Fall 1994
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.

Table of Contents

• Switchgrass production costs estimated by ORNL
• Hawaiian researchers model alternative land use
• Intern birdwatches for BFDP
• BFDP needs your help
• Publications of Interest

Switchgrass production costs estimated by ORNL

Marie Walsh, BFDP

Farmers, policymakers, and chemical and electrical companies are increasingly interested in biomass energy systems due to the many air, soil, and water quality benefits they offer. New policies to encourage biomass commercialization and decisions to use or produce biomass will depend on its economic competitiveness relative to other energy supplies. A major determinant of competitiveness is the cost of producing the energy crop.

We have estimated switchgrass production costs in the Lake States (Michigan, Minnesota, Wisconsin); Corn Belt (Iowa, Illinois, Indiana, Missouri, Ohio); Southeast (Alabama, Georgia, South Carolina); Appalachia (Kentucky, North Carolina, Tennessee, Virginia, West Virginia); North Plains (Kansas, Nebraska, North Dakota, South Dakota); and South Plains (Oklahoma, Texas). These regions correspond to the U.S. Department of Agriculture, Economic Research Service major crop production regions. Switchgrass can be grown in other states as well.

Switchgrass is not produced currently for commercial sale; historical production cost data are not available. Production costs estimated in the analysis are based on assumptions regarding likely management practices. Machinery specifications are used to calculate the number of hours required for each production operation. Costs per acre are calculated by multiplying the per-hour machinery costs by the number of hours in operation. All input costs are in 1993 dollars.

The analysis does not include transportation costs from the site of production to the end user. These costs are expected to be about $0.10 per dry ton per mile for hauling distances of less than 50 miles.

Variable cash costs of production are presented in Table 1. Variable cash costs are the out-of-pocket expenses of production and include expenditures for seeds, fertilizers, chemicals, twine, machinery repair, and fuel and lubrication. For short-run farmer decisions regarding which crop to plant each year, variable cash costs are the most relevant costs.

* The first number in each range corresponds to the lowest yield.
** Switchgrass is assumed to contain 14.5 MBtu per dry ton.

Full economic costs of production are provided in Table 2. Economic costs include fixed cash costs (e.g., overhead costs associated with farm maintenance, taxes and insurance, real estate interest costs, etc.) and the opportunity costs of owned resources (e.g., depreciation on farm equipment, the value of the producer's labor, the value of land, etc.), as well as the variable cash costs. Economic costs are important for policy analysis and are important considerations for the survivability and long-term potential of the farm operation and the quality of life of the farm operator.

* The first number in each range corresponds to the lowest yield.
** Switchgrass is assumed to contain 14.5 MBtu per dry ton.

Switchgrass is a perennial and, once established, can remain productive for many years. The analysis assumes that switchgrass stands remain in production for 10 years. Establishment costs are annualized over the 10-year stand life using a 7.5 percent discount rate.

The analysis also assumes that switchgrass is produced by individual farm operators who own the necessary equipment. Costs are estimated for two different machinery complements a large-scale and a small-scale complement typically associated with larger and smaller farms. The costs shown in Tables 1 and 2 are averages of the two estimates. If farm operators do not own haying equipment (i.e., mowers, rakes, balers) and must rely on custom harvesting, costs will be higher.

In the analysis, fields are prepared for planting by plowing and disking. Weed control is important for establishment; herbicide applications are included. Phosphorous, potassium, and lime are added as needed before planting; levels assumed in the analysis are typical of those used for other crops in the region.

In the years following establishment, nitrogen fertilizer is applied in quantities sufficient to replace that removed as a result of harvesting; quantity applied is generally about 0.5

Only one harvest per year is assumed. Harvest costs are adjusted for yield. As yields increase, the per acre harvesting cost correspondingly increases, but the per ton harvesting cost decreases.

The yields used in the analysis are based on research plot data and expert opinion. Yields are expected to be low during the establishment year, increase during years 2 and 3, and maintain a relatively constant annual yield in years 4 through 10. Harvesting losses of about 5 to 7 percent of growth have been included in the analysis. Long-term storage losses, expected to be about 10 to 13 percent for bales stored outside on the ground, are not included in the analysis.

Production costs for each farm operation will vary from these estimated costs depending on local conditions and management practices. However, the estimated production costs provide a basis for analyzing the regional costs and profitability of switchgrass production in the United States. The complete study, with documentation of data and methodology, will be published as an ORNL report some time in 1995.

