Wood Pellets for BioPower in the US and in the EU

Anthony Baldridge, Tina Dreaden, Matyas Kosa, Kathy Woody, Christina YoungArt J. Ragauskas

07-14-2009Georgia Institute of Technology

Department of Chemistry and Biochemistry

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Outline

What is BioPower?Effect on Climate ChangeForces that accelerateBioPower researchWood pelletsProduction facilitiesMarkets for wood pelletsChemical compositionProspects

Ragauskas, A. J. et al. (2006) Science 311, 484-489

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Biopower

Renewable biomass → energy/ electricityBiomass can be virgin or waste

ForestsCultivated landSewageAgricultural crop &forestry residues

Petrou, E. C. and Pappis, C. P. (2009) Energy and Fuels 23, 1055-1066http://www.ipst.gatech.edu/faculty_new/faculty_bios/ragauskas/ragauskas_biofuels_1.html

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Why biopower?

Considerations:worldwide energydemand expected togrow by > 50% by 2025rising oil pricesglobal climate changeeconomic downturn in U.S.

Biopower from biofuels:Decrease greenhouse gas emissions (CO2 & CH4)Shift dependence away from foreign petroleumEconomic capital

Ragauskas, A. J. et al. (2006) Science 311, 484-489Koh, L. P. and Ghazoul, J. (2008) Biological Conservation 141, 2450-2460http://www.ipst.gatech.edu/faculty_new/faculty_bios/ragauskas/ragauskas_biofuels_today.html

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Biopower applications

Electricity productionGas & coal fired power plants

Residential space heatingPellet burning fireplaces

Transportation fuelsPersonal & mass transportation

Junginger, M. et al. (2008) Biomass and Bioenergy 32, 717-729http://www.ipst.gatech.edu/faculty_new/faculty_bios/ragauskas/ragauskas_biofuels_today.html

66Image taken from: www.ornl.gov

Biopower Cycle

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Greenhouse gas emissions are of great concern.

Finding ways to decrease amount of emitted CO2 , CH4 , and other gases is needed.

Biopower addresses these by:

Using sources that can produce a “carbon neutral” system/cycle

Use of animal waste can reduce pollution and methane emission

Biomass (wood) use prevents wildfires which:

Globally are 40% of gross global CO2emissions

Allows for controlled combustion uses (180%) more efficient

Motivates forest understory gathering of wood material

Environmental Impacts of Cycle

http://www.ipst.gatech.edu/faculty_new/faculty_bios/ragauskas/ragauskas_biofuels.html

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Power Choices and Climate Change

By adapting current methods emitted CO2and other greenhouse gases could greatly diminish.

Currently, wood pellets are gaining use in co firing plants that use coal.

Biopower production is rising in the United States and Europe.

Substitution of fossil fuel with biomass/ biopower decreases net emissions by 750% (note figure).

Image taken from: http://www.uscg.mil/d1/sfoSouthwestHarbor/Innovation/images/pellet_enviro.jpghttp://www.eia.doe.gov/cneaf/solar.renewables/page/biomass/biomass.gif

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Categories of biofuels

Solid biofuelsPellets, sewage, wood

Liquid biofuelsBiodiesel (i.e., long-chain fatty acids),bioethanol, biobutanol, green diesel

Gaseous biofuelsThermal or microbial degradation of biomass used to form biogas, i.e. CH4 or H2

Petrou, E. C. and Pappis, C. P. (2009) Energy and Fuels 23, 1055-1066

ethanol

methyl-palmitate

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Pertinent research

Plant biochemistry & genetics increased yield, resistance,sustainability

Biorefineries: conversion & fractionation of raw materials (polysaccharides & lignin) to products

Direct energy, transportation fuels, chemical products (solvents, plastics, fragrances)

Production of biofuelsCost reduction & efficiency

Ragauskas, A. J. et al. (2006) Science 311, 484-489

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Biopower support

Global: International Energy Agency (IEA) Bioenergy Task 40 (2003)

Develop bioenergy trade to secure supply & demand in a sustainable way

National: Obama’s Economic Stimulus (2009)$54 billion towards green energy (research, tax cuts, etc.)

