Transcript GHG emissions in the production and use of ethanol from sugarcane The expansion since 2002 LUC , ILUC effects: some data and discussion I.

GHG emissions in the production and use of
ethanol from sugarcane
The expansion since 2002
LUC , ILUC effects: some data and discussion
I C Macedo, NIPE/UNICAMP
July 2008
Cane bioethanol and GHG emissions
• Methodology “harmonization” (system boundaries, mitigation
accounting, by-products allocation, the land use change impacts,
N2O emissions, methane GWP, baselines for electricity
production emissions, etc):
Renewable Transport Fuel Obligation, UK (bio-fuels)
NREL/DoE and NIPE/UNICAMP: introducing the ethanol
from cane in the GREET model
GHG Working Group (RSF), EPFL
Global Bioenergy Partnership (GBEP, FAO, G8+5)
→Transparency, adequate simplification
Cane Bioethanol: GHG emissions and mitigation
in the life cycle
Carbon fluxes associated with C absorption (photosynthesis) in
plants and its release as CO2 : trash and bagasse burning,
residues, sugar fermentation and ethanol use
Carbon fluxes associated with fossil fuel utilization in agriculture
and with all inputs used in agriculture and industry; also in
equipment and buildings production and maintenance.
GHG fluxes not related with the use of fossil fuels; mainly N2O
and methane: trash burning, N2O soil emissions from Nfertilizer and residues (including stillage, filter cake, trash)
GHG emissions mitigation: ethanol and surplus bagasse (or
surplus electricity) substitute for gasoline, fuel oil or
conventional electricity.
Macedo IC, Seabra JEA, Silva JEAR. Green house gases emissions in the production and use of
ethanol from sugarcane in Brazil: The.... Biomass and Bioenergy (2007),
doi:10.1016/j.biombioe.2007.12.006
Note 1: the data base quality
Data: even for a homogeneous set of producers (Brazil Center
South region) differences in processes (agricultural and
industrial) impact energy flows and GHG emissions.
• 2005/2006: sample of 44 mills (100 M t cane / season), all in
the Center South; data from CTC “mutual benchmarking”:
last 15 years, agriculture and industry.
• Additional information from larger data collection systems for
some selected parameters
Parameter
N-fertilizer use
Trucks’ energy efficiency
Transportation distance c
Mechanical harvesting
“Other” agr. (diesel)
Unburned cane
Cane productivity
Ethanol yield
Bagasse surplus
Electricity surplus e
a.
b.
c.
d.
e.
Units
Average
SDa
Min.
Max.
Mills
Caneb
kg N (ha.year)-1
t.km L-1
Km
%
L ha-1
%
tc ha-1
L tc-1
%
kWh tc-1
60
52.4
23.1
49.5
67
30.8
87.1
86.3
9.6
9.2
16
9.7
6.1
27.1
38
21.7
13.7
3.5
6.4
35
38.9
9.3
0
2.7
0
51.3
78.9
0
0
97
74.3
39.0
87.7
136
87.7
119.8
94.5
30.0
50.0
31
36
39
44
27
44
44
41
30
22
72.52
80.83
84.50
98.59
67.23
98.59
98.59
43.71d
29.48d
28.61d
Standard deviation.
Mt year-1.
Cane transportation
For industrial parameters, weighted averages considered the cane used exclusively for ethanol production.
Average from (Cogen’s estimation [16]); no standard deviation available.
Selected parameters for sensitivity analysis (2005/2006 )
Note 2: diversification → higher complexity
• Almost all (>90%) of the mills produce sugar (~50% of the
cane); and surplus yeast
• Other sucrose co-products are commercially produced in
many mills (citric acid, lysine, MSG, special yeast and
derivatives, etc)
• Bagasse is becoming rapidly a source of electricity; cane trash
recovery and use for power is already being done.