Hawaiian researchers model alternative land use

Victor D. Phillips, Wei Liu, and Robert A. Merriam; College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, HI 96822

A research team in the College of Tropical Agriculture and Human Resources at the University of Hawaii at Manoa has developed a decision support system for those interested in short-rotation, intensive-culture (SRIC) forestry on former sugarcane and pineapple plantation lands to produce a variety of wood products, including renewable biofuels. The system has three integrated components: (1) empirical SRIC yield models of promising tropical hardwoods (Eucalyptus spp.) that were constructed using growth data, site characteristics, and management variables from field trials in Hawaii; (2) a SRIC biomass system model of production costs, including establishment, maintenance, harvesting, transport, and storage; and (3) a geographical information system to extend the analysis to areas where no field trials exist and to present the results as a map. Our system can predict the potential biomass supply (dry ton) and delivered cost ($/dry ton) of Eucalyptus spp. at potentially available locations for tree plantations on both an island-wide scale for general land-use planning and a specific-site scale for field-level recommendations.

The Hilo coast plantations that were modeled could provide more than 1.8 million dry tons over 7 years; most of the feedstock would cost under $36/dry ton. Using an optimized SRIC management strategy that recommends a planting density of 578 trees/acre and 7 years of age at harvest, the average cost of chips delivered to the Pepeekeo factory is $36/dry ton. The least-cost production target is the minimum delivered cost of E. saligna from the Hilo coast plantation to the bioconversion facility achieved by optimizing growing space and rotation age. A prediction of the potential biomass supply of E. saligna from the Hilo coast indicates that 220,000 dry tons/year could be produced at $36/dry ton. Sensitivity analyses revealed that delivered cost is affected mostly by biomass yield and harvesting costs.

These results were then used with specific bioconversion processes for estimating the costs of manufacturing energy products at a plant capacity of 25 million gallons/year for ethanol and methanol fuels and 25 MWe for electricity. Calculations for ethanol production were based on a simultaneous saccharification and fermentation system that would produce 100 gallons ethanol/dry ton and would require approximately 245,000 dry tons of feedstock annually. Calculations for methanol production were based on a low-pressure indirect gasifier with hot-gas conditioning and methanol synthesis that would provide 86 gallons methanol/dry ton and would require approximately 148,000 dry tons of feedstock annually. Electricity calculations were based on a fixed-bed gasifier coupled to an open-cycle turbine that would generate 393 kWh/dry ton feedstock and would require approximately 110,000 dry tons of feedstock annually.

Preliminary levelized cost estimates are $1.21/gallon for ethanol, $0.80/gallon for methanol, and $0.071/kWh for electricity. For comparison, the prices of the current sources of energy in Hawaii are roughly $1.51/gallon for unleaded regular gasoline and $0.10 0.12/kWh for electricity generated by burning residual fuel oil, which fluctuates between $15 20/barrel.

In Hawaii, the SRIC biomass system model can reliably estimate yield and optimized economic costs of tropical hardwood production at the state, county (island), and plantation (field) levels. The decision-support tools and information are useful to land owners and decision-makers in evaluating the economic viability of short-rotation forestry in Hawaii, including growing biomass crops for manufacturing energy products. This methodology is readily transferable to other areas of the United States and to the rest of the world.

Intern birdwatches for BFDP

Nathan Rice; University of Wisconsin, Stevens Point

In July 1994, Audubon ornithologist Wayne Hoffman and I conducted the second of two bird surveys for the BFDP in switchgrass plantings near Centerville, Iowa. The study site contains nearly 400 acres of switchgrass. It is owned by the Iowa Department of Natural Resources and is managed as public hunting land.

Seven fields on this site were separated into two survey areas. Area one included a newly planted switchgrass field (points 1 and 2), a switchgrass field planted in 1993 (points 3 and 4), and a switchgrass planting harvested in 1993 (points 5-8). Vegetation at points 1 and 2 was approximately 2 feet high and contained 90% switchgrass stems. Weeds grew where switchgrass had not established. Common yellowthroats were the most commonly observed bird in this area, although the number of birds detected was low.

