Biofuel Resources: Overview

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Biofuel Resources Overview
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Overview

• U.S. Energy sources
• Biomass defined
• Plants and solar energy storage
• Bioenergy defined
• Biomass energy sources/supply
• Dedicated bioenergy crops food vs. fuel
• Biomass conversion processes/pathways (general)

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U.S. Energy Sources

• a fossil-fuel dependent country (gt85)!

Source (2005) http//www1.eere.energy.gov/biomass
/pdfs/final_billionton_vision_report2.pdf
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Biomass

• Living matter (dead or alive) any organic matter
  which is available on a renewable or recurring
  basis
• A tiny, but critically important of earths
  matter
• For humans, an enormous energy supply
• Continually replenished by the SUN
• Through the process of PHOTOSYNTHESIS

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Review of Photosynthesis
Conversion of light energy into chemical energy
by living organisms
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What are sugars used for in plants?

• Primary cell walls
• Microfibrils (500,000 cellulose chains, cellulose
  molecules are gt6,000 sugars long)
• Secondary cell walls
• Much thicker than primary walls
• Cellulose microfibrils, hemicellulose, and
  lignins
• Starch
• Food storage in seeds (endosperm)

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Typical composition of plant matter
Types of plant compounds
Elemental composition of biomass
(Figures adapted from Brady and Weil, 2002)
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Plant Biomass

• Plants store solar energy through
  photosynthesisas sugars such as cellulose and
  lignin.
• Cellulose is a polysaccharide (chain) of 6-carbon
  sugars (e.g., glucose see image above).
• Lignin is the substance, or glue, that holds
  cell walls together.
• When burned, these sugars break down and release
  energy, giving off CO2, heat, and steam

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Bioenergy

• Bioenergy, or biomass energy, is renewable energy
  from biological sources
• Biomass energy can be converted into electricity,
  heat, steam, and (liquid) fuels

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Biomass Carbon-neutral Energy?The Carbon Cycle
http//eo.ucar.edu/kids/green/images/carboncycle.j
pg
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Bioenergy Supply Global Energy Comparisons
25,000 EJ total storage in land biomass
400,000 Mt/yr land biomass produced
(compiled data from Boyle 2004)
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Biomass Fuel Sources

• biomass processing residues (e.g., from pulp and
  paper operations)
• agricultural and forestry wastes
• urban wood wastes
• municipal solid wastes
• landfill gas
• wastewater treatment gas
• animal wastes
• terrestrial aquatic crops grown solely for
  energy purposes dedicated bioenergy crops

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87 of the biomass is wood or wood processing
residues
U.S. Energy Consumption by Energy Source,
2001-2005 (Source US Energy Information
Administration www.eia.doe.gov, Accessed 3/2008)
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National Biomass Supply

• Assessment of whether land resources in the U.S.
  could sustainably produce over 1 billion tons of
  biomass annually
• Enough biomass to replace 30 of the countrys
  petroleum consumption

Source (2005) http//www1.eere.energy.gov/biomass
/pdfs/final_billionton_vision_report2.pdf
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Source (2005) http//www1.eere.energy.gov/biomass
/pdfs/final_billionton_vision_report2.pdf
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National Biomass Supply Challenges

• Meeting targets for yield increases
• Improving production and harvesting/transportation
  efficiency
• Connecting the potential supply with end users
• Changing attitudes of producersand consumers

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Food vs. FuelA debate over scarce resources

• A farmer has a choice grow corn to be used as
  ethanol or as a food (human or cattle or)
• Corn can serve as a biofuel (ethanol from the
  fermentation of sugars)
• As a result, land is taken out of food production
  which increases the price of corn on the food
  market
• What should this farmer do?

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Food vs. FuelA debate over scarce resources

• But, what about a crop like willow?
• Ethanol production, combustion (heat)
  gasification (heatelectricity)
• Willow grows best on which types of land?
• On which types of land do crops grow best?
• The food vs. fuel debate does not end with corn
  or soybeans, but can be an issue for any
  dedicated bioenergy crop

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Bioenergy, or not?
Yes!
Yes!
Yes!
No!
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Abundant, renewable vs. Energy Dense?

• Biomass is a great renewable energy source.
• However, it is typically not a good (unprocessed)
  fuel, because it often contains more than 70
  air/void space. 
• This results in a low volumetric energy density
  makes it difficult to collect, ship, store and
  use.

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Biomass Energy Density
(Source Gaur and Reed, Dekker, 1998)
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Paths of Biomass Energy Conversion
Carbon Dioxide
Water
Land (nutrients)
PRODUCT FARMING (existing)? Agriculture ?
Silviculture ? Industry
ENERGY FARMING (potential)? Aquaculture ?
Silviculture ? Agriculture
BIOMASS FOR ENERGY
Residues
Farm Forest Products
Municipal Wastes
drying densification
maceration
THERMAL CONVERSION PROCESSES (Dry)?
BIO-CONVERSION PROCESSES (Wet)?
Gasification
Pyrolysis
Liquefaction
Combustion
Extraction
Digestion
Fermentation Distillation
Oil ? gas
Oil ? gas ? charcoal
Heat systems
air
Methane
Chemicals
Ethanol
Low-BTU gas
oxygen
Med-BTU gas ? methanol ? ammonia
Needs
CHEMICALS
GASEOUS FUELS
LIQUID FUELS
SOLID FUELS
ELECTRICITY
HEAT
(adapted from Solar Energy Research Institute,
1988)
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Contact Information

• Ben Ballard, Ph.D.Director, RETC
• Assistant ProfessorPh 315-684-6780
• Email ballarbd_at_morrisville.edu
• Web http//people.morrisville.edu/ballarbd/
• Phil Hofmeyer, Ph.D.Assistant ProfessorPh
  315-684-6515
• Email hofmeypv_at_morrisville.edu
• Web http//people.morrisville.edu/hofmeypv/

http//retc.morrisville.edu