• Ethanol derived products using the mill’s surplus energy are
being considered in new plants (ethylene → plastics, other)
• More complex systems (production of soy and its bio-diesel in
crop rotation with cane) are being implemented
→ Need for more comprehensive analyses
Results
• 2006
• Scenario 2020: trash recovery (40%) and surplus power
production with integrated commercial, steam based cycle
(CEST system)
• Scenario 2020 B: trash recovery, use of surplus biomass to
produce ethanol from hydrolysis in a (hypothetical) SSCF
system, integrated with the ethanol plant
Energy flows in ethanol production (MJ/t cane) (Seabra, 2007)
2005/2006
Scenario
2020
Scenario
2020 - B
210,2
238,0
225,4
23,6
24,0
30,7
233,8
262,0
256,1
Ethanol
1926
2060
2901,9
Surplus bagasse
176,0
0,0
0,0
Surplus electricity
82,8
972,0
64,8
2185
3032
2966,7
Ethanol + bagasse
9,0
7,9
11,3
Ethanol + bagasse + electricity
9,3
11,6
11,6
Cane production / transportation
Ethanol production
Fossil Input (total)
Renewable Output (total)
Energy Ratio (Renewable/Fossil)
GHG emissions in ethanol production (kg CO2eq/m3) (Seabra, 2007)
2005/2006
Ethanol
Hydrated
Emissions
Scenario 2020 (and B)
Anhydrous
Hydrated
Anhydrous
417
436
330 - 240
345 - 250
201
210
210 - 150
219 - 150
80
84
0-0
0-0
136
143
120 - 90
126 - 100
(202)
( 212)
( 784)
(819)
Biomass surplus
143
150
0
0
Electricity surplus
59
62
784
819
Fossil Fuels
Cane Burning
Emissions from soil
Credits
Gasoline
Substitution
Notes:
Emissions from land use change not included
Emissions from ethanol transport (ethanol plant to gas station) not included (average distance 330 km); it increases total
emissions in 50 kg CO2eq/m3 for 2005 – 2006
Use of ethanol: in each case, the ethanol – gasoline technical (actual) equivalence for the specific utilization must be considered
In Brazil:
HDE: 1 L ethanol (H) = 0.75 L gasoline
E25: 1 L ethanol (A) = 0.8 L gasoline
FFV: 1 L ethanol (H) = 0.72 L E25
General considerations: LUC and ILUC effects
• The IPCC methodology (IPCC, 2006) may be used to evaluate direct
emissions due to LUC , considering both above and below ground carbon
stock changes. The different levels of data presented (global, national and
regional) may be combined and used, when adequate local data is not
available.
For the LUC indirect GHG emissions:
• Exceptions (biofuel sources with no LUC indirect GHG emissions) are:
1. Waste or residues; use of marginal or degraded land; unused or fallow
arable land
2. Improving yields in currently used land
General considerations: LUC and ILUC effects
• Although some indirect impacts may happen in all other cases, we do not
have suitable tools (or sufficient information) to quantify them.
Many agricultural products are interchangeable; many are
(increasingly) traded globally; and the drivers of LUC vary in time
and regionally. “Equilibrium” conditions are not reached.
Drivers are established by local culture, economics, environmental
conditions, land policies and development programs.
→ Need for the development of a range of methodologies and acquisition /
selection of suitable data to reach acceptable, quantified conclusions on
iLUC effects.
General considerations: LUC and ILUC effects
• Simplified methodologies to evaluate the iLUC effects may look to
“regions” in the world (with the problem of losing the global implications)
or rely on indexes for too large areas, to by-pass the lack of data. They
may also consider “distributing” the total iLUC emissions equally among all
biofuels. They are welcome, but it is possible that their results would need
a large number of significant corrections to accommodate the actual
specificities o f many different situations.
• Land used for agriculture today is ~1300. M ha, excluding pasture lands;
biofuels use less than 1.5% of that; and possibly less than 4% in 2030 (1).
Today’s distribution of production among regions / countries has never
considered GHG emissions; it was determined by the local / time
dependent drivers. The better knowledge of those “drivers” and their
effects could be much more effective if used to re-direct land use over the
1300. M ha (plus pasture lands) worldwide than just to work on the
“marginal” biofuels growth areas.
(1) Alternative Policy Scenario, IEA – 2006
Ethanol: direct effects of land use change
• Change in Carbon storage in soil and above ground, when the land
use is changed (from 1984 to 2002: no change for ethanol!)
Evolution of Brazilian Production of Cane, Sugar and Ethanol
25000
20000
250000
200000
15000
150000
10000
100000
5000
50000
Crop Season
Cane
Sugar
Total Ethanol
02/03
00/01
98/99
96/97
94/95
92/93
90/91
88/89
86/87
84/85
82/83
80/81
78/79
76/77
74/75
0
72/73
0
70/71
Cane x 103 (t)
300000
Sugar (t ) and Ethanol (m3) x 103
350000
Ethanol: direct effects of land use change
• The growth (sugar cane areas) increased since 2002; it was nearly 10% in
the 2007-08 season. The new areas came essentially from pasture lands
(mostly from the extensive grazing areas; not planted pasture) and some
annual crops:
1. Detailed Report from the CONAB (MAPA/DCAA) for the changes in land
use (2007 to 2008); all sugar cane producing units (349, in 19 states) were
analyzed, including cane for ethanol, sugar, cattle feed, seeds, liquor and
other uses (1).
