GHG emissions in the production and use of ethanol from sugarcane

The expansion since 2002LUC , ILUC effects: some data and discussion

I C Macedo, NIPE/UNICAMPJuly 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 modelGHG Working Group (RSF), EPFLGlobal 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 N-fertilizer 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 ofethanol 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 Units Average SDa Min. Max. Mills Caneb

N-fertilizer use kg N (ha.year)-1 60 16 35 97 31 72.52 Trucks’ energy efficiency t.km L-1 52.4 9.7 38.9 74.3 36 80.83 Transportation distance c Km 23.1 6.1 9.3 39.0 39 84.50 Mechanical harvesting % 49.5 27.1 0 87.7 44 98.59 “Other” agr. (diesel) L ha-1 67 38 2.7 136 27 67.23 Unburned cane % 30.8 21.7 0 87.7 44 98.59 Cane productivity tc ha-1 87.1 13.7 51.3 119.8 44 98.59 Ethanol yield L tc-1 86.3 3.5 78.9 94.5 41 43.71d

Bagasse surplus % 9.6 6.4 0 30.0 30 29.48d

Electricity surplus e kWh tc-1 9.2 0 50.0 22 28.61d

a. Standard deviation. b. Mt year-1. c. Cane transportation d. For industrial parameters, weighted averages considered the cane used exclusively for ethanol production. e. 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

Cane production / transportation 210,2 238,0 225,4

Ethanol production 23,6 24,0 30,7

Fossil Input (total) 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

Renewable Output (total) 2185 3032 2966,7

Energy Ratio (Renewable/Fossil)

Ethanol + bagasse 9,0 7,9 11,3

Ethanol + bagasse + electricity 9,3 11,6 11,6

GHG emissions in ethanol production (kg CO2eq/m3) (Seabra, 2007)

2005/2006 Scenario 2020 (and B)

Ethanol Hydrated Anhydrous Hydrated Anhydrous

Emissions 417 436 330 - 240 345 - 250

Fossil Fuels 201 210 210 - 150 219 - 150

Cane Burning 80 84 0 - 0 0 - 0

Emissions from soil 136 143 120 - 90 126 - 100

Credits (202) ( 212) ( 784) (819)

Biomass surplus 143 150 0 0

Electricity surplus 59 62 784 819

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 land2. 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!)

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. 23.1Orange, Coffee 33. 5.4New areas 9. 1.4Other 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

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.

SP MG PR MS GO MT

TOTALS  Pasture Crops Orig. Veg. Total

2002 to 2006 916 112 n.a. 1,029

2007 to 2008 370 200 9 579

Sugarcane Expansion: Displacement of Pasture, Crops and Original Vegetation (1,000 ha) in Selected States, 2002 - 2008

• Crop area displacement by sugarcane: 0.5%Crop area increase 10.%Cereal + Oilseeds production growth 40. %

• Pasture area displacement by sugar cane: 0.7%Pasture area decrease 1.7%Beef production growth 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 effectsThe productivity effectsSugar cane:

Sugar cane Yields (t/ha): + 1.6% /year since 1975Trend: keep the growth rate till 2020

Ethanol yield (m3/ha): + 2.7% /year since 1975Trend: like sugar cane growths, till 2020

Electricity surplus (kWh/t cane): ~ zero till 2000Trend: 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 ConversionHeads/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.