ghg emissions of biomass: consequence of modelling choices
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GHG emissions of biomass: Consequence of modelling choices
Dr. Heinz StichnotheJohann Heinrich von Thünen-Institut
Institute of Agricultural Technology and Biosystems Engineering
Braunschweig, Germany
Outline
• Methodological approaches
• Basis of comparison and allocation
• Indirect Emissionen (default values)
• Lack of knowledge
• Bio-based economy - limited resource
• Limits
• Conclusions
Life cycle of biofuelsRM
Transp.
Field
Transp.
Convers.
Transp.
Land use change
Use
Waste management
Co-products
Methodological approaches
• Attributional LCAdirect impacts due to diesel, fertiliser and pesticide usestandardised procedure (system boundaries, allocation, etc.)used for product declaration and certification systems
Advantage: comparable Disadvantage: blind spots
• Consequentional LCAstudies the consequences of changeactivities in- and outside the LC effected by changes are investigatedincludes alternative uses of constrained production factors
Advantage: more complete Disadvantage: less precise
Basis of comparison• Carbon intensity per energy output• Annual emissions
Not suitable for material useCascade use (all burdens to first life) Catch crops, crop rotation shift of emissions
• Energy content• Exclusion of agricultural co-products
Allocation
Specialities of palm oil
• Used as food, raw material and energy source
• Yield (PO 3.7, rapeseed 0.6; soja 0.4 t/ha)
• World production 45-50 Mt
• 86% occurs in Malaysia and Indonesia
• Export (approx. 80%)
• 250.000 ha/a 3. GHG-emitter
Agricultural residuesEU-RED Annex 5 (18) Exclusion of nut shells, husk, etc
Compostplant
FFB
Input Process
Diesel
Water
Biogasplant
EFB POME
Power plant
Fibre Shells Electr .
Biogas
Compost Ash
Plantation 1000 kg
92 kg
650 kg230 kg
Output
CPO
Kernel
AirWaterSoil
Energycarrier
Products
By-Products
Emissions
Oil mill
Diesel
Fertilizer22 kg
Pesticides
Diesel
0.07 L
Steam
8.7 m ³ CH 4
Compost
Compostplant
FFB
Input Process
DieselDiesel
WaterWater
Biogasplant
EFB POME
Power plant
FibreFibre ShellsShells Electr .Electr .
Biogas
Compost Ash
Plantation 1000 kg
92 kg
650 kg230 kg
Output
CPO
Kernel
AirWaterSoil
Shells
Products
By-Products
Emissions
Oil mill
DieselDiesel
Fertilizer22 kg FertilizerFertilizer22 kg
PesticidesPesticides
DieselDiesel
0.07 L
SteamSteam
8.7 m ³ CH 4
CompostCompostCompost
CH4 from POME
• Default value 27 g/MJ (1.5 times higher)
• CH4 capture - Yes or no
• No difference between flaring and utilisation• Use of biogas hampered by exclusion of by-
products (nut shells)• Efficiency of biogas capture is not
considered (THREAT: leackage can outbalance the benefits)
Biowaste managementBiowaste “treatment” on palm oil plantations
0
50
100
150
200
250
300
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Anaerobic condition in the pileG
WP
fro
m E
FB
[C
O2e
q/
t F
FB
]
1 t FFB = 0.2 t palm oil; 150 – 1125 kg CO2eq. per t Palm oil 4 – 30 g CO2eq/MJ Biodiesel: 37 g CO2eq/MJ
50% reduction
35% GHG reduction
Currently not specified in palm oil production systems according to EU-RED
Indirect emissions
• Nitrogen fertiliser production18 g N2O per kg N (average without N2O removal)
• After implementation of catalytic N2O reduction measures in Western Europe9 g N2O per kg N (current average)
• Technically possible 3 g N2O per kg N (future average in Western Europe)
In comparison approx. 10 g N2O is formed per kg N applied
Emission intensive fertiliser production is treated preferentially if Global default values are used; consequently GHG reduction from imported biomass might be overestimated
Direct emissions
• Organic Nitrogen is currently excluded in GHG calculations(examples in Annex V)
• IPCC 2006 Guidelines (table 11.1), the default emission factor is 1% of applied (inorganic and organic) N.
Example total N demand per t palm oil: 25 kg N, thereof 3,7 kg „returned“15% N input is not considered and consequently nitrous oxide from this input is also not taken into account
Advantage: Nutrient recycling is fostered; simplified approachDisadvantage: GHG emission savings are overestimated
Land use change - Indonesia
Mit 100 t CO2e/ha = 25 Mt CO2e = 50% THG LW in D.
0,7
1,2
2,5
3,0
3,33,4
3,73,9
4,4
4,9
0
1
2
3
4
5
1990 1995 2000 2001 2002 2003 2004 2005 2006 2007
Are
a [M
ha]
Assuming 100 t CO2e/ha = 25 Mt CO2e = 50% GHG German agriculture
Context
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
Pa
lm o
il [1
00
0*t]
18075 16100 14150 5400 2988 2100 312
Indonesia MalaysiaIndia/China
EU-27 EU-FoodEU-
IndustryEU-Energy
16% 9% 6% 1%
55%38%
6%
Limited resource - Oil
Limited resource - P
Limits
• National versus international responsibilitywho is contributing what to which extent
• Influence sphere• Default values versus „real values“,
management practise• Lack of knowledge – organic nitrogen, soil
carbon• Focus on GHG blind spots• Crude oil and phosphorous are limited
Conclusions
• Do we want to be accurate or comparable?Indirect land use change, soil carbon storage
• Technology - European average values for developing countries?
• Right incentives for imported biomass?• Simplification - overestimation of savings• For imported biomass
Learning curve yes, but GHG savings?
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