2. Data for 2002 – 2006: evaluation at micro-regional level (295 groups),
comparing sugarcane area variation to pasture and other crops areas; no
estimates for original vegetation displacement (2).
3. Preliminary data from the EIA – RIMA (approved Environmental Impact
Analyses) for all units being built in Brazil 2002 - 2008 (ICONE): confirms
the above results, indicating very small use of original vegetation areas.
(1) Perfil do setor de açúcar e álcool no Brasil; CONAB, April 30, 2008
(2) ICONE, with IBGE data: Sustainability Considerations for Ethanol, A M Nassar, May 12, 2008
Ethanol: direct effects of land use change
• 2007 – 2008: Increase in planted area from 7.1 to 7.8 M ha
• Sugar cane (Center-South) substituted for (1000 ha):
Pasture lands
409.
66.4%
Soy and Corn
143.
23.1
Orange, Coffee
33.
5.4
New areas
9.
1.4
Other
23.
3.7
The pasture lands (with large fraction of degraded areas) and annual crops
correspond to 90% of the total; the “new areas” may include forest, or
cerrados. Considering the nature of the new sugar cane developments
(semi-perennial crop, only mechanized harvesting, no cane burning, with
some trash remaining in soil) it is expected that the land use change is
occurring without increasing GHG emissions. In many cases it will help
increase the carbon stock in soil (current studies).
Sugarcane Expansion: Displacement of Pasture, Crops and
Original Vegetation (1,000 ha) in Selected States
SP
MG
PR
TOTALS
Pasture
Crops
Orig. Veg.
Total
2002 to 2006
916
112
n.a.
1,029
2007 to 2008
370
200
9
579
MS
GO
MT
Source: IBGE; CONAB, ICONE. Elaboration: ICONE for 2002-06 data and CONAB for 2007-08 data.
Notes for 2002-06 data: Calculated in a micro-regional level (295 groups of municipalities). Sugarcane area variation were compared to the
variation of pasture and other crops areas. Does not include estimations with respect of original vegetation displacement.
Notes for 2007-08 data: Extracted from “Perfil do Setor do Açúcar e do Álcool no Brasil”. Information collected from interviews in 343
sugarcarne crushing plants.
Sugarcane Expansion: Displacement of Pasture, Crops and
Original Vegetation (1,000 ha) in Selected States, 2002 - 2008
• Crop area displacement by sugarcane:
Crop area increase
Cereal + Oilseeds production growth
• Pasture area displacement by sugar cane:
Pasture area decrease
Beef production growth
0.5%
10.%
40. %
0.7%
1.7%
15.%
For Brazil, from 2002-2006, (1000 ha) Sugar cane area increased
972; Other Crops increased 5370; Pasture decrease 1960. (but
cattle heads increased 20.5 milion).
Ethanol: LUC and ILUC effects
How far can it go?
• Brazil has 28.3% (440 M ha) of all original forests in the
world, over a total surface of 850 M ha.
• With 276 M ha of arable land, only 16.9% (46.6 M ha) are
used for grain; 72% (199 M ha) correspond to “pasture”; large
fraction of this is somewhat degraded land (not planted
pasture). Sugar cane for ethanol today uses 1.4% (~4 M ha) of
the arable land in Brazil.
• The conversion of low quality pasture land to higher efficiency
productive pasture is liberating area to other crops; using
areas with sugar cane may actually increase carbon stocks.
Ethanol: LUC and ILUC effects
The productivity effects
Sugar cane:
Sugar cane Yields (t/ha):
+ 1.6% /year since 1975
Trend: keep the growth rate till 2020
Ethanol yield (m3/ha):
+ 2.7% /year since 1975
Trend: like sugar cane growths, till 2020
Electricity surplus (kWh/t cane): ~ zero till 2000
Trend: growing from 9. to 120., till 2020 (23% more energy/t cane)
Ethanol, hydrolysis:
+ 45% energy/t cane, 2020
(only availability; not trend)
Pasture Land Conversion
Heads/ha, Brazil: 0.86 (1996); 0.99 (2006) (nearly 50% planted pasture)
São Paulo State: 1.2 - 1.4 (last years)
Conversion of “natural” pastures could release ~ 40 M ha.