 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.
48Potential 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.FeedstockYield, DM tons/acreAcres needed to grow 625,000 DM tons/yearPercent of land in 25-mile radiusLIHD11.75357,00028Shawnee switchgrass25125,00010Corn150 bu/acre111,1118.8Bioenergy switchgrass37.484,4606.6Hybrid switchgrass49.466,4895.31Low-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).
49Question 3Is 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.
50Question 4Can 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.
51Where will Cellulosic Ethanol Plants Fit? A 50-million gallon Ethanol Plant Will Require:125,000 acres of switchgrass assuming 5 tons/acre and 80 gallons of ethanol/ton of switchgrass.The Upper Big Blue NRD has 1.83 million acres, 1 million irrigated acres, and 4,600 center pivots. This NRD could grow 128,800 acres of switchgrass in pivot corners alone.Has 4 existing corn ethanol plants and others under construction or in various planning stages.25-mile radius
52Conclusions There is no one-size-fits-all bioenergy system. Based on nearly 20 years of bioenergy research, we can grow switchgrass in the central USA and be near 50% full production 5 months after seeding and near full production 15 months after seeding.Switchgrass will not displace corn on prime cropland.Switchgrass is productive on marginal land when properly managed.
53ConclusionsSwitchgrass biofuel production systems are economically feasible on marginal cropland in the central USA east of the 100th Meridian.Properly managed switchgrass and warm-season grass mixtures will provide adequate feedstock supply for efficient transport.The green revolution was successful because of improved genetics and agronomics. Production of sustainable green energy will likewise depend on improved genetics and agronomics.