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Johannes LehmannDepartment of Crop and Soil SciencesCornell University
Biochar Systems Science: Climate Change Mitigation with
Multiple Sustainability Outcomes?
Agricultural Carbon Sequestration
Tillage practicesOrganic matter applications (manures, composts)Residue retentionAgroforestryBiochar systems
©Kimetu
Climate Change mitigation must first explore all emission reductions from energy generation!
Multiple Biomass Use in Agricultural and Forestry Systems
FoodBioenergyBioproductsSoil health (soil protection, soil organic matter, nutrients)Climate forcing (carbon dioxide, methane, nitrous oxide, black carbon)
Smart Biochar Systems – Exploring Synergies
Lehmann, 2007, Frontiers in Ecology and the Environment 7, 381-387
CO2 …making more out of a scarce resource.
Systems Components
Type of Biochar
Biochar Properties
Lehmann, 2007, Frontiers in Ecology and the Environment 7, 381-387
Temperature (°C)0 200 400 600 800 1000
Car
bon
reco
very
(% o
f ini
tial C
)
50
60
70
80
90
100
110
pH
2
4
6
8
10
12
14
CE
C (m
mol
c kg-1
)Su
rface
are
a (m
2 g-1
)
0
50
100
150
200
250
300
350Carbonrecovery
pH
Opt
imum
CEC
Surface area
Biochar from black locust(N=3)
Quality of Biochar - Stability
Corn-BC Oak-BC0
5
10
15
20350°C600°Ca
bb b
(1 year, 30°C, in sand culture, N=8)
Car
bon
loss
rate
(% y
ear-1
)
Nguyen and Lehmann, 2009, Organic Geochemistry 40, 846-853
A (corn-350-BC) B (corn-600-BC)
5 nm 5 nm
Quality of Biochar – N2O Emissions
Bhupanderpal-Singh et al., 2009, JEQ in press
N2O: Up to 73% reduction
VertisolAlfisol
poultry manure 400°C
poultry manure 550°C
wood 550°C
wood 400°C
control
Climate Change Mitigation with Biochar
Lehmann, 2007, Nature 447, 143-144
…conversion is not enough!
Systems Components
Emissions Budgets
Biochar Systems View
Roberts et al., Environmental Science and Technology, in press
Life-cycle energy and emission balances
Life-Cycle Emissions
Roberts et al., Environmental Science and Technology, in press
0 300 600 900
emit.
reduct.
emit.
reduct.
emit.
reduct.
emit.
reduct.
emit.
reduct.
Greenhouse gases (kg CO2e t-1 dry feedstock)
LUC & fieldemiss.agrochems
field ops
other
stable C
avoid foss fuelgen. & comb.land-use seq.
reduced soilN2O emiss.avoid compost
Late
st
over
Ear
ly
stov
e rS
witc
h gr
ass
BY
ard
was
te
Net = - 864
Net = - 793
Net = - 442
Net = + 36
Net = - 885
Sw
itch
gras
s A
(b)0 300 600 900
emit.
reduct.
emit.
reduct.
emit.
reduct.
emit.
reduct.
emit.
reduct.
Greenhouse gases (kg CO2e t-1 dry feedstock)
LUC & fieldemiss.agrochems
field ops
other
stable C
avoid foss fuelgen. & comb.land-use seq.
