Biomass Energy:
Bioenergy Overview
Biomass Resources
Creating Energy from Biomass
Biomass Economics
Biomass Environmental Issues
Promise of Bioenergy
Ethanol Production
Biomass resources include any organic matter available on a renewable basis, including dedicated energy crops and trees, agricultural food and feed crops, agricultural crop wastes and residues, wood wastes and residues, aquatic plants, animal wastes, municipal wastes, and other waste materials. Material handling, collection logistics and infrastructure are important aspects of the biomass resource supply chain.
Resources
Herbaceous Energy CropsHerbaceous energy crops are perennials that are harvested annually after taking two to three years to reach full productivity. These include such grasses as switchgrass, miscanthus (also known as Elephant grass or e-grass), bamboo, sweet sorghum, tall fescue, kochia, wheatgrass, and others.
Woody Energy CropsShort-rotation woody crops are fast growing hardwood trees harvested within five to eight years after planting. These include hybrid poplar, hybrid willow, silver maple, eastern cottonwood, green ash, black walnut, sweetgum, and sycamore.
Industrial CropsIndustrial crops are being developed and grown to produce specific industrial chemicals or materials. Examples include kenaf and straws for fiber, and castor for ricinoleic acid. New transgenic crops are being developed that produce the desired chemicals as part of the plant composition, requiring only extraction and purification of the product.
Agricultural CropsThese feedstocks include the currently available commodity products such as cornstarch and corn oil; soybean oil and meal; wheat starch, other vegetable oils, and any newly developed component of future commodity crops. They generally yield sugars, oils, and extractives, although they can also be used to produce plastics and other chemicals and products.
Aquatic CropsA wide variety of aquatic biomass resources exist such as algae, giant kelp, other seaweed, and marine microflora. Commercial examples include giant kelp extracts for thickeners and food additives, algal dyes, and novel biocatalysts for use in bioprocessing under extreme environments.
Agriculture Crop ResiduesAgriculture crop residues include biomass, primarily stalks and leaves, not harvested or removed from the fields in commercial use. Examples include corn stover (stalks, leaves, husks and cobs), wheat straw, and rice straw. With approximately 80 million acres of corn planted annually, corn stover is expected to become a major biomass resource for bioenergy applications.
Forestry ResiduesForestry residues include biomass not harvested or removed from logging sites in commercial hardwood and softwood stands as well as material resulting from forest management operations such as pre-commercial thinnings and removal of dead and dying trees.
Municipal WasteResidential, commercial, and institutional post-consumer wastes contain a significant proportio
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Sugar Platform
1. Convert biomass to sugar or other
fermentation feedstock
2. Ferment biomass intermediates using
biocatalysts
• Microorganisms including yeast and
bacteria;
3. Process fermentation product
• Yield fuel-grade ethanol and other fuels,
chemicals, heat and/or electricity
http://www.nrel.gov/biomass/proj_biochemical_conversion.html
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Gasification
• Biomass heated with no oxygen
• Gasifies to mixture of CO and H2
– Called “Syngas” for synthetic gas
• Mixes easily with oxygen
• Burned in turbines to generate electricity
– Like natural gas
• Can easily be converted to other fuels,
chemicals, and valuable materials
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Biomass Gasifier
• 200 tons of wood
chips daily
• Forest thinnings;
wood pallets
• Converted to gas at
~1850 ºF
• Combined cycle gas
turbine
• 8MW power output McNeil Generating Station
biomass gasifier – 8MW
http://www.nrel.gov/biomass/photos.html
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Pyrolysis
• Heat bio-material under pressure
– 500-1300 ºC (900-2400 ºF)
– 50-150 atmospheres
– Carefully controlled air supply
• Up to 75% of biomass converted to liquid
• Tested for use in engines, turbines, boilers
• Currently experimental
http://www1.eere.energy.gov/biomass/pyrolysis.html
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Anaerobic Digestion
• Decompose biomass with microorganisms
– Closed tanks known as anaerobic digesters
– Produces methane (natural gas) and CO2
• Methane-rich biogas can be used as fuel
or as a base chemical for biobased
products.
• Used in animal feedlots, and elsewhere
http://www1.eere.energy.gov/biomass/other_platforms.html
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Carbon Rich Platform
• Natural plant oils such as soybean, corn, palm,
and canola oils
– In wide use today for food and chemical applications
• Transesterification of vegetable oil or animal fat
produces fatty acid methyl ester
– Commonly known as biodiesel.
