Switchgrass and Perennial Grasses, Biomass, and … Energy...2007 Energy Independence and Security...
Transcript of Switchgrass and Perennial Grasses, Biomass, and … Energy...2007 Energy Independence and Security...
Switchgrass and Perennial
Grasses, Biomass, and Biofuels-
2012 Ken Vogel
USDA-ARS,Lincoln, NE
http://feedstockreview.ornl.gov/pdf/billion_ton_vision.pdf
Main Conclusion
U.S. can displace over
30% of current
petroleum consumption
by 2030 using crop
residues and other
sources including
biomass from perennial
herbaceous crops for
the production of
cellulosic ethanol.
Emphasis on cellolosic
energy because of food
vs fuel problem.
2007 Energy Independence and
Security Act (EISA) • EISA requires EPA to revise the
Renewable Fuels Standards (RFS)
program to increase renewable fuel
blended into transportation fuel from 9
billion gallons in 1998 to 36 billion gallons
per year by 2022.
• Revised standards (RFS2) was finalized in
2010.
Renewable Fuel Standard
revised 2010 (RFS2) • The RFS goal is 36 billion gallons per year
for renewable fuels by 2022.
• RFS2 limits the amount of corn ethanol
that counts toward the requirement to 15
million gallons per year.
• The remaining 21 billion gallons must
come from other non-food or cellulosic
sources
• Other sources are corn stover, perennial
grasses, woody biomass, and algae.
U.S. Billion-Ton Update 2011
• Increased emphasis
on dedicated energy
crops including
herbaceous
perennials such as
switchgrass, other
grasses and woody
species.
• Sustainable use of
crop residues.
Some Questions
• Why not just use corn stover?
• Why switchgrass?
• Why other perennial grasses?
• How are we going to get fuels out of this
stuff?
• Where are we at on management,
cultivars, and other improvements?
Long term Carbon sequestration Study-
Corn & Switchgrass, Mead, NE
• Quantify carbon sequestration on cropland converted to switchgrass.
• Compare to no-till corn.
• Experiment in eastern NE established in 1998.
• In 2000, plots split and stover removed (50%) on split half of corn plots.
Corn Grain Yield – Effect of removing ½ of stover
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
mo
ve
d
- 7.2% grain
Wally Wilhelm Gary Varvel
Factors Limiting Crop Biomass
Removal S
tove
r to
reta
in (
ton
ac
-1)
0
2
4
6
8
Soil organic carbon
Water erosion
Wind erosion
Continuous corn Corn-soybean
Moldboard
plow
No or
conservation
tillage
3.38
1.39
0.77
2.34
0.29
0.06
5.58
3.56
1.22
3.52
0.43
0.15
Moldboard
plow
No or
conservation
tillage
Wilhelm et al., 2007. Agron. J. 99:1665-1667. ARS-REAP
Switchgrass Biomass Feedstock
Research • 1980’s, : Oak Ridge National Laboratory, DOE, in
cooperative work with Universities & USDA-ARS. Species evaluations. Selected switchgrass & hybrid popular & willow.
• 1990’s, 2000-2002. Funded research at Univ. & ARS.
• 2002. DOE switchgrass work discontinued. All feedstock and conversion research switched to corn stover and crop residues.
• 2002 to present. New thrust by USDA-ARS. Perennial energy crop research. A few land-grant universities continue programs.
• 2006 – present. DOE renews major funding effort with focus on basic biology & conversion. New USDA funding. Private Companies funding inhouse research.
Why Switchgrass?
• Native to N. America east of Rocky Mtns.
• Adapted germplasm available.
• High yield potential
• Can harvest and grow like hay using farm equipment.
• Multiple uses on/off farm
• Low energy input
• Increased carbon storage.
• Soil and water conservation benefits.
• Excellent wildlife habitat.
• Buffer strips, wetlands
• Seed easy to plant
Switchgrass
Panicum virgatum L.
Upland switchgrass plant Natural distribution of switchgrass
In North America
USDA-ARS Grain, Forage, &
Bioenergy Research Unit, Lincoln, NE
Switchgrass research
1930’s to present
• Native prairie species, domestication, breeding & management work to revegetate grasslands after drought of the 30’s
• Use by livestock was emphasized
• 1990 - began work to develop switchgrass into a biofuel crop.
• 2000 - Information used for farm scale production trials
Biomass Power
Back to the Future
• 1920 - 27,000,000 horses & mules, USA
• 1954 - < 5,000,000
• Resulted in major land use change.
• 80 million acres of pasture & hayland (biomass) released for other uses.
Horse power to tractor power – land use changes,
government programs, & bioenergy
• Marginal land previously in pasture converted to grain crops. Severe erosion.
