Evaluating the System Logistics of a Centralized Biomass Recovery Operation in Northern California

초록

In this study, we evaluated the productivity and cost of each component in a unique centralized biomass recovery operation to determine cost-effective system logistics. The system was divided into three segments: collection, comminution, and transportation. Cost analysis determined a stump-to-truck and transportation cost of $30.39and$13.91 per bone dry ton (BDT), respectively. These costs did not include support equipment, overhead, profit, or risk allowance. Transportation cost was evaluated for a total one-way haul distance of 15 miles. To control overall cost it is imperative to maintain maximum productivity of processing, our most expensive component. Therefore, upstream and downstream practices were examined to determine how they influenced the system. Analysis of the loader operation showed a 33 percent increase in cycle time when handling hardwood whole trees piled at a landing, compared with conifer slash piled within the unit. Regression analysis of the modified dump truck used in the prehaul confirmed that distance had a significant impact on overall centralized biomass grinding operations. Sensitivity analysis showed that a 20 percent reduction in productivity owing to increased travel time resulted in a 25 percent increase in grinding cost. A decoupled transport system used all-wheel drive tractors to haul comminuted biomass from the grinder to a trailer landing, where regular highway tractors completed the trip to the power plant. This system reduced delays in loading and improved access to the grinding location. Through an understanding of the complete system, a manager could identify cost saving elements, adjust upstream productivity to meet demand, and reduce the overall cost of a centralized biomass recovery operation.

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