• Biodiesel an important commercial air-emission
reducing additive / substitute for diesel fuel
– could be platform chemical for biorefineries.
http://www1.eere.energy.gov/biomass/other_platforms.html
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BioFuels
• Ethanol
– Created by fermentation of starches/sugars
– US capacity of 1.8 billion gals/yr (2005)
– Active research on cellulosic fermentation
• Biodiesel
– Organic oils combined with alcohols
– Creates ethyl or methyl esters
• SynGas Biofuels
– Syngas (H2 & CO) converted to methanol, or
liquid fuel similar to diesel
http://www.eere.energy.gov/RE/bio_fuels.html
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Plant Products Platform
• Selective breeding and genetic
engineering
• Develop plant strains that produce greater
amounts of desirable feedstocks or
chemicals
• Even compounds that the plant does not
naturally produce
• Get the biorefining done in the biological
plant rather than the industrial plant.
http://www1.eere.energy.gov/biomass/other_platforms.html
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Economic Issues
• Sustainable Development
– Move toward sustainable energy production
• Energy Security
– Reduce dependence on imported oil
• Rural Economic Growth
– Provide new crops/markets for rural business
• Land Use
– Better balance of land use
http://www.eere.energy.gov/RE/bio_integrated.html
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Environmental Issues
• Air Quality
– Reduce NOx and SO2 emissions
• Global Climate Change
– Low/no net increase in CO2
• Soil Conservation
– Soil erosion control, nutrient retention, carbon
sequestration, and stabilization of riverbanks.
• Water Conservation
– Better retention of water in watersheds
• Biodiversity and Habitat
– Positive and negative changes
http://www.eere.energy.gov/RE/bio_integrated.html
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Heat and CO2 Content
Boyle, Renewable Energy, Oxford University Press (2004)
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Net Life Cycle Emissions
Boyle, Renewable Energy, Oxford University Press (2004)
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Crop Erosion Rates
Michael Totten, Conservation International, January 27, 2006
SRWC = Short Rotation Woody Crops
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Biomass Infrastructure
• Biomass Production Improvements
– Genetics, breeding, remote sensing, GIS,
analytic and evaluation techniques
• Biomass Material Handling
– Storage, handling, conveying, size reduction,
cleaning, drying, feeding systems, systems
• Biomass Logistics and Infrastructure
– Harvesting, collecting, storing, transporting,
other biomass supply chain elements
http://www.eere.energy.gov/RE/bio_resources.html
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Multiple benefits would accrue:
www.bioproducts-bioenergy.gov/pdfs/NRDC-Growing-Energy-Final.3.pdf.
Benefits of Bioenergy
• Rural American farmers
producing these fuel crops
would see $5 billion of
increased profits per year.
• Consumers would see
future pump savings of $20
billion per year on fuel
costs.
• Society would see CO2
emissions reduced by 6.2
billion tons per year, equal
to 80% of U.S.
transportation-related CO2
emissions in 2002.
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Nathaniel Greene et al., Growing Energy, www.bioproducts-bioenergy.gov/pdfs/NRDC-Growing-Energy-Final.3.pdf.
Growing US Energy
• 2004 assessment by the National Energy
Commission concluded that a vigorous
effort in the USA to develop cellulosic
biofuels between now and 2015 could:
– Produce the first billion gallons at costs
approaching those of gasoline and diesel.
– Establish the capacity to produce biofuels at
very competitive pump prices equivalent to
roughly 8 million barrels of oil per day (122
billion gallons per year) by 2025.
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TODAY & BUSINESS AS USUAL
30 million hectares soy
NEXT DECADE & FUTURE
30 million hectares switchgrass
Switchgrass 1 to 3x protein productivity +
5 to 10 x mass productivity of soybeans
animal
protein
feed
oils animal
protein
feed
Cellulose
hydrolyzed into
30 billion
gallons ethanol
oils
http://thayer.dartmouth.edu/thayer/rbaef/.
US Grows its Gas
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Ethanol Production
• Corn kernels are ground in a hammermill to
expose the starch
• The ground grain is mixed with water, cooked
briefly and enzymes are added to convert the
starch to sugar using a chemical reaction called
hydrolysis.
• Yeast is added to ferment the sugars to
ethanol.
• The ethanol is separated from the mixture by
distillation and the water is removed from the
mixture using dehydration
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Ethanol Production
• Energy content about 2/3 of gasoline
– So E10 (10% ethanol, 90% gasoline) will
cause your gas mileage to decrease 3-4%
• Takes energy to create ethanol from
starchy sugars
– Positive net energy balance
– Energy output/input = 1.67
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Federal Reformulated Gasoline
Required year round in high pollution metro areas
e.g. L.A., San Diego, Dallas, Houston, Washington, D.C.
Federal Winter Oxygenated Fuels
Required during winter in selected high pollution metro areas
e.g. Denver, Phoenix, Las Vegas
Ethanol Use by Market
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MTBE
• MTBE (methyl tertiary-butyl ether)
– A chemical compound that is manufactured by the
chemical reaction of methanol and isobutylene
– Used almost exclusively a fuel additive in gasoline
– It is one of a group of chemicals commonly known as
"oxygenates" because they raise the oxygen content
of gasoline.
– At room temperature, MTBE is a volatile, flammable
and colorless liquid that dissolves rather easily in
water.
Source: EPA (http://www.epa.gov/mtbe/gas.htm)
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MTBE
• Oxygen helps gasoline burn more completely,
reducing tailpipe emissions from motor vehicles
• Oxygen dilutes or displaces gasoline
components such as aromatics (e.g., benzene)
and sulfur
• Oxygen optimizes the oxidation during
combustion.