• Crop surpluses depressed prices requiring farm subsidizes
• Conservation Reserve Program (CRP): over 35 million acres in CRP.
• Annual cost is $1.7 billion.
• CRP land east of 100o W. Long. could be used for perennial biomass energy crops (switchgrass).
• All conservation benefits would be retained.
• Equivalent amount of marginal cropland in USA.
Fields in northeast Nebraska
Switchgrass field in same region
Research Accomplishments
• Harvest management and timing
• Nitrogen fertilization rates
• Cultivar evaluations, classification, and
geographic adaptation
• Genetic improvements and new cultivar
development
• Genetic diversity and gene pools
• Production economics
Harvest Management Vogel et al. (2002)
0
2
4
6
8
10
12
1 2 3 4 5 6 7 8
First cut
Second cut
Harvest interval (late June to late August)
Bio
mas
s Y
ield
(M
g/h
a)
Nitrogen Fertilization Vogel et al. (2002)
6
7
8
9
10
11
0 60 120 180 240 300
Nitrogen Applied (kg/ha)
Bio
mas
s Y
ield
(M
g/h
a)
Mead, NE
Ames, IA
Above this point, N application rate
exceeded N removal rate, increasing NO3-N
in the soil.
Northern Plains Switchgrass Field Scale
Production & Economic Trials 2000-2005
31”-33”
Annual
Precipitation
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.
DOE/USDA Biomass Feedstock
Stage Gate Review Meeting
March 14-16, 2005
• Improved Plant & Production
Practices for Grasslands &
Biomass Crops in the Mid-
Continental USA
Kenneth P. Vogel
USDA-ARS, Lincoln, NE
Plant Genomics for Biofuels"
BP-DOE Office of Science Review June/05
Ari Patrinos (DOE) & Steve Koonin (BP)
• Participants
– Justin Adams, BP
– John Pierce, DuPont
– C. Saunders, Pioneer
– Don Doering, Winrock
– Jim Barber, Metabolix
– Biotechnology Ind. Org.
Reps.
– Other invited industry reps.
– USDA & DOE Senior
Executives
• Speakers
– Chris Somerville
– Richard Flavell
– Elliott Meyerowitz
– Craig Venter
– Jerry Tuscan
– Steve Straus
– Ed Buckler
– Ken Vogel
– 4 others
Science editorial:
1/27/ 2006
Steve Koonin, BP
Chief Scientist
endorses biofuels
from cellulosic
sources such as
switchgrass.
Science 2006 cover story.
Tillman et al.
Science 2006 314:1598-
1600. Low input-high
diversity grasslands for
biofuels.
Switchgrass for Bioenergy – On farm
economic study in NE, SD, ND.
• Field shown at left had a five year cumulative average cost of $33/T switchgrass biomass including land & money costs.
• Average costs for 10 farms was $60/T; two experienced farmer’s costs were $39/T.
• Each big bale (left) represents a 50 gal barrel of ethanol at conversion rate of 0.38 L/kg with average farm gate cost of $0.64/gal. Low cost producers = $0.53/gal at the farm gate.
Switchgrass field in NE South Dakota in 2005. Yields averaged 4T/acre.
Perrin et al. 2008 BioEnergy Research 1:91-98 (US units)
Take Home Lessons
• Economic production efficiency can be improved via research and producer training.
• Adaptation and production trials in potential biomass production areas are needed.
• Improved high yielding cultivars/hybrids with improved conversion efficiency will be needed.
• Additional agronomic research on fertility, establishment, seed quality, & other factors.
• Feedstock harvesting and storage research needed.
Net energy and petroleum inputs from corn
and cellulosic (switchgrass) ethanol (Ferrell et al. Science 2006 311:506-508)
Ignored co-products &
Used outdated
agronomics
Models over-estimate switchgrass
inputs
0
3
6
9
12
15
Estab. Post. Farrell et al.,
2006
Pimentel &
Patzek 2005
Wang et al.,
1999
Ag
ricu
ltu
ral In
pu
ts (
GJ h
a-1
)
Other
Machinery & Labor
Herbicide
Seed
Diesel
Fertilizer
Actual farm
inputs from 5-yr
USDA study
Estimated Inputs
On-farm Switchgrass Production in
the Great Plains – Net 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, environmentally sustainable, 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
Ethanol from switchgrass:
Input - output illustration.
Output
50 gal
(180 L)
Input
Net energy 8 gal.(30 L)
Big round bale of
switchgrass – 0.7 ton
(0.63 Mg). Conversion
rate of 80 gal/ton (330
L/Mg)
Based on Schmer et al., 2008. PNAS105: 464-469.
