Background
Archeologists believe man gained an understanding of how to manage fire long ago, fundamentally altering our ability to survive, expand our range, and exploit our environment. We've been burning plant material, or biomass, for a very long time. Abundant cheap fossil fuels finally crowded biomass aside in much of the industrialized world in the 20th century. Biomass, though not often scarce, was more costly, less convenient, and given available combustion technology, less environmentally friendly in many respects.
The residential wood pellet fuel industry in North America was created in the early 1980s as a response to the energy crisis. The modern pellet stove dates from 1983. Today, almost one million tons of pellets are sold each year – to heat nearly 500,000 pellet stoves and fireplace inserts in homes the United States and Canada. Consumption is greatest in the Pacific Northwest and Northeastern states where pellets are manufactured from sawmill and wood product residues and where heating energy requirements are significant.
This Web page focuses on the potential for pelleting warm season prairie grasses. Other potential energy uses of grass, such as co-firing, are not addressed. Information about pelleting wood sawdust is included where it provides useful information on pelleting technology or market development.
This page is intended to serve as a resource for people interested in expanding the use of biomass pellets through the use of warm-season grasses as a feedstock. If you have additional information that you feel would be helpful, if you see errors, or if you see information that you feel has been inaccurately credited, please contact us.
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Joseph E. King, Architect |
Dr. Richard Nelson |
This report was prepared by Coriolis and Kansas State University as an account of work sponsored by the Kansas Corporation Commission (KCC), funding for which was provided by the U.S. Department of Energy’s Western Regional Biomass Program (WRBEP). Neither the KCC, WRBEP, Coriolis, Kansas State University, nor any person acting on their behalf a) makes any warranty, express or implied, with respect to the use of any information, apparatus, method, or process disclosed in this report or that such use may not infringe privately owned rights; or b) assumes any liabilities with respect to the use of, or damages resulting from the use of, any information, apparatus, method, or process disclosed in this report or its appendices.
This material was prepared with the support of the U. S. Department of Energy (DOE) Grant No. DE-FC48-02R820204. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the author(s) and do not necessarily reflect the views of DOE.
Previous Reports and Analyses
Assessment of Pelletized Biofuels
R. Samson and P. Duxbury
Resource-Efficient Agricultural Production — Canada
Box 125, Ste. Anne de Bellevue, Quebec, H9X 3V9
Tel 514-398-7743 Fax (514) 398-7972
reap@interlink.net
in collaboration with:
M. Drisdelle and C. Lapointe
DELL-POINT Bioenergy Research
3 rue Montmartre, Blainville, Quebec, J7V 2Z6
Tel (514) 331-6212
Fax (514) 331-9474
Drisdell@pelletstove.com
April 2000
Executive Summary
Increasing concerns about climate change mitigation and rising oil prices are
creating unprecedented interest in the development of economical and convenient
renewable energy fuels. Recent advances in biomass feedstock development and
conversion technologies have created new opportunities for using agricultural
land as a means of producing these renewable fuels in larger quantities than
relying on wood and agricultural residues alone. Dedicated agricultural
feedstocks such as switchgrass and short-rotation willow can abate greenhouse
gas emissions by increasing carbon storage in the landscape, as well as by
displacing fossil fuels in combustion applications. This project examined the
potential of using these materials and other biomass residues as new feedstocks
for the pellet industry.
Switchgrass has been identified as a promising pelleting feedstock as it
facilitates higher throughput rates and requires less energy for crop drying
than wood. Although switchgrass is a higher cost feedstock to procure than wood
residues, it could become an economical biofuel. The overall energy balance of
switchgrass is 14.5:1, which includes energy for switchgrass production,
transportation to the conversion facility, preprocessing, pelleting, and
marketing.
As a herbaceous pelleting feedstock, switchgrass behaves similarly to alfalfa,
enabling research on alfalfa pelleting to be applied to switchgrass pelleting.
