TDOC g8T7P§245J 8-1382 M04382 January 1982 Economic Implications of Pelleting Cotton Gin Trash as an Alternative Energy Source LlERAR" nPR -1 Texas A&M Univ, The Texas Agricultural Experiment Station, Neville P. Clarke, Director, The Texas A&M UniversitylSystem, College Station, Texas CONTENTS Page SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 DESCRIPTION OF THE STUDY AREA . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Map of the Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 _ DESCRIPTION ‘OF COTTON GIN TRASH . . . . . . . . . . . . . . . . . . . . . . . . 4 Volume of Gin Trash Produced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Potential Energy Value from Gin Trash . . . . . . . . . . . . . . . . . . . . . . . . . . 5 METHODOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Costs of Feedstock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Payments to gins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Moduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Costs of Pelleting _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Electricity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Diesel fuel and lubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l. . 8 Salaries, labor, employment benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Insurance, property taxes, rent, etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Depreciation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 RESULTS . . . . . . . . . . . ., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Benchmark Cost Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l9 Costs of feedstock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Costs of pelleting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Sensitivity of costs to alternative assumptions . . . . . . . . . . . . . . . . . . . 9 CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11 BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11 ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Appendix Table I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . inside back cover The research upon which this report is based was funded in part by the Center for Energy and Mineral Resources and the Texas Agricultural Experiment Station, Texas A&M University. Economic Implications of Pelleting Cotton Gin Trash as an Alternative Energy Source AUTHORS Donald S. Moore, associate professor (retired) Texas Agricultural Experiment Station (De- partment of Agricultural Economics) ’ Ronald D. Lacewell, professor, Texas Agricul- tural Experiment Station (Department of Agricultural Economics) Calvin Parnell, associate professor, Texas Ag- ricultural Experiment Station and Texas Ag- ricultural Extension Service (Department of Agricultural Engineering) SUMMARY Conversion of crop residues to energy is one possible alternative for supplementing increas- ingly scarce and costly traditional sources of energy. This report estimates the costs of con- verting cotton gin trash to energy pellets. Es- timated costs per unit of energy available from gin trash are compared with costs of other sources of energy. The analysis is directed specifically to the area around Lubbock, Texas, because of its concentrated cotton production. Costs estimated are for (1) moduling trash soon after ginning, (2) storing modules, (3) trucking the modules to a pelleting plant at xubbock, and (4) pelletizing gin trash at the l plant. The estimates do not include the costs of market development and distribution of the i product from the pelleting plant to the point of use. An analysis of the energy balance involved shows that about 200,000 Btu’s of energy would be required to produce 1,000,000 Btu’s of energy from pelletized gin trash. The results indicate it would cost between $2.20 and $3.89 per million Btu’s, or around $3 per MBtu as an overall subjective estimate, to produce pelletized gin trash at Lubbock. The wide range in costs results from alternative levels of payment to gins and different heat losses resulting from storage. Thus, pelletized gin trash is not currently competitive with natural gas or coal. But it is potentially an attractive alternative as a stationary engine fuel source to replace diesel or fuel oil. INTRODUCTION Agricultural biomass may be an alternative to scarce and costly traditional energy sources for several reasons. First, the potential volume of agricultural biomass is substantial. One estimate placed the amount of crop residues that might be collected in the U. S. with current harvesting equipment at 3 quads/yearl; about 2.3 quads per yr. of the total are needed to prevent soil erosion, so the quantity of crop residues available as an energy source would be about 0.7 quads/yr. Crop residues contain energy equivalent to about 13 million Btu/ton (Office of Technology Assessment 1980). Second, agricultural biomass is a renewable source of energy. While variations in production do occur from year to year because of weather and other factors, there is no problem of exhaustion or depletion over time. With proper husbandry and continued technological advance, the production of crops and crop residues may be ex- pected to increase over time. Third, since agriculturally-based energy is domes- tically produced, it could help reduce dependence for energy on foreign sources. And fourth, much of the residue from agriculture, beyond that needed for erosion control and soil enhance- ment, now goes unused. If residue conversion to energy were an economically viable alternative, it could elimi- nate waste while providing an additional source of in- come to the agricultural and energy industries. Although the production of substantial quantities of energy from agricultural biomass is technically feasible, considerable uncertainty exists over its economic feasi- bility. Among the many agricultural residues or wastes that offer possible economic potential for energy produc- tion, cotton gin trash may be one of the most attractive. The over-all purpose of this study was to estimate the costs and assess some of the economic implications that would be associated with producing a pelletized solid fuel from cotton gin trash. The analysis was directed primarily to the southern High Plains of Texas and specifically at the area around Lubbock. OBJECTIVES The specific objectives of this study were as follows: 1. To estimate the amount of gin trash produced in the High Plains, the amount produced close enough to be economically accessible to a pelleting plant in Lubbock, the year to year variability in the amount of gin trash production, and the total heat content that might be converted from gin trash for commercial use. 2. To describe the production processes involved in converting gin trash to pellets for use as a source of fuel and to estimate the total costs of each of the production processes, the costs in terms of units of energy (MBtus), and the sensitivity of costs to changes in some of the variables. 