The Economic and Energy Tradeoffs Associated with Three Alternatives for Utilizing Urban Wood Waste
| Alternative | Cost (Dollars/day) | Energy Cost (mm Btu/day) |
| I. Haul to Remote Landfill | ||
| 1. Fuel, labor & equipment to concentration point | $12,064.00 | 15.386a |
| 2. Fee, labor, handling and transport to the landfill | 411.21 | 6.208b |
| Total Cost | $12,475.21 | 21.576 |
| II. Chip and haul to power plant | ||
| 1. Fuel, labor, and equipment to concentration yard | $12,064.00 | 15.386a |
| 2. Labor, handling, chipper operation | 275.00 | 20.507c |
| 3. Chipper depreciation | 151.00d | |
| 4. Energy gained from the waste | -2,265.000e | -904.000 |
| Total Cost | $10,225.00 | 868.107 |
| III. Sell to outside firm | ||
| 1. Fuel, labor, and equipment to concentration yard | $12,064.00 | 15.386 |
| 2. Labor, handling, and chipper operation | 275.00 | 20.507 |
| 3. Chipper depreciation | 151.00 | |
| 4. Revenue to firm for chips sold at $1.25/ton | -152.00 | |
| Total Cost | $12,348.00 | 35.893 |
↵a Breakdown for this energy cost into its elements are (1) transportation, 69,450 Btu/ton, (2) chipping, 51.250 Btu/ton, (3) equipment, 15,800 Btu/ton, and (4) 113 tons processed per day for a 265-day year.
↵b Breakdown is as follows: (1) transport, 4.618 mm Btu/day and (2) handling, 1.590 mm Btu/day.
↵c Breakdown is as follows: (1) transport, 6.2 mm Btu/day, (2) chipping, 2.904 mm Btu/day, and (3) handling, 11.385 mm Btu/day
↵d Initial cost of chipper was $200,000. It is assumed that its value will decrease (straight line) to zero in five years.
↵e Energy value was calculated as follows: oil cost=$20/bbl, oil firing efficiency=82.5%, wood firing efficiency=62%, and oil energy content=6 mm Btu/bbl.