A Productivity and Cost Comparison of Two Systems for Producing Biomass Fuel from Roadside Forest Treatment Residues

摘要

Forest operations generate large quantities of forest biomass residues that can be used for production of bioenergy and bioproducts. However, a significant portion of recoverable residues are inaccessible to large chip vans, making use financially infeasible. New production systems must be developed to increase productivity and reduce costs to facilitate use of these materials. We present a comparison of two alternative systems to produce biomass fuel (i.e., "hog fuel") from forest residues that areinaccessible to chip vans: (1) forwarding residues in fifth-wheel end-dump trailers to a concentration yard, where they can be stored and then ground directly into chip vans, and (2) grinding residues on the treatment unit and forwarding the hog fuel inhigh-sided dump trucks to a concentration yard, where it can be stored and then reloaded into chip vans using a front-end loader. To quantify the productivity and costs of these systems, work study data were collected for both systems on the same treatment unit in northern Idaho in July 2009. With standard machine rate calculations, the observed costs from roadside to loaded chip van were $23.62 per bone dry ton (BDT) for slash forwarding and $24.52 BDT1 for in-woods grinding. Results indicate that forharvest units with conditions similar to the test area, slash forwarding is most appropriate for sites with dispersed residues and long-distance in-woods grinder mobilization. For sites with densely piled roadside residues, in-wood grinding is likely tobe a more productive and less costly option for residue recovery.