Based on a literature review and pilot laboratory studies, the main factors
which were identified to contribute to the successful pelleting of switchgrass
were the length of chop, application of high-temperature steam, and use of a
die with a suitable length/diameter (L/D) ratio. Strong research support and
significant production experience in the alfalfa pellet industry in Canada
provides a solid foundation for switchgrass to be developed as a pellet
feedstock for bioenergy applications. There also appears to be significant
scope for further advances in technologies to increase pellet durability and
productivity.
Combustion trials conducted by the CANMET laboratories using switchgrass in the
Del-Point close-coupled gasifier indicated that switchgrass has a similar
combustion efficiency (82-84%) to wood (84-86%). Switchgrass also has a fuel
energy content that is 96% of the energy of wood pellets on a per tonne basis.
Some adjustment of the cleaner grate settings on the Del-Point close-coupled
gasifier stove is required to burn switchgrass more efficiently, as clinker
formation was observed when high feed rates of switchgrass were used in the
combustion appliance.
High-yielding closed-loop biofuels harbor significant potential for assisting
Canada to meet its climate change commitment, while stimulating rural
development and export market opportunities. Further advances in biomass energy
feedstock production, pelleting technologies, and combustion appliances to burn
these materials will create strong economic momentum for switchgrass pellets to
become a leading, low-cost greenhouse-gas abatement strategy from the
agricultural sector.
www.reap-canada.com/Reports/pelletaug2000.html
Changing the Energy Climate: Clean and Green Heat from Grass Biofuel
Pellets
R. Jannasch, R. Samson, A. de Maio, T. Adams, and
C. Ho Lem.
Abstract
Volatile energy markets, concerns over energy security, and international agreements to reduce greenhouse gas (GHG) emissions have created unique opportunities for biofuel development. Feedstock for pelletized fuels from warm-season grasses such as switchgrass (Panicum virgatum) can be grown for $3-4/GigaJoule (GJ) and pelletized for $3/GJ, with only minor emissions of CO2. Assuming hay prices provide a shadow price for switchgrass, the price volatility of switchgrass appears low relative to the price volatility of fossil fuels. Using close-coupled gasifer combustion technology, switchgrass
fuel pellets emit 85%, 91%, 87%, and 89% less CO2 than electricity, heating oil, natural gas, and propane, respectively. Every 100 ha of switchgrass converted into pellet form and used to displace the same fuels in space-heating applications prevents the emission, on average, of 1800 tonnes of CO2. Heating an average Ontario house with a 90GJ heat demand costs $1213 with switchgrass pellets compared to $2234, $1664, $882, and $2302 with electricity, heating oil, natural gas, and propane, respectively. An estimated 23 and 130 million acres of agricultural land in Canada and the U.S., respectively, could be converted to perennial grass biofuel production. The depressed farm sector would benefit economically from energy farming through economic diversification and absorption of excess production capacity. Low-grade heat energy derived from grass pellets could displace some of the 30,000 giga watt hours of electricity currently used for home heating in Quebec, Ontario, and Manitoba. Surplus electricity could be exported where it would likely displace fossil-fired electricity. Pelletized grass biofuels could provide consumers without access to natural gas with less expensive heating options than fossil energy options. For consumers with access to natural gas, the price premium for switching to a much lower GHG emitting alternative would be modest, except during natural gas price spikes when switchgrass could be cheaper. Developing the switchgrass pellet market could help ease the political challenges in implementing the Kyoto Protocol.
www.cns-snc.ca/events/CCEO/graphics/2a_jannasch_paper.pdf
Reducing Bioenergy Cost by Monetizing the Environmental Benefits of Reservoir Water Quality Improvements from Switchgrass Production: Pelletized Switchgrass for Space and Water Heating
Joseph E. King, AIA
Coriolis
September 1999
Executive Summary
Recent efforts to increase the use of biomass for renewable energy production have focused on plantation grown mono-crops, both trees and grasses, for electric power generation, primarily by co-firing with coal. Investigators recently participated in a detailed evaluation of the potential for using biomass as a fuel for electric utility boilers in Kansas and concluded that under the most positive scenario co-firing switchgrass with coal would result in a “green electricity” premium of $0.010 – 0.150 per kiloWatt-hour above the cost of Wyoming coal. While this is significantly less than the cost premium for wind-generated electricity there is no consensus that the Kansas green electricity market is large enough to support the minimum-scale development of biomass co-firing, barring a regulatory or legislative mandate, state or federal. Electric power generation may offer an enormous market but it also means competing against the cheapest energy.