At points 3 and 4 the vegetation was more than 3 feet tall and was again mainly switchgrass. Dickcissels, common yellowthroats, and a few grasshopper sparrows were observed. Points 5-8 contained little switchgrass. Only 30% of the area, typically lowland, had vigorously growing switchgrass; the majority of the site had been invaded by weeds. This area had the highest singing male densities of dickcissels and grasshopper sparrows.

Points 1 and 2 in the second study area were located in a field planted with big bluestem and switchgrass. Vegetation height ranged from 2-4 feet. Sedge wrens, common yellowthroats, and dickcissels were common at these points. Points 3 and 4 were planted with switchgrass on upland areas and orchard grass in lower areas. The switchgrass was approximately 3 feet high. Flocks of more than 100 red-winged blackbirds were sighted at these points along with numerous forest-edge species (northern cardinal, gray catbird, and brown thrasher). The third field (points 5-7) had been planted in 1993 with switchgrass that was now more than 4 feet high. Sedge wrens, dickcissels, and red-winged blackbirds were the most abundant birds at these points. Points 8 and 9 were located near a small stand of trees and the previously mentioned switchgrass field. Forest birds (northern cardinal, northern oriole, black-capped chickadee, house wren, and downy woodpecker) were common at these points.

Sedge wrens and grasshopper sparrows should be considered as indicators of habitat quality when evaluating the habitat value of herbaceous energy crops. Sedge wrens preferred lush, dense, lowland switchgrass sites while the grasshopper sparrows tended to inhabit drier, upland sites. Both species are in decline and their presence in switchgrass plantings is an indication that herbaceous energy crops can potentially provide usable habitat for wildlife.

Information gained from these surveys has highlighted areas in need of further study and has provided baseline data for comparison with scale-up projects. In all cases, breeding grassland bird densities were higher in 1994 than in 1993. This is most likely a function of the weather and the age and size of the grass. More research is needed on larger, more intensively managed switchgrass fields. Research should also be considered on multiple species plantings and grasses should also be considered.

[Editor's note: Nate was participating in the Science and Engineering Research Semester at ORNL. Contact the Oak Ridge Institute for Science and Education at P.O. 117, Oak Ridge, Tennessee 37831-0117, 865-576-3427 for information about this program.]

BFDP needs your help

The Biofuels Feedstock Development Program (BFDP) is soliciting your advice and suggestions about establishing a biomass job bank. We frequently receive resumes from people seeking employment and occasional notices about employment opportunities in biomass energy.

This situation has led us to believe that there is a need for a forum in which to post information about biomass-related jobs and job hunters. One option is to add a positions open section to the Biofuels Information Network's Worldwide Web server.

BFDP is also interested in expanding the Biofuels Information Network's links to other services on the Internet especially in the areas of agriculture, economics, climate, utilization, environment, and policy. Please send your suggestions and comments about either or both of these needs to bfdp@ornl.gov or to the address listed at the end of the newsletter.

Publications of Interest

Wright, L.L. and W.G. Hohenstein (ed.). 1994. Dedicated feedstock supply systems: Their current status in the U.S.A. Biomass and Bioenergy:6(3). This special issue contains articles on woody and herbaceous species under consideration as energy crops, production technologies, environmental considerations, land availability, and economics analyses.

U.S. Department of Energy, Biofuels System Division. 1994. Biofuels: Project Summaries. DOE/CH10093-297. 121 pages. This report contains summary sheets for each project funded and/or in existence during Fiscal Year 1993 (October 1, 1992 through September 30, 1993).

U.S. Department of Energy, Biofuels System Division. 1994. Biofuels: A Win-Win Strategy. Stabilizing Global Climate Change While Acheiving a Sustainable Energy Future. 15 pages.

Phillips, V.D., W. Liu, R.A. Merriam, and D. Singh. 1994. Potential for short-rotation intensive-culture hardwood production in Hawaii. Agricultural Systems 46:33-57.

Liu, W., R.A. Merriam, V.D. Phillips, and D. Singh. 1993. Estimating short-rotation Eucalyptus saligna production in Hawaii. Bioresource Technology 45:167-176.

Phillips, V.D., W. Liu, R.A. Merriam, and D. Singh. 1993. Biomass system model estimates of short-rotation hardwood production in Hawaii. Biomass and Bioenergy 5(6):421-429.

Liu, W., V.D. Phillips, and D. Singh. 1992. A spatial model for the economic evaluation of biomass production systems. Biomass and Bioenergy 3(5):345-356.