• Most refiners have chosen to use MTBE over
other oxygenates primarily for its blending
characteristics and for economic reasons
Source: EPA (http://www.epa.gov/mtbe/gas.htm)
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MTBE and
The Clean Air Act
• The Clean Air Act Amendments of 1990 (CAA) require
the use of oxygenated gasoline in areas with unhealthy
levels of air pollution
– The CAA does not specifically require MTBE. Refiners may
choose to use other oxygenates, such as ethanol
– Winter Oxyfuel Program: Originally implemented in 1992, the
CAA requires oxygenated fuel during the cold months in cities
that have elevated levels of carbon monoxide
– Year-round Reformulated Gasoline Program: Since 1995, the
CAA requires reformulated gasoline (RFG) year-round in cities
with the worst ground-level ozone (smog).
Source: EPA (http://www.epa.gov/mtbe/gas.htm)
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MTBE and
Groundwater Pollution
• MTBE has the potential to occur in high
concentrations in groundwater
• Some MTBE has appeared in drinking water
wells throughout the U.S
• Highly water soluble
– Not easily absorbed into soil
– Resists biodegradation
• Travels far from leak sources,
– Hazard on a regional scale.
• Some states are banning MTBE
Source: Lawrence Livermore National Laboratory (http://www.llnl.gov/str/Happel.html)
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Energy Policy Act of 2005
• Small Producer Biodiesel and Ethanol Credit
– 10 cent per gallon tax credit
– Up to 15 million gallons annually per producer
– Expires year end 2008
• Fueling stations
– 30% credit for cost of installing clean-fuel vehicle
refueling equipment
– $30,000 maximum
– e.g. E85
• 85% Ethanol, 15% gasoline
• GM pushing their E85 vehicles as an alternative to hybrids
• Seven SUV/Trucks, two sedans
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Energy Policy Act of 2005
• The Renewable Fuel Standard
– Requires use of 7.5 billion gallons of biofuels by 2012
• includes ethanol and biodiesel
– Up from 3.4 billion gallons in 2004
• All refiners required to abide by targets
– Credit trading mechanism in place
• For example, refiners in states with little or no ethanol
production may buy credits from refiners in states with
excess production
• Increased costs across the nation
• Decrease oil imports by 2.1%
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Cellulosic Ethanol
• Ethanol produced from agricultural
residues, woody biomass, fibers,
municipal solid waste, switchgrass
• Process converts lignocellulosic feedstock
(LCF) into component sugars, which are
then fermented to ethanol
Source: American Coalition for Ethanol (http://www.ethanol.org/documents/ACERFSSummary.pdf)
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Cellulosic Ethanol
Energy Policy Act of 2005
• Minimum 250 million gallons/year by 2012
• Incentive grants for facility construction
– 2006: $500 million
– 2007: $800 million
– 2008: $400 million
• Other research grants/production
incentives
– 2006 – 2010: $485 million
Source: American Coalition for Ethanol (http://www.ethanol.org/documents/ACERFSSummary.pdf)
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Ethanol
Energy Policy Act of 2005
• President Bush
– Reduce our “addition to oil”
• Replace 75% of U.S. oil imports from the
Middle East by 2025
– But that’s just 4.3 million barrels/day
– Total consumption of 26.1 million barrels/day
Source: American Coalition for Ethanol (http://www.ethanol.org/documents/ACERFSSummary.pdf)
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U.S. Petroleum Supply
2004
8.6
1.8
6.2
3.3
2.6
Domestic Oil
Domestic Ethanol
Western Hemisphere
Europe/Africa
Persian Gulf
2025
5.1
5.3
6.7
3.2
5.8
Domestic Oil
Domestic Ethanol
Western Hemisphere
Europe/Africa
Persian Gulf
MMBPD
Source: Department of Energy/Energy Information Agency
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Ethanol
Energy Policy Act of 2005
• Brazil produces ethanol at $25/oil equivalent
barrel
– Adjusted price taking into account energy differences
between ethanol and oil
– Compare $25/barrel to current oil price of $60+/barrel
• Largest commercial application of biomass
energy in the world
– Sugar cane used a feedstock
• Domestic automakers building flex-fuel vehicles
Source: Federal University of Rio de Janeiro
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Promoting Bioenergy
• Why not import ethanol from Brazil?
• The U.S. imposes a $22/barrel import tariff on
Brazilian ethanol
• So, are the ethanol subsidies in the EPAct05
just a payoff to the agricultural lobby?
• Or, are we attempting to build a domestic
ethanol industry by subsidizing its early efforts?
• How best to promote bioenergy?
Source: American Coalition for Ethanol (http://www.ethanol.org/documents/ACERFSSummary.pdf)
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Sugar Platform
• Most plant material consists of cellulose
– Not starch and starch and sugar
• Need to break cellulose into its sugars
– Research underway to make economical
http://www1.eere.energy.gov/biomass/sugar_platform.html
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Other Platforms
• Biogas Platform
• Carbon-Rich Chains Platform
• Plant Products Platform
– Selective breeding and genetic engineering
– develop plant strains that produce greater amounts of
desirable feedstocks or chemicals
– even compounds that the plant does not naturally
produce
– getting the biorefining done in the biological plant
rather than the industrial plant.
http://www1.eere.energy.gov/biomass/other_platforms.html