Emerging Environmental Challenges for Biofuels Production

Elliott Campbell University of California, Merced

EBI, September 24, 2010

Liquid Biofuel

(EPA, 2010)

Biopower

(EIA, 2010)

Why Bioenergy? Similarities to current energy system Near-term Cost effective Scalable Deployable/storable Carbon-negative potential Rural economic development Appropriate technology options for the

developing world Synergies with fossil fuels Synergies with other renewables Perhaps better to ask “How?”

Roadmap

1. Air Quality2. Short-Lived Climate Forcers3. Land-Use Efficiency

1) Air Quality

Vehicle Phase Emissions

Ozone increase in LA and northeast offset by decrease in southeast

E85 unlikely to improve air quality Emissions outside of vehicle phase neglected

(Jacobson, ES&T, 2007)

Life-Cycle Emissions

Human health costs ~ Climate change costs Importance of upstream emissions relative to

vehicle emissions

(Hill et al., PNAS, 2007)

Sugarcane Ethanol Emissions

0

100

200

300

400

500

600

700

800

900

NOx VOC SOx CO

Life

-cyc

le E

miss

ion

(g e

mitt

ed /

mm

Btu

fuel

)

Sugarcane Ethanol

Corn Ethanol

Importance of Open Burning

VOC NOx PM10 PM2.5 SOx CO

Emis

sion

Fac

tor (

g em

itted

/ mm

Btu

)

0

1000

2000

3000

7000Straw Field Burning Straw Field Burning (50% Area Burned) Other Farming Ethanol Refinery Ethanol T/D Vehicle Use

Emissions Currently Underpredicted

1. Create a market for sugarcane trash2. Emissions from indirect land-use

change

Relation to Next-Generation Biofuels

(Morton et al., GCB, 2008)

2) Short-Lived Climate Forcers

Aerosols and Ozone Atmospheric lifetimes of days to

weeks Cooling and warming properties Spatial-explicit climate impacts Black Carbon has 55% of the RF

caused by CO2 and a greater forcing than all other SLCFs (Ramanathan and Carmichael, 2008)

Short Live Climate Forcers (SLCFs)

(Unger et al., PNAS, 2008)

0

10

20

30

40

50

60

70

80

90

100

Gasoline Sugarcane Sugarcane + BC_low

Sugarcane + BC_high

Clim

ate

Forc

ing

(g C

O2-

e /

MJ f

uel)

Need for a Regional Analysis

(Naik et al., GRL, 2007)

3) Land-Use Efficiency

19

Global Land Use

(Campbell et al., ES&T, 2008)

20

County-Level Abandoned Agriculture

0

200

400

600

800

1,000

1,200

Aban

done

d Ar

eas (

1000

km

2 )

County crop

HYDE crop high

HYDE crop low

SAGE crop

HYDE pasture high

HYDE pasture low

(Campbell et al., in prep)

Regional Land Use

(Debolt, Campbell, et al., GCB-Bioenergy, 2010)

Source for stratospheric sulfate aerosol.

Important role in stratospheric ozone.

A novel tracer of terrestrial photosynthesis?CO2 COS

Fig. 1. The dominant land fluxes of CO2 are photosynthesis and respiration while OCS uptake is influenced by a process linked to photosynthesis.

Carbonyl Sulfide (COS, OCS, CSO)

Vertical Profiles

(Campbell et al., Science, 2008)

Energy Conversion Pathways

25

0

10,000

20,000

30,000

40,000

50,000

Gro

ss E

lect

ricity

Out

put

Fuel

Cyc

le E

lect

ric I

nput

Fuel

Cyc

le G

asol

ine

Inpu

t

Veh

icle

Cyc

le E

lect

ric I

nput

Veh

icle

Cyc

le G

asol

ine

Inpu

t

Net

Out

put

0

10

20

30

40

50

Gro

ss E

than

ol O

utpu

t

Fuel

Cyc

le E

lect

ric I

nput

Fuel

Cyc

le G

asol

ine

Inpu

t

Veh

icle

Cyc

le E

lect

ric I

nput

Veh

icle

Cyc

le G

asol

ine

Inpu

t

Net

Out

put

Tra

nspo

rtat

ion

Mile

age (

103

mi h

a-1

y-1 )

a) Ethanol b) Bioelectricity

(Campbell, Lobell, & Field, Science, 2009)

Transportation per Cropland Area

Conversion Pathways

Advantages to expanding focus to include electricity in addition to liquid fuels

Greater emphasis on jet and tanker fuels

Lignin rich feedstock

Questions for Emerging Issues Win-win solutions where environmental

mitigation results in more bioenergy supply? E.g. Sugarcane burning vs. second-

generation fuels SLCFs incorporated in mandated GHG

thresholds? International leakage of air quality

impacts? Abandoned lands and other alternative

land resources?