bioenergy

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Biomass Energy

Professor Stephen LawrenceLeeds School of Business

University of Colorado – Boulder

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Biomass Agenda

• Bioenergy Overview

• Biomass Resources

• Creating Energy from Biomass

• Biomass Economics

• Biomass Environmental Issues

• Promise of Bioenergy

• Ethanol Production

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BioEnergy Overview

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Global Energy Sources 2002

Boyle, Renewable Energy, Oxford University Press (2004)

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Renewable Energy Use – 2001


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Bioenergy Cycle

http://www.repp.org/bioenergy/bioenergy-cycle-med2.jpg

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Bioenergy Cycle


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Carbon Cycle


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Commercial Carbon Cycle

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US Energy Cropland

http://www.cbsnews.com/htdocs/energy/renewable/map_bioenergy_image.html

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US Biomass Resources

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Biomass Resource Potential

http://www.eia.doe.gov/cneaf/solar.renewables/page/biomass/biomass.gif

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Biomass Basic Data


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Solar Energy Conversion


1 hectare = ~2.5 acres

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Boiling 1l of Water


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Biomass Energy Production

Sector/Source 2000 2001 2002 2003 2004P

Total 2,907 2,640 2,648 2,740 2,845

Wood Energy Total 2,257 1,980 1,899 1,929 1,989

Residential 433 370 313 359 332

Commercial 53 40 39 40 41

Industrial 1,636 1,443 1,396 1,363 1,448

Electric Powera 134 126 150 167 168

Waste Energy Total 511 514 576 571 560

MSW/Landfill Gas 400 419 467 440 443


Industrial 64 74 87 85 88


Other Biomassb 111 95 108 131 117


Industrial 81 76 81 85 84


Alcohol Fuelsc 139 147 174 239 296

Transportation 139 147 174 239 296

http://www.eia.doe.gov/cneaf/solar.renewables/page/biomass/biomass.html

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Bioenergy Technologies


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Biomass Resources

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Types of Biomass

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Biomass Resources

• Energy Crops– Woody crops– Agricultural crops

• Waste Products– Wood residues– Temperate crop wastes– Tropical crop wastes– Animal wastes– Municipal Solid Waste (MSW)– Commercial and industrial wastes

http://www.eere.energy.gov/RE/bio_resources.html

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Corn

http://www.geo.msu.edu/geo333/corn.html

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Soybeans

http://agproducts.unl.edu/

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Sorghum

http://www.okfarmbureau.org/press_pass/galleries/grainSorghum/

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Sugar Cane Bagasse

http://www.nrel.gov/biomass/photos.html

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Switchgrass


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Hybrid Poplar


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Corn Stover


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Wood Chips & Sawdust

http://www.nrel.gov/biomass/photos.html http://www.energytrust.org/RR/bio/

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Tracy Biomass Plant

Truck unloading wood chips that will fuel the Tracy Biomass Plant, Tracy, California.

http://www.eia.doe.gov/cneaf/solar.renewables/page/biomass/biomass.html

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Municipal Solid Waste

http://www.eeingeorgia.org/eic/images/landfill.jpg

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Creating Energy from Biomass

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Bioenergy Conversion


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Biomass Direct Combustion


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Heat Energy Content


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MSW Power Plant


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Composition of MSW


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Integrated Waste Plant


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EU MSW Incineration


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Landfill Gasses


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Biorefinery

http://www.nrel.gov/biomass/biorefinery.html

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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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Thermochemical Platform

• Direct Combustion

• Gasification

• Pyrolysis

http://www1.eere.energy.gov/biomass/thermochemical_platform.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


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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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Pyrolysis Schmatic

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.


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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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Biodiesel Bus


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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.


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Biomass Economics

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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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Landfill Gas Costs


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Switchgrass Econ

Tons Per Acre

Total Variable Cost Per

Acre

Total Fixed Cost Per

AcreTotal Cost

Per Acre

Ethanol Min Price per

Gallon

2 $131.00 $66.50 $197.50 $2.47

3 $87.33 $44.33 $131.67 $1.65

4 $65.50 $33.25 $98.75 $1.23

5 $52.40 $26.60 $79.00 $0.99

6 $43.67 $22.17 $65.83 $0.82

7 $37.43 $19.00 $56.43 $0.71

8 $32.75 $16.63 $49.38 $0.62

9 $29.11 $14.78 $43.89 $0.55

10 $26.20 $13.30 $39.50 $0.49 http://www.agecon.uga.edu/~caed/Pubs/switchgrass.html

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Energy Crop Potential

Michael Totten, Conservation International, January 27, 2006

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Environmental Impacts

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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


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Heat and CO2 Content


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Net Life Cycle Emissions


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Crop Erosion Rates


SRWC = Short Rotation Woody Crops

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Biocide Requirements


Short RotationWoody Crops

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Promise of Bioenergy

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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


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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 USUAL30 million hectares soy

NEXT DECADE & FUTURE30 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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Fuel Efficiency vs. Land

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Bioenergy Forecasts


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One Scenario


Semi-Efficient, Ambitious Renewable Energy Scenario

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Ethanol Production

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Ethanol Yields


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Ethanol Production Plant


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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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In comparison, US consumedan 140,000 million gallons ofgasoline in 2004

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US Ethanol Facilities

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Ethanol by State

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Ethanol Fuel Use 2003

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Federal Reformulated GasolineRequired year round in high pollution metro areas

e.g. L.A., San Diego, Dallas, Houston, Washington, D.C.

Federal Winter Oxygenated FuelsRequired 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)

http://www.epa.gov/otaq/consumer/fuels/oxypanel/r99021tb.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


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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).


http://www.epa.gov/otaq/fuels.htm#oxy



http://www.epa.gov/otaq/rfg.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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State MTBE Bans

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Corn Use for Ethanol

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Corn Use by Segment

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Sorghum Use by Segment

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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 EthanolEnergy 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


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EthanolEnergy 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


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U.S. Petroleum Supply

2004

8.6

1.86.2

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

MMBPDSource: Department of Energy/Energy Information Agency

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EthanolEnergy 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?


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Midterm Review

Next Week:

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Extra Slides

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Biomass Basics

http://www.eere.energy.gov/RE/bio_basics.html

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BioPower Electricity

• Direct Combustion– Burn biomass to create steam

• Co-Firing– Mix biomass with coal in coal plants– Economically attractive

• Gasification

• Pyrolysis

• Anaerobic Digestion

http://www.eere.energy.gov/RE/bio_biopower.html

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Integrated Systems


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Biomass Resources

• Herbaceous Energy Crops• Woody Energy Crops• Industrial Crops• Agricultural Crops• Aquatic Crops• Agricultural Crop Residues• Forestry Residues• Municipal Waste• Animal Waste


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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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Biorefinery Platforms

http://www1.eere.energy.gov/biomass/

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Average UK Fuel Prices


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Energy Crop Yields


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Biodiversity friendly Bioenergy?Perennial prairie grasses

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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.


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Direct Hydrothermal Liquifaction

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Thermochemical R&D

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Simple vs. CCGT Plant


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Carbon/Solar Cycle

bioenergy

Documents

renewable energy use

oxford university press

types of biomass

us energy cropland

solar energy conversion

global energy sources

heat energy content

us biomass resources