Summer 1992
U.S. Department of Energy
Bioenergy Feedstock Development Program at
Oak Ridge National Laboratory
Energy Crops Forum was published periodically by the Bioenergy
Feedstock Development Program, Environmental Sciences Division, Oak Ridge
National Laboratory, managed by UT-Battelle, LLC., for the U.S. Department of
Energy under Contract No. DE-AC05-00OR22725.
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Table of Contents
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Edward Hansen; Project Leader, U.S. Forest Service, North Central Forest
Experiment Station
The North Central Forest Experiment Station in Rhinelander, Wisconsin in 1970
began research on the culture of short-rotation hybrid poplar crops for fiber.
Early studies concentrated on the basics of growing a new crop: planting
material, fertilization, water requirements, pest problems, tree spacing,
rotation length, and -- most important -- potential yield. This research
provided the necessary information to grow hybrid poplar as a farm crop.
In the mid-1980s, a large midwestern power company became interested in wood
fuel for generating electricity which led to the establishment of 10- to
20-acre hybrid poplar plantations across a four-state area. These plantations
were designed to identify suitable hybrids for the region and to obtain better
yield estimates and more realistic economic data for a commercially sized
plantation.
The U.S. Congress established the Conservation Reserve Program (CRP) to address
the chronic problem of agricultural overproduction of food and to reduce
erosion by removing erodible land from production. The needs for clean
renewable energy, a reduction of surplus agricultural crops, and crop
alternatives were emerging as problems with a common solution and tree planting
on CRP lands was encouraged.
Minnesota, which lies in the prairie/forest transition zone with more than 2
million acres enrolled in the CRP program, is particularly interested in
developing hybrid poplars as a new energy crop. Building on initial research
information, wood energy developmental projects are under way in a number of
areas. A state nursery is preparing for extensive production of the best hybrid
planting stock. Biochemical changes are being measured in a pile of poplar wood
chips to determine storage-related effects on use of the chips for ethanol
production. A 100-ft-high pile of whole trees has been constructed, and drying
trials will soon be initiated to test the feasibility of whole-tree stacking
and drying in preparation for burning the trees to produce electricity. A
geographic information system project has been initiated to develop siting
information for hybrid poplar plantations. Two proposals for planting as many
as 14,000 acres of hybrid poplar plantations have been submitted to a state
legislative commission for funding. These proposals are sponsored by consortia
of state and local agencies and private business.
The objective of these related efforts is to establish energy plantations to
produce fuelwood for direct burning for production of electricity or for
conversion to ethanol. The program is a good example of the practical
application of research information -- a true Research-to-Reality success
story.
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Jack Ranney; BFDP
The Biofuels Feedstock Development Program (BFDP) is working with other
interested organizations to develop an environmental action agenda for biofuels
technologies. Assessments and studies currently underway are furnishing some of
the background for developing this agenda, including
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DOE-coordinated efforts to estimate net emissions from the complete
energy-crop-to-ethanol pathway;
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development of selected subregional cost-supply relationships for energy crops
and analysis of associated environmental and land-use impacts;
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collection of data on the biodiversity of energy crops relative to neighboring
land uses;
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assessments of the probable fate of chemicals applied to energy crops using
agricultural systems as models;
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evaluation of possibilities for using energy crops in the remediation of
degraded sites; and
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assessments of special issues such as the relationships between wetlands and
energy crop deployment.
Collaborators with the BFDP in these and related activities include other
national laboratories, utilities, industry, academia, the U.S. Department of
Agriculture (USDA), the U.S. Environmental Protection Agency, the National
Audubon Society, the Nature Conservancy, and state agencies. Reaching agreement
on a definition of environmental acceptability is requiring cross-education and
in-depth exchange of views.
Energy crops offer opportunities to achieve significant environmental advantages
as well as energy independence. Some benefits relate to primary emissions, but
many involve a wide range of secondary issues. Net greenhouse gas emission
reductions, sustainable production systems, and increased landscape
biodiversity dominate the spectrum of apparently achievable benefits.
Innovative methods of biomass production which go beyond monocultures will need
to be included in response to these opportunities and issues. Mixed species,
habitat corridors, agroforesty concepts, fertilization of early successional
plant communities, a range of harvesting approaches, and variations in weed
management may be included. Biomass production systems can have specific roles
to fill in the framework of energy, economics, and the environment. It is
critical to understand the economic and environmental roles these alternatives
can provide and to develop an integrated framework for evaluating and improving
them.
A team is being formed at ORNL to develop an integrated framework for evaluating
and adapting biomass energy systems using a wide and adjustable range of
criteria. This will permit us to examine synergies between developing biomass
for energy, other agricultural production programs, and the emerging
environmental imperatives. Including innovative biomass production systems and
characterizing their environmental, supply, and economic roles is central to
meeting such a challenge.
This is the first time since the beginning of energy crop research in 1975 that
such diverse groups have agreed work together on biofuel technologies.
Environmental issues including the Clean Air Act and concern over climate
change have stimulated a great deal of cooperation. The National Audubon
Society intends to form a "round table" of experts from all the interested
organizations to discuss policy and technology options for biofuels systems in
the hope that both the biofuels industry and the environment will benefit.
Early in 1993, the BFDP will hold a workshop to develop its environmental action
agenda. Environmental risk analysis, data collection, experimental studies,
economic evaluations, and policy considerations will be discussed. Participants
will consider how much emphasis should be placed on site-specific, regional and
national considerations. Other issues affecting energy crop development will
need clarification before environmental R&D prioritization can be
discussed.