Development of renewable biomass energy in Kansas will require parallel efforts to reduce edge-of-field costs and to identify and penetrate higher value energy markets. This task focuses on the potential for pelletized herbaceous energy crops (HEC) like switchgrass to provide residential space- and water-heating energy within 50 miles of the Perry Reservoir basin in northeast Kansas.
Pellet-Embodied Energy
For any biomass development strategy to be truly renewable, it must have a high-energy profit ratio (EPR). The estimated embodied energy of HEC pellets totals 2,580,000 Btu/t for an EPR of 6.1. Reduction in fertilizer use and green electricity for pellet plant operation could reduce embodied energy to 1,525,000 Btus with an EPR of 10.4. Other steps such as biodiesel for harvesting and delivery and use of renewably generated electricity for pelleting would improve the EPR.
Barriers to HEC Biomass Pellet Market
Development
An acre of Kansas farmland, worth perhaps $1,000, is capable of producing an average annual yield of HEC biomass sufficient to meet the annual space and water heating needs of an average Kansas home with an energy profit ratio above 6.0. An HEC pellet system would be cheaper and environmentally far superior to a ground-source heat pump. Yet there are real barriers to the development of such a market.
Harvesting
CRP-Enrolled Land for Biomass Energy
Biomass energy production cannot compete for land use with grain crops in northeast Kansas, at least when commodity prices are normal. Access to biomass produced on CRP land at something less than hay market value is essential for biomass to compete with fossil fuels. Current CRP regulations preclude harvest for any purpose. Federal initiates to ease this restriction for biomass energy are anticipated and will be tracked closely in the months ahead.
Lack
of Suitable Combustion Equipment
Not counting systems designed to burn corn, no high-performance, residential-scale, high-ash pellet boilers (or furnaces) are readily available at retail in North America today. Companies reportedly developing such equipment appear to be focusing on the European market where fossil fuels are more expensive, incentives for biomass use more widely available, and the general population more supportive of renewable energy use.
Dominance of
Relatively Low-Cost Natural Gas in the Residential Space/Water Heating Market
Nearly 80% of northeast Kansas homes are heated with natural gas. With the exception of the occasional ardent environmentalist, natural gas users do not represent a market for HEC biomass pellets at current natural gas prices.
The
Importance of Full-Plant Operation on Pellet Cost
The encouraging cost and energy-profit ratio involved in manufacturing HEC pellets summarized above is highly dependent on the pelleting plant operating three shifts a day, five days per week, 48 weeks per year. Fewer hours and less production would significantly increase per unit cost. The potentially high ash content of HEC pellets and the high cost of transporting them may mean there is limited potential for markets beyond what is created locally. Realistically, several years would be required for a sufficient local market to develop to consume the production of the plant envisioned. Future work should include a more thorough evaluation of incremental growth.
Market
Acceptance of HEC Pellet Boilers
The market for residential space-and water-heating equipment is notoriously conservative. A very carefully planned marketing program with appropriate allies such as farmer coops or propane marketers may be essential to achieve the rapid market penetration necessary to bring a pelleting operation into full-scale operation.
Hedging the Risk of Poor Harvest
Grains are fungible global commodities. Producing HECs locally for local markets means the risk of inadequate harvest to meet demand, as a result of drought or even heavy rain, is significantly higher. The following options are available: 1) have adequate acres available to meet demand at lower than-average yield; 2) import wood pellets; 3) plant a portion of acres to trees that will serve as a standing reserve; 4) combine the pellet market with utility co-firing, allowing coal to become the buffer.
Low Priority
of Small-Scale Combustion in Federal Energy Programs
Small-scale biomass combustion does not enjoy significant support from the U.S. Department of Energy.
Anti-Renewable
Energy Kansas Tax Policy
Since 1979, Kansas residential electric sales have been exempt from Kansas sales tax. Pellets would enjoy no such exemption.