Fuel-Cycle Energy and Greenhouse Gas Emission Impacts of Fuel Ethanol Michael Wang Center for Transportation Research Argonne National Laboratory Workshop on Economic and Environmental Impacts of Bio- Based Production Chicago, IL, June 8-9, 2004

U.S. Now Consumes about 19 Million B/D of Oil, Transportation Accounts for ~75% Data sources: ORNL (2003), the Transportation Energy Databook; EIA (2003), Annual Energy Outlook; Annual Energy Review

North America Has Relatively Little Conventional Oil But 30% of Unconventional Oil Reserves

The Transportation Sector is the Second Largest U.S. GHG Emitting Source EPA (2003), Inventory of U.S. Greenhouse Gas Emissions and Sinks:

U.S. Has Had and Will Continue to Have the Highest Total GHG Emissions GAO (2003), Greenhouse Gas Emission Intensity

Reductions of Oil Use and GHG Emissions Could Be Major Goals for the U.S. Transportation Sector  Many ways have been studied and have potentials to reduce transportation oil use and GHG emissions  Advanced vehicle technologies  Hybrid electric vehicles  Fuel cell vehicles  New transportation fuels  Biofuels such as cellulosic ethanol  Non-petroleum fuels  Hydrogen produced from different energy sources, especially from renewable sources

Cycles for Vehicle/Fuel Systems The Illustration is for Petroleum-Based Fuels Vehicle Cycle Fuel Cycle Well to Pump Pump to Wheels WTP: well-to-pump PTW: pump-to-wheels WTW: well-to-wheels (WTP + PTW)

WTW Analysis Is a Complete Energy/Emissions Comparison As an example, greenhouse gases are illustrated here

The GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) Model  GREET includes emissions of greenhouse gases  CO 2, CH 4, and N 2 O  VOC, CO, and NO x as optional GHGs  GREET estimates emissions of five criteria pollutants  VOC, CO, NO x, PM 10, and So x  Total and urban emissions separately  GREET separates energy use into  All energy sources  Fossil fuels (petroleum, natural gas, and coal)  Petroleum  The GREET model and Its documents are available at ; there are 1,200 registered GREET users

Biofuel Pathways and Fueled Vehicle Technology Options Currently in GREET Feedstock Fuel Prod. Technology Fuel Vehicle Technology Corn Fermentation Ethanol Farmed Woody and Herbaceous Biomass Oxygenated RFG: GVs Low-level blend (~E10): GVs High-level blend (~E85): FFVs and hybrids E100: FCVs (on-board reforming) Soybeans Transesterification Biodiesel Blend of BD10-BD50: CI engines CI hybrids

Additional Bio-fuel Production Pathways Are Being Added to GREET  Biomass gasification to produce  Ethanol  Methanol  FT diesel  Dimethyl ether  Hydrogen  Hydrogen production from reforming of ethanol and methanol at refueling stations

U.S. Fuel Ethanol Use Has Increased Steadily Source: Renewable Fuels Association’s 2004 Ethanol Industry Outlook Report. In 2003, the U.S. used 2.8 billion gallons of fuel ethanol

Energy Effects of Fuel Ethanol Have Been Subject to Debate  Some studies, especially those completed between late 1980s and early 1990s, concluded negative energy balance value of ethanol  Those past studies basically examined energy use of producing ethanol  Though self evaluation of ethanol’s energy balance is easy to understand, it may not be useful to fully understand true energy benefits of fuel ethanol  A more complete way is to compare fuel ethanol with the fuels to be displaced by ethanol (i.e., gasoline)  The GREET model has been applied to conduct a comparative analysis between ethanol and gasoline

Ethanol Pathways Include Activities from Fertilizer to Ethanol at Stations Agro-Chemical Production Corn Farming Refueling Stations Agro-Chemical Transport Corn Transport Transport, Storage, and Distribution of Ethanol Electricity (Cell. Ethanol) Woody Biomass Farming Herbaceous Biomass Farming Woody Biomass TransportHerbaceous Biomass Transport Animal Feed (Corn Ethanol) Ethanol Production