1A quad is one quadrillion Btu's, or about 8 billion gallons of gasoline. 2 3. To review and evaluate the major problems and uncertainties involved in converting gin trash to energy at a pelleting plant in Lubbock, the like], competitiveness of pellets with alternate sources of energy in the area, and the energy balance (energy produced compared with energy consumed in the conversion plant). DESCRIPTION OF THE STUDY AREA The Southern High Plains of Texas is the major cotton- producing area in the State, yielding approximately two- fifths of the annual State production of 3 to 4 million bales. Figure 1 shows locations of principal cotton- producing counties in the area; Lubbock County usually leads other counties in volume of production. Cotton production diminishes sharply in counties farther north because of a shorter growing season and dangers of early frost. Acres of cotton harvested and number of bales produced are shown in Appendix Table 1 for the decade of the 1970s for each of the major cotton-producing counties in the area. During the 1970s, cotton acreage accounted for ap- proximately half the crop acres harvested in the South- ern High Plains (see Appendix Table 1). However, there was some variability from year to year because of weath- er and changes in prospective income relationships with other crops. Grain sorghum ranked second to cotton in number of acres harvested, accounting for approximately one-third of the total. Other crops each usually account-w C.) ed for less than 5 percent of harvested acres and in- ; cluded wheat, corn, sunflower, soybeans, and hay. Although cotton has consistently been the major crop produced in the area, there have been wide year to year variations in production. Over the past 1O years, for example, production has fluctuated from slightly over 1 to nearly 3 million bales per year (see Appendix Table 1). Although changing income relationships with other crops, primarily grain sorghum, is probably the most important reason for the variability, weather is also a very important factor. Since rainfall averages only about 18 inches a year, drought is a major hazard. During severe dry spells, production can be reduced to almost nothing on non-irrigated fields. Hail also is a major hazard and can reduce production substantially. Occa- sionally early frost strikes before cotton reaches full maturity, particularly in the northern part of the area. On the favorable side, insect and disease problems usually are much less severe in the High Plains than in the more humid cotton-producing areas. Less use of pesticides and natural dessication or defoliation reduce the environmental problems associated with using gin trash as an energy feedstock in the High Plains com- pared with other areas. In gin trash which contains large amounts of pesticide, chemicals such as arsenic acid are released in the combustion process and can create envi- ronmental or control problems. Annual variability in the amount of gin trash availablfi e as an energy feedstock is a factor that needs to b considered in evaluating the economic feasibility of pel- leting cotton gin trash. F Figure 1. BAILEY LAMB HALE FLOYD COCHRAN HOCKLEY LUBBOCK CROSBY YOAKUM TERRY LYNN GAINES DAWSON 1 ANDREWS MARTIN HOWARD MIDLAND GLASS- COCK Principal cotton-producing counties in the Southern High Plains ofTexas. An important factor of cotton production in the South- ern High Plains is irrigation. The development of irriga- tion from groundwater, primarily since the end of World War II, has increased the level of cotton production in the High Plains and decreased the instability of produc- tion due to drought. The proportion of cotton acreage that is irrigated, however, varies considerably among counties, as is shown for 1979 in Table I. In counties directly to the south of Lubbock (e.g., Lynn, Dawson, and Martin) production is mainly dryland. In Lubbock county and most of the counties to the north and west, however, production on irrigated land considerably ex- ceeds the production on non-irrigated acres. Variability of production is likely to be greatest in counties that are mostly non-irrigated. Declining water tables and increasing costs of fuel for irrigation pumps create some uncertainty for the future of irrigation in the High Plains. The aquifer is replen- ished at a far slower rate than the rate of use for irrigation. As water tables decline, well yields decline. This, accompanied by rising fuel costs, has caused some decline in irrigation in parts of the area. This trend has been most common in the area south of Lubbock. Irriga- tion in that area is likely to continue to decline because of groundwater depletion. However, much of the High Plains, particularly the area north and west of Lubbock, appears to have sufficient water to continue irrigation for many more years. DESCRIPTION OF COTTON GIN TRASH Virtually all of the cotton produced in Texas today is harvested by machine. There are two types of machine harvestors, (l) spindle pickers and (2) strippers. Pickers are used primarily in areas where the growing season is long, the cotton matures over an extended period o®\ time, and more than one picking is required. They are _ most commonly used in the irrigated areas of South and Southcentral Texas. Since pickers are designed to be a more selective method of machine harvesting than strip- pers, the amount of trash or waste that is collected in the harvesting process is considerably less. Cotton strippers go over the field only once, after the plant is dessicated either by