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., 2006
USDA study
Switchgrass grown for bioenergy:
Soil carbon storage in 5 years: 0-120 cm
Switchgrass Soil Carbon Sequestration
when grown and managed as a biomass
energy crop • Field at left for period
2000 to 2005
- 0 to 30 cm: 5 Mg C/ha increase in soil carbon (2.2 t/A)
- 0 to 120 cm: 18.4 Mg C/ha increase in soil carbon (8.2 t/A)
(Liebig et al., Agron. J. 2008).
Douglas, Nebraska Field
Coffee Break – Stretch Break
• After break topics
– Adaptation
– Yield
– Breeding & new cultivars
– Other species
– Conversion methods
– Biomass quality
– Improve Agronomic and Genetics
Ecoregions Geographic regions for which thermal and
moisture (amount and season) determine
dominant plant populations.
Ecoregions of the USA
1990 USDA Plant Hardiness Zones
growing season length, temperatures.
Plant Adaptation Regions of the USA USDA Hardiness Zones
Bailey’s Ecoregions
Vogel et al., 2005
Target Plant Adaptation Regions 251-HZ 4&5 Prairie Parkland
332-HZ 4&5 Great Plains Steppe
331-HZ 4&5 Great Plains-Palouse Dry Steppe
Switchgrass Adaption
• Switchgrass is photoperiod sensitive (Benedict, 1941) and is a determinate species.
• Photoperiod requirements are based on the latitude-of-origin of individual ecotypes. Flowering is induced by decreases in daylength following the summer solstice. Photoperiod also affects winter sensence.
• When grown in the central Great Plains, switchgrasses from the Dakotas (northern ecotypes) flower and mature early and are short in stature while those from Texas and Oklahoma (southern ecotypes) flower late and are tall (Cornelius and Johnson 1941; McMillian 1959).
Switchgrass Adaption (cont.)
• In North America, moving northern ecotypes south exposes them to a shorter-than-normal daylength during summer month, which causes early flowering, reducing biomass yield.
• The opposite occurs when southern ecotypes are exported north. They remain vegetative for a longer period of time, with a longer photosynthetically active period, often producing more forage than northern ecotypes (Newell, 1968).
• The physiological development of switchgrass as determined by a maturity staging system is highly correlated to Day of Year and Growing Degree Days with DOY being the most important.
Switchgrass General Adaptation
Rule • Switchgrass strains should not be exported more than
one USDA Plant Hardiness Zone north or south of their area of origin for long term survival under biomass production conditions.
• East-west adaptation is a function of disease resistance (more humid conditions – more disease pressure) or drought tolerance.
• Plant Adaption Region (PAR) of origin is a good indicator or where switchgrass strain can be used. In current environmental conditions, switchgrass strains can be used in origin PAR and adjacent PAR. Some cultivars have wider adaptation zones.
Revised USDA Plant Hardiness
Zone Map 2012
Plant Hardiness Zones have shifted
½ zone north since 1990
PHZ 4b
PHZ 5a
Adaptation and Breeding and
Management for Biomass Yield • The easiest way to breed for improved biomass yield
is to use southern ecotypes to extend the effective length of the pre-flowering growing season.
• Problem is winter survival. Plants need to move storage carbohydrates to the roots for winter survival. Because of photoperiod, southern ecotypes may start this too late in northern latitudes and winter kill.
• Basic research on physiology and genetics of fall sensence and spring green-up being conducted by G. Sarath.
• If climate warming continues, it will affect adaptation and also pathogen and insect populations.
• Regional trials are being used to track adaptation and productivity.
Land required to produce feedstock for a 50 million
gallon (190 ML) cellulosic ethanol plant in a 25 mile
(40 km radius).
Feedstock Yield
tons/acre (Mg/ha) Acres (Mg/ha) % of Land Area
1 (2.2) 625,000 (250,000) 50
2 (4.5) 312,500 (125,000) 25
3 (6.7) 208,333 (85,000) 17
4 (9.0) 156,250 (63,000) 12
5 (11.2) 125,000 (50,000) 10
7.5 (16.8) 83,333 (34,000) 6.6
10 (22.4) 62,500 (25,000) 5
A 50 million gallon plant requires 625,000 tons (567,00 Mg) of feedstock/year at
80 gal/ton or 330 L/Mg conversion rate.
Breeding Progress for Conventional Switchgrass
Cultivars
Yield 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 Late YD
C4*
7.0 (15.7) 55.2
Improve biomass yields – hybrid
cultivars
Strain Yield
T/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.