Key Parameters for Ethanol’s Energy and Emission Effects  Energy use for chemicals production  Fertilizers (N, P 2 O 5, K 2 O)  Herbicides  Insecticides  Farming  Corn and biomass yield  Chemicals use intensity  Energy use intensity  Soil N 2 O and NO x emissions  Soil CO 2 emissions or sequestration  Ethanol production  Corn ethanol: wet vs. dry milling  Ethanol yield  Energy use intensity  Co-product types and yields  Vehicle fuel economy  Gasoline vehicles with E10  Flexible-fuel vehicles with E85

Bushels/lb. Fertilizer U.S. Corn Output Per Pound of Fertilizer Used Has Risen (3-yr Moving Average) Source: from USDA data. Precision farming, etc.? ? Some earlier studies showed negative energy balance for corn ethanol

For Corn EtOH, N 2 O Emissions from Nitrogen Fertilizer Are a Key GHG Source  Some nitrogen fertilizer is converted into N 2 O and NO X via nitrification and denitrification in farmland  Depending on soil type and condition, 1-3% of N in nitrogen fertilizer is converted into N in N 2 O  On the well-to-wheels basis, N 2 O emissions from nitrogen fertilizers could account for up to 25% of total GHG emissions from corn ethanol

Technology Has Reduced Energy Use Intensity of Ethanol Plants Source: from Argonne’s discussions with ethanol plant designers and recent USDA data.

Well-to-Gate Energy and Emissions Allocated to Co-Products (Animal Feed) Vary by Allocation Method Weight and energy methods no longer used Some studies did not consider co-products at all

System Boundary Affects Results of Ethanol Greatly Operation-Related Activities: Fertilizer, Farming, Farming Transportation Activities, Ethanol Production, Ethanol Transportation, Energy Use for Producing Process Fuels Farming Equipment Materials and Manufacture Ethanol Plant Materials and Construction Food Intake by Farmers Solar Energy Embedded in Biomass

Energy Benefits of Fuel Ethanol Lie in Fossil Energy and Petroleum Use Energy in fuel Energy for producing fuel Uncertainty Range Energy Use for Each Btu of Fuel Used

Energy in Different Fuels Can Have Very Different Qualities Fossil Energy Ratio (FER) = energy in fuel / fossil energy input But, petroleum energy ratios for ethanol, coal, and electricity are much greater than one!! Increase in Energy Quality

Petroleum Refining Is the Key Energy Conversion Step for Gasoline Petroleum Recovery (97%) Gasoline at Refueling Stations Petroleum Transport and Storage (99%) Transport, Storage, and Distribution of Gasoline (99.5%) MTBE or EtOH for Gasoline WTP Overall Efficiency: 80% Petroleum Refining to Gasoline ( %, Depending on Oxygenates and Reformulation) Petroleum Refining to Gasoline ( %, Depending on Oxygenates and Reformulation) NG to MeOHCorn

Key Issues for Simulating Petroleum Fuels  Beginning in 2004, gasoline sulfur content is reduced nationwide from the previous level of ppm to 30 ppm  In addition, marginal crude has high sulfur content  New crude supply such as Canadian oil sands is energy intensive to recover and process  Desulfurization in petroleum refineries adds stress on refinery energy use and emissions  Ethanol could replace MTBE in RFG nationwide  Energy and emission differences in MTBE and ethanol  Differences in gasoline blend stocks for MTBE and ethanol

Changes in Energy Use Per Gallon of Ethanol Used (Relative to Gasoline)

Changes in Greenhouse Gas Emissions per Gallon of Ethanol Used (Relative to Gasoline)

Changes in Greenhouse Gas Emissions per Mile Driven (Relative to GVs)

Transportation Logistics Could Affect Ethanol Energy and Emissions Rail Barge Truck Rail Barge Ocean Tanker Truck Local Collection Long-Distance Transportation Local Distribution Ethanol Plants Bulk Terminals Terminals Refueling Stations

Transportation of Midwest Ethanol to California is Accomplished via Rail and Ocean Based on Pat Perez of CEC. Midwest Supply - Majority of Supply to California SF Bay Refineries Los Angeles Refineries Oregon Terminals

Changes in Greenhouse Gas Emissions by Corn Ethanol: Midwest Use vs. California Use Results are based ethanol in E85

