Fuel-Cycle Energy and Greenhouse Gas Emission Impacts of Fuel Ethanol Michael Wang Center for...

Fuel-Cycle Energy and Greenhouse Gas Emission Impacts of Fuel Ethanol

Michael WangCenter 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%

0

3

6

9

12

15

18

21

24

27

30

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025

Pe

tro

leu

m U

se

(M

MB

DO

E)

Water

Rail

Actual Projection

Automobiles

Air

Light Trucks

Heavy Veh

U.S. ProductionOff-Road

Other Uses

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

0

200

400

600

800

1000

1200

Middle East North America Other Total

Bill

ion

Barr

els

Cru

de E

qv

Conventional Oil

Unconventional Oil

The Transportation Sector is the Second Largest U.S. GHG Emitting Source

EPA (2003), Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2001

0

500

1,000

1,500

2,000

2,500

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

Mil

lio

n M

etr

ic T

on

s o

f C

O2

Eq

.

Electricity Generation TransportationIndustry AgricultureResidential Commercial

U.S. Has Had and Will Continue to Have the Highest Total GHG Emissions

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

U.S

.

Ch

ina

Ind

ia

Ja

pa

n

Ge

rma

ny

Ca

na

da

S.

Ko

rea

U.K

.

Ita

ly

Fra

nc

e

CO

2-E

qu

iv.

GH

Gs (

Mil

lio

n M

T)

2001

2025

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 SystemsThe Illustration is for Petroleum-Based

Fuels

Vehicle Cycle

Fuel Cycle

Well to Pump

Pu

mp

to W

heels

WTP: well-to-pumpPTW: pump-to-wheelsWTW: 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

CO2, CH4, and N2O

VOC, CO, and NOx as optional GHGs

GREET estimates emissions of five criteria pollutants

VOC, CO, NOx, PM10, and Sox

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

http://greet.anl.gov; 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: GVsLow-level blend (~E10): GVsHigh-level blend (~E85): FFVs and hybridsE100: 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 produceEthanolMethanolFT dieselDimethyl etherHydrogen

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.

0

500

1,000

1,500

2,000

2,500

3,000

Mill

ion

Ga

llon

s/Y

ea

r

19

80

19

81

19

82

19

83

19

84

19

85

19

86

19

87

19

88

19

89

19

90

19

91

19

92

19

93

19

94

19

95

19

96

19

97

19

98

19

99

20

00

20

01

20

02

20

03 In 2003, the U.S. used 2.8

billion gallons of fuel ethanol

Type Purpose Mil. Gal.FRFG Oxygenate (E6-E10) 1,350 F.Winter Oxy. Fuels Oxygenate (E10) 250 MN Oxy. Fuels Oxygenate (E10) 260 Conv. Gasoline Octane/Extender 950 Total 2,810

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 FarmingCorn Farming

Refueling Stations

Agro-Chemical Transport

Corn Transport

Transport, Storage, and Distribution of Ethanol

Electricity (Cell. Ethanol)

Woody Biomass FarmingWoody Biomass Farming Herbaceous Biomass FarmingHerbaceous Biomass Farming

Woody Biomass Transport Herbaceous Biomass Transport

Animal Feed (Corn Ethanol)

Ethanol ProductionEthanol Production

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

1965 1970 1975 1980 1985 1990 1995 2000 2005

Bu

shel

s/lb

. Fer

tiliz

er

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, N2O Emissions from Nitrogen Fertilizer Are a Key GHG Source

Some nitrogen fertilizer is converted into N2O and NOX via nitrification and denitrification in farmland

Depending on soil type and condition, 1-3% of N in nitrogen fertilizer is converted into N in N2O

On the well-to-wheels basis, N2O 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.

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

Btu

/Ga

llon

Wet Mill Dry Mill

1980s

2000s

Well-to-Gate Energy and Emissions Allocated to Co-Products (Animal Feed) Vary by Allocation Method

Allocation Method Wet milling Dry milling Weight 52% 51%

Energy content 43% 39%

Process energy 31% 34%

Market value 30% 24%

Displacement ~16% ~20%

• 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, EthanolProduction, 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

0.0

0.5

1.0

1.5

2.0

2.5

3.0T

ota

lE

ner

gy

Fo

ssil

Pet

role

um

To

tal

En

erg

y

Fo

ssil

Pet

role

um

To

tal

En

erg

y

Fo

ssil

Pet

role

um

RFG Corn EtOH Cell. EtOH

Btu

/btu

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

1.4

0.980.8

0.42

0

1

2

3

4

Cell. EtOH Corn EtOH Coal Gasoline Electricity

Fo

ssil

En

erg

y R

atio

18.5

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 Transportand Storage (99%)

Transport, Storage, and Distribution of Gasoline (99.5%)

MTBE or EtOH for Gasoline

WTP Overall Efficiency: 80%

Petroleum Refining to Gasoline (84.5-86%, Depending on Oxygenates and Reformulation)

Petroleum Refining to Gasoline (84.5-86%, Depending on Oxygenates and Reformulation)

NG to MeOH Corn

Key Issues for Simulating Petroleum Fuels

Beginning in 2004, gasoline sulfur content is reduced nationwide from the previous level of 150-300 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)

