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