Carbon implications of different biofuel pathways

1. Carbon implications of different biofuel pathways Pep Canadell Global Carbon Project CSIRO Marine and Atmospheric Research Canberra, Australia

2. Most biofuels on existing agricultural lands have a significant C offset capacity (20%-80%), there are exceptions. Direct (or indirect) expansion of biofuels into forest systems leads indisputably to net carbon emissions for 10s to 100s. Expansion of biofuels on abandoned and degraded lands can produce net C offsets immediately or in < 10 years and generate 8% of global current primary energy demand, an amount most significantly in regions such as Africa. A full radiative forcing approach needs to be explored. Key Messages

3. 1.Industrial life-cycle Cultivation, harvest, conversion, including fertilizers, energy requirements, embedded C in machinery, etc. (sensitive to boundary conditions) Co-products (easy for electricity and heat co-generation, difficult for others) Full GHGs life cycle (CO2 equivalents) Life-cycle and Impacts on Climate

4. Biofuels are NOT carbon neutral GHG emissions reduction Biodiesel Ethanol Thow & Warhurst 2007

5. Potential Annual C offsets (tons C/ha/year) Gibbs et al 2008, ERL, in press

6. Most Studies Show Benefits from Corn Ethanol Net GHG emissions to the atmosphere Net GHG emissions avoided

7. Full GHGs: Large contribution from N2O Global Warming Potential: 300 x CO2 Mid-range values New inversion calculations by Paul Crutzen show that biofuels such as rapeseed may produce large quantities of nitrous oxides, and for corn and canola it is worse than using gasoline. Elsaved et al 2003; Crutzen et al. 2007, ACPD

8. 1.Industrial life-cycle Cultivation, harvesting, processing including fertilizers, energy, embedded C footprints in machinery, etc. Co-products (easy for electricity and heat co-generation, difficult for others) Full GHGs life cycle (CO2 equivalents) Life-cycle and Impacts on Climate 2.Ecological life-cycle • Land use change and ecosystem carbon lost (Ecosystem Carbon Repayment Time, ECRT) • Soil carbon sequestration • CO2 sink lost • Additional full GHGs work (N2O) emissions)

9. Ecosystem Carbon Payback Time (ECPT) Number of years after conversion to biofuel production required for cumulative biofuel GHG reductions, relative to fossil fuels they displace, to repay the biofuel carbon debt. Fargione et al. 2008, Science

10. Ecosystem Carbon Payback Time (Tropics) Only Carbon taken into account With current crop yields Peatlands 918 years Gibbs et al 2008, ERL, in press

11. Ecosystem Carbon Payback Time (ECPT) Using 10% percentile global yield Peatlands 587 years Gibbs et al 2008, ERL, in press

12. Bioenergy Potential on Abandoned Ag. Lands 385-472 M ha Abandoned agricultural land 4.3 tons ha-1 y-1 Area weighted mean production of above-ground biomass 32-41 EJ 8% of current primary energy demand Abandoned Crop %Area Abandoned Pasture Abandoned Agriculture Campbell et al 2008, ESC, in press

13. Biofuel Crops versus Carbon Sequestration Cumulative avoided emissions over 30 years Cumulative avoided emissions per hectare over 30 years for a range of biofuels compared with the carbon sequestered over 30 years by changing cropland to forest Land would sequester 2 to 9 times more carbon over 30-years than the emissions avoided by the use of biofuels Righelato and Spracklen 2007, Science

14. Additional 61 ppm by 2100 Lost of C Sink Capacity by Deforestation A1 SRES Lost of biospheric C sink due to land use change

15. 1.Industrial life-cycle Cultivation, harvesting, processing including fertilizers, energy, embedded C footprints in machinery, etc. Co-products (easy for electricity and heat co-generation, difficult for others) Full GHGs life cycle (CO2 equivalents) Life-cycle and Impacts on Climate 2.Ecological life-cycle • Land use change and ecosystem carbon lost (Ecosystem Carbon Repayment Time, ECRT) • Soil carbon sequestration • CO2 sink lost • Additional full GHGs work (N2O) emissions) 3.Full radiative forcing life-cycle • All GHGs • Biophysical factors, such as reflectivity (albedo), evaporation, and surface roughness

