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

Abstract

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 are inaccessible 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 in high-sided dump trucks to a concentration yard, where it can be stored and then reloaded into chip vans using a frontend 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 BDT À1 for in-woods grinding. Results indicate that for harvest 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 to be a more productive and less costly option for residue recovery. Forest operations for timber harvest, precommercial thinning, fuels management, and other vegetation treatments generate large quantities of treatment residues (also called ''slash''), including tops, limbs, cull sections, and unmerchantable roundwood. These by-products are a promising source of biomass for the production of energy, fuels, and products because they are widespread, renewable, and can be used to produce products that offset the use of fossil fuels and reduce greenhouse gas emissions (Jones et al. 2010). Use of forest residues can also improve the financial feasibility of some silvicultural prescriptions by reducing site preparation costs and can improve air quality in areas where open burning is a common method of residue disposal (Gan and Smith 2007, Jones et al. 2010). The most prevalent use of forest residues is as hog fuel for combustion boilers used in the generation of heat and electricity. In this article, the term ''hog fuel'' denotes woody biomass fuel produced from forest residues, fuelwood, and wood waste by all methods of comminution, including grinding, chipping, and shredding. Combustion of hog fuel and other by-products by the forest industry accounts for more than 50 percent of all biomass energy in the United States (US Department of Energy 2011). In some regions, electric utilities, industrial boilers, and institutions with wood-fired heating systems represent additional hog fuel demand outside the forest sector.

Harvesting Cost and Productive of Tree-Length Thinning in a Pinus densiflora Stand Using the Tower Yarder (HAM300)

“…Mechanical delays were those caused by breakage or repair of the equipment. Non-mechanical delays were divided into operational delays and personal delays, where operational delays were those that occurred during work, whereas personal delays referred to time for workers to rest or relieve physiological needs (Vitorelo et al 2011;Anderson et al 2012).…”

Subregional Comparison for Forest- to-Product Biomass Supply Chains on the Pacific West Coast, USA

“…Residuals are assumed to be sorted into loglike material (tops) and branches. These governing supply chain options are well studied (e.g., Anderson et al, 2012;Johnson et al, 2012;Bisson et al, 2016) with the model's specific supply chain discussed in Berry and Sessions (2018b).…”

The Economics of Biomass Logistics and Conversion Facility Mobility: An Oregon Case Study

“…Biomass extraction operations involve the comminution of material in the woods (at the landing), at a central in woods-facility or its shipment directly to a conversion facility. Biomass processing, conversion and transportation technologies, methods and limitations are generally well known with a number of studies analyzing these different supply chain options (Anderson et al, 2012;Zamora-Cristales et al, 2013;Johnson et al 2012;Wolfsmayr and Rauch, 2014). Other studies and proposed methods for forest biomass operations include the use of hook-lift trucks, dump trucks, as well as baling and bundling (Rawlings et al, 2004;Harrill and Han, 2010;Kash and Dodson 2010;Bisson et al, 2015;ZamoraCristales et al, 2015).…”