-120,000

-80,000

-40,000

0

40,000

80,000

120,000To

tal

Ene

rgy

Foss

il

Pet

role

um

Tota

lE

nerg

y

Foss

il

Pet

role

um

Tota

lE

nerg

y

Foss

il

Pet

role

um

Tota

lE

nerg

y

Foss

il

Pet

role

um

E85 FFV: Corn EtOH E85 FFV: Cell. EtOH E10 FFV; Corn EtOH E10 FFV: Cell. EtOH

Btu

Cha

nge/

EtO

H G

allo

n

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

-10000

-8000

-6000

-4000

-2000

0

CO

2

GH

G

CO

2

GH

G

CO

2

GH

G

CO

2

GH

G

E85 FFV: Corn EtOH E85 FFV: Cell. EtOH E10 FFV: Corn EtOH E10 FFV: Cell. EtOH

GH

G C

hang

e in

Gra

ms/

EtO

H G

allo

n

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

-90%

-80%

-70%

-60%

-50%

-40%

-30%

-20%

-10%

0%C

O2

GH

G

CO

2

GH

G

CO

2

GH

G

CO

2

GH

G

E85 FFV: Corn EtOH E85 FFV: Cell. EtOH E10 GV: Corn EtOH E10 GV: Cell. EtOH

Ch

ang

es R

elat

ive

to G

Vs

Transportation Logistics Could Affect Ethanol Energy and Emissions

Rail

Barge

Truck

Rail

Barge

Ocean Tanker

Truck

Truck

Local Collection

Long-Distance Transportation

Local Distribution

Ethanol Plants

Bulk Terminals

TerminalsRefueling 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

-4000

-3000

-2000

-1000

0

CO

2

GH

G

CO

2

GH

G

CO

2

GH

G

Corn EtOH in Midwest Corn EtOH in CA via Rail Corn EtOH in CA via Ocean

GH

G C

han

ge

in G

ram

s/E

tOH

Gal

lon

Results are based ethanol in E85

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

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

CO

2

GH

G

CO

2

GH

G

CO

2

GH

G

LSD Bus ED10 BUS ED15 BUS

Gra

ms/

Mile

Energy Balance of Corn Ethanol Results Among Studies

-40,000

-30,000

-20,000

-10,000

0

10,000

20,000

30,000

40,000

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Net

En

erg

y V

alu

e (

Btu

/gallo

n)

Ho

Marland and Turhollow

Pimentel Pimentel

Keeney and DeLuca

Lorenz and Morris

Shapouri et al.

Shapouri et al.

Wang et al.

Agri. Canada

Kim and Dale

Graboski

Wang

Corn Ethanol GHG Emission Changes Among Studies

-80%

-60%

-40%

-20%

0%

20%

40%

60%

80%

100%

EPA(1989):E100

EPA(1989):

E85

Ho(1990):E100

Marland(1991):E100

Delucchi(1991):E100

Ahmed(1994):E100

Delucchi(1996):

E95

Wang(1996):E100

Wang(1996):

E85

Wang(1997):

E85

Agri.Can.

(1999):E85

Delucchi(2001):

E90

Wang(2003):

E85

GH

G C

ha

ng

es

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

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

CNGV LPGV E85 FFV GasolineHybrid

DieselHybrid

GasolineandEtOHFCV

MeOHFCV

GH2 FCV BP EV

Fu

el E

co

no

my

Ra

tio

MIT 2003 GM 2001 MIT 2000

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 technologiesRFG ICE LPG ICE

LS Diesel ICE RFG ICE hybrid

Gasoline FCV LS diesel ICE hybrid

Natural gas-based technologiesFT diesel ICE CNG ICE

FT diesel ICE hybrid MeOH FCV

G.H2 FCV

Bioethanol and ElectricityCorn E85 ICE FFV Cellulosic EtOH FCV

U.S. average electri.-to-G.H2 FCV Renewable electricity-to-G.H2 FCV

U.S. average electricity battery-powered EV

Vehicle/Fuel Technologies for WTW Criteria Pollutant Emission Results

Crude oil-based technologiesRFG displacement on demand (DOD) SI conventional drive (CD)

RFG DI SI CD LS Diesel DI CI CD

RFG DOD SI hybrid LS diesel DI CI hybrid

Gasoline fuel-processor (FP) FCV

Natural gas-based technologiesCNG DOD SI CD FT diesel DI CI CD

G.H2 SI CD MeOH FP FCV

G.H2 FCV L.H2 FCV

Bioethanol and ElectricityCorn E85 DOD SI CD Cellulosic E85 DOD SI CD

Cellulosic EtOH FP FCV U.S. average electri.-to-G.H2 FCV

NG CC electri.-to-G.H2 FCV Renewable electricity-to-G.H2 FCV

37

WTW Total Energy Use of Selected Vehicle/Fuel Systems

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

Btu

/Mile

Crude oil feedstock

Natural gas feedstock

Electricity and EtOH

WTW Fossil Energy Use of Selected Vehicle/Fuel Systems

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

Btu

/Mile

Crude oil feedstock

Natural gas feedstock

Electricity and EtOH

WTW GHG Emissions of Selected Vehicle/Fuel Systems

0

100

200

300

400

500

600

Gra

ms

/Mile

Crude oil feedstock Natural gas

feedstock

Electricity and EtOH

WTW Urban NOx Emissions of Selected Vehicle/Fuel Systems

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

WT

W U

rban

NO

x E

mis

sio

ns, g

/mile Well to Pump Pump to Wheels

Oil-BasedNG-Based

Bioethanol and Electricity

WTW Urban PM10 Emissions of Selected Vehicle/Fuel Systems

0.00

0.01

0.02

0.03

0.04

0.05

WT

W U

rban

PM

10 E

mis

sio

ns, g

/mile Well to Pump Pump to Wheels

Oil-BasedNG-Based

Bioethanol and Electricity

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