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Biochar and bioenergy production systems in small-holder farms in
Western Kenya Pyrolysis of biomass residues while cooking, can provide syn-gas as a source of fuel energy and biochar as a soil amendment; improving the
livelihoods of poor rural farming households
Dorisel Torres
• Environmental impact of unsustainable use of biomass as fuel:– Global warming and atmospheric pollution– Deforestation– Land degradation
• Human Impact:– Increase workload– Health problems due to emissions
Agriculture, Land Degradation and Energy
• Major limitations of farm productivity:– Constant cultivation – Removal of soil nutrients w/o replenishment– Soil erosion – Weathering
Agriculture, Land Degradation and Energy
Energy Overview
What is Biochar?
Main Objective
Soil Improvement
Climate Change
Waste Management
Energy
Development of sustainable biochar systems
System Components
Markets
Energy Infrastructure
Sales and Distribution
Outlets
Industrial Or
Local Skills
Transportation
Ag/Land UseBase
Resource Base
Biochar Systems
Objectives
• Initial assessment of resource base and energy consumption
• Traditional and pyrolytic stove performance testing
• Characterization of biochar produced
• Maize biomass production under different applications of fresh biomass, biochar and ash
Vihiga and South Nandi Districts, Western Kenya
MethodsAboveground Biomass EstimationTree Standing Biomass: Allometric measurements were taken on all live trees in the farm. Mixed species allometric equations for tropical moist trees (Brown et al. 1995) were applied to determine total aboveground standing biomass.
Banana and Collard Green Stalks: DBH for banana trees, were measured and specific allometric equations (Hairiah et al. 2002), used to calculate standing biomass. Repeated plot sampling and destructive harvest were used to determine, Collard Green stalks biomass.
Maize Residues: Secondary data collected from Kimetu et al. (2008) on maize yields, provided estimates of maize stalks and cobs with no nitrogen applications.
Energy Consumption: A sample size of 20 HH was used to conduct, cooking tests to evaluate specific fuel and energy consumption; following a modified HEH Shell Foundation Protocol
Maize Biomass Production:Screen house growth experiments with different types of biochar’s under field conditions Complete Block Randomization (5 replicates, 3 control)
Methods
Yrs since conversion
0 20 40 60 80 100 120
Tot
al B
iom
ass
Pro
duct
ivity
(to
n/ha
/yr)
0
2
4
6
8
10
12
14
Yrs vs Total Biomass Pr (ton/ha/yr) x column 1 vs y column 1
Results
Temporal variability
Biomass Productivity per Farm
Results
Temporal variability
Biomass Productivity per Farm
Farm Size (ha)
0 2 4 6
Tot
al B
iom
ass
Pro
duct
ivity
(to
n/yr
)
0
2
4
6
8
10
12
14
16
18
20
Farm Size vs Total Biomass Productivity (ton/yr) x column vs y column
Results
Traditional Stove Improved Stove Biochar Stove
Mas
s (g
/kg
food
coo
ked)
-200
-100
0
100
200
300
400
Wood Use Crop Residues Charcoal Residue Biochar
Wood and Biomass Consumption/Biochar Production
a a b
n=20n=10
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5R
oo
t: S
ho
ot
Ash
M. C
obs
Ash
Saw
dust
Ash
Sto
vers
Ash
Suk
uma
B. M
. Cob
s
B. S
awdu
st
B. S
tove
rs
Bio
mas
s S
UK
Cha
r
M. C
obs
Cha
r S
awdu
st
Cha
r S
tove
r
Cha
r S
ukum
a
Con
trol
Sample Name
All Pairs
Tukey-Kramer
0.05
Maize Biomass Production
Results
Emissions
Emissions
Emissions of non-CO2 greenhouse gases during pyrolysis
Effects of feedstock and pyrolysis procedure on energy, emission, economics, soil productivity, leaching, stability, etc
Better understanding of the mechanisms of stability and stabilization for prediction of variable biochar quality
Water and biological effects (both as carrier for beneficial microorganisms as well as risk)
Economic feasibility, markets, carbon trading
Poor documentation of opportunities/constraints
Emissions for GWP of CO2 non-CO2 greenhouse gases, PM and BC during the use of pyrolytic stoves
Effects of feedstock and pyrolysis procedure on energy, emission, economics, soil productivity, leaching, stability, etc
Nominal Combustion Efficiencies
Economic feasibility, markets, carbon trading
Future Projects/Expectations
Thanks
Enaudi Center, Cornell UniversityMicroUnity Group, CaliforniaRichard Bradfield Research Award