Production and Economic Analyses of Woody Biomass Utilization for Energy

A mechanized harvest system combined with whole-tree chipper producing mixed hardwood chips was investigated on two harvesting sites in the central Appalachian region, USA. Production and machine rate data of the operations were collected through time-motion study, with chipping time elements categorized into feeding, chipping, and loading. Chipping cycles averaged 21.5 minutes to produce 23.54 green tons per truckload, providing an hourly rate of 65.82 green tons/PMH (41.1 dry tons) by the whole-tree chipper. Total cycle time including truck delivery averaged 183 minutes, giving an hourly rate of 7.7 green tons/PMH (4.8 dry tons/PMH). The hourly cost of the harvesting system including one feller-buncher, two grapple skidders, and the chipper was $376/PMH, the chipper alone has hourly rate of $ 72/PMH. Given the hourly rate and production chipping alone cost $ 4.89/cunit or $ 1.09/green ton ($ 1.75/dry ton). Combined unit cost including felling, skidding, and chipping gives a total cost of $ 50.68/cunit or $ 11.34/green ton ($ 18.14/dry ton) to produce in-woods chips at the landing. Total operational costs for felling, skidding, chipping, and truck delivery is estimated at $ 13 to $ 17 per green ton or $ 21 to $ 27 per dry ton dependent upon transportation cost. Chips were sampled from the operations to characterize properties and evaluate whole-tree chips as a bioenergy feedstock according to ANSI Standard AD17225-4:2014 Solid Biofuels. Results of properties testing indicated 37.5% green moisture, 0.212 g/cm3 bulk density, 10.5% bark content, 0.49 % ash, and 7,992.5 Btu/lb calorific heating value. These whole-tree chips were found to meet the highest grade A1 requirements of the U.S. wood chip fuel quality standard. A techno-economic feasibility assessment was conducted for use of woody biomass as an energy source in poultry production, which is one of the largest agriculture industries in West Virginia and also one of the largest consumers of liquid propane in the state. Woody biomass availability and integration was assessed based on wood chip production and characteristics results along with data acquired through a survey of local industrial poultry growers to determine energy and heating requirements of the poultry operations. Average current propane consumption from survey results was 7,036 gallons per year per poultry house. Wood fuel consumption for a wood boiler system to supply heat to a single poultry house was estimated at 85 tons of green wood chips or 45 tons of wood pellets. It was determined that at current local market conditions of $1.04 per gallon propane an average annual fuel cost savings of $2,885 could be achieved with $35 per ton wood chips, while wood pellets at a cost of $180 per ton were found to have break-even cost with $1.30 per gallon propane