ENVIRONMENTAL IMPACT AND ENERGY
PRODUCTION: EVALUATION OF BIOCHAR
APPLICATION ON TAIWANESE SET-ASIDE
LAND
Chih-Chun Kung
November 2012
Austin, Texas
Motivation
Energy insecurity of Taiwan
More than 99% of fossil fuels are imported;
Taiwan is vulnerable to distortions and high
energy prices and wants to enhance energy
security
Taiwan is interested in bioenergy
 Limited information about bioenergy.
Research objectives
The objective of this work is to provide
information on
Bioenergy on set aside land production;
Market effects and GHG offset magnitude
information;
Bioenergy crop selection;
Bioenergy technique selection including
consideration of electricity, conventional and
cellulosic ethanol, pyrolysis/biochar
Bioenergy prospects in Taiwan using Set-Aside Land: An Economic
Evaluation
 Sweet potato, poplar, willow and switchgrass are bioenergy
feedstock alternatives.
 Sweet potato can be used to produce ethanol while poplar,
willow and switchgrass can be used to produce ethanol and/or
electricity.
 The Taiwan Agricultural Sector Model (TASM) is extended
by incorporating bioenergy production and GHG emissions.
 Model bioenergy crops : get estimated yield, production costs,
hauling costs and processing costs.
 GHG terms: bioenergy conversion rate and GHG offset rate of
each crop.
Bioenergy prospects in Taiwan using Set-Aside Land: An Economic
Evaluation
 Study setup
Ethanol price: NT$ 20, 30, 40, 50 per liter
(gasoline price since 2005 is between NT$20 and 38)
Coal price: NT$ 1.7, 3.45, 6.0 per kg
(coal price since 2005 is between NT$1.7 and 4.35)
CO2 price: NT$ 300, 500, 1000 per ton
(CO2 price in Taiwan is zero, NT$1,100 in European \
Climate Exchange and NT$130 in Chicago Climate
Exchange in 2008).
Government subsidy: NT$50,000 per ha for sweet potato,
NT$45,000 for willow, poplar and switchgrass.
Economics of biochar production, utilization and GHG offsets
 Feedstock cost (US$/ton)
56
75
94 112
 Electricity cost
(cent/kwh)
Fast pyrolysis
5.15 5.79 6.44 7.01
Slow pyrolysis
6.78 7.63 8.48 9.23
Economics of biochar production, utilization and GHG offsets
Returns and costs (US$ t-1)
Fast
Slow
($105.81)
($105.81)
Pyrolysis cost (Modules I and II)
($46.82)
($46.82)
Generating cost (Module III)
($43.26)
($35.04)
Electricity value
$206.00
$170.90
$10.11
-($16.77)
0.14
0.31
$1.95
$9.55
(-$1.03)
(-$2.28)
$11.03
(-$9.5)
$8.96
$8.48
$19.99
(-$1.02)
Feedstock cost
Net margin (electricity only)
Biochar yield (t)
Biochar value
Biochar haul cost
Net margin (electricity + biochar)
GHG value
Net margin all
Environmental Impact and Energy Production Evaluation of Biochar
Application on Taiwan Set-Aside Land
 Biomass can provide energy by
 Chemical transformation to provide liquid fuels for
combustion or transportation;
 Direct combustion to provide heat that can be used
in electricity generation;
 Pyrolysis to provide liquid fuels for fuel oil in static
heating or electricity generation.
 Taiwan can produce bioenergy using above
technologies.
Environmental Impact and Energy Production Evaluation of Biochar
Application on Taiwan Set-Aside Land
 Assumptions
 Willow and switchgrass generate exactly the same amount of
outputs as poplar in pyrolysis and pyrolysis output of sweet
potato is the same as corn stover.
 Pyrolysis plant is located in Chiayi. The average hauling
distance from pyrolysis plant to rice fields is 10 km within
Chiayi and an additional 25 km for adjacent counties.
 Biochar is applied at a rate of 5 tons per hectare.