frost or the application of chemicals. In the process of harvesting, strippers collect a much larger quantity of leaves, burs, stalks, other plant materials, and soil particles than do pickers. Strippers harvest about 85 to 9O percent of all cotton in Texas and all the cotton in the High Plains. All material collected by the harvesting machines is transported to gins, which separate lint, seed and foreign matter. The amount of foreign material or gin trash that is collected varies considerably according to season, geographic location and the harvesting process, but pre- vious research indicates that it would average close to I50 pounds for each bale of spindle-machine-picked cotton and 700 pounds per bale for stripper-harvested cotton (Oursbourne, 1978). Since the trash is delivered to the gins with the seed cotton, no specific field collec- tion of residues is required. Thus, collection and trans- portation of residues from stripper-harvested cotton is less costly than most other agricultural residues and wastes. The amount of trash that accumulates at gins is some-u times massive and has constituted a severe disposal problem for many gins. Until prohibited by atmospheric pollution regulations, gin operators usually disposed of TABLE 1. COTTON: IRRIGATED AND NON-IRRIGATED ACRES PLANTED AND HARVESTED AND PRODUCTION IN THE PRINCIPAL COTTON PRODUCING COUNTIES OF THE TEXAS HIGH PLAINS, 1979 Irrigated Non-I rrigated Planted Harvested Production Planted Harvested Production County (acres) (acres) (bales) (acres) (acres) (bales) Andrews 8,500 6,800 5,600 53,100 32,500 11,500 Bailey 60,000 51,600 41,200 95,000 77,100 50,400 Coch ran 87,500 85 ,700 71,100 100,800 99,900 - 67,200 Crosby 132,000 126,000 111,700 94,300 86,200 72,000 Dawson 32,000 27,200 25,800 276,800 247,800 218,000 Floyd 163,900 115,000 59,000 78,600 61,500 35,400 Gaines 193,000 176,000 117,400 258,700 217,000 111,300 Glasscock 34,000 32,700 39,600 22,800 20,300 25,100 Hale 228,900 180,300 112,000 56,500 47,700 26,400 Hockley 173,000 112,000 67,200 154,600 100,200 58,300 Howard 8,000 7,800 8,300 99,400 95,800 105,000 Lamb 180,000 122,000 73,200 100,300 71 ,500 48,200 Lubbock 222,000 198,000 154,000 126,200 106,500 86,800 Lynn ‘ , 62,000 57,000 43,100 242,100 236,000 178,900 Martin 13,000 12,300 14,800 152,600 126,200 144,600 Midland 10,000 8,000 8,800 33,400 25,900 27,200 Terry 145,000 115,000 93,200 214,300 169,000 104,200 Yoakum 70,000 58,900 41 ,000 114,100 93,100 40,300 Total 1,822,800 1,492,300 1,087,000 2,273,600 1,914,200 1,410,800 Source: Texas Crop and Livestock Reporting Service. 4 i’! the trash by incineration. The most prevalent disposal method used currently is hauling the trash back t0 farms and distributing it over the fields. This method involves additional hauling and distribution costs. Also, the pres- ence of weed seeds and diseases in the trash may consti- tute problems. The erosion and soil enhancement value of gin trash has not been quantified; hence, it is unclear whether there is any value in returning gin trash to the field. Other methods of disposal have been by feeding to cattle and by composting, but market outlets for these alternatives are limited. Because of the large quantities of gin trash available, increasing attention has been given to its potential as a source of energy. Approximately 3 to 4 million bales of cotton are ginned in Texas annually, most of which is stripper-harvested. Since approximately 700 pounds of trash are associated with each bale of stripper-harvested cotton, and each pound of trash can yield about 7000 Btu’s, the potential energy resource appears large enough to warrant investigation. There are problems involved with using trash for energy, however, such as the difficulty of handling trash, the dispersion of the trash among a large number of gins, the seasonal nature of ginning operations, the uncertainty of being able to establish reliable market outlets for the energy pro- duced, and certain environmental questions. The aver- age number of bales of cotton ginned annually in the High Plains is less than 5000 per gin. Gins operate only during the harvesting season, usually a 2 or S-month period. An approach that may reduce the problems of using gin trash for energy is to compress the gin trash into modules for easy storage and handling. The modules would then be transported to a centrally-located plant for conversion to a pelletized solid fuel. The purpose of this study is to estimate the economic potential of this alternative in some detail. Lubbock was chosen as the site for a hypothetical pelleting plant because it is the ’ center of the most intensive area of stripper-harvesting of cotton in the State. Volume of Gin Trash Produced The estimated quantity of gin trash produced in the major cotton-producing counties of the High Plains dur- ing the period 1970-79 is shown in Table 2. These estimates were developed by multiplying 700 by the number of bales produced (Appendix Table l). There- fore, the estimates reflect volume by county where the cotton was grown rather than where the cotton was ginned. Some cotton is hauled across county lines for ginning. The gin trash estimates shown in Table 2 are the gross residues remaining after the operations of drying, clean- ing, extracting, and lint-seed separation have been com- pleted. As indicated previously, these residues consist of burs, bits of lint, sticks, and soil particles or fine trash. This fine trash, commonly referred to as “fines” consti- tutes one of the uncertainties or problems involved with using gin trash as a source of energy, because it may cause clogging in the combustion equipment. For gin trash to be more attractive and competitive as a source of energy, the fines must be removed, preferably in the ginning process. Currently, fines are not removed; thus, removal will increase ginning costs. One study of the composition of gin trash among gins in various parts of Texas revealed that fines constitute from slightly more than one-tenth to well over one-third of the total volume at the gins sampled (Schacht, 1978). TABLE 2. AMOUNT OF COTTON GIN TRASH PRODUCED IN THE MAJOR COTTON PRODUCING COUNTIES OF THE HIGH PLAINS, 1970-74 AVERAGE AND ANNUALLY 1975 THROUGH 1979 Gin Trash Produced (1,000 lbs.) 1970-74 County Ave rage 1975 1976 1 977 1978 1979 And rews 2,436 4,060 11 ,760 8,820 4,690 11 ,970 Bailey 34,944 22,050 16,240 64,890 49,210 64,120 Cochran 36,064 21 ,700 22,400 79,800 54,460 96,810 Crosby 85,176 67,200 95,900 108,500 99,400 128,590 Dawson 122 ,444 86,380 1 70,940 161 ,000 64,400 1 70,660 : Floyd 68,376 38,430 63,980 126,000 115,430 66,080 Gaines 98,924 83,1 60 141,470 204,400 120,400 160,090 Glasscock 12,334 14,770 16,380 34,720 21 ,700 45,290 Hale 89,810 56,070 84,350 154,700 115,360 96,880 Hockley 91 ,882 61 ,390 70,000 182,700 99,400 87,850 Howard 35,882 52,500 53,900 64,890 23,800 79,310 Lamb I 77,840 58,310 58,940 146,300 114,800 84,980 D Lubbock 152,208 95,690 136,710 242,200 159,600 168,560 Lynn 105,210 101,360 140,420 143,500 86,800 155,400 Martin 54,166 74,410 91,700 82,600 35,350 111,580 idland 11,886 11,970 18,060 20,160 12,740 25,200 werry 85,778 45,920 77,280 166,600 92,400 138,1 80 Yoakum 28,616 12,530 22,400 54,320 28,350 56,910 Total 1,193,976 907,900 1 ,292,830 2,046,100 1 ,298,290 1 ,748,460 5 Potential Energy Value from Gin Trash The heat value of cotton gin trash is dependent upon the chemical composition and moisture content. Schacht (1978) analyzed gin trash from cotton harvested with stripper machines. The results of his study are shown in Table 3. Measurements of the heat values of gin trash indicate year to year variability of cotton and gin trash produc- tion. Since these estimates of energy values were dew veloped from the gross quantity of gin trash produced as a shown in Table 2, with no allowance made for the removal of fines, they probably overstate the actual quantity of energy that could be produced by the pellet- ing plant. Another factor that would likely reduce the quantity of energy that would be produced from gin trash in an operation that runs throughout the year is loss associated with storage and transportation. For a 12- month pelleting operation, some of the trash would need t0 be stored for a maximum period of nearly a year, since cotton gins usually operate only during the 2- t0 3-month cotton-harvesting season. During the period of storage, some losses could be expected to occur due to natural deterioration and wind loss. an average of about 7000 Btu’s per pound of material, although there is some variability due to differences in constituent parts of the material and in moisture con- tent. The estimate. of 7000 Btu’s per lb. is associated with about 11 percent moisture (Oursbourn et al., 1978). The estimated maximum potential quantity of energy available from cotton gin trash is shown in Table 4 for the major cotton-producing counties of the High Plains. These estimates were derived by multiplying 7000 by the quantity of gin trash produced as shown in Table 2. The year-to-year variability in energy values reflects the METHODOLOGY Costs associated with producing and delivering feed- stock to a pelleting plant in Lubbock and of pelleting the feedstock are estimated by budgeting analysis. The num- TABLE 3. TYPICAL CHARACTERISTICS OF COTTON GIN TRASH ON THE TEXAS HIGH PLAINS |tem (ggfgigls, ber of gins, the number of bales ginned, and the as- sociated quantity of gin trash that would be available for PITYSICQI Pmpertles pelleting in an average or typical year are shown in Table Lin‘ 7-7 5 for specified distances from Lubbock up to a maximum B?“ 56b of 50 miles. As of 1980, there are 231 active gins located it'd“ 127 within a 50-mile radius of Lubbock; they gin approxi- me 2 '9 mately 1 million bales in a typical year. The basis for Chemical Pmperlies these data are ginning records in the Cotton Ginner Carbon 4Z0 Redbook. The number of bales ginned per year average 2213302? i‘: 4,329 per gin, with the volume for only two of the 231 Sum}? <05 gins exceeding 10,000 bales per year. ‘The amount of Oxygen and Error 350 trash available for pelleting 1n a typical year would average 276,876 tons for the 231 gins, or an average of almost 1200 tons per gin. The estimate of 276,876 tons of Source: Schacht TABLE 4. ESTIMATED ENERGY VALUE FROM COTTON GIN TRASH, 1970-74 AVERAGE AND ANNUALLY 1975 THROUGH 1979 Energy Value (Mil. Btu)" County 1970-74 1975 1976 1977 1978 1979 Andrews 1 7,052 28,420 82,320 61 ,740 32,830 83,790 Bailey 244,608 154,350 113,680 454,230 344,470 448,840 Cochran 252,448 151 ,900 156,800 558,600 381 ,220 677,670 crosby 596,232 470,400 671 ,300 759,500 695,800 900,130 Dawson 857,108 604,660 1,196,580 1,127,000 450,800 1,194,620 Floyd 478,632 269,010 447,860 882,000 808,010 462,560 Gaines 692,468 582,120 990,290 1 ,430,800 842,800 1 ,120,630 Glasscock 86,338 103,390 114,660 243,040 151,900 317,020 Hale 628,670 392,490 590,450 1 ,082,900 807,520 678,160 Hockley 643,174 429,730 490,000 1,278,900 695,800 614,950 Howard 251,174 367,500 377,300 454,290 166,600 555,170 Lamb ;=_ 544,880 408,170 412,580 1 ,024,100 803,600 594,860 Lubbock " 1,065,455 669,830 956,970 1,695,400 1,117,200 1,179,920 Lynn 736,470 709,520 982,940 1,004,500 607,600 1,087,800‘? Martin 379,162 520,870 641,900 578,200 247,450 781,060 Midland 83,202 83,790 126,420 141,120 89,180 176,400 Terry 600,446 321,440 540,960 1,166,200 646,800 967mg Yoakum 200,312 87,710 156,800 380,240 198,450 398,37 Total 8,357,832 6,355,300 9,049,810 14,322,760 9,088,030 12,239,220 “Based on an energy conversion value of 7000 Btu’s per lb. of gin trash. 