An ambitious wood research project that began more than four years ago recently published its final report. The project aimed to expand on existing research focused on the conversion of forest residues into renewable fuel and other valuable biobased products, and was funded by a $5.88 million grant from the U.S. Department of Energy as part of the Biomass Research and Development Initiative.
The project, titled “Waste to Wisdom: Utilizing forest residues for the production of bioenergy and bioproducts,” was led by Humboldt State University and previous HSU Forestry Professor Han-Sup Han along with 15 regional research partners, including: Green Diamond Resource Company, the University of Washington, Oregon State University, the Bureau of Land Management, USDA Forest Service, USFS Rocky Mountain Research Station, USFS Forest Products Lab and others.
The primary goal of the project was to utilize waste forest residues for the production of bioenergy and biobased products as a strategy to:
1) Increase energy supply from renewable sources
2) Improve the environment
3) Promote economic development in rural, forest-dependent communities in the western U.S.
The project’s three research areas focused on feedstock supply, conversion technologies and economic life-cycle analysis. The feedstock supply group focused on the economics of converting forest residue into high quality feedstocks. Researchers conducted experiments and developed biomass recovery systems that improved the economics, accessibility and production of quality feedstocks from forest residues.
The conversion technologies group studied biomass conversion technologies that converted slash or wood chips into biomass fuels and products at or near collection sites in the forest. Methods included gasification to produce biochar, pyrolysis to produce torrefied pellets and densification to produce briquettes.
Harvest residues used in the production of feedstocks through comminution. SOURCE: Waste to Wisdom
The economic life-cycle analysis group performed analyses documenting the economic benefits and other environmental effects related to utilizing forest residues.
Just a few of the “lessons learned” via the project’s research include:
- Quality feedstocks that meet the specifications for different biomass conversion technologies can be produced by using different comminution machines, especially when stemwood is separated from the forest residue piles during logging or thinning operations.
- Although transportation costs are important, they are overshadowed by the cost of biomass conversion technologies examined in this research. Biomass conversion costs are technology dependent and may be the key to lowering supply chain costs to enable market viability.
- Near-woods bioenergy production systems using power from on-site wood gasifier showed better environmental performance than their fossil fuel alternatives: on-site diesel and in-town grid electricity.
- Utilization of post-harvest residues as biofuel as opposed to the typical pile and burning practice shows a notable environmental advantage.
Using forest residues as a feedstock for biomass conversion technologies provides substantial social and economic benefits for rural, timber-dependent communities, including providing jobs for local workers and improving air quality through reduced emissions from open pile burns. In addition, converting forest residues into biochar is an effective strategy for carbon sequestration and improving the productivity of forest soils while reducing the incidence of catastrophic wildfires.