Sustainable Agriculture for a Sustainable Society

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Sustainable Agriculture for aSustainable Society

• Tom Richard
• Penn State University
• www.bioenergy.psu.edu

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Potential of underused renewable energy sources
TW
1000000
100000
10000
1000
100
10
1
0.1
Hydro
Wind
Geothermal
Solar
Current use
Tides currents
From Basic Research Needs for Solar Energy
Utilization, DOE 2005
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US Biomass inventory 1.3 billion tons
Wheat straw
Corn stover
6.1
Soy
19.9
6.2
Crop residues
7.6
Grains
5.2
Manure
4.1
Urban waste
2.9
Perennial crops
35.2
Forest
12.8
From Billion ton Vision, DOE USDA 2005
(projections to 2030)
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Perennials Capture More Energy
Courtesy of Steve Long, University of Illinois
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Biomass production in double crop systems
Dry matter production (mass / time)
Dry matter production or resource loss (mass /
time)
Source A.H. Heggenstaller
spring crop
summer crop
Winter
Autumn
Spring
Summer
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• Integrating bioenergy crops in food crop
  rotations
• Canola, brassicas, and soy for biodiesel
• Canola 115 gal/A _at_ 50 bu/A vs.
• Soybeans 71 gal/A _at_ 50 bu/A
• Hulless barley for ethanol
• winter cover crop
• summer ethanol feedstock

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Energy types comparison
Food Energy
QUALITY
EFFICIENCY
Fuel Energy
Direct Combustion Energy
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Cow calf
Meat 12.6 Mg
Energy Balance 806 MJ Ratio 1.25
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Soy/Wheat Red Clover - Corn
Energy Balance 26,620 MJ/ac. Ratio 10
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Switchgrass Combustion
Energy Balance 34,737 MJ/ac. Ratio 17.5
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Integrating Food and Fuel
Energy Balance 13,408 MJ/ac. Ratio 5.2
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Sustainable and Renewable Energy Systems

• Wind, solar, biomass
• Electricity, heat
• Combustion, biogas, biodiesel, cellulosic ethanol
• Integrated, efficient
• Community based, distributed

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Food versus Fuel? How shall we live on a finite
planet?
http//www.ukimagehost.com/uploads/7a20b75e30.jpg
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Heller and Keoleian, U. Michigan, 2000
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(No Transcript)
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Biofuels and the Bay, 2007
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Paths to Sustainable Biofuels

• Utilize existing organic wastes and residues
• Increase productivity of abandoned and marginal
  land with perennials
• Ecological intensification of existing cropland
  to enhance production of both food and fuel.

Photo credits A. Heggenstaller, J. Carlson, G.
Roth, T. Richard
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Issues and Challenges

• Crop prices
• Food prices
• Land prices
• Farm income
• Rural development
• Criteria for sustainability
• Proactive policy framework