Presentation on theme: "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."— Presentation transcript:
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, N 2 O 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 CO 2 : 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 N 2 O and methane: trash burning, N 2 O 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 of ethanol from sugarcane in Brazil: The.... Biomass and Bioenergy (2007), doi: /j.biombioe
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
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 mills 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
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). Todays 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 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 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 (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 % Soy and Corn Orange, Coffee New areas Other 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 data and CONAB for data. Notes for 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 data: Extracted from Perfil do Setor do Açúcar e do Álcool no Brasil. Information collected from interviews in 343 sugarcarne crushing plants. SPMGPRMSGOMT TOTALS PastureCropsOrig. Veg.Total 2002 to n.a.1, to
Sugarcane Expansion: Displacement of Pasture, Crops and Original Vegetation (1,000 ha) in Selected States, 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 decrease1.7% Beef production growth15.% For Brazil, from , (1000 ha) Sugar cane area increased 972; Other Crops increased 5370; Pasture decrease (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 (m 3 /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: (last years) Conversion of natural pastures could release ~ 40 M ha.