Man-made prairies
One location
Small-plots
Hand-seeded
Irrigated during establishment
Hand-weeded
Hand-harvested using 4” strips
14% to 78% more annual
precipitation than USDA
switchgrass fields
USDA switchgrass
study
10 locations
165 acres seeded
Seeded with
commercial drills
Dryland sites
Harvested entire field
with commercial hay
equipment
Biomass Energy Crops for the Central USA
• Perennial grasses such as switchgrass and big bluestem.
• Biomass sorghums.
• Corn stover
Big bluestem
Switchgrass
Corn
Stover Biomass
Sorghum
Other Prairie Species with Biomass Energy
Potential
Big bluestem cv Goldmine
‘Scout’ Indiangrass
Partridge Pea – germplasm
release
Illinois
Bundleflower
PAR germplasm
releases
pending
Switchgrass seed – a principal attribute
• Switchgrass seed is easy to harvest and plant.
• Seed yields can be high 400 to 1000 lbs/acre. Seed cost less than for other native species.
• Limited amounts (3-4.5 lbs PLS) needed to plant a field.
• Other natives have chaffy seed requiring special processing and planters.
Perennial grasses
Crop residues
Manure
Wood waste
Lig
no
ce
llulo
sic
Bio
ma
ss
Gasification
Pyrolysis
Synthesis gas
Bio-oil
Gasification
Fischer- Tropsch
Methanol
Jet Fuel
Diesel
Gasoline Heat
Power
Hydrotreating- Hydrocracking
Saccharification Sugar
Fermentation Ethanol
Butanol
Biofuels from Biomass
Saccharification
Sugar Liquid Phase
Processing
Kerosene
Diesel
Gasoline
Jet Fuel
Biological Conversion
Thermochemical Conversion
Liquid Phase Chemical Processing
Thermochemical
Biological Catalytic
Liquid Phase
Processing
Starch
Glycerol
Saccharification Sugar
Fermentation Ethanol
Butanol
Biological Conversion of Biomass
Swithchgrass
Corn stover
Manure
Wood waste
Lig
no
ce
llulo
sic
Bio
ma
ss
Biological
Status: Pilot plants are in operation, first full scale
biorefineries will go into operation next year using crop
residues and perennial grasses
Gasification
Pyrolysis
Synthesis gas
Bio-oil
Gasification
Fischer- Tropsch
Methanol
Jet Fuel
Diesel
Gasoline Heat
Power
Hydrotreating- Hydrocracking
Thermochemical Conversion of Biomass
Swithchgrass
Corn stover
Manure
Wood waste
Lig
no
ce
llulo
sic
Bio
ma
ss
Thermochemical
Catalytic
Deoxygenation
Status: Pilot plants in operation;
Some scale up next year. Several
Companies with major funding:
CoolPlanet, LanzaTech, & others
Why fast pyrolysis? Rapid thermal decomposition of
organic compounds in the absence
of oxygen to predominately produce
liquid product known as bio-oil.
Fast pyrolysis can be built at small
scales suitable for distributed
processing.
Co-product biochar
is produced at yields
of 12-20 wt%
biomass.
Biochar
Bio-oil is refined like petroleum into
synthetic gasoline and biodiesel.
Biorefineries and Biomass
Feedstock Quality
(source: Nebraska Ethanol Board)
ETO yield now about 330 L Mg-1
Potential yield = 450 L Mg-1.
Genetic effects on lignin, anatomy & ethanol yield
from switchgrass cellulose
Mean Ethanol Yield mg/g
64
66
68
70
72
74
76
78
80
C-1 Hi Lig C-1 Lo Lig C+3 Hi Lig C+3 Lo Lig
Population
Eth
an
ol yie
ld (
mg
/g)
Stem Lignin 63.2 g/kg
Stem Lignin 50.7 g/kg
Thick, lignified layer
↓
Current switchgrass cultivars & agronomics
equivalent to 1960’s corn system
Corn yield improvement
50% genetic-50% agronomics
Switchgrass technology similar
to1960’s corn and Volkswagen
– a basic, good system with
improvement potential.
Bottom Line
• Switchgrass is an economically feasible biomass energy crop for use on marginal cropland.
• Improvements in genetics and agronomics will improve:
– biomass yields
– biomass quality
– conversion
– ethanol or biocrude yield per acre
Conversion information
Biomass to ethanol
80 gallon/US ton
(Current technology)
110 gal/ton potential.
Feedstock cost per
gallon
$ton/80 gal.
$40 ton/ 80 gal = $0.50
gallon feedstock cost.
Corn grain to ethanol
2.5 to 2.9
gallon/bushel
Feedstock cost per
gallon
$ bushel/2.9 gal.
$2.50 bu/ 2.9 gal
=$0.86/gallon
feedstock cost.
$3.50 bu = $1.21/gal
cost.