Local: Georgia Power will convert coal-fired power plant to burn wood chips (2009)

One of largest biomass power plant in U.S.

Junginger, M. et al. (2008) Biomass and Bioenergy 32, 717-729Department of Energy, www.doe.gov

http://www.georgiapower.com/nuclear/plantmitchell.asp

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What are Wood Pellets?

Made from wood waste(e.g. sawdust and wood chips)

Densified wood particles:less then 10% moisture

CylindricalDiameter: 6‐12 mmLength: 5‐30 mm

http://www.ipst.gatech.edu/faculty_new/faculty_bios/ragauskas/ragauskas_biofuels_2.html

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Applications of Wood Pellets

Household use

Central heating boilers: Heat transferred to water heater and heat distribution system for entire home

Hartmann, D.; et al. Biomass and Bioenergy 1999, 16, 397.

Combined Heat and Power (CHP) Plants

Woody biomass-fueled power plants

Co-firing wood pellets and coal:wood pellets partially substitute for coal, decreasing net CO2 and SO2 emissions with respect to burning straight coal.

Stoves: Provide heating and cooking for a single room

Fiedler, F. Renewable and Sustainable Energy Reviews 2004, 8, 201.http://www.pelletheat.org/3/residential/burningFuel.html

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Production process overview

Holm, J. K.; et al. Energy & Fuels 2006, 20, 2686‐2694.

Raw wood waste

Pelletisation Wood pellets

http://www.ipst.gatech.edu/faculty_new/faculty_bios/ragauskas/ragauskas_biofuels_2.html

(pellet-press or die)

milling

drying

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Pellet Production

Wang, C.; Yan, J. International Journal of Green Energy 2005, 2, 91‐107.

Cooling Pellet Transport/ Storage

Drying and Processing

Raw Material

Pelletisation(Compression of Pellets)

After the raw material is dried, it is extruded through cylindrical channels. The friction between the raw material and the press results in compression of the wood into pellets.

http://www.ipst.gatech.edu/faculty_new/faculty_bios/ragauskas/ragauskas_biofuels_2.html

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Compression of Wood Pellets

Obernberger, I. et al. Biomass and Bioenergy, 2004, 27, 653; Holm, J. K. et al. Energy & Fuels 2006, 20, 2686-2694.

• Dense particles give longer burn times and higher energy efficiency

• Lower transportation costs

• Increases storage capacity

Vs.

Compressing pellets requires energy so why make densified wood pellets?

http://www.ipst.gatech.edu/faculty_new/faculty_bios/ragauskas/ragauskas_biofuels_2.html

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Current Production Plants in the Southeast

Image taken from: http://www.pelletheat.org/3/residentail/fuelAvaliablity.cfm#south

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Current Production Plants in Europe

Image taken from: http://www.bioenergyinternational.com

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Market for wood pellets

Depends on:Availability (cost of transport)Heating-value/cost ratio compared to other fuels

Possible consumers:Energy suppliersCommercial/IndustrialResidential

Creating demand for equipment used in production and consumption of pellets

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Heating Value vs. Cost in the US

Pellet Fuels Institutewww.pelletheat.org

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Energy SuppliersBiomass is the only truly “carbon neutral” energyDOE: 45x109 kWh/y from biomass in US1 MWh of biomass power -> 1.6 t of CO2 emission is avoided, hence substituting “new” carbon release with recycling CO2 => reduction of 30x106 t/yOglethorpe as an example:

Building: 3, 100 MW biomass electric generating plants by 2015Fuel: process round wood, primary manufacturing residue, harvest residue400-500x106 $/facility with 40 jobs in eachNRECA, Green Power, Ag Energy Working: 25% of energy from renewable locally grown sources

Department of Energy (DOE)USA Biomass

Oglethorpe PowerNational Rural Electric Cooperative Association

Green Power EMCAg Energy Working Group

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Other Markets

Commercial/Industrial:Examples: Theater (Elma, WA), manufacturing facility (Claremont, NH), farm (Sutton, Quebec), prison (Walla Walla, WA)