 If biochar is used as an energy source, then no biochar can be
hauled to rice fields and vice versa.
Environmental Impact and Energy Production Evaluation of Biochar
Application on Taiwan Set-Aside Land
 Ethanol production (1000, liters) when biochar is
burned/hauled under varying GHG prices
300000
250000
A11
A12
A21
250000 A22
A31
A32
200000
ETHPROD
ETHPROD
B11
B12
B21
200000 B22
B31
B32
150000
150000
100000
100000
50000
50000
0
0
5
10
15
20
GHGPRICE
25
30
5
10
15
20
GHGPRICE
25
30
 Finding:
Ethanol production increases as ethanol price increases, but it
decreases as GHG and coal price increase.
Ethanol production is higher when biochar is burned at low
GHG price scenarios.
Environmental Impact and Energy Production Evaluation of Biochar
Application on Taiwan Set-Aside Land
 Electricity production when biochar is burned/hauled under varying GHG prices
4e+006
2.8e+006
B11
2.6e+006 B12
B21
2.4e+006 B22
B31
2.2e+006 B32
ELECPROD
ELECPROD
A11
A12
3.5e+006 A21
A22
A31
3e+006 A32
2.5e+006
2e+006
1.8e+006
1.6e+006
2e+006
1.4e+006
1.5e+006
1.2e+006
1e+006
1e+006
800000
500000
5
 Finding:
10
15
20
GHGPRICE
25
30
600000
5
10
15
20
GHGPRICE
25
30
When biochar is burned, it provides up to 1.79% of electricity demand.
When biochar is hauled at low carbon and ethanol price but high coal price,
fast pyrolysis dominates and generates less biochar. This switches to slow
pyrolysis when GHG price increases.
Environmental Impact and Energy Production Evaluation of Biochar
Application on Taiwan Set-Aside Land
 CO2 reduction when biochar is burned/hauled under varying GHG prices
2.6e+006
2.2e+006
B11
2.4e+006 B12
B21
2.2e+006 B22
B31
B32
2e+006
CARBONRED
CARBONRED
A11
A12
2e+006 A21
A22
1.8e+006 A31
A32
1.6e+006
1.8e+006
1.4e+006
1.6e+006
1.2e+006
1.4e+006
1e+006
1.2e+006
800000
1e+006
600000
800000
400000
600000
5
10
15
20
GHGPRICE
25
30
5
10
15
20
GHGPRICE
25
 Finding:
Net GHG emission reduction is higher when biochar is used as a soil
amendment.
Both biochar applications reduce GHG emissions less than 1%.
At higher GHG prices, GHG emission reduction increases.
30
Environmental Impact and Energy Production Evaluation of Biochar
Application on Taiwan Set-Aside Land
 Findings:
When bioenergy is produced in Taiwan, given available
bioenergy feedstock alternatives, only sweet potato and poplar
are produced.
Energy production and GHG offsets may not be maximized at
the same time.
When pyrolysis is available alternative, biopower is driven out
at all cases.
As GHG price keeps rising, ethanol becomes less competitive
than pyrolysis.
Conclusions
 Taiwan get benefits from bioenergy in terms of energy
security, farmers’ revenue and welfare.
 Taiwan’s bioenergy production does not contribute much in
terms of GHG offsets.
 Pyrolysis can be profitable but energy price, GHG price and
other factors may affect results substantially.
 At a high coal price, electricity production expands and at a
high ethanol price, ethanol production expands.
 At low GHG and coal prices, ethanol can still compete with
pyrolysis.
 When GHG price increases, pyrolysis dominates ethanol and
biopower.
Limitations and Future Research
 Pyrolysis decomposition rate of sweet potato is assumed to be
the same as corn stover, and that of willow and switchgrass is
assumed to be the same as poplar.
 If different location of pyrolysis plant is chosen, then the
simulated result will vary.
 Same rice yield increase regardless of soil and weather
condition.
 Fixed government subsidy.
 GHG emission change due to land use change is not
incorporated.