switchgrass for biomass energy
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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 - PowerPoint PPT PresentationTRANSCRIPT
Switchgrass for Biomass Energy
Rob Mitchell
USDA-ARSGrain, Forage, and Bioenergy Research Unit
Lincoln, Nebraska
BackgroundEstablishmentProduction, Harvest and StorageSwitchgrass Production EconomicsSwitchgrass Energy ProductionLand Requirements and FeedstocksAnswer Biorefinery Questions
Where are We Going?
Native to Tallgrass PrairieEcologically functions as a monoculture
Switchgrass Biomass EnergyCurrent 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 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
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”
. } = 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 2006
2.5 tons/acre5 May 2006
Worst-Case Scenario for Switchgrass Establishment
27 September 2007
4 tons/acre
2 tons/acre regrowth
31 July 2007
4 tons/acre
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
Switchgrass Harvest & Storage
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
2000-2005On-Farm ProductionTrials: 15-20 acre (6-9 ha) fields
Cooperating farmers paidto 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. 2008
Cost Item $/Acre $/Ton
Planting 12.74 5.74
Herbicide Applied 12.95 5.84
Fertilizer Applied 15.04 6.78
Harvest 32.65 14.72
Total Operating Costs 73.38 33.08
Land Rent 59.70 26.91
Total Cost 133.08 59.99
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. 2008
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 100th Meridian
Schmer et al. 2008 – 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
0
1000
2000
3000
4000
Switchgrass(Field-scale)
LIHD LI-SW Corn grain(NGP)
Eth
an
ol
Yie
ld (
L h
a-1
)
Low yielding farms
Mean yield
High yielding farms
Managed switchgrass produced 97% more ethanol yield than man-made prairies
Tilman et al., 2006Tilman 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
- 3.7 Mg SOC/ha/y in the top 120 cm of soil
Liebig et al. 2008 (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., 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 fescue and bluegrass sod
Soybeans in indiangrass sod
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.
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
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
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.
0.0
2.0
4.0
6.0
8.0
10.0
12.0
H1 H2 H1 H2 H1 H2
Grain Stover Total
Yiel
d (M
g/ha
)Figure 2.
Varvel et al. 2008 Biomass & Bioenergy.
Removing ½ of stover reduced grain yield by 7.2%
0
5
10
15
20
25
2000 2001 2002 2003 2004 2005 2006 2007 Mean
Gra
in B
iom
ass
(Mg
/ha)
Corn Grain Corn Grain after removal
½ s
tove
r re
mov
ed
- 7.2% grain
Removing ½ of stover reduced biomass yield by 5%
0
5
10
15
20
25
2000 2001 2002 2003 2004 2005 2006 2007 Mean
To
tal
Bio
mas
s (M
g/h
a)
Corn (Grain + Stover) Corn (Grain + Stover) after removal
½ s
tove
r re
mov
ed
- 5% biomass
Switchgrass Harvested Post Frost was Greater than August
0
2
4
6
8
10
12
14
16
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Mean
Bio
mas
s (M
g/h
a)
August Post Frost
* ***
Switchgrass Biomass Increased as N Increased
02468
1012141618
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Mean
Bio
mas
s (M
g/h
a)
0 60 120
Corn Biomass was Greater than Switchgrass in August
0
5
10
15
20
2000 2001 2002 2003 2004 2005 2006 2007 Mean
Bio
mas
s (M
g/h
a)
Corn (Grain + Stover) Switchgrass
½ s
tove
r re
mov
ed
Corn Biomass was Similar to Switchgrass Post Frost
0
5
10
15
20
2000 2001 2002 2003 2004 2005 2006 2007 Mean
Bio
mas
s (M
g/h
a)
Corn (Grain + Stover) Switchgrass
½ s
tove
r re
mov
ed
Se
ed
ing
ye
ar
In an 84-month period, 62 months (74%) were in drought
When Should Switchgrass be Harvested?
y = -0.4893x + 986.27
R2 = 0.57
y = 0.0917x - 175.57
R2 = 0.075
0
2
4
6
8
10
12
14
16
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
Bio
mas
s (M
g/h
a)Linear (August) Linear (Post Frost)
10
11
12
13
14
15
16
17
18
200 225 250 275 300 325
Day of Year
Bio
mas
s (M
g/h
a)
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 ProgressYield Trial Mead, NE 2003-2005
Cultivar Year released
Biomass yield -Ton/a
(Mg/ha)
IVDMD
(%) (mature)
Trailblazer 1984 6.3 (14.1) 52.5
Shawnee 1995 6.5 (14.5) 54.8
NE 2000C1 In seed increase
7.4 (16.6) 53.8
NE Late YD C4
In seed increase
7.0 (15.7) 55.2
Hybrid Switchgrass
Strain Yield
Tons/A (Mg/ha)
Kanlow & Summer F1’s
9.4 (21)
Kanlow 7.1 (16)
Summer 6.1 (14)
• Improved hybrid cultivars with modified cell walls could improve ethanol yields & reduce costs.
Vogel & Mitchell, Crop Sci. 2008, In press.
High-input low-diversity polycultures, currently-available switchgrass, and hybrid
switchgrass are feasible feedstocks
Mixture Yield T/A (Mg/ha)
SN40, PV20, BC40 6.9 (15.5)
AG40, SN20, BC40 6.7 (15.1)
AG20, SN60, PV20 6.7 (15.1)
AG40, SN40, PV20 6.7 (15.1)
Forage-type Switchgrass
5.1 (11.4)
Hybrid Switchgrass 9.4 (21.2)
Biorefinery Investor Questions1. 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 1 Year 2 Year 3 Year 4 Year 5
Harvest Foundation Seed
500-1000# PLS/a
500-1000# PLS/a
500-1000# PLS/a
500-1000# PLS/a
500-1000# PLS/a
Plant Certified Seed - 2 # PLS/acre
Harvest Certified Seed
- - 500-1000# PLS/a
500-1000# PLS/a
500-1000# PLS/a
Plant Biomass Fields - - - 4 # PLS/acre
Harvest Biomass Fields
- - - 2 tons/acre 4 tons/acre
Biorefinery - - BeginConstruction
FinishConstruction
FullProduction
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.
FeedstockYield, DM tons/acre
Acres needed to grow 625,000 DM tons/year
Percent of land in 25-mile radius
LIHD1 1.75 357,000 28
Shawnee switchgrass2 5 125,000 10
Corn 150 bu/acre 111,111 8.8
Bioenergy switchgrass3 7.4 84,460 6.6
Hybrid switchgrass4 9.4 66,489 5.3
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).
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 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.
Questions?
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Gasoline CellulosicEthanol (Same $
costs as gas)
CellulosicEthanol (Same %
costs as gas)
CellulosicEthanol (Sametax + 2x D&M +2x Refining &
Profit)
Tra
nsp
ort
atio
n F
uel
Co
st (
$/g
allo
n)
Feedstock Refining & Profit Distribution & Marketing Taxes
U.S. Average Regular Pump Price in 2008 was $3.29/gallonwww.eia.doe.gov/steo
$2.13
$3.02$3.29
$1.29