Residential:Over 1 million homes using pellet stoves in the US, in 2008 (www.pelletfuel.org)

Equipment:For pelletizing: mills, grinders, dryers, pelletizing, packagingFor consumers: silos, stoves, boilers

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General Chemical Properties of Pellets

high density ensures high heating value and steady combustion behaviorlower water content -> better heating valuelower ash content -> avoid slagbinding agent, preferably natural like corn or maize starch to improve pellet formation

avoid chemical glues which contribute to pollution

F. Fiedler, The State of the Art of Small Scale Pellet-Based Heating Systems and Relevant Regulations in Sweden, Austria, and Germany.

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Fuel Properties as a Function of Chemical Constituents

Ideally, wood pellets should contain chemically untreated material that is free of additivesHowever, sometimes this is not the case what results in pollutant emissions, deposit formations, and corrosion issuesEmission - increased contents of N, Cl, and S as well as heavy metalsCorrosion - increased heavy metals and Cl contaminate ashDeposit formation - increased K - negative effect on ash melting and contributes to higher aerosol formation

I. Obernberger, G. Thek, Physical Characterization and Chemical Composition of Densified Biomass Fuels with Regard to their Combustion Behavior, Proceedings of 1st World Conference on Pellets, Sept. 2002, Stockholm, Sweden, ISBN 91-631-2833-0, pg. 115-122.

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Chemical Composition of Wood Pellets (General Analysis)parameter unit average

value minimum maximum standard deviation

diameter D mm 7.1 5.9 10.2 1.2length mm 16.1 8.6 29.6 5.2bulk density kg/m3 591 520 640 39particle density kg/dm3 1.18 1.03 1.3 0.06water content wt.% (w.b.) 7.7 5.7 9 0.9ash content wt.% (d.b.) 0.51 0.17 1.61 0.3GCV MJ/kg (d.b.) 20.3 19.8 20.7 0.2NCV MJ/kg (d.b.) 19 18.6 19.4 2C wt.% (d.b.) 50.3 49.5 51.9 0.6H wt.% (d.b.) 5.7 5.5 6.1 0.2N wt.% (d.b.) 0.22 0.2 0.64 0.1S mg/kg (d.b.) 278 52 1,922 454Cl mg/kg (d.b.) 48 10 126 27K mg/kg (d.b.) 493 302 1,180 252abrasion wt.% (w.b.) 4.05 0.58 12.53 3.52starch content wt.% (d.b.) 0.22 0 1 0.42Cd mg/kg (d.b.) 0.14 0.06 0.2 0.03Pb mg/kg (d.b.) 0.43 0.07 2 0.44Zn mg/kg (d.b.) 13.2 9.3 25.4 3.6Cr mg/kg (d.b.) 0.6 0.1 3 0.8Cu mg/kg (d.b.) 1.1 0.7 2.7 0.5

Table/data adapted from: I. Obernberger, G. Thek, Physical Characterization and Chemical Composition of DensifiedBiomass Fuels with Regard to their Combustion Behavior, Proceedings of 1st World Conference on Pellets, Sept. 2002,Stockholm, Sweden, ISBN 91-631-2833-0, pg. 115-122.

38 densified biofuels were studied (60%) were wood pellets collected from 30

different producers located in Austria, Spain,

Sweden, Italy, Czech Republic, and Norway

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Example: Wood Pellets, Sweden

Fuel pellets production in Sweden is mainly from sawdust and planar shavings of Scots pine and Norway sprucePellets were analyzed for moisture and composition

M. Arshadi, R. Gref, P. Geladi, S.-A., Dahlqvist, T. Lestander, The Influence of Raw Material Characteristics on the Industrial Pelletizing Process and Pellet Quality, Fuel Processing Technology, 89 (2008), 1442-1447.