6 Q TABLE 5. ESTIMATED TYPICAL AMOUNT OF COTTON GIN TRASH THAT WOULD BE AVAILABLE ANNUALLY FOR PELLETING WITHIN SPECIFIED DISTANCES OF LUBBOCK Bales Ginned Tons Trash Available for Pelleting“ Distance from No. of Average Average Lubbock (miles) gins Total per gin Total per gin 0 - 30 71 311,806 4,392 83,315 1,173 31 - 40 79 346,762 4,389 98,935 1,252 41 - 5O 81 341,448 4,215 94,626 1,168 Total 231 1,000,016 4,329 276,876 1,199 “Excluding fines. gin trash available for pelleting excludes fines. Since special separating equipment, hence additional invest- .7} ment, is required at the gin for removal of the fines, there is some uncertainty whether all gins would be willing to make this investment and also whether all gins would be willing to make their entire supply of trash available for pelleting. Two major types of cost items were included in the budgeting analysis. These two types were (1) costs as- sociated with acquisition and delivery of the feedstock to a pelleting plant in Lubbock, and (2) costs of pelleting at the plant. Because of the uncertainty over the size of payments to gins that would be required, alternative levels of payment for the trash were incorporated in the ' budgeting analysis to determine their effect on total costs. Costs of Feedstock A computer model developed at the Department of Agricultural Engineering at Texas A&M was used to assist in estimating the quantity of gin trash that would be available for pelleting and the costs of processing and delivering the feedstock to the plant in Lubbock. It was assumed the trash would be compressed into 20,000 pound modules shortly after ginning, that the modules would be stored at or near the gin, and that the modules would be hauled to the plant in Lubbock as required to maintain steady operations around the year. Four major costs would be involved for the feedstock. These four costs are (1) payments to gins for the trash and the removal of fines, (2) moduling, (3) storage, and (4) trans- portation of the modules from the storage area to the _, pelleting plant in Lubbock. Payments to gins As indicated previously, the payment that would be required for gins to remove the fines and make the trash available for pelleting constitutes one of the major uncer- tainties involvedl in evaluating the economic feasibility of pelleting gin trash. Currently, many of the gins in the area pay about $5 per ton for disposal of the trash. It - seems likely that some payment to gins would be re- quired for removing the fines and contracting access to the trash, but the actual amount is speculative. In this analysis, it was assumed that payment of $5 per ton would be the amount required, but alternative payments of zero and $10 per ton also were included to analyze sensitivity of total cost of pellets to the amount of pay- ment for gin trash. Long-term contracts between the gins and the pelleting plants would help alleviate the uncertainty of supply. Moduling Loose gin trash is bulky, unwieldy to handle, and subject to much greater wind and decomposition (ener- gy) losses during storage. In this analysis, it was assumed that trash would be formed into modules soon after ginning, using the same type of equipment that is cur- rently used for moduling seed cotton at many gins to ease the problems of storage and handling during periods of peak harvest. During peak harvest periods, harvest rates usually greatly exceed ginning rates. With- out the use of modules, seed cotton waiting for access to the gin would have to be stored in trailers, which greatly increases costs and which may, if harvesting is delayed because trailers are tied up at the gin, cause losses due to adverse weather. For this analysis, it was assumed a module builder would be used exclusively for moduling gin trash. The module builder assumed in this analysis consists of a unit 32 feet long and 8 feet wide, with an initial cost of $20,000. Both the fixed and the variable costs of moduling were developed on the basis of cost per ton, using procedures similar to those used by Lalor (1977). The cost estimates were based on the assumption that one 20,000 pound (10 ton) module could be built in about half an hour. A 10-year life and 10 percent interest with no salvage were assumed in estimating investment costs for the module builder. Other assumptions in- cluded a labor rateof $4.50 per hour and an average ginning volume of 5000 bales annually, yielding a total of about 3.5 million pounds of gin trash per year. Actually, this isslightly larger than the average volume of gins in the study area, as is indicated in Table 4. For gins with an annual volume of less than 5000 bales per year, the per-ton costs of moduling would be somewhat higher than the cost estimates in this analysis, while for larger gins the costs would be lower because fixed investment costs would be spread over a larger volume. The detail for the moduling costs per ton which were used in this analysis is as follows: " at Cost Per Ton Investment (depr. (S: int.) $1.86 Labor .22 Repairs .38 Power .40 Total $2.86 The costs shown above do not include the costs of pallets and tarpaulin. Use of these items probably would reduce significantly the problem of deterioration during storage. However, they are expensive to use. In this analysis, cost estimates were developed both with and without the use of pallets and tarp, accompanied by alternative estimates of energy losses due to deteriora- tion. Where pallets and tarp were included, the costs involved the following assumptions: an initial investment cost of $430 for a pallet and tarp, a 5-year life, and an average annual use rate of 1.5 times per year. Costs per ton of gin trash for pallets and tarp are in addition to moduling costs and were estimated as follows: Cost Per Ton Investment $7.54 Repairs .64 Total $8. 18 Storage After the modules had been built, it was assumed they would be transferred to a storage area near the gin where they would remain until needed by the pelleting plant. It was also assumed that storage space could be leased, with space requirements averaging about 1 acre per 5O modules. The storage costs were estimated on the basis of a flat annual charge of $2000 per gin plus a charge of $2 per 20,000 pound module. The total storage costs for each gin were calculated by the computer model avail- able in the Department of Agricultural Engineering, Texas A&M University. Transportation Estimated costs for transportation were based on cur- rent rates for hauling by truck published by the Texas Railroad Commission. Little if any transportation would be by rail. The distance from each of the 231 gins within the study area to Lubbock was determined. Total trans- portation costs for each gin were then estimated by multiplying the volume of trash for each gin by the published truck transportation rate for the determined distance. These data are internal t0 the computer model. Costs of Pelleting The estimated costs of pelleting cotton gin trash were based on the pelleting costs of the Tennessee Woodex pelleting plant at Knoxville, Tennessee. For the past several years, their plant has been producing a densified solid fuel from sawmill