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

Key Messages 1.Most biofuels on existing agricultural lands have a significant C offset capacity (20%-80%), there are exceptions. 2.Direct (or indirect) expansion of biofuels into forest systems leads indisputably to net carbon emissions for 10s to 100s. 3.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. 4.A full radiative forcing approach needs to be explored.

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 (CO 2 equivalents) Life-cycle and Impacts on Climate

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

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

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

Biofuel GHG Emissions (kg CO 2equiv /GJ) CO 2 CH 4 N2ON2OTotal Rape Methyl Ester Sugarbeet Ethanol Wheat Ethanol Wheat straw Ethanol Pure Rapeseed Oil Full GHGs: Large contribution from N 2 O Global Warming Potential: 300 x CO 2 Elsaved et al 2003; Crutzen et al. 2007, ACPD 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.

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 (CO 2 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 CO 2 sink lost Additional full GHGs work (N 2 O) emissions)

Ecosystem Carbon Payback Time (ECPT) Fargione et al. 2008, Science 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.

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

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

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

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 Righelato and Spracklen 2007, Science Cumulative avoided emissions over 30 years Land would sequester 2 to 9 times more carbon over 30-years than the emissions avoided by the use of biofuels Biofuel Crops versus Carbon Sequestration

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

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 (CO 2 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 CO 2 sink lost Additional full GHGs work (N 2 O) emissions) 3. Full radiative forcing life-cycle All GHGs Biophysical factors, such as reflectivity (albedo), evaporation, and surface roughness

Tropical forest Cropland Grassland Temperate deciduous Bruce Hungate, unpublished Albedo Roughness Evapotranspiration Cloud formation Full Radiative Forcing 5. Full Radiative Forcing Boreal forest

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

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 (CO 2 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 CO 2 sink lost 3. Full radiative forcing life-cycle All GHGs Biophysical factors, such as reflectivity (albedo), evaporation, and surface roughness

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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.

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

GM, et al (European study). Direct N 2 O from annual crops, Germany N 2 O from short-rotation willow, NE USA Heller, et al N 2 O emissions depend on type of crop (e.g., annual vs. perennial), agronomic practices, climate, and soil type.

Courtey of Gernot Klepper; Quelle: BMU, BMWi, DLR, meó Wind Hydro Biomass electr. Photo- voltaics Bio- ethanol Bio- diesel Bio- ethanol BRA ETS Mitigation Cost per ton of CO 2 (Euros) Germany

From eric larsen presnetation

Striking features of LCA studies reviewed 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. From eric larson

outline 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