Run Moisture Content (%)

Fresh pine fraction (%)

Stored pine fraction (%)

Spurce fraction (%)

S1 10 45 45 10S2 8.2 100 0 0S3 11.7 100 0 0S4 11.7 80 0 20S5 8.2 80 0 20S6 10 45 45 10S7 11.7 0 80 20S8 8.2 0 80 20S9 8.2 0 100 0S10 11.7 0 100 0S11 10 45 45 10S12 8.2 50 50 0

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Pellet Standards Ensure Quality

F. Fiedler, The State of the Art of Small Scale Pellet-Based Heating Systems and Relevant Regulations in Swedent, Austria, and Germany.

Table 4: Pellet standards in Sweden, Austria and Germany1bulk density2particle in weight % <3mm3amount must be specified4type and amount must be specified

Pellet standard Austria

Parameter Unit Class 1 Class 2 Class 3 O-Norm M7135 DIN 51731 DIN plus

Diameter (d) mm 25 25 25 4-10 4-10 4-10Length mm 4 x d 5 x d 6 x d 5 x d 50 5 x dDensity kg/dm3 0.61 0.51 0.51 1.12 1.0-1.4 1.12Water content % 10 10 12 10 12 10Abrasion/small particles % 0.82 1.52 1.52 2 - 2.3Ash content % 0.7 1.5 <1.5 0.5 1.5 0.5Upper caloric value MJ/kg 16.9 16.9 15.1 18 15.5-19.5 18Sulphur content % weight 0.08 0.08 3 0.04 0.08 0.04

Nitrogen content % weight 3 3 3 0.3 0.3 0.3

Chlor content % weight 0.02 0.02 3 0.02 0.03 0.02

Additives % 4 4 4 2 - 2

Sweden - SS 187120 Germany

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Future of BioPower in the US

*only corn stover and cereal straw

Chart showing predicted BioPower usage, including wood pellets versus the predicted cost of logistics for biomass, including: harvest & collection, preprocessing, storage & queuing, transportation & handlingTable shows the predicted growth in biomass production, including: corn stover, switchgrass, cereal straw and woody biomass

DOE, Biomass: Multiyear Program Plan, May 2009DOE, Vision for Bioenergy and Biobased Products in the US, 2006

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Future of BioPower in the EU

2005: 41 TWh/y of electricity from solid biomass and 13 from biowaste20% of all energy consumption must come from renewable sources by 2020, according to the “Renewable Energy Roadmap”, as accepted and published by the Commission of the European Communities. Their goal of reaching 12% until 2012 most likely won’t be met however.Reduce annual fossil fuel consumption by 250 Mtoe annually600-900 Mt decrease in CO2 emission, saving of 150-200 billion euro

Communication: Renewable Energy Road Map, Brussels, 10-01-2007

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Main references

Petrou, E. C. and Pappis, C. P. (2009) Energy and Fuels 23, 1055-1066Ragauskas, A. J. et al. (2006) Science 311, 484-489Koh, L. P. and Ghazoul, J. (2008) Biological Conservation 141, 2450-2460Junginger, M. et al. (2008) Biomass and Bioenergy 32, 717-729Bain, Richard L; Overend, Ralph P. Forest Products Journal. 2002, 52, 2, 12-19

Fiedler, F. Renewable and Sustainable Energy Reviews 2004, 8, 201Hartmann, D.; et al. Biomass and Bioenergy 1999, 16, 397Holm, J. K.; et al. Energy & Fuels 2006, 20, 2686-2694Wang, C.; Yan, J. International Journal of Green Energy 2005, 2, 91-107Obernberger, I. et al. Biomass and Bioenergy, 2004, 27, 653I. Obernberger, G. Thek, Physical Characterization and Chemical Composition of Densified Biomass Fuels with Regard to their Combustion Behavior, Proceedings of 1st World Conference on Pellets, Sept. 2002, Stockholm, Sweden, ISBN 91-631-2833-0, pg. 115-122M. Arshadi, R. Gref, P. Geladi, S.-A., Dahlqvist, T. Lestander, The Influence of Raw Material Characteristics on the Industrial Pelletizing Process and Pellet Quality, Fuel Processing Technology, 89 (2008), 1442-1447