residues. It is believed the same system of pelleting wood residues could be used to pelletize cotton gin trash. The costs to the Woodex plant were obtained by H. G. Corneil of Exxon Enterprises, Inc. and made available to Texas A&M University (Cor- neil, 1980). These costs were adapted, or adjusted where 8 deemed appropriate, to reflect pelleting costs likely at a plant in Lubbock. The major cost items are detailed as p follows: Electricity The number of kwh required per ton of product for the Lubbock plant was based on kwh input requirements of the Tennessee Woodex plant. Cost per kwh was estimated at $.06, which is the approximate current rate charged for electricity in the Lubbock area. Diesel fuel and lubes The cost was estimated at $.85 per ton of feedstock, which is the same as the cost to the Woodex plant. Repairs Again the same cost rate to the Woodex plant was used. This amounted to $5.00 per ton of feedstock. Salaries, labor, employment benefits The costs supplied by Woodex for this item reflected slight economies of size. Reduced costs per unit of product from economies of size were adapted by interpo- lation to reflect unit costs deemed appropriate for the scale of operations at the Lubbock plant. Insurance, property taxes, rent, etc. Costs per unit of product for this item were based on unit costs to Tennessee Woodex. Depreciation Capacity of the Woodex plant was 100,000 tons per year and could be duplicated at an estimated investment cost of 3.5 million dollars. The same size plant and investment cost were assumed for Lubbock. Where the volume of product exceeded the 100,000 ton capacity, an additional plant or plants were assumed with the same investment and operating costs. Depreciation was cal- culated on a 10-year, straight-line basis. RESULTS Considerable uncertainty exists with respect to what amount to estimate for several of the cost items. One of the uncertainties is the level of payment needed to obtain the trash from the gins. In this analysis, it was assumed that payments of $5 per ton would be near the level of payment required. To determine theeffect on total costs of alternative levels of payments, however, the analysis also shows results with the assumption of no payments and of payments of $10 per ton. A second uncertainty concerns the extent of loss in heat value that might be anticipated from the storage of gin trash over the period of up to one year. This has not been thoroughly documented. One study revealed a 10 percent loss of gross heat content of a module after 9 months storage, even though the top of the module was covered with canvas (Schacht, 1978). Use of pallets and tarpaulin could be expected to reduce deterioration significantly, but it seems likely that some loss would still occur due to some deterioration on the sides and. losses from wind and handling. Because of the high cost of pallets and tarp, there is some question whether the savings in deterioration losses would be sufficient to 0‘ f‘ a justify their additional expense. If pallets and tarp were not used, the maximum loss in heat content after a full ear of storage is estimated t0 be 20 percent. This would e equivalent to an average loss over the year of 10 percent since, if the gin trash were pelleted at a steady rate during the year, the modules would be stored for an average period of 6 months. Due to the uncertainty regarding gin trash deterioration on the High Plains, cost estimates were developed both with and without the use of pallets and tarp, and with average annual deterioration losses of zero, 6 percent and 10 percent. While it seems unrealistic to expect that use of pallets and tarp would eliminate deterioration losses entirely, the most optimistic assumption was still included to obtain some additional insight in the potential savings from using pallets and tarp. Benchmark Cost Estimates Costs are shown in detail for only one base set of assumptions. The base set of assumptions selected was (1) payment to gins of $5 per ton for use of their gin trash, (2) no pallets and tarp, and (3) an average loss in heat value of 10 percent, equivalent to a maximum loss of 20 percent over a full 12-month period. This means that each pound of gin trash, rather than yielding 7000 Btu’s, would yield 6300 Btu’s. Costs are not shown in detail for other than the one set of base assumptions because most of the cost items do not change and to show them in full detail would be repetitive. Rather, P only the total costs of the feedstock and of pelleting are i hown per MBtu for each of the alternative assumptions. Total costs of the feedstock per ton also are shown for each of the alternate assumptions. It was felt this would be sufficient to show the sensitivity of costs to a rather wide range of conditions. A detailed summary of the major production cost items is shown in Table 6. This shows the estimated cost of acquiring, handling, and pelleting the product up to marketing. In order to show the effect on volume and on costs of acquiring feedstock from varying distances from Lubbock, the results are shown for three sets of assump- tions regarding range of acquisition distances. One col- umn in Table 6 shows the results if the acquisition of gin trash is restricted to within a 30-mile radius of Lubbock. A second column shows results if acquisition is expanded to a radius of 40 miles, and a third column shows the results if expanded to a radius of 50 miles. If the process- ing capacity of each pelleting plant is restricted to ? 