reduced soilN2O emiss.avoid compost
Late
st
over
Ear
ly
stov
e rS
witc
h gr
ass
BY
ard
was
te
Net = - 864
Net = - 793
Net = - 442
Net = + 36
Net = - 885
Sw
itch
gras
s A
(b)
Economic Analysis
Roberts et al., Environmental Science and Technology, in press
-120 -80 -40 0 40 80 120 160 200cost ($ t-1 dry feedstock)
+$35
-$17Late
st
over
Switc
h gr
ass
AYa
rd
was
teSw
itch
gras
s B
+$8
-$18
-$28
-$30
+$69 +$16
(a)
-120 -80 -40 0 40 80 120 160 200cost ($ t-1 dry feedstock)
+$35
-$17Late
st
over
Switc
h gr
ass
AYa
rd
was
teSw
itch
gras
s B
+$8
-$18
-$28
-$30
+$69 +$16
(a) biomass collectionpyrolysisbiochar applicationtipping feebiochar P & K contentcarbon value
biomass collectionpyrolysisbiochar applicationtipping feebiochar P & K contentcarbon valuebiomass transportbiochar transportlost compost revenueavoided compost costbiochar improved fertilizer usesyngas heat
biomass transportbiochar transportlost compost revenueavoided compost costbiochar improved fertilizer usesyngas heat
Sensitivity Analysis
Roberts et al., Environmental Science and Technology, in press
Biomass collection energy sensitivity: <2%Biomass collection emissions sensitivity: <12%Biochar yield emissions sensitivity: <13%Stable C emissions sensitivity: <25%Syngas energy sensitivity: <63%Syngas emissions sensitivity: <19%
(scenario where corn stover is harvested late)
Sensitivity Analysis
Roberts et al., Environmental Science and Technology, in press
Distance (km)
0 200 400 600 800 1000
Net
GH
G (k
g C
O2e
t-1 d
ry s
tove
r)
-1000
-800
-600
-400
-200
0
Net
ene
rgy
(MJ
t-1 d
ry s
tove
r)
0
1000
2000
3000
4000
5000
6000
Rev
enue
($ t-1
dry
sto
ver)
-90
-60
-30
0
30
60
Net energy
Net revenue
Net GHG
(b)
Distance (km)
0 200 400 600 800 1000
Net
GH
G (k
g C
O2e
t-1 d
ry s
tove
r)
-1000
-800
-600
-400
-200
0
Net
ene
rgy
(MJ
t-1 d
ry s
tove
r)
0
1000
2000
3000
4000
5000
6000
Rev
enue
($ t-1
dry
sto
ver)
-90
-60
-30
0
30
60
Net energy
Net revenue
Net GHG
(b)
Transportation distance
Late stover scenarioHigh revenue
Energy vs Soil Amendment
Roberts et al., Environmental Science and Technology, in press
Biochar as fuel -617 kg CO2e t-1 biomass
Biochar to soil -864 kg CO2e t-1 biomass +29%
Late stover scenario
Cook StovesLower indoor pollution=lower respiratory
+ eye infections
©Torres
Cook Stoves - ExamplesWorldStoves Project - Burkina Faso, Burundi
Mulcahy
Cook Stoves - ExamplesGOOD STOVES AND BIOCHAR COMMUNITIES PROJECT - India
Sai Bhaskar Reddy
Emission Reductions with Biochar Cookstoves
Whitman and Lehmann, Environmental Science and Policy 12, 1024-1027
Emission Reductions
Whitman et al., unpublished
MRT of BC 600yrsFraction of passive BC: 0.85Fraction of crop residue used: 25%Fraction converted to BC: 0.6Systems dynamics modeling (Vensim)
Case Study Western Kenya – preliminary data
Time since conversion (years)
0 20 40 60 80 100 120
Mai
ze g
rain
yie
ld (t
ha-1
)
2
4
6
8
10
12BiocharSawdust Manure Tithonia
LSD0.05
Soil and Crop BenefitsCase Study Western Kenya
Kimetu et al., 2008, Ecosystems 11: 726-739
Biochar applied each seasonKenya (n=3)
Biochar Systems – Waste ManagementPoultry Manure: low value, risk of pathogen contamination,
disease development in chickenWest Virginia Poultry Farm
99,000 chickens125-600 t/yr poultry litter
Pyrolysis of 300 kg/hr dry litter(at 500°C) Off-sets 114,000L propane gasUS$66,000 /yr
25-120 t/yr biochar
Biochar Systems – Waste Management
Wasatch-Cache National Forest, UtahUSDA Forest Service - Ogden Archive, USDA Forest Service
Biochar Systems – Waste Management
Flottwick
Canada
Integrated Biomass Systems with Biochar
EnergyProduction
SoilImprovement
Mitigation ofClimate Change
Social, Financial Benefits
Biochar SystemsWhat systems benefits have to be harnessed?
WasteManagement
EnergyProduction
SoilImprovement
Mitigation ofClimate Change
Social, Financial Benefits
Biochar Systems
WasteManagement
EnergyProduction
SoilImprovement
Mitigation ofClimate Change
Social, Financial Benefits
Biochar SystemsHow many opportunities exist?
WasteManagement
Biochar – The Way Forward
Not “WHETHER”, but “WHERE/HOW”
Biochar – The Way Forward
Informed by solid science
Taking a “systems perspective” (also together with other approaches)
Implementation with R&D support where we know enough
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