An Argonne Study Shows That Corn Ethanol in Diesel May Not Have GHG Benefits

Energy Balance of Corn Ethanol Results Among Studies

Corn Ethanol GHG Emission Changes Among Studies

Vehicle Fuel Economy Is One of the Most Important Factors for WTW Results Fuel economy ratios are relative to improved future gasoline ICE technology; On-road 55/45 MPG of baseline GV is assumed to be 27.5, a 22% improvement from 2000 MY midsize car MPG

A GM/ANL Study Takes the Following Key Assumptions for PTW Emissions Propulsion System Assumed Emission Performance Gasoline and E85 ICE Tier 2 Bin 5 Diesel and CNG ICE Tier 2 Bin 5, but no evap VOC Hydrogen ICE Tier 2 Bin 2, no evap, Bin 5 NOx Fuel processor fuel cell Tier 2 Bin 2 Hydrogen fuel cell Tier 2 Bin 1 (zero emissions) 2010 MY Vehicle Emissions Targets  Fuel consumption penalties of aftertreatment systems to meet standards were considered in the study  Bin 5 diesel has not been demonstrated  MY 2010 vehicle in-use emissions in 2016 were modeled using EPA MOBILE 6.2 ARB EMFAC2002 version 3

Vehicle/Fuel Technologies for WTW Energy and GHG Emission Results  Crude oil-based technologies RFG ICELPG ICE LS Diesel ICERFG ICE hybrid Gasoline FCVLS diesel ICE hybrid  Natural gas-based technologies FT diesel ICECNG ICE FT diesel ICE hybridMeOH FCV G.H2 FCV  Bioethanol and Electricity Corn E85 ICE FFVCellulosic EtOH FCV U.S. average electri.-to-G.H2 FCVRenewable electricity-to-G.H2 FCV U.S. average electricity battery-powered EV

Vehicle/Fuel Technologies for WTW Criteria Pollutant Emission Results  Crude oil-based technologies RFG displacement on demand (DOD) SI conventional drive (CD) RFG DI SI CDLS Diesel DI CI CD RFG DOD SI hybridLS diesel DI CI hybrid Gasoline fuel-processor (FP) FCV  Natural gas-based technologies CNG DOD SI CDFT diesel DI CI CD G.H2 SI CDMeOH FP FCV G.H2 FCVL.H2 FCV  Bioethanol and Electricity Corn E85 DOD SI CDCellulosic E85 DOD SI CD Cellulosic EtOH FP FCVU.S. average electri.-to-G.H2 FCV NG CC electri.-to-G.H2 FCVRenewable electricity-to-G.H2 FCV 37

WTW Total Energy Use of Selected Vehicle/Fuel Systems Crude oil feedstock Natural gas feedstock Electricity and EtOH

WTW Fossil Energy Use of Selected Vehicle/Fuel Systems Crude oil feedstock Natural gas feedstock Electricity and EtOH

WTW GHG Emissions of Selected Vehicle/Fuel Systems Crude oil feedstock Natural gas feedstock Electricity and EtOH

WTW Urban NOx Emissions of Selected Vehicle/Fuel Systems

WTW Urban PM 10 Emissions of Selected Vehicle/Fuel Systems

Conclusions  Either corn or cellulosic ethanol helps substantially reduce transportation’s fossil energy and petroleum use  Ethanol’s energy balance alone has limited public policy information content  Corn-based fuel ethanol achieves moderate reductions in GHG emissions  Cellulosic ethanol will achieve much greater energy and GHG benefits

Outstanding Issues in WTW Analyses Need to Be Addressed Continuously  Multiple products  System expansion vs. allocation (GREET takes both)  System expansion: allocation vs. attribution of effects  Technology advancement over time  Current vs. future technologies – leveling comparison field  Static snap shot vs. dynamic simulations of evolving technologies and market penetration over time (a new GREET version conducts simulations over time)  Dealing with uncertainties  Stochastic analysis vs. conventional sensitivity analysis  Regional differences, e.g, CA vs. the rest of the U.S.  Trade-offs of impacts: value-driven?  WTW results may be better for identifying problems than for providing the answers