Using life-cycle assessment to evaluate environmental impacts of briquette production from forest residues.
This report presents a life-cycle impact assessment analysis of near-woods processing of post-harvest forest residues into wood briquettes as an alternative to other fuels such as propane in residential heating systems. The study was part of the Waste to Wisdom project with a broader goal of evaluating the feasibility of using semimobile biomass conversion technologies to overcome the barriers of valorizing woody biomass residues for renewable energy and material production. The cradle-to-grave system boundary included feedstock procurement, hauling, feedstock preparation, production of briquetted biomass from forest residues, briquette transportation (distribution), and heat generation at the residential wood stove (use phase) life-cycle stages. The feedstock preparation stage contributed the most to the global warming (GW) impact of the near-woods wood briquette production supply chain. This was because of the drying process, which contributed 72% of the overall GW impact. Near-woods biomass conversion using wood gasifier as the power source was favorable compared with the other scenarios, which included diesel power and in-town processing of forest residues using grid electricity. The overall decrease in GW impact was 33%, after taking into account the avoided pile and burn emissions. Thus, substituting propane with wood briquettes in heating systems provided greenhouse gas reduction while aiding forest restoration activities.