100,000 tons a year, one plant would be sufficient if r acquisition of trash came from only a radius of 30 miles, but two plants would be required if acquisition was expanded to a 40-mile radius, and 3 plants for a 50-mile radius. This however, is based only on production for a typical year and does not take into consideration the high ' ear-to-year variability in cotton production characterist- ic of the area (see Table 2). / osts of feedstock Of the four components of feedstock costs considered (payments to gins, moduling, storage, and transporta- tion) payments to gins was the largest, amounting to $0.40 per MBtu or slightly over one-third of total feed- stock costs. This indicates that the level of payment to gins is indeed a significant factor in evaluating the eco- nomic feasibility of pelleting gin trash. The costs of transportation were the second largest of the four components of feedstock costs. Although rates per ton for distances of about 50 miles from Lubbock were over one-third higher than the rates per ton for distances of 15 miles or less, the marginal rate differ- ences had only a nominal effect in raising average costs. Transportation costs hauled from a 50-mile radius av- eraged $0.39 per MBtu, only 4 cents higher than the $0.35 per MBtu average if hauls were restricted to a 30- mile radiusfHowever, the profitability of hauls from longer distances should be evaluated in terms of margin- al rather than average comparisons. Transportation costs per MBtu are the only one of the four feedstock cost components that would be affected significantly by haul- ing from longer distances. Slight differences are evident for storage costs when these costs are estimated on the basis of dollars per ton. These differences are caused by the way the storage costs are calculated, which gives slightly lower average unit costs to larger gins. The differences were not large enough, however, to be. re- flected in costs per MBtu. If gin trash hauls are restrict- ed to within a 30-mile radius of Lubbock, total costs of feedstock to the pelleting plant would average $1.13 per MBtu or $14.24 per ton. This compares with averages of $1.17 per MBtu or $14.58 per. ton if the hauls are expanded to within a radius of 50 miles. Costs of pelleting Total costs of pelleting average $1.78 per MBtu or $22.36 per ton of product if the gin trash pelleted is drawn from within a 30-mile radius of Lubbock, com- pared with costs of $1.69 per MBtu or $21.32 per ton if the trash is drawn from within a radius of 50 miles. The slightly lower unit costs when hauls are expanded to a 50-mile radius reflect slight size economies in the salaries, insurance, taxes, and depreciation components. Actually, these size economies were sufficient to offset the effects of higher transportation on the feedstock costs. Total production costs (feedstock and pelleting costs combined) average $2.91 per MBtu or $36.30 per ton for hauls within a radius of 30 miles compared with an average of $2.86 per MBtu or $35.90 per ton for hauls within a radius of 50 miles. Sensitivity of costs to alternative assumptions Costs per MBtu with alternative assumptions in sever- al of the variables are shown in Table 7. These alterna- tive assumptions include the choice of pallets and tarp, payments per ton to gins of 0, $5, and $10, and average annual rates of heat loss of 0, 6 percent, and 10 percent. Only data for a 50-mile radius are shown in Table 7, since the data in Table 6 indicated differences in dis- tances made little differences in average unit costs. Pallets andftarp are by far the most important of the cost variables considered. Their use would not appear justified within the range of assumptions considered. Even if the use of pallets and tarp eliminated heat losses 9 ., ‘l TABLE 6. PRODUCTION COST SUMMARY ASSUMING A $5 PER TON PAYMENT TO GlNS, NO USE OF PALLETS AND TARP, AND A 10 PERCENT LOSS OF HEAT VALUE IN FEEDSTOCK Miles from Lubbock 30-Mile Radius 40-Mile Radius 50-Mile Radius A Production Trash Available (tons/year) 83,315 182,250 276,876 Energy Production (KMBtu/year)“ 1,050 2,297 3,488 Cost of Production ($1 ,000) Cost 0f Feedstock to Pelleting Plant: Payment to gins @ $5lton 417 912 1,385 Moduling 238 521 792 Storage 159 337 518 Transportation 372 847 . 1,343 Total feedstock cost 1,185 2,617 4,038 Cost of Pelleting: Electricity (.06/Kwh) 405 886 1,346 Diesel fuel & lubes @ 0.85/tons product 71 155 235 Repairs @ $5/ton product 417 912 1,385 Salaries, labor, employment benefits 508 1,032 1,553 U Insurance, property taxes, rent, etc. 112 224 336 Depreciation 350 700 1,050 Total pelleting cost 1,863 3,909 5,905 Total Production Cost 3,048 6,526 9,943 Cost of Production ($/MBtu) Cost of Feedstock to Pelleting Plant: Payment to gins .40 .40 .40 Moduling .23 .23 .23 Storage .15 .15 .15 Transportation .35 .37 .39 n Total feedstock cost 1.13 1.15 1.17 ' Cost of Pelleting: Electricity .39 .39 .39 Diesel fuel, lubes .07 .07 .07 Repairs .40 .40 .40 Salaries, labor, employment benefits .48 .45 .44 Insurance, property taxes, rent, etc. .11 .10 . .09 Depreciation .33 .30 .30 Total pelleting cost 1.78 1.71 1.69 Total production cost 2.91 2.86 2.86 Cost of Production ($/ton) Cost of Feedstock to Pelleting Plant: Payment to gins 5.01 5.01 5.00 Moduling 2.86 2.86 2.86 Storage 1.91 1.85 1 .87 Transportation 4.46 4.46 4.85 Total feedstock costs 14.24 14.37 14.58 Cost of Pelleting: Electricity 4.86 4.86 4.86 Diesel fuel, lubes .85 .85 .85 Repairs 5.01 5.00 5.00 Salaries, labor, employment benefits 6.10 5.66 5.61 Insurance, property taxes, rent, etc. 1.34 1.23 1.21 Depreciation 4.20 3.84 3.79 Total pelleting costs 22.36 21.44 21.32 Q Total Production Cost 36.60 35.81 35.90 ‘Assuming an average of 6300 Btu’s per lb. of gin trash residue, which reflects heat loss of 10 percent from the original 7000 Btu per lb. 9 l0 ~ / TABLE 7. ESTIMATED COST PER MBTU UNDER ALTERNATIVE ASSUMPTIONS REGARDING USE OF PALLETS AND TARP, PAY- v/BIENTS TO GINS, AND ENERGY LOSS DUE TO DETERIORATION , F FEEDSTOCK“ Average % Heat Loss Use of Pallets Payment Per and Tarp ton to gins 0 6 10 Cost of Feedstock to Pelleting Plant Yes 0 $1.27 $1.35 $1.41 Yes $ 5 1.63 1.73 1.81 Yes $10 1.98 2.11 2.20 N0 0 .68 .73 .76 N0 $ 5 1.04 1.11 1.17 No $10 1.40 1.49 1.55 Cost of Pelleting Yes 0 $1.52 $1.62 $1.69 Yes $ 5 1.52 1.62 1.69 Yes $10 1.52 1.62 1.59 N0 0 1.52 1.62 1.69 N0 $ 5 1.52 1.62 1.69 No $10 1.52 1.62 1.69 Total Production Cost Yes 0 $2.79 $2.97 $3.10 Yes $ 5 3.15 3.35 3.50 Yes $10 3.50 3.73 3.89 No 0 2.20 2.35 2.45 N0 $ 5 2.56 2.73 2.86 No $10 2.92 3.11 3.24 ‘Assuming the feedstock is hauled from within a radius of 50 miles. coal delivered to Texas is about $30 per ton or $1.66 MBtu while Texas lignite is $12 per ton at the mine or $0.92 MBtu. Cotton gin trash pellets do not appear to be currently competitive with natural gas or coal, but they are potentially an attractive alternative as a stationary engine fuel source to replace diesel or fuel oil. Use of trash pellets as an alternative fiiel to