Table 1--Energy input assumptions of recent corn-ethanol studies Study/year Nitrogen Inputs Corn Corn fertilizer for ethanol yield application nitrogen conversion rate fertilizer rate bu/acre lb/acre Ethanol Total Coproducts' Net conversion energy process use energy energy credits value Btu/lb gal/bu Btu/gal Btu/gal Btu/gal Btu/gal Pimentel (1991) 73,687 110 136.0 37,551 2.50 131,017 21,500 -33,517 (LHV) Keeney and 48,434 119 135.0 37,958 2.56 91,127 8,072 -8,431 DeLuca (LHV) (1992) Marland and 40,105 119 127.0 31,135 2.50 73,934 8,127 18,324 Turhollow (HHV) (1991) Morris and 46,297 Ahmed 120 127.0 31,000 2.55 75,297 24,950 25,653 (LHV) (1992) 57,000 Ho (1989) 90 NR NR NR 90,000 10,000 -4,000 (LHV) This study 53,277 122 124.5 22,159 2.53 82,824 15,056 16,193 (1995) (HHV) Average 113 129.9 31,961 NA NA NA ΝΑ 2,373 Notes: NR: Not reported NA: Average values are not appropriate in this case because studies using high heat values cannot be directly compared to studies using low heat values. This study and the Marland and Turhollow study used high heat values and the others used low heat values. LHV: Low heat value--76,000 Btu per gallon of ethanol. HHV: High heat value--83,961 Btu per gallon of ethanol. 'The midpoint is used when studies report a range of values. Table 3--Energy requirements of farm inputs for 9 States and 9-State weighted average Item IL IN IA MN NE OH MI SD WI Weighted Average Btu/bu Seed 170 189 141 148 271 162 217 290 211 186 Fertilizer Nitrogen 26,995 26,356 20,322 14,671 24,228 22,382 25,719 19,163 20,828 22,631 Potash 757 660 452 576 218 609 529 411 693 539 Phosphate 2,936 3,743 1,580 2,011 85 3,142 2,390 588 1,635 1,992 Lime 2,331 1,757 1,335 208 0 721 3,839 0 654 Energy 1,232 7,713 3,493 2,575 3,432 464 0 927 1,271 3,619 90 2,058 1,371 5,766 964 1,134 1,062 Diesel 4,793 5,843 4,686 5,427 18,881 5,131 8,620 10,650 9,184 Gasoline 3,439 3,710 3,281 3,019 4,301 2,723 3,530 4,846 2,802 LPG 1,515 1,619 3,292 3,287 2,510 2,780 2,654 5,705 1,578 Electricity 1,207 2,927 511 2,907 9,270 1,011 1,209 13,627 7,537 Natural Gas 479 85 0 0 12,632 85 Custom Work 1,480 1,213 1,289 1,131 1,106 981 Chemicals 5,635 7,176 5,730 5,380 5,448 5,433 5,936 5,723 5,784 Custom Drying 902 1,153 1,463 1,321 1,153 764 1,654 39 Input Hauling 1,062 1,062 1,062 1,062 1,062 1,062 1,062 1,062 1,062 Total Energy 53,702 57,493 45,144 41,148 81,165 46,986 58,750 63,375 56,641 | 55,164