16. 5. Full Radiative Forcing Temperatedeciduous Tropicalforest Full Radiative Forcing Albedo Roughness Evapotranspiration Cloud formation Borealforest Cropland Grassland Bruce Hungate, unpublished

17. Monthly Surface Albedo (MODIS) Jackson, Randerson, Canadell et al. 2008, PNAS, submitted

18. 1.Industrial life-cycle Cultivation, harvest, conversion, including fertilizers, energy requirements, embedded C in machinery, etc. (sensitive to boundary conditions) Co-products (easy for electricity and heat co-generation, difficult for others) Full GHGs life cycle (CO2 equivalents) Life-cycle and Impacts on Climate 2.Ecological life-cycle • Shifting from GHG emissions per GJ biofuel or per v-km to emissions per ha y-1. • Land use change and ecosystem carbon lost (Ecosystem Carbon Repayment Time, ECRT) • Soil carbon sequestration • CO2 sink lost 3.Full radiative forcing life-cycle • All GHGs • Biophysical factors, such as reflectivity (albedo), evaporation, and surface roughness

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20. Lignocellulosic biofuels will be able to achieve greater energy and GHGs benefits than highly intensive crops such as corn and rapeseed because: require less fertilizer can grow in more marginal lands allows for complete utilization of the biomass (which can compensate smaller yields per ha.

21. Most studies focus on GHG emissions per GJ biofuel or per v-km. Emissions per ha/yr may give different ranking. Elsayed, et al. 2003.

22. Direct N2O from annual crops, Germany N2O from short-rotation willow, NE USA GM, et al. 2002 (European study). N2O emissions depend on type of crop (e.g., annual vs. perennial), agronomic practices, climate, and soil type. Heller, et al. 2003.

23. Mitigation Cost per ton of CO2 (Euros) Germany 800 700 600 500 400 300 200 100 0 Wind Hydro Bio-ethanol Photo-voltaics Bio-ethanol BRA Biomasselectr. Bio-diesel ETS Courtey of Gernot Klepper; Quelle: BMU, BMWi, DLR, meó

25. From eric larsen presnetation

26. Wide range of biofuels have been included in different LCAs: Biodiesel (fatty acid methyl ester, FAME, or fatty acid ethyl ester, FAEE) rapeseed (RME), soybeans (SME), sunflowers, coconuts, recycled cooking oil Pure plant oil rapeseed Bioethanol (E100, E85, E10, ETBE) grains or seeds: corn, wheat, potato sugar crops: sugar beets, sugarcane lignocellulosic biomass: wheat straw, switchgrass, short rotation woody crops Fischer-Tropsch diesel and Dimethyl ether (DME) lignocellulosic waste wood, short-rotation woody crops (poplar, willow), switchgrass LCAs are almost universally set in European or North American context (crops, soil types, agronomic practices, etc.). One prominent exception is an excellent Brazil sugarcane ethanol LCA. Extremely wide range reported for LCA results for GHG mitigation Across different biofuels Across different LCA studies for same biofuel Lack of focus on evaluating per-hectare GHG impacts. Most analyses report GHG savings per GJ biofuel. Some report GHG savings per-vkm. Few focus on understanding what approaches maximize land-use efficiency for GHG mitigation All studies are relatively narrow engineering analyses that assume one set of activities replaces another. Striking features of LCA studies reviewed From eric larson

27. Evolution of the components and boundaries of life cycle Range of variation but have a general sense for ethanol and biodiessel for main crops , largely Eu and USA conditions When land use change is taking into account Show science paper with years needed to become beneficial. Palm oil example When carbon sequestration is taking into account outline