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Judd Isebrands; USDA Forest Service, Forestry Sciences Laboratory
ECOPHYS is an ecophysiological whole-tree model that simulates the growth of
poplar in the establishment year. The model was developed as part of the USDA
Forest Service, North Central Forest Experiment Station's research program,
"Increasing Yields of Poplar Energy Plantations," and was funded in part by the
U.S. Department of Energy's Biofuels Feedstock Development Program.
The model uses a geometric approach to simulate canopy architecture. Leaves on a
young poplar are displayed in a three-dimensional coordinate system so that the
orientation (lamina angle, midrib angle, and azimuth) of each leaf is known. By
keeping track of the sun's position over the course of a day, the model
calculates the amount of light received by each leaf in any given hour of the
day over the growing season. This strategy accounts for both the angle of
incidence and mutual leaf-shading patterns.
The direct and diffuse radiation received by each leaf is then used to calculate
hourly photosynthate production. Photosynthates are periodically translocated
to various growth centers within the plant (leaves, stem, roots) and used to
determine increases in biomass and dimensional growth. The model runs on an
hourly time step over the growing season until the date of bud set.
ECOPHYS was developed for two purposes: first, to determine the effect of
genetically selectable factors such as leaf shape or orientation on tree growth
and, second, to develop a tool for rapidly screening genetic material -- clones
that appear productive can be carried on to field trials. Because there was a
strong theoretical basis in developing the model, it is well suited for
teaching basic concepts of plant physiology, including the relationship between
light interception and photosynthesis, the translocation of photosynthates
throughout the plant, and the growth of plants as affected by climate.
In the first phase the model was based primarily on the aboveground structure
and processes in trees growing under optimal conditions. Current work focuses
on the simulation of root structure and belowground processes. The model is
also being expanded to accommodate such environmental factors as moisture,
nutrient stress, and changes in air chemistry (i.e., elevated ozone and CO2).
The model may someday enable researchers to understand the mechanisms of stress
effects on tree growth. Recently, ECOPHYS has been generalized to simulate
aspen, yellow poplar and other hardwood trees. The model's high-quality
graphics show the aboveground as well as belowground structure of a tree at any
hour of any day.
ECOPHYS runs on IBM-compatible machines with hard disk, 640K RAM, and CGA or
better graphics and is distributed on three 360K 5.25 in. floppy disks.
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Sandy McLaughlin; BFDP
In November 1991, the BFDP issued a request for proposals (RFP) to develop
improved techniques for selecting and growing switchgrass as a biofuels crop.
Southeastern and south central states were targeted in order to take advantage
of the longer growing season, a major determinant of yield potential for this
warm-season species.
Three research areas -- breeding, cultural improvement, and biotechnology --
were included. Of the 12 proposals received, 5 proposals were selected:
- C. M. Talliaferro, Oklahoma State University
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Breeding and Selection of New Switchgrass Varieties for Increased Biomass
Production
- B. V. Conger, University of Tennessee
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Researchon Improving Productivity of Switchgrass as a Biofuels
Crop--Development of In Vitro Cultural Systems for Switchgrass (Panicum
virgatum)
- D. I. Bransby, Auburn University
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Development of Optimal Establishment and Cultural Practices for Switchgrass as
an Energy Crop
- M. A. Sanderson, Texas A&:M University
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Evaluation of Switchgrass Cultivars and Cultural Methods for Biomass Production
in the Southcentral U.S.
- D. J. Parrish, Virginia Polytechnic Institute
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Switchgrass as a Biofuels Crop in the Upper Southeast: Variety Trials and
Cultural Improvements.
A related project, "Research on Improving the Productivity of Switchgrass as a
Biofuels Crop: Genotypic Diversity in Carbon Acquisition, Allocation, and in
the Utilization of Limiting Water and Nutrient Resources" was begun at ORNL
with S. D. Wullschleger as principal investigator.
The investigators met in March in Oak Ridge, Tennessee to exchange ideas and
approaches. The potential for interactions among projects appears quite high
and should lead to some excellent interdisciplinary studies. As the research
gets underway, efforts will be made to promote the linkage of this work with
other related studies.
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Anthony Turhollow; BFDP
Program researchers are often asked how much biomass can be produced in the U.S.
BFDP, working with the University of Tennessee, is developing supply curves for
energy crops to provide the answer to that question. An existing agricultural
modeling system is being linked with an econometric model to evaluate
price-quantity relationships.
The linear program model in the Agricultural Resource Interregional Modeling
System (ARIMS) selects the mix of crops which will minimize the cost of
producing a fixed set of agricultural commodities, including energy crops. The
Erosion Productivity Index Calculator (EPIC), developed by the U.S. Department
of Agriculture, projects crop growth by soil type and management system. It
also calculates soil erosion and other environmental impacts. Both EPIC and a
crop budget generator provide input to the ARIMS linear program.
As the quantity of biomass required for energy purposes increases, the cost of
energy crops will also increase. At some level, producing energy crops will
have effects on the cost and supply of other crops. ARIMS output will be
coupled to POLYSIM (Policy Simulator), an econometric model, to examine the
supply and demand interactions between energy crops and other agricultural
products.
Regional supply curves will be calculated by running regressions on
ARIMS-generated data regarding the cost of biomass in relation to its quantity.
The supply curves will examine the effects of such variables as energy prices,
crop demand, and yields on the cost of energy crops.
The modeling system will first be used to examine the production of corn for
ethanol. This test case should be completed before the end of 1992. Cellulosic
energy crops, alone and in combinations with corn, will be examined next year.
The Energy Information Administration of the U.S. Department of Energy is
cosponsoring this effort. The U.S. Department of Agriculture's Soil
Conservation Service will use this modeling system to examine the environmental
impacts of energy crop production.
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