oil raises questions of energy balance. A rather crude estimate of energy use to produce gin trash pellets includes .209 gallons of diesel per MBtu or 2.55 gallons per ton of trash and 175 cubic feet of natural gas per MBtu to produce electricity for pelletizing (or 212 thousand cubic feet). With one gallon of diesel equivalent to 120,000 Btu and one thousand cubic feet of natural gas equivalent to one million Btu, a rough estimate is 200,000 Btu’s of energy required to produce one million Btu’s of energy in the form of pelletized gin trash. Thus, this study indicates potential for the use of cotton gin trash as an alternative energy source. Howev- er, there are several limitations to many aspects of the study. These include development of a market for cotton gin trash pellets, cost to transport the pellets from Lubbock to users, and assured long-term supply of cotton gin trash. ifintirely, which is a highly optimistic assumption, the a savings would not be sufficient to offset the additional costs if the maximum loss over a 12-month period totaled no more than 20 percent. For pallets and tarp to be justified, savings in heat loss would have to be greater than the range considered here, or use would have to be justified on the basis of other factors, such as ease in handling and transportation. The significance of the level of payments to gins is reflected in Table 7. For each increase of $5 per ton in payments, costs of feedstock increase from $0.35 to $0.40 per MBtu. This is also shown in Table 8 on a per ton basis with and without the use of pallets and tarps. It is expected the cost of feedstock delivered to a pelleting plant in Lubbock would range between $10 and $30 per ton. CONCLUSIONS This study indicates that it would cost between $2.20 e and $3.89 per million Btu to produce pelletized cotton gin trash at Lubbock. A best subjective judgment would be approximately $3.00 per MBtu. This does not include costs of distribution from Lubbock to the point of use. It would be necessary to develop markets for the gin trash pellets and assure the users of a stable long-term supply. To assess the competitive position of cotton gin trash pellets as an energy source, approximate costs of current fuels are useful. Of course, prices of energy are rapidly yvphanging. However, a natural gas price in the range of $3.00 per MBtu is reasonable. Diesel fuel at $1.00 per gallon is equivalent to about $7.57 per MBtu; i.e., there are 7.57 gallons of diesel per MBtu. Cost for Northwest BIBLIOGRAPHY College of Agriculture, Purdue University, The Potential of Producing Energy from Agriculture, contractor report prepared by the staff of the College of Agricul- ture, Purdue University, for the Office of Technology Assessment, Congress of the United States, 1979. Condra, C. D. and Ronald D. Lacewell, The Impact 0f Natural Gas Pricing on Irrigated Agriculture in the Trans-Pecos Region 0f Texas, Texas Agricultural Ex- periment Station, TA-12683, 1976. Corneil, H. C., “Economics Data for Woodex Pelletiz- ing System”, personal communication to R. D. Lacewell, Exxon Enterprises, Inc., Florsham, New Jersey, October 1980. Continued 11 IIIIIIIIIIIIIII _ I @3- ‘41535 HLEDSU Dugas, Doris J., “Fuel From Organic Matter”, Paper P- 5100, The Rand Corporation, Santa Monica, Califor- nia, 1973. Dugas, Doris J., “Fuel From Organic Matter: Pos- sibilities for the State of California", Paper P-5107, The Rand Corporation, Santa Monica, California, 1973. Lacewell, R. D., C. Robert Taylor and Edward A. Hiler, “Energy Generated From Cotton Gin Trash", report prepared for the Texas Energy and Natural Resources Advisory Council and Ofiice of Technology Assess- ment, Texas Agricultural Experiment Station, Center for Energy and Mineral Resources, College Station, Texas, 1980. Lalor, W. F., J. K. Jones, G. A. Slater, Gary Under- brink and L. H. Wilkes, “Dump Trailers for Central Moduling Facilities”, Agro-Industrial Report Vol. 4i No. 2, Cotton Incorporated, Raleigh, North Carolina 1977. Lalor, W. F., J. K. Jones and G. A. Slater, “Cotton Gin Trsh as a Ruminant Feed”, Agro-Industrial Report Vol. 2, No. 1, Cotton Incorporated, Raleigh, North Carolina, 1975. Lalor, W. F. and M. L. Smith, “Use of Cotton Ginning Wastes as an Energy Source”, proceedings of the 1977 Cornell Agricultural Waste Management Conference, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York. Ofiice of Technology Assessment, Energy from Biologi, cal Processes, Volume I and Volume II, Congress of the United States, Washington, D. C., 1980. Oursbourne, C. D., W. A. LePori, R. D. Lacewell, K. Y. Lam and O. B. Schacht, Energy Potential 0f Texas Crop and Agriculture Residues, MP-1361, Tex- as Agricultural Experiment Station, Center for Ener- gy and Mineral Resources, College Station, Texas, 1978. Railroad Commission of Texas Motor Freight Commodi- ty Tariff No. 8-f, Containofs Rates, Rules, Regula- tions, and Changes Governing the Transportation of Livestock, Livestock Feedstuffs, Farm Machines, Cottonseed and Grain by Specialized Motor Carriers Between Points in Texas, 1979. Schacht, Otto Byron, Energy Analysis 0f Cotton Gin Waste, unpublished Ph.D. dissertation, Department of Agricultural Engineering, Texas A&M University, College Station, Texas 1978. Texas Department of Agriculture and USDA Statistical Reporting Service, “Cotton Statistics”, reports for 1970 through 1979, Austin, Texas. Texas Cotton Ginners Association, “Cotton Ginners Redbook”, reports for 1970 through 1979. 1 ACKNOWLEDGEMENTS Special appreciation is expressed to Mr. H. G. Corneil for assistance in developing the costs of the pelleting operation. Also, the cooperation and assistance of Mr. Jeff Galyon of Tennessee Woodex is gratefully acknowl- edged. Tennessee Woodex was most helpful in develop- ing estimates of pelleting costs and by volunteering to pelletize cotton gin trash for study by Texas A&M. Mr. Lambert Wilkes provided consultation and arti- cles relative to moduling operations. We certainly ap- preciate his wisdom and help. The manuscript was significantly improved through suggestions by Ron Griffin, John Sweeten and Glenn Collins. For their time and patience in reviewing the manuscript we are most appreciative. 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