Presentation on theme: "Switchgrass for Biomass Energy Rob Mitchell USDA-ARS Grain, Forage, and Bioenergy Research Unit Lincoln, Nebraska."— Presentation transcript:
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 Answer Biorefinery Questions Where are We Going?
Native to Tallgrass Prairie Ecologically functions as a monoculture
Switchgrass Biomass Energy Current Goals & Research 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
…to this? How do you get from this… Establishing Switchgrass
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 ft 2 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 Switchgrass Establishment Recipe
Switchgrass seedling morphology, seedbed firmness, and planting depth Seedlings develop adventitious roots at soil surface not at seed. Seed < 1/2” deep Soft seedbed with packer wheel depression The seed is too deep and will have problems emerging Planting depth } = 1/2”. Seed First rain fills the depression } = 1” Seed .
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 Worst-Case Scenario for Switchgrass Establishment 6 October tons/acre 5 May 2006
Worst-Case Scenario for Switchgrass Establishment 27 September tons/acre 2 tons/acre regrowth 31 July tons/acre
Worst-Case Scenario for Switchgrass Establishment 17 October tons/acre ~1 ton/acre regrowth 7 August tons/acre Averaged over 4 tons/acre for the planting year and the first 2 production years
Switchgrass Harvest & Storage
24% DM loss in 12 months 3 or 4 wraps reduces spoilage Chopping reduces densityBig squares rapidly degrade outside Switchgrass Harvest & Storage
Major Questions for Perennial Herbaceous Bioenergy Crops 1.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 $35/barrel oil.) 2.Are perennial biomass energy crops net energy positive? 3.New Question: Are they greenhouse gas neutral or negative?
31”-33” Annual Precipitation 15”-17” Annual Precipitation On-Farm Production Trials: acre (6-9 ha) fields Cooperating farmers paid to manage fields as biomass energy crops. Northern Plains Field Scale Production and Economics Trial
USDA switchgrass study 10 locations for 5 years 165 acres seeded Seeded with commercial drills Dryland sites Harvested entire field with commercial hay equipment
Switchgrass Average Annual Production Costs Perrin et al Cost Item$/Acre$/Ton Planting Herbicide Applied Fertilizer Applied Harvest Total Operating Costs Land Rent Total Cost Costs are annualized at 10%.
Previous Switchgrass Producer vs. New Crop Producer Five Year Average Cumulative Costs Total costs $/ton Costs (no land $) $/ton Experienced (2)$43.13$26.42 New crop producer (8)$69.16$37.28 Experience helped producers reduce production costs by $10.86/ton during the 5 production years. Perrin et al. 2008
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
Paramount Herbicide vs. No Paramount in Establishment Year Five Year Average Cumulative Costs Total costs $/ton Costs (no land $) $/ton Paramount used (4)$44.06 $28.35 No Paramount (6)$77.22$39.62 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
Year 1 Harvests vs. No Year 1 Harvest Comparisons Five Year Average Cumulative Costs Total costs $/ton Costs (no land $) $/ton Year 1 Harvest (3)$44.22 $27.61 No Year 1 Harvest (7)$72.41$38.32 Perrin et al Harvestable yields in the establishment year reduced production costs by $10.71/ton over the 5 production years.
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 100 th Meridian Schmer et al – Proceedings of the National Academy of Science
Man-made prairies One location Small-plots Hand-seeded Irrigated during establishment Hand-weeded Hand-harvested - 10cm wide strips USDA switchgrass study 10 locations 67 ha seeded Seeded with commercial drills Dryland sites Harvested entire field with commercial hay equipment
Managed switchgrass produced 97% more ethanol yield than man-made prairies Tilman et al., 2006 USDA study
What about soil carbon?
Switchgrass grown for bioenergy: Soil carbon storage in 5 years: 0-30 cm
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 Mg SOC/ha/y in the top 120 cm of soil Liebig et al (in press) Field near Douglas, Nebraska
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., Renovating pastures with glyphosate tolerant soybeans. Online. Forage and Grazinglands doi: /FG BR. Soybeans in big bluestem sod Soybeans in fescue and bluegrass sod Soybeans in indiangrass sod
Change in soil C – bromegrass sod to no-till corn: cm for 6 years. Mead, NE Data from R. Follett et al., in review.
Switchgrass for Bioenergy Economics 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
Long-term Study of Corn & Switchgrass Mead, 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
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 Biomass & Bioenergy.
Removing ½ of stover reduced grain yield by 7.2% ½ stover removed - 7.2% grain
Removing ½ of stover reduced biomass yield by 5% ½ stover removed - 5% biomass
Switchgrass Harvested Post Frost was Greater than August * ** *
Switchgrass Biomass Increased as N Increased
Corn Biomass was Greater than Switchgrass in August ½ stover removed
Corn Biomass was Similar to Switchgrass Post Frost ½ stover removed
Seeding year In an 84-month period, 62 months (74%) were in drought
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.
Where Are We Going? Conventional Breeding Progress Yield Trial Mead, NE CultivarYear released Biomass yield -Ton/a (Mg/ha) IVDMD (%) (mature) Trailblazer (14.1)52.5 Shawnee (14.5)54.8 NE 2000C1In seed increase 7.4 (16.6)53.8 NE Late YD C4 In seed increase 7.0 (15.7)55.2
Hybrid Switchgrass StrainYield Tons/A (Mg/ha) Kanlow & Summer F1’s 9.4 (21) Kanlow7.1 (16) Summer6.1 (14) Improved hybrid cultivars with modified cell walls could improve ethanol yields & reduce costs. Vogel & Mitchell, Crop Sci. 2008, In press.
Biorefinery Investor Questions 1.How soon can switchgrass be supplied to the biorefinery? 2.Can adequate biomass be produced and delivered to the biorefinery in a timely manner? 3.Is production system information available, verified and sustainable? 4.Bottom Line: Can the area provide a reliable & affordable feedstock supply for the long- term?
How soon can switchgrass be supplied to the biorefinery? Answer: Full scale switchgrass production could occur in as little as 5 years. Question 1
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. Year 1Year 2Year 3Year 4Year 5 Harvest Foundation Seed # PLS/a # PLS/a # PLS/a # PLS/a # PLS/a Plant Certified Seed-2 # PLS/acre Harvest Certified Seed # PLS/a # PLS/a # PLS/a Plant Biomass Fields---4 # PLS/acre Harvest Biomass Fields ---2 tons/acre4 tons/acre Biorefinery--Begin Construction Finish Construction Full Production
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
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. Feedstock Yield, DM tons/acre Acres needed to grow 625,000 DM tons/year Percent of land in 25-mile radius LIHD ,00028 Shawnee switchgrass ,00010 Corn150 bu/acre111, Bioenergy switchgrass , Hybrid switchgrass , Low-input, high-diversity mixtures (Tilman et al. 2006). 2 Upland forage-type switchgrass cultivar released in Lowland Bioenergy-specific switchgrass in the cultivar release process. 4 F1 hybrid of Summer and Kanlow switchgrass cultivars that will likely reach field-scale production in 10 years (Vogel and Mitchell 2008).
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
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
Where 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
Conclusions 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.
Conclusions Switchgrass biofuel production systems are economically feasible on marginal cropland in the central USA east of the 100 th 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.
U.S. Average Regular Pump Price in 2008 was $3.29/gallon $